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After Engine Rebuild - Lack of power/Acceleration through entire range

Kim, according to earlier posts, the bore is standard (4.000”) and the stroke is 3.480”..... which keeps the displacement at 5.7L...... same as previous engine!

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It just strikes me funny it has to be TDC to even start maybe get a new damper pully to take that variable out of the loop. If 10 degrees base timing is spec it should easily start there correct?
 




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Originally Posted by kimcrwbr1
It just strikes me funny it has to be TDC to even start maybe get a new damper pully to take that variable out of the loop. If 10 degrees base timing is spec it should easily start there correct?



Kim, most SBCs will fire up on a BASE advance of 6*, 8* or 10*...... depending on the S C/R.

As you know, an EST distributor has no mechanically advancing mechanism. In other words, the driven gear/shaft/rotor are fixed.
The housing is initially indexed so that the triggering mechanism offers full advance in a mechanical fashion.
Then through the controller's electronic algorithm, the spark event is then delayed as to offer advance as seen at the various crankshaft angles.
Once RPM increase, the delay is then altered in a variable fashion throughout the RPM range. I.E., more RPM, the less the delay.

But I digress here, so grab a cup of coffee..... this is a long one.


This thread has become somewhat addictive. It's like a good TV series that you can't help but to tune into each day or each week.


I'm reading back through each post.
As I just mentioned to Kim, this newly rebuilt engine is apparently a 5.7L SBC, std 4.000" bore with a std 3.480" stroke.
The new engine allegedly develops 343 hp @ 5k RPM.

The original 2011 Vortec engine was most likely fitted with the dreaded GM F/D pistons. This engine developed 320 hp, of which is somewhat erroneous to be begin with since GM rated these @ 5,200 to 5,400 RPM, depending on which day of the week.

In post #4 I asked if the new engine build specs could be posted. I have yet to see this in full and complete detail.
What we did get was this:

Engine specs
**Hydraulic Roller Camshaft
Compression Ratio: 9:4:1
Bore: standard
Stroke: 3.750" (unless this is a 377 cu in, this will actually be 3.480")
Valves: intake 1.94: Exhaust 1.50
Valve springs: 135lbs 1.255" O. D.
CRANKSHAFT DIA: 2.650"
Compress height: 1.560" (?)
18cc D-cup pistons
Cylinder compression : 9.6:1

** in post #7 I mention that this is missing the full details. Then later in post # 10 Chris says; "Listen to what Ricardo is saying... WHERE ARE THE CAM SPECS? The incorrect cam will not let your engine rev in a marine environment."
** then further in post #


In post #6, Jay sends us to CenterStateEngine.com.... but I am not able to see anything regarding full and/or complete build specs!

In post # 15 I asked MandMcustomperformance to post the build specs.
In post # 22 we finally see the cam specs;
Camshaft Style:Hydraulic flat tappet
RPM Range:1,000-5,000
Intake Duration at 050 inch Lift:212
Exhaust Duration at 050 inch Lift:218
Duration at 050 inch Lift:212 int./218 exh.
Valve Lift with Factory Rocker Arm Ratio:0.447 int./0.462 exh.
Lobe Separation (degrees):112

If we look back at post #5 we can see that Jay believes this was built using a Roller Cam profile, yet in post #22 MandM says Hydraulic Flat Tappet.

Now in post # 26, MandM says that the rotating assembly is an OEM direct replacement (we all know that GM used those F'ing Full Dished pistons)...... yet in post # 5, Jay describes the pistons as; 18cc D-cup pistons

So.... someone needs to be forthright and give us the correct information.


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Originally Posted by post #28
I've been accused of being too precise and picky at times that's why I write down all measurements



If ever there is a time to be precise, now is it! Without the correct and complete info, our hands are tied!


In post # 29, Chris asks; "so, the timing gear set was installed without any advance?"
In posts # 30 and #31, it appears that MandM misunderstood the question thinking that Chris was asking about Ignition Advance.
If I understood Chris, I think that he was asking if the cam was phased in at ZERO, or if it was advance/retarded via eccentric bushings, etc as per my post #37!

In post #38, I basically asked for clarification re; piston profile.

In post #40, I asked if the ignition advance curve could be verified.
I got these responses: "according to his tach around 900-1000 rpm"....... "No don't know the variable timing"...."I only verified ecu advance to 10°BTDC at idle with light"



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Originally Posted by post #48
I think we have established that the timing is not the problem.



How so? No one has yet looked at the Progressive or TA! These systems are not without occasional fault!

MandM, please read post #50 again.


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Originally Posted by post #63
and I believe we have exhausted the timing issue



Unless the progressive advance and the total advance is viewed dynamically and is plotted out in graph form so that we can see it......, I would disagree with you!


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Originally Posted by post #65
If it ran WOT before the build and now will not do it after.......there is something wrong in the build..... The Cam is what I am thinking. I know it pulled WOT on the dyno.......



Chris, I tend to agree with you.



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Originally Posted by post #85
Rick 8 step was used



Excellent!


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Originally Posted by post #85
I can't give you spark at 3k rpm I don't have the boat anymore



Why was this NOT looked at, checked or verified during the dyno testing, or at least during the trouble-shooting procedure?
I have NEVER sent an engine out without having looked at what the Ignition advancing system is doing re; Progressive and TA!

Like I've mentioned earlier..... with all else being OK, the ignition lead (aka advance) has the last word in the placement of LPCP.
If we end up with a lazy LPCP, the torque will be lousy.



Bottom line for me;
I sense that MandM has limited marine SBC experience.
Jay's knowledge is also limited and he is relying on MandM for help.
This thread has lacked complete information from the beginning.
If this is due to simple lack of experience or knowledge...... that's one thing.
Otherwise, this thread has all of all of the symptoms of a troll thread.
 
After reading through all the posts, problem seems to be the "10-15 seconds" to get on plane and this quote "It takes longer to get up on plane once on plane tops out at 40mph @ 4000 rpm. The power band arc is at 4800. It will stand the boat up on launch but while trimming it losses that thrust."

Sounds like it will rev past 4000rpm the boat just won't go faster ..... Ventilating the props.

I don't think the drive is trimming all the way down/in......
 
Docksidemarineservices said:
After reading through all the posts, problem seems to be the "10-15 seconds" to get on plane and this quote "It takes longer to get up on plane once on plane tops out at 40mph @ 4000 rpm. The power band arc is at 4800. It will stand the boat up on launch but while trimming it losses that thrust."

Sounds like it will rev past 4000rpm the boat just won't go faster ..... Ventilating the props.

I don't think the drive is trimming all the way down/in......
Click to expand...

I am the original owner of the boat and have been boating over 10 years. M&M is the builder. The trim was fine and all the way down. The post was inaccurate. The boat did not stand the boat up on launch...It launched with some porpousing less then original engine and took a while to wind up to 40 MPH at 4000 rpms WOT. Trimming, I could get it to 41-42 mph.

There is no growth and the bottom is painted.
Thank You everyone for trying to help here. ​
You have been awesome.

Provided there is no snow or ice this coming weekend, I plan to drop the boat in the water to:
1) Try to test again with loose gas cap to test tank vent not clogged
2) Drain as much gas as I can and refill with 87 octane to dilute octane booster that was added.
3) I will re-verify outdrive is fully down.

Anything else I can test. I know nothing about engine internals or ECU's but willing to do almost anything other then change the duo-props which are not the problem.
 
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JayPW said:
I am the original owner of the boat and have been boating over 10 years. M&M is the builder. The trim was fine and all the way down. The post was inaccurate. The boat did not stand the boat up on launch...It launched with some porpousing less then original engine and took a while to wind up to 40 MPH at 4000 rpms WOT. Trimming, I could get it to 41-42 mph.

There is no growth and the bottom is painted.
Thank You everyone for trying to help here. ​
You have been awesome.

Provided there is no snow or ice this coming weekend, I plan to drop the boat in the water to:
1) Try to test again with loose gas cap to test tank vent not clogged
If a fuel tank vent system was to become clogged, it would take a while before the negative pressure within the fuel tank could possibly restrict fuel pump operation.

2) Drain as much gas as I can and refill with 87 octane to dilute octane booster that was added.
Did you sense that the engine was undergoing Detonation during the tests?

3) I will re-verify outdrive is fully down.

Anything else I can test. I know nothing about engine internals or ECU's but willing to do almost anything other then change the duo-props which are not the problem.
At this point, I would ask the builder to once again verify the assembly specs.
Use a dial indicator and degree wheel and see if the camshaft is indexed correctly according to how the manufacturer intended.
Perhaps check cylinder pressures.
Ask the builder for an EXACT piston profile.
Ask him what he used for a Quench dimension.
And certainly take a good look at the Progressive Ignition Advance and the Total Advance @ the RPM in which the reading was taken.
Look closely at the MPI system.

Until you roll up your sleeves and get more deeply into this........ you will continue to be puzzled.
Click to expand...
 
Is the knock senser functioning properly? While the engine is running have someone tap quickly on the block next to the knock senser while watching the timing with a light. The timing should retard with the tapping just dont tap on the senser they are very delicate. Was it installed at the proper torque value with sealant on the threads?
 
Several items:
1) Anyone on here is central to southern NJ willing to give me a private message and estimate to diagnose this?
I have no ability or the tools to perform testing regarding timing lights, piston stops, crankshaft mounted degree wheels, etc. My builder is 800 miles away and spring is fast approaching. I don't have much after all this work but I also cant go without my boat​
2) Someone stated very early in this thread you must use a genuine VP Distributor cap and rotor or it wont work. Apparently, M&M used part number 3861987 which I found on several online sites as a direct replacement for VP part number 3858975. Could this be the problem?

I am extremely frustrated and the boat is like a part of my body. I just don't know what to do at this point.
 
JayPW said:
Several items:
1) Anyone on here is central to southern NJ willing to give me a private message and estimate to diagnose this?
I have no ability or the tools to perform testing regarding timing lights, piston stops, crankshaft mounted degree wheels, etc. My builder is 800 miles away and spring is fast approaching. I don't have much after all this work but I also cant go without my boat​
2) Someone stated very early in this thread you must use a genuine VP Distributor cap and rotor or it wont work. Apparently, M&M used part number 3861987 which I found on several online sites as a direct replacement for VP part number 3858975. Could this be the problem?

I am extremely frustrated and the boat is like a part of my body. I just don't know what to do at this point.
Click to expand...

I said you cannot use a Napa Cap and rotor.
 
JayPW said:
I am extremely frustrated and the boat is like a part of my body. I just don't know what to do at this point.
Click to expand...


Understood.

As suggested earlier, I believe that the P of E will be the best way to get to the bottom of this. This means starting from the bottom and working your way up (metaphorically speaking). The Process of Elimination is used so that ALL work and ALL components can be verified.
No offense to the builder! None of us are completely immune to an occasional error, mistake or an over-sight!

Your engine builder is 800 miles from you, correct? If so, it may not be feasible or practical to have him come out, or for you to ship the engine back to him.

In order to eliminate any bios, perhaps an independent assessment may be in order. Perhaps by a local mechanic with very extensive SBC building and MPI tuning experience.

For myself, I would want to know the complete build specs, including some data that may not appear to be necessary at this time.
Leave no stone un-turned!

We know that the bore is 4.000" and we know that the stroke is 3.480", and this engine is a 5.7L SBC.
We know the combustion chamber volume is 64cc.
I am not clear on the piston profile, other than it offers a 18cc dish volume and the mention of D-dish!
To my knowledge, there has been no mention of a quench effect or quench dimension.

I would suggest that cylinder pressures be taken. Make sure that each cylinder is cycled through at least 3 compression strokes (I.E., 7 crankshaft rotations to be safe).

It would be nice to have the actual camshaft profile info so that it can be verified via degree wheel and dial indicator.
At the same time, true #1 TDC could be verified via a spark plug port PPS. I would suggest using a 30* +/- split (in either direction) for greater accuracy. (I would NOT use 10* as commonly suggested)

And again, I would suggest that the harmonic balancer be accurately marked off up to approx 35* for later use in checking the Progressive and Total ignition advance.
By doing this a standard timing light can be use, thus eliminating any potential user error or equipment error.
This offers us what I refer to as viewing Real Degrees in Real Time!

It has been suggested that the 8 stop cam follower adjustment was used to set the depth of the hydraulic follower plungers. (we do not adjust valves, we adjust the hydraulic plunger depth to OEM specs)

Once the build specs have been verified and are proven to be appropriate for SBC Marine use, and once the critical phasing of the camshaft has been verified as per the manufacturer, he can move on to the Ignition System and/or the MPI system.

As said earlier....... this all boils down to the correct LPCP.

All things being equal, and with nothing regarding the boat or stern drive having been changed, there has to be a reason why this fresh engine is not performing as well as the previous engine.

A methodical and systematic P of E will be your best friend here.


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Agreed. I want to thank everyone for all their attention, advice and roll up the sleeves attitude.

I no have an aggressive plan and will be working locally after I replace the cap and rotor ensuring the rotor plate I not loose to the shaft, check fuel vent is not clogged, siphon off as much gas as I can and fill with Marine gas, check all wires are fully seated, the drive is fully down and the throttle plate is vertical at WOT.

Will post results when I have them.
 
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