Engine miss and new rattle developed in exhaust manifold

91 OMC King Cobra, 5.7LE Chevy

Just rebuilt carb, and reinstalled, changed fuel water separator. Motor started on first bump and bench settings were perfect. It idled as smooth, as good as it ever has. Measured 15-16 inches Hg vacuum and needle rock steady. Took it out for test drive and ran great. Opened it up to 4000 RPM @ 45-50 mph. Was ready for a great weekend. Wait for it...

Couple hours later, daughter wanted to go out, as soon as I started to throttled up, I could feel Engine miss and got progressively worse with more throttle. Engine sputtered and popped. I turned around Immediately. Did the following checks.

Fuel Pressure ~ 5 psi

Base timing 8 -10 BTDC per manual

Checked Distributor and rotor. Noticed significant green corrosion all way around inside cap. I touched up all contacts with sand paper, shined up the rotor.

Pulled plugs, dry. A couple had some light carbon but I’ve seen them worse before rebuilding carb. Double checked gap @ 35 degrees. To no avail, engine miss still there and I noticed
a new noise. Sounded like a faint rattle. I thought it may have been rocker arm or something worse deep in the engine, but after listening more closely, I think it’s coming from the port side exhaust manifold. I read through the cooling system section in the manual thinking there might be some sort of flapper in there. I thought perhaps it might be contributing to the engine miss some.

I know that’s a lot. What do you think? I was so pumped that it was running so well. I should know better...

Do I check Fuel,Air, or Fire? I thought I had the fuel nailed with the new separator and carb rebuild.

I dropped the rubber couple that connects the exhaust pipe to Y pipe. The hinge pin was all that was left. Guess the rest of it fell off. I wonder if it was when I took it out for the test drive. I went to WOT and water was choppy, wondering if a piece came off. After I dropped the rubber coupler, I reached as far as I could down into the Y pipe but didn't detect anything. Wondering if some part of the flapper may be stuck in exhaust stream downstream of where it used to be. I sure "hope not" because that looks like a major repair to take apart upper and lower housing to check the path. I I've not had the engine running much since then but have not noticed rise in temp. Appreciate your thoughts on that.


Before the partial plug thought occurred to me this evening while thinking about the engine miss, I spent most of the day, fully checking all ignition components. Here is what I found.

Distributor is Pertronix Ignitor II My OMC manual references Prestolite which is brand of alternator is.

• Lots of green corrosion all over the copper contacts, lots of rust on the cams and springs.
• Observed small burn spots at the base of where the copper contacts meet the plastic. I can see evidence of carbon tracking on on at least one pair of contacts in the distributor cap.
• I tried to clean as best I could. Sprayed PB Blaster on the rust on cams (cover the electronics with shop towel, and in the cap. Ran some sandpaper on the contacts to try and clean, figured I had nothing to lose.
• The electronic module appears to have cracked wires.

All the wires had very low resistance. Does not match my OEM Manual. I have one plug wire and and the coil wire which are different brand do fall with in the OEM manual for resistance. Not sure if or how the different wires might impact ignition.

I'm thinking replace the electronics module and cap. I think wires are ok.

Thoughts?

....................

swc65 said:

91 OMC King Cobra, 5.7LE Chevy

Just rebuilt carb, and reinstalled, changed fuel water separator. Motor started on first bump and bench settings were perfect. It idled as smooth, as good as it ever has. Measured 15-16 inches Hg vacuum and needle rock steady. Took it out for test drive and ran great. Opened it up to 4000 RPM @ 45-50 mph. Was ready for a great weekend. Wait for it...

Couple hours later, daughter wanted to go out, as soon as I started to throttled up, I could feel Engine miss and got progressively worse with more throttle. Engine sputtered and popped. I turned around Immediately. Did the following checks.

Fuel Pressure ~ 5 psi

Base timing 8 -10 BTDC per manual

Checked Distributor and rotor. Noticed significant green corrosion all way around inside cap. I touched up all contacts with sand paper, shined up the rotor.
The distributor cap contacts and the rotor tip, do not necessarily need to be perfectly clean and shiny.
The entire inside area needs to be free from any conductive carbon dust and/or conductive moisture.


Pulled plugs, dry. A couple had some light carbon but I’ve seen them worse before rebuilding carb. Double checked gap @ 35 degrees.
Please explain "double checked gap @ 35 degrees".

If you are adjusting ignition distributor contact points, you will want to set them using a Dwell Meter, not by setting Gap.
Gap is an estimate ONLY of correct Dwell Angle.

If you are adjusting spark plug electrode gap, your ignition system output voltage will determine the best gap.
Most low output systems will require a .028" to .032" gap.

To no avail, engine miss still there and I noticed
a new noise. Sounded like a faint rattle. I thought it may have been rocker arm or something worse deep in the engine, but after listening more closely, I think it’s coming from the port side exhaust manifold. I read through the cooling system section in the manual thinking there might be some sort of flapper in there. I thought perhaps it might be contributing to the engine miss some.
https://www.google.com/search?hl=en...&ved=0ahUKEwj9r5KphqnpAhVTj54KHel_DwEQ4dUDCAs

Click to expand...

swc65 said:

I dropped the rubber couple that connects the exhaust pipe to Y pipe. The hinge pin was all that was left. Guess the rest of it fell off. I wonder if it was when I took it out for the test drive. I went to WOT and water was choppy, wondering if a piece came off. After I dropped the rubber coupler, I reached as far as I could down into the Y pipe but didn't detect anything. Wondering if some part of the flapper may be stuck in exhaust stream downstream of where it used to be. I sure "hope not" because that looks like a major repair to take apart upper and lower housing to check the path. I I've not had the engine running much since then but have not noticed rise in temp. Appreciate your thoughts on that.
Borrow a bore scope and look down into the Y-pipe until you get to the Y.
No broken pieces should be there.


Before the partial plug thought occurred to me this evening while thinking about the engine miss, I spent most of the day, fully checking all ignition components. Here is what I found.

Distributor is Pertronix Ignitor II My OMC manual references Prestolite which is brand of alternator is.

• Lots of green corrosion all over the copper contacts, lots of rust on the cams and springs.
• The cams are the flyweights. The tiny springs control the rate at which the flyweights progressively (via centrifugal force) advance the ignition spark.
• If this area is rusty, the flyweights may be stuck and/or the spring value may be compromised, in which case you may not be getting the proper ignition advance, and/or you may be getting an aggressive advance that will lead to very destructive detonation.
• Your system should allow for a BASE advance of 8 to 10 degrees (no mechanical advance during BASE).
• The centrifugal force (along with the governing springs) should allow for a linear progressive advance.
• As the flyweight system reaches near it's limit, you should see a Total Advance of approx 28 degrees @ 3,200 RPM, and no earlier than 3,200 RPM.

• Observed small burn spots at the base of where the copper contacts meet the plastic. I can see evidence of carbon tracking on on at least one pair of contacts in the distributor cap. Carbon tracking can cause a misfire.

• I tried to clean as best I could. Sprayed PB Blaster on the rust on cams (cover the electronics with shop towel, and in the cap. Ran some sandpaper on the contacts to try and clean, figured I had nothing to lose. See above.

• The electronic module appears to have cracked wires. If you end up replacing this system, steer clear of Pertronix.
• Pertronix uses Hall Effect for the triggering. The way in which Pertronix uses Hall Effect is with a magnet embedded small diameter plastic wheel. The sensor that is triggered as each embedded magnet passes near it.
• Pertronix themselves have admitted to previous errors of 1 to 1.5 degrees with regard to the degree spread between each embedded magnet.

All the wires had very low resistance. Does not match my OEM Manual. I have one plug wire and and the coil wire which are different brand do fall with in the OEM manual for resistance. Not sure if or how the different wires might impact ignition.

I'm thinking replace the electronics module and cap. I think wires are ok.

Thoughts?

Click to expand...

.

RicardoMarine said:

If you are adjusting spark plug electrode gap, your ignition system output voltage will determine the best gap.
Most low output systems will require a .028" to .032" gap.

Click to expand...

My mistake, yes its 0.035" gap

Borrow a bore scope and look down into the Y-pipe until you get to the Y.
No broken pieces should be there.

Click to expand...

Is this something I should be concerned about. I am the type that always focuses on what "could go wrong" but it often does not. In you experience is it common for these flapper remnants to get lodged in the downstream exhaust path?

The cams are the flyweights. The tiny springs control the rate at which the flyweights progressively (via centrifugal force) advance the ignition spark.

• If this area is rusty, the flyweights may be stuck and/or the spring value may be compromised, in which case you may not be getting the proper ignition advance, and/or you may be getting an aggressive advance that will lead to very destructive detonation.
• Your system should allow for a BASE advance of 8 to 10 degrees (no mechanical advance during BASE).
• The centrifugal force (along with the governing springs) should allow for a linear progressive advance.
• As the flyweight system reaches near it's limit, you should see a Total Advance of approx 28 degrees @ 3,200 RPM, and no earlier than 3,200 RPM.

Click to expand...

The comments on the corrosion occurred to me. I sprayed liberally with PB Blaster and wire brushed it multiple times. It seems to operate freely by hand now. I have not been able to check total timing as I didn't know what what size my balancer was until yesterday. 6.5" my next step is to get timing tape however I anticipate getting the engine up to higher RPM may be difficult but I can try, I don't want to damage anything.

• If you end up replacing this system, steer clear of Pertronix.
• Pertronix uses Hall Effect for the triggering. The way in which Pertronix uses Hall Effect is with a magnet embedded small diameter plastic wheel. The sensor that is triggered as each embedded magnet passes near it.
• Pertronix themselves have admitted to previous errors of 1 to 1.5 degrees with regard to the degree spread between each embedded magnet.

Click to expand...

That is concerning... Have not priced whole system vs parts. I'd prefer to fix what I have if possible. Pulling distributor intimidates me although I;ve read up on it and watched video and I have a manual.

OEM manual shows Prestolite. Would you recommend that brand? I've not researched if they are even in business.

Any comments on the following. If a couple mismatched wires are not harmful then I'm compelled to use what I have. But if there is a chance that it will damage system I will replace.

Most of the wires had very low resistance compared to manual as they are Pretronix. Ohm values ranged from 1.543 kOhm for 39" wire to 974 ohms for 14" wire.

I have one plug wire and and the coil wire which are different unknown brand that do fall with in the OEM manual for resistance. Not sure if or how the different wires might impact ignition. I'm thinking replace the electronics module and cap. I think wires are ok. I need to research pricing on components vs whole replacement. I really dont wan t to pull that distributor. vs length.

Am I exacerbating issue with different plug wires?

I'll do some additional research on distributor parts.

Well, I need to change my name to Murphy because his law always seems to apply. I dropped a tiny Locking washer of the electronic module post under Dist cap. I think it fell under base plate. I assume I need to now remove distributor to retrieve...?

Got the distributor out and recovered the washer. I can’t seem to get the plastic grommet to disengage from Distributor housing. Pertronix show a video where the guy simply pulls straight down and then releases a grip mechanism on the wires. Mine is not budging. I’ve used a pick to gently pry but I do t want to break it as it seems I have to reuse and splice the wires if I found the correct video. Still not clear on how to identify what model I have. Only number I can find is printed on tag attached to electronic module. Searching the Pertronix site results in nothing for 24AD-AI2B.

Searching their web site I think I have a model D200800 but I’m only going by a picture. I guess I’ll need to call them Monday. I’m underwhelmed with their web site and their product use identification so far...

....................

swc65 said:

My mistake, yes its 0.035" gap
.035" should work if your ignition system's high tension voltage is above average.


Is this something I should be concerned about. I am the type that always focuses on what "could go wrong" but it often does not. In you experience is it common for these flapper remnants to get lodged in the downstream exhaust path?
It does happen. And if so, the pieces need to be retrieved.


The comments on the corrosion occurred to me. I sprayed liberally with PB Blaster and wire brushed it multiple times. It seems to operate freely by hand now.
I have not been able to check total timing as I didn't know what what size my balancer was until yesterday. 6.5" my next step is to get timing tape however I anticipate getting the engine up to higher RPM may be difficult but I can try, I don't want to damage anything.
Knowing that your ignition system is offering the correct progressive and total advance is extremely important.

That is concerning... Have not priced whole system vs parts. I'd prefer to fix what I have if possible. Pulling distributor intimidates me although I;ve read up on it and watched video and I have a manual.
The Pertronix will work.
I was just mentioning that if you do replace it, DO NOT go back in with another Pertronix.

OEM manual shows Prestolite. Would you recommend that brand? I've not researched if they are even in business.
You have many choices;
Anything using Hall Effect would be OFF my list.
VR (variable reluctor) is tried and proven.
Photo-eye appears to be working very well.
EST (electronic spark timing) where all advance is accomplished via electronics and the algorithm of the electronics.
HEI (High Energy Ignition) and can be EST or mechanical advance.

Or..... stick with what you now have and verify the progressive and total advance.

Any comments on the following. If a couple mismatched wires are not harmful then I'm compelled to use what I have. But if there is a chance that it will damage system I will replace.

Most of the wires had very low resistance compared to manual as they are Pretronix. Ohm values ranged from 1.543 kOhm for 39" wire to 974 ohms for 14" wire.

Replacing spark plug cables is never a bad idea.


I have one plug wire and and the coil wire which are different unknown brand that do fall with in the OEM manual for resistance. Not sure if or how the different wires might impact ignition. I'm thinking replace the electronics module and cap. I think wires are ok. I need to research pricing on components vs whole replacement. I really dont wan t to pull that distributor. vs length.

Am I exacerbating issue with different plug wires?

I'll do some additional research on distributor parts.

Click to expand...

swc65 said:

Well, I need to change my name to Murphy because his law always seems to apply. I dropped a tiny Locking washer of the electronic module post under Dist cap. I think it fell under base plate. I assume I need to now remove distributor to retrieve...?
If you are not able to pull the magnetic wheel and then remove the breaker plate (while the distributor is still installed), then yes..... you would want to remove the distributor from the engine.

Before doing so, bring the #1 cylinder around to TDC on the Compression Stroke.
Remove the cap and lay it off to the side.
Disconnect the ignition wires and label them.
Note where the rotor is aiming.... (if the last guy in did it correctly, the rotor will be aiming towards #1 cylinder)
Take a marking pen and make an alignment mark on the hold down flange and on the intake manifold.
Now loosen the hold down clamp bolt and remove it.
Lift the distributor up and out.
Note that the rotor will have moved CCW a bit while lifting it out (caused by the helical gear cut).
This is normal.

Now.... if you question the advancing of this unit, you can take it to a shop who owns and operates an old-school Sun, Allen or King distributor machine, and have them test it. If they have the curve graph for your Marine engine, they can make any corrections that are necessary.

Going back in, do the reverse of the above.
You may encounter a slight mis-alignment of the oil pump drive shaft.
If so, don't forget that the rotor will have moved CCW a bit while removing it.
Give the rotor the same lead when reinstalling, and it should down in.

Install the hold-down clamp and bolt.
Align the marks that you made earlier.
Snug the bolt only at this point.

Fire the engine up, and set BASE advance.
Once set, tighten the hold-down clamp bolt.

Click to expand...

swc65 said:

Got the distributor out and recovered the washer.
Dang... I should have continued reading!

I can’t seem to get the plastic grommet to disengage from Distributor housing. Pertronix show a video where the guy simply pulls straight down and then releases a grip mechanism on the wires. Mine is not budging. I’ve used a pick to gently pry but I do t want to break it as it seems I have to reuse and splice the wires if I found the correct video. Still not clear on how to identify what model I have. Only number I can find is printed on tag attached to electronic module. Searching the Pertronix site results in nothing for 24AD-AI2B.
I'm not sure what you are calling a plastic grommet that you want to disengage from the housing.
Post a few photos of your distributor.

Searching their web site I think I have a model D200800 but I’m only going by a picture. I guess I’ll need to call them Monday. I’m underwhelmed with their web site and their product use identification so far...

Click to expand...

Here is a pic of the what they call the grommet. I’ll find a procedure to test the module. If it tests ok then I don’t have to remove it but at some point in time I know the module will need replacing.

If this is a Pertronix Hall Effect unit, there will be a magnet triggering wheel and a pick-up sensor only.

Not quite. Here is mine. There is no magnetic wheel. Just the white plastic which what appears to be embedded with magnet or some sort of wheel. You can see the “teeth” through the plastic.

i don’t know is the linked procedure is valid for my electronic Module. Pertronix is on west coast so Will not be open for a while, assuming I can get through to tech support

hrough to tech support. http://www.pertronix.com.au/assets/pdf/Pertronix_Power_Ground_Voltage_Testing.pdf

swc65 said:

Not quite. Here is mine. There is no magnetic wheel. Just the white plastic which what appears to be embedded with magnet or some sort of wheel. You can see the “teeth” through the plastic.

Those are the tiny magnets that the sensor (what they are calling the module) picks up on.
This type of triggering is known as "Hall Effect".
Hall Effect is great when the angle (between the embedded magnets) are more accurately separated (i.e., larger diameter).

Click to expand...

Had a good conversation with Pertronix Tech Support and as result don’t think ignition system is the issue. Performed some tests and cleaned up the distributor clamp and it seems to be improved.

Getting closer finding the rattle. Turns out both flappers are gone and think likely have been for sometime. I used a long breaker bar as a “stethoscope and I thing the rattle is near starter/flywheel interface. It would make sense based on the noise. It’s not synchronous with RPM. Almost like the starter teeth have not completely returned to the original position or something like that And the flywheel might be pinging it. I need to read up on the starter section in my manual to better understand what can go wrong there. Not sure if it’s worth dropping the starter to investigate. If I do, I might as well change to a Marine version to be in compliance. I was able to tap the starter several times and got the rattle to subside for a moment.

I also discovered more regarding timing. Measured my harmonic balancer and it’s 6 3/4. However the timing plate that is fastened to the block has marks that do not comply with my balancer. If I did my math correctly the engine timing indicator is for a 7” balancer. This would mean that my timing has been advanced pretty significantly for a while. Waiting on timing time to arrive I made my own and co
paring mi e to the engine indicator is how I’m deducing the indicator on engine and the balancer do not match. Since the motor is not original and I was told it was a “crate motor”. I’m suspecting that whoever replaced it simply used the balancer from the original motor or used the wrong one. Is there any way to tell what size HB came on the original motor? I’d like to use my advanced timing references in the manual.

I’d like to put my tape on the motor and try it but the rattle is concerning me. I’d rather not spin the engine more than needed until I resolve the rattle. I feel a bit better it the source of rattle is due to starter, that’s is something g I can resolve. Deep engine components are out of my league and I can afford pay to pull the motor.

In order to locate true Top Dead Center for #1 cylinder, you would need to perform a PPS (positive piston stop) procedure.
This is done with using a piston stop and a degree wheel.

The Piston Stop threads into the #1 spark plug port.
The center threaded portion is adjustable so that the piston can be stopped at approximately 30 degrees before TDC.




The degree wheel will attach to your harmonic balancer.
(you can also use the harmonic balancer in lieu of the degree wheel.... but that can be tricky if you've not done it before)

You will use a temporary wire pointer against the degree wheel.

You will then bring the #1 piston around until it gently touches the stop.
You will adjust the stop so that the piston stops at approx 30 degrees before the alleged top of stroke.
(it can be 28 degrees or 32 degrees.... or somewhere in that neighborhood)

Note where the pointer is aiming.

You will next roll the crankshaft in the opposite direction until it once again touches the stop.
Again, note where the pointer is aiming.

Do this several times as to get a feel for it, and to eliminate any errors.
Your goal is to stop the piston at approx 30 degrees before it is at top of the stroke.

Continue adjusting the pointer until you get an equal angle between each direction from when the piston is stopped.


Now, without touching the pointer or degree wheel, you will remove the stop.
Next you will bring the crankshaft around until the pointer aims at ZERO.

That will be your TRUE TDC.

You will then verify your existing markings, or you will make new TDC markings.

This is the only true means of locating true TDC while the cylinder heads are in place.



In a rather crude fashion, think of this as though you were folding a string in half, in order to find the exact center or middle of the string.



.

Regarding the rattle, I think it's very likely that you hear the springs built into the damper plate. This plate, a wear item, is where the engine flywheel connects to the transmission. When an engine has a miss, the springs in the damper plate work to smooth out the rotation speed. I'll let others describe it further. I just wanted to get this possibility out there.

I’ve run across the procedure skimming the internet. Was hoping to use the TDC mark on my current balancer but I guess that is inaccurate based on what I just what I just discovered...

Can you post a pic of the wire pointer and degree wheel. Not quite following. I’ll look for video.

I will still use 0 degree mark on the current timing tab affixed to engine as TDC reference correct? I just can’t use the other references on the tab because they are scaled for a 7” HB.

Thank you. If I resolve the miss will that resolve the rattle. Or are you saying that because I hear the rattle the plate should be replaced. Basi g this on you comment that it’s a “wear item”.

A damper plate typically lasts many years. Yes, the rattle might go away when the miss is resolved. I'm not advocating changing the plate before you correct the engine miss.

Gotcha. So would the rattle just be the springs vibrating? Is it detrimental to motor to run it while verifying timing? Looks like I’ve got so
work to do there but have to get some parts to find TDC.

Is the damper plate between flywheel and the engine? See pic from my OMC manual. I don’t see any references to the plate. Damper plate not same as engine coupler is it? Manual does reference engine coupler.

The coupler your manual shows would accomplish the same thing as the damper I was describing. If that's what you have, you can forget I mentioned the noise that the springs in a damper plate might make.

Appreciate your input. I’ll keep looking and listening...

..............

swc65 said:

I’ve run across the procedure skimming the internet. Was hoping to use the TDC mark on my current balancer but I guess that is inaccurate based on what I just what I just discovered...
I would not roll the dice on this. It is critical that the TDC marks align properly.
See my post regarding the PPS procedure.

Can you post a pic of the wire pointer and degree wheel. Not quite following. I’ll look for video.

In this image below, the pointer that I refer to is a movable wire pointer.
The pointer on your engine is stationary.



I will still use 0 degree mark on the current timing tab affixed to engine as TDC reference correct?
Your engine does not have a timing tab.
Your engine is equipped with a stationary pointer that corresponds to the ZERO slot and degrees are on the harmonic balancer.

I just can’t use the other references on the tab because they are scaled for a 7” HB.

Click to expand...

DJR said:

A damper plate typically lasts many years. Yes, the rattle might go away when the miss is resolved. I'm not advocating changing the plate before you correct the engine miss.

Click to expand...

swc65 said:

Gotcha. So would the rattle just be the springs vibrating? Is it detrimental to motor to run it while verifying timing? Looks like I’ve got so
work to do there but have to get some parts to find TDC.
The springs that DJR mentions are found on a Borg Warner or Diesel drive coupler.
Your OMC King Cobra uses a rubber hub drive coupler as you show below.
Neither has anything to do with TDC or ignition timing.

Is the damper plate between flywheel and the engine?
No.... you do not have a damper plate. Your flywheel bolts directly to the crankshaft flange.

See pic from my OMC manual. I don’t see any references to the plate. Damper plate not same as engine coupler is it?
Correct.
You have a rubber hub drive coupler.
Inboard transmissions and the AQ series Volvo Penta use a drive coupler similar to this one.


By the way, your OMC coupler requires annual engine/coupler alignment.

Manual does reference engine coupler.
View attachment 23493

Click to expand...

Correction to my previous post.

......... It is critical that the TDC marks align properly and that they are accurately indicating true #1 TDC.
If off by let's say 4 degrees, your ignition timing will also be off by 4 degrees.

RicardoMarine said:

Correction to my previous post.

......... It is critical that the TDC marks align properly and that they are accurately indicating true #1 TDC.
If off by let's say 4 degrees, your ignition timing will also be off by 4 degrees.

Click to expand...

No fuggin kidding! Wow did u think that up all on your own?
Can you possibly be any more of a troll? Post Count!!!

I think it’s much ado about nothing as I mis measured my balancer. I pulled the back seat out of my boat so I can actually see what I’m doing. I measured the balancer accurately, and verified that the marks on the timing tab are a match for my balancer. So I think I can trust my TDC mark on the balancer.

I also think the rattling was coming from the starter. Using my metal breaker bar as a stethoscope I could hear it more direct when placing the bar directly on the starter motor. I pulled it to inspect. I didn’t see anything on the flywheel but the teeth on the starter gear had been wearing. I probably didn’t install it appropriately. It had a sticker indicating shims might be required but I didn’t install any a few years ago when I put it on. I was not aware I neede a Mari e starter.

Looking at replacements I see OEM from Evninride Johnson for $282, one from Sierra for $162 and this one from Rareelectrical on Amazon for $62. Are starter motors a case of ”you get what to pay for?” It’s hard to believe the range of price. Does quality and relatability mirror price?

I’m hoping this resolved the rattle and I know it makes me electrically compliant which makes me feel safer.

got my LOP switch today and waiting on relay to arrive tomorrow. I did notice that the starter motor sole found from Sierra has an R terminal for my LOP switch.

Andy advice on starter motor selection?

pic are from the starter I pulled off and the flywheel. Let me know if you see something.

Along with your ME dot com thread here, I've also been helping another forum member with his 5.8L Ford ignition timing.
In your post #21, I had the 5.8L Ford in mind, and mentioned that you did not have a timing tab in lieu of a pointer only.
That was incorrect and I apologize.
(the fact that o2bat did not catch that clearly shows that he does not read an entire thread before leaving his childish and disruptive comments)


So to sum up...... your 5.7L GM SBC will use a timing tab that will be marked up to approx 10 or 12 degrees BTDC for use in setting BASE advance.
Your OEM harmonic balancer will have nothing more than the ZERO slot on it. If you wish to perform a total advance check, you will need to add the timing decal.


..................

swc65 said:

I think it’s much ado about nothing as I mis measured my balancer. I pulled the back seat out of my boat so I can actually see what I’m doing. I measured the balancer accurately, and verified that the marks on the timing tab are a match for my balancer. So I think I can trust my TDC mark on the balancer.
In post #12, you mentioned that something was wrong with your timing marks and that your; "timing has been advanced pretty significantly for a while."
This is why I suggested verifying the markings by performing the PPS procedure.
In other words, if the harmonic balancer's outer ring/hub has slipped on the inner hub, the outer ring/hub will no longer be indexed correctly with regard to the timing marks.
NOTE that is fairly common with an older SBC harmonic balancer!

Also, if the timing tab is the bolt-on style, it could be incorrect for the balancer diameter and/or the position of the ZERO slot.



But I digress....... are you now saying that the timing marks are OK, and if so, how did you verify that?



Also in post #12, you mentioned that you'd like to use your digitally advancing timing light.
Please note that the digitally advancing timing light will not compensate for incorrect TDC markings.


In post #13 I explained the PPS procedure for you.
Once that has been done, you will know if the markings are OK or not OK.
If not OK, you will make a new True TDC mark and will high-lite it to avoid later confusion.


I also think the rattling was coming from the starter. Using my metal breaker bar as a stethoscope I could hear it more direct when placing the bar directly on the starter motor. I pulled it to inspect. I didn’t see anything on the flywheel but the teeth on the starter gear had been wearing. I probably didn’t install it appropriately. It had a sticker indicating shims might be required but I didn’t install any a few years ago when I put it on. I was not aware I neede a Mari e starter.
Did you use the correct length and properly knurled bolts when you installed it?
The bolts must fully clamp the nose housing to the block without first bottoming out.
I mention this because today's SBC starter motors are not all the same.
The nose housings very between manufacturers, causing the need for specific bolt lengths.


Looking at replacements I see OEM from Evninride Johnson for $282, one from Sierra for $162 and this one from Rareelectrical on Amazon for $62. Are starter motors a case of ”you get what to pay for?” It’s hard to believe the range of price. Does quality and reliability mirror price?
It should, but it does not always.

The best ones will use all steel spur gears for their reduction system.
The inexpensive ones will use a nylon ring gear in a planetary gear reduction system (shown below).

Andy advice on starter motor selection?
A good brand HTGR/PMGR motor that uses a spur gear reduction system.

Keep in mind that we will see two flywheels being used on the SBC
..... 153 tooth ring gear
..... 168 tooth ring gear

Each requires a different starter motor.
153 tooth ring gear requires the straight across bolt pattern
168 tooth ring gear requires the staggered bolt pattern


The two motors below use the planetary reduction system with the nylon ring gear.
My experience has shown me that the nylon ring gears may eventually fail.

Click to expand...

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Ricardo you have brought exactly nothing to the thread except your desire to make the OP jump through your hoops. Please just go!

RicardoMarine said:

Along with your ME dot com thread here, I've also been helping another forum member with his 5.8L Ford ignition timing.
In your post #21, I had the 5.8L Ford in mind, and mentioned that you did not have a timing tab in lieu of a pointer only.
That was incorrect and I apologize.
(the fact that o2bat did not catch that clearly shows that he does not read an entire thread before leaving his childish and disruptive comments)


So to sum up...... your 5.7L GM SBC will use a timing tab that will be marked up to approx 10 or 12 degrees BTDC for use in setting BASE advance.
Your OEM harmonic balancer will have nothing more than the ZERO slot on it. If you wish to perform a total advance check, you will need to add the timing decal.

Click to expand...

No sweat, I make mistake daily and even post them on forums . See the attached pics. The math tells me its correct and when I made my homemade timing tape it matched the existing tab. The mark ground into the balancer is about a 1mm wide so there is some erros but I believe I'm there. After removing the distributor and and using the mark to get TDC on compression stroke, I found the rotor pointing at #1. I also pulled the valve cover to confirm both intake and exhaust valves were closed. When I choose and install a starter I'll be able to confirm Total advance timing.



This raises another question in my vacuum filled cranium, Can I use the total advance timing printer in the OMC manual? This is a different engine, will it have same timing curve? According to manual Max timing advance is 30.4 degrees at 4600 RPM using 89 AKI fuel. I assume 89 is the Octane level. I have no ides what my octane is, I but ethanol free from Murphy's USA (Walmart).

RicardoMarine said:

I also think the rattling was coming from the starter. Using my metal breaker bar as a stethoscope I could hear it more direct when placing the bar directly on the starter motor. I pulled it to inspect. I didn’t see anything on the flywheel but the teeth on the starter gear had been wearing. I probably didn’t install it appropriately. It had a sticker indicating shims might be required but I didn’t install any a few years ago when I put it on. I was not aware I neede a Mari e starter.
Did you use the correct length and properly knurled bolts when you installed it?
The bolts must fully clamp the nose housing to the block without first bottoming out.
I mention this because today's SBC starter motors are not all the same.
The nose housings very between manufacturers, causing the need for specific bolt lengths.

Click to expand...

I used bolts that I took out from the old starter, they are knurled but did not measure them. They worked for the incorrect auto starter that I just removed. Take a look at the wear on the tip of the starter gear.

What would cause the wear? Is the wear to the rattling I was hearing? Tried to upload the starter pic but not working. I can try again later. The starter gear is word on the end. I'm wondering is may the gear was not retracting far enough after the start terminals dis engaged and that was the rattling I was hearing. I cold see bit of metal in the starter housing and in the flywheel housing.

How do I prevent the wear on the new marine starter when I choose one? The good news for me is that after starter installation with the relay and LOP switch, I'm completely complaint with marine requirements. Safer operation.

.............

swc65 said:

No sweat, I make mistake daily and even post them on forums . See the attached pics.


The math tells me its correct and when I made my homemade timing tape it matched the existing tab. The mark ground into the balancer is about a 1mm wide so there is some erros but I believe I'm there.
I'm not sure that you are understanding this.
Placing the decal onto the balancer does not mean that the balancer's slot is accurate, nor that the outer ring/hub has not slipped on the inner hub.
These do occasionally slip.
There is only 1 way to verify this while the cylinder heads are installed........., and it's using the PPS procedure.

Let's take another approach:
When the #1 piston is at true Top Dead Center, the center of the crankshaft, the crankshaft's connecting rod journal and connecting rod will be aligned, and will be aiming directly at the piston (minus the wrist pin offset).
At this point, the piston will be at the extreme top of it's travel.
(see red line)




While in this position, the mark on the balancer should align perfectly with the ZERO mark on the timing tab.
This is also the point at which we index the camshaft and at which we base our ignition advance from.

However, if the outer ring has slipped, and when using the harmonic balancer TDC mark against the timing tab ZERO mark, the #1 piston may NOT be at true TDC.
NOTE: This has ZERO to do with any changes to the internal components. It only has to do with the timing marks that will be used for ignition timing!

If the balancer has slipped to the tune of 2 or 4 degrees, then when you adjust the ignition advance, it will also be off by that very same 2 or 4 degrees.
2 or 4 degrees can and will make a difference in engine performance, and even lead to Detonation damage.

Another approach:
Imagine that the harmonic balancer was not keyed to the crankshaft.
Let's say that the #1 cylinder is at true TDC.
Let's say that we loosen the center bolt and turn the balancer 5 degrees one way or the other.
Now we tighten the bolt.
We now turn the crankshaft over until the balancer TDC marks align with the ZERO tab mark.
The #1 piston will actually be off by 5 degrees regardless of the marks being aligned.
Doing this would represent an outer ring/hub that has slipped on the inner hub by 5 degrees.


After removing the distributor and and using the mark to get TDC on compression stroke, I found the rotor pointing at #1. I also pulled the valve cover to confirm both intake and exhaust valves were closed. When I choose and install a starter I'll be able to confirm Total advance timing.
In order to check the Total Advance, the engine must be operating at/near 3,200 RPM.
In other words, there is no way to check total advance with out operating the engine at/neat the "Full In" ignition advance RPM.
For your SBC Marine engine, this will be at/near 3,200 +/- RPM, depending on your ignition system and the curve that it offers.

This raises another question in my vacuum filled cranium, Can I use the total advance timing printer in the OMC manual?
Please explain what you mean by the "total advance timing printer in the OMC manual"!

This is a different engine, will it have same timing curve?
If this engine was built for true Marine use, yes.

According to manual Max timing advance is 30.4 degrees at 4600 RPM using 89 AKI fuel.
Unless you plan to run at 4,600 RPM (of which will shorten the life of your engine), looking for a TA at 4,600 RPM is rather useless.

I assume 89 is the Octane level. I have no ides what my octane is, I but ethanol free from Murphy's USA (Walmart).
Good for you.... Non-Ethanol is expensive but is a great way to go.

I used bolts that I took out from the old starter, they are knurled but did not measure them. They worked for the incorrect auto starter that I just removed. Take a look at the wear on the tip of the starter gear.
As said earlier, not all nose housing are the same.
It is very important to check the bolt length against the nose housing bolt bore depths.
If the bolts are a bit too long, they may bottom out in the female threads before they fully clamp the nose housing to the engine block.

What would cause the wear? Is the wear to the rattling I was hearing?
Tough to say from a key board.

Tried to upload the starter pic but not working. I can try again later. The starter gear is word on the end. I'm wondering is may the gear was not retracting far enough after the start terminals dis engaged and that was the rattling I was hearing.
Possibly.


How do I prevent the wear on the new marine starter when I choose one?
Seldom do we encounter this issue.

The good news for me is that after starter installation with the relay and LOP switch, I'm completely complaint with marine requirements. Safer operation.
If done correctly, Yes!

Click to expand...

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RicardoMarine said:

.............
This raises another question in my vacuum filled cranium, Can I use the total advance timing printer in the OMC manual?
Please explain what you mean by the "total advance timing printer in the OMC manual"!

Click to expand...

Typo, Meant to say "Printed in the manual"

RicardoMarine said:

This is a different engine, will it have same timing curve?
If this engine was built for true Marine use, yes.

According to manual Max timing advance is 30.4 degrees at 4600 RPM using 89 AKI fuel.
Unless you plan to run at 4,600 RPM (of which will shorten the life of your engine), looking for a TA at 4,600 RPM is rather useless.

Click to expand...

I was told it was a crate engine so not sure if it was built for marine use. My neighbor passed away so I have noway to ask further.

Is there a typical advanced timing for SBC 350 that I can shoot for to optimize total timing? Otherwise, all i know to do is set the initial timing for maximum engine vacuum @ 550-600 RPM per the manual.

RicardoMarine said:

There is only 1 way to verify this while the cylinder heads are installed........., and it's using the PPS procedure.

Let's take another approach:
When the #1 piston is at true Top Dead Center, the center of the crankshaft, the crankshaft's connecting rod journal and connecting rod will be aligned, and will be aiming directly at the piston (minus the wrist pin offset).

Click to expand...

I get it, its the only way to be 100% sure. PIA, but I see your point since I do not know for sure.