Different firing order than stock?

Has anyone experienced a firing order different than what is printed in a manual or on the intake manifold? For example my 1993 454 crusader xl starboard motor has a RH rotation and is in sequence with the standard firing order, but my port side motor firing order is different because the #1 & #8 are directly across from one another instead of side by side. Any suggestions why this is and how I can figure out the firing order w/o looking in the manual or on the manifold? These are 93' 454 xl w/carbs and a prestolite dist. w/ Ign. mod., not points.

Thanks and I am courious to see what everyone says, because I have never see this before.

Whoa! The numbering of those cylinders dows NOT change, only the firing order on the distributor cap.

Jeff

Thats what I mean, the dist cap. Like I said, if you are standing at the rear of the motor and looking at the dist cap, the #8 wire is at the 5 o;clock and the #1 wire is at the 11 o;clock position. As you can tell it is very different tht the stock order which is the #1 & #8 dist wires are about the 7 & 8 o'clock position. I only ask this because when I changed the dist cap I marked the cap w/ the #1 & #8 wires and when I changed the ign mod my mate changed the wires to the stock order and now it wont start. I only know that the stock order is wrong on my motor because the #1 & #8 dist wire are marked onthe dist cap, from when it was running, direclty across from one another and not beside one another like the standard order shows. Very confusing, but when I changed the wires back from stock to where I thought they were before he removed them, I got a backfire out of the carb instead of just cranking and spitting fuel back out of the carb. I know this sounds crazy and to someone that understands mechanics, just doesn't make any sense, but I was the one who tracked the wires and marked the dist cap, so I know thatwhere they used to be. I never removed the dist, only replace the cap one wire at a time. very confusing, how can i trace the firing order old school? Bump the motor and write down each cyl as it hits the valve?
Any ideas would be appreciated, i am dazed and confused on this one, thanks

#1 and #8 should always be adjacent on the distributor cap on both your engines.
LH = 1-8-4-3-6-5-7-2
RH = 1-2-7-5-6-3-4-8

ON both motors, #1 is opposite the fuel pump, towards the alternator.
#8 is diagonally opposite.

You see, the firing order just reverses, it doesn't get mixed up. To mix it up, you need a different crank and cam geometry. Highly unlikely.

Keep in mind that each engine's distributor will rotate in the same direction.
Only the orientation of the spark plug wires change here.... and is why #1 and #8 will remain adjacent to one another...... just on the oposite side from one another.

Let me carry out the firing order to include more revolutions:
LH STD Engine = 1-8-4-3-6-5-7-2-1-8-4-3-6-5-7-2-1-8-4-3-6-5-7-2
RH REV Engine = 1-2-7-5-6-3-4-8-1-2-7-5-6-3-4-8-1-2-7-5-6-3-4-8-1
you'll see that #1 and #8 remain adjacent to each other in the cap position... just in a different order.

Each of the above will be in a CW orientation at the cap.


It may be that the RH REV Rotation Engine distributor is using the standard cap, of which would be labeled for a LH Std Rotation Engine.
Pay no attention to the markings!
Do as Dave suggests, and your firing order will be correct for either LH or RH engine according to what he posted above.

So I'm a little confused; you stated in your first post that the RH rotation starboard engine had the "standard" firing order? If it's a counter rotator (RH), it would not be the standard firing order. Secondly, can you confirm that you in fact have a counter rotator in a 1993 application. Would have thought that vintage would be two standard rotation engines with shaft rotation changed at the tranny.

I will check on everything that you have said, but like I said earlier, I personly marked the cap w/ #1 & #8 plug wires and they were directly across from one another, not side by side like on the starbord motor. starbord motor is corrct w/ the firing order and starts every time. I know its wierd.

WoodieMan said:

So I'm a little confused; you stated in your first post that the RH rotation starboard engine had the "standard" firing order? If it's a counter rotator (RH), it would not be the standard firing order. Secondly, can you confirm that you in fact have a counter rotator in a 1993 application. Would have thought that vintage would be two standard rotation engines with shaft rotation changed at the tranny.

Click to expand...

I share Woodie's confusion.
Can you clarify for us?

East Coast Charters said:

I will check on everything that you have said, but like I said earlier, I personly marked the cap w/ #1 & #8 plug wires and they were directly across from one another, not side by side like on the starbord motor. starbord motor is corrct w/ the firing order and starts every time. I know its wierd.

Click to expand...

ECC, I've only seen maybe one or two engines whereby the OEM Marinizer opted for an optional firing order, and of course, this demands an entirely different camshaft. One that I recall is the small block Ford.

I'm not aware of any Marinizer doing this to the GM engines.
IOW, whether Std LH.... or REV RH, the crankshaft/camshaft relationship has always dictated the ignition firing order.
As we reverse rotation, and we reverse ignition firing order.
It's all tied in physically to the crankshaft/camshaft relationship and orientation..... (that and a firing order that works dynamically with balancing the rotating mass..... but that's another story!)
But hopefully you get my point!

ECC, if you are suggesting that #1 plug location in the cap is not adjacent to #8 plug location in the cap.... then ya got me.
Everything in the firing order would appear to dictate (no matter which rotation, LH or RH)........, that #1 and #8 will remain adjacent to one another...... either in front of, or behind the other..... but definitely "adjacent".

Here's one sure fired method to find the actual intended firing order, and it's fairly good proof.
Pull the valve covers.
Beginning at #1 cylinder... bring her up on C/S #1.
No question about #1.... we're there, and we know that this one is about to fire (or has just fired).

Rotate crank 90* in the direction that the engine is intended for.
Note which cylinder has just cycled an Intake Stroke, and is now on C/S.
This one is next to fire (or has just fired).
Note this on paper.... and repeat this cycle indexing the crankshaft 90*.

By the time that you have made a 720* crank sweep, you'll have your ignition firing order.

Optional method:
Intall 7 compression test gauges (no need to do #1), and monitor them as you make a 720* crank sweep!
Of course I'm joking on that..... but it would actually work... and it would well!



Hey Woodie.... did you notice that he's a Charter Boat operator?
Can you smell a nice package of smoke Salmon in the mail for all this help we've been offering?

.

Oregon asking florida for salmon??? hmmmm. maybe yellowfin. Most of the central FL offshore fishing industry is on its knees with snapper/grouper restrictions, and so little swords here. Some guys are even resorting to shrimping, inside the one mile line. Its tough right now.

Rick: Sadly, your preferred treat isn't indigenous to his locale.

ECC: If a non-standard firing order is used, both the Crankshaft and the Camshaft need to be modified; technically possible but highly unlikely due to the setup costs. I'd suggest somebody get a good service manual out and research the appropriate nomenclature...there's NFW a reverse rotation engine will run with a "standard rotation firing order" - the parts just don't work like that. Understand LH, RH, cylinder numbering, etc, is essential so we all get a good understanding of what exists in any given situation.

One other point to ponder - there is no "requirement" that the #1 plug lead position be in the typically shown 11 o'clock orientation. What is critical is the firing order (proper arrangement of the plug leads).

diver_dave said:

Oregon asking florida for salmon??? hmmmm. maybe yellowfin. Most of the central FL offshore fishing industry is on its knees with snapper/grouper restrictions, and so little swords here. Some guys are even resorting to shrimping, inside the one mile line. Its tough right now.

Click to expand...

makomark said:

Rick: Sadly, your preferred treat isn't indigenous to his locale.

Click to expand...

Ya know..... I just hate it when you guys catch my boo boos! LOL
( I should have looked at ECC's location! My bad! )
OK then...... we'll take some smoked shimp or whatever he has to offer!

makomark said:

ECC: If a non-standard firing order is used, both the Crankshaft and the Camshaft need to be modified; technically possible but highly unlikely due to the setup costs. I'd suggest somebody get a good service manual out and research the appropriate nomenclature...there's NFW a reverse rotation engine will run with a "standard rotation firing order" - the parts just don't work like that.
Understand LH, RH, cylinder numbering, etc, is essential so we all get a good understanding of what exists in any given situation.

One other point to ponder - there is no "requirement" that the #1 plug lead position be in the typically shown 11 o'clock orientation.
What is critical is the firing order (proper arrangement of the plug leads).

Click to expand...

Ditto Mark.

ECC, don't misunderstand me/us...... there is an importance as to keep things somewhat standard.
For many.... the rotor will often be aimed towards #1 physical cylinder location when the distributor is indexed correctly for #1 TDC C/S.
But it's not a deal breaker if not.
In reality, the spark plug wires don't care where they are located in the cap...., as long as each cyinder receives a spark at the correct timing!
All will work as intended.

Edit:
BTW, if the numbering on the cap is important to you, and if these do not align, the entire distributor can be raised and re-indexed.
There is nothing that dictates how the distributor housing is to install..... (unless there would interferance with where the power/triggering leads exit the housing).
Since the cap is indexed to the distributor housing, this should correct it, and place the post that is marked #1 plug wire, close to where you want it.
Now the only issue becomes.... is there a LH and RH cap?

.

The only difference would be the (molded in) numbers, or lack of any. Most of the ones i've touched had both sets (either firing order).

Mark, that's what I was trying to suggest.... however, I did know that both firing order directions would be marked on the same cap.
Ya learn sump'n new every day!

.

Can't wait for an update. Something doesn't seem right and it's keeping me up!!

Rick, I'll deffinately settle for grouper (blackened please), but only after we put this to bed. BTW, safe to eat anything from the gulf side or is the oil spill still an onging issue down there?

Sorry to be so slow on the reply, I have been out knocking down the dolphin, not salmon, what ever that is. FWC has put most of the reef fish on a season, which is now mostly open so we are back in business as far as the commercial catch goes, but the charter bus. is dead. Now, I want to thank everyone who has contributed to my delima. I figured out the firing order by doing a compression test on each cylinder, when the valve opened I placed that wire where the rotor button was pointing. I also found that the motors were installed opposite of each other, st. turned cw & pt turned ccw, opposite of what my manual states. I know it was very confusing, but your comments were very helpful and steared me on the right path. Thanks again and happy fishing.

I'm glad that you figured in all out.

So you're saying that the OEM manual listed the engine rotation incorrectly? Hmmm.

Now, at the risk of redundancy, be sure to not only set BASE or Initial Timing....., but more importantly, check to see what your TA (total advance) is doing.
If the OEM hasn't fouled this up also, it should give you a spec or advance curve/limit for Ignition Advance.
Performance will suffer if your ignition is not offering the correct advance throughout the RPM range until it reaches what's called "full in".
The RPM where this occurs, as well as the amount of spark lead (in degrees), is critical.
We cannot have a TA in degreess without an associated RPM.

Your specs should call this out for you.



.

Glad you got her. Curious though, still can't sleep! Strb turning CW and Port turning CCW is the norm; you're saying that your manual states an unconventional Strb CCW and Port CW engine rotation? That's understandable with the Warner 1.91:1 reduction gear? Is that the way your props are rotating? I trust you are looking for rotation direction from the back of the engine facing the flywheel yes?

The best way to see if CCW or CW just look at timming marks, on damper

Steve

On a side note about distributer caps, the newer mercruiser engines use a vortec (style) crab cap like its auto counterpart, the plug wires don't match the firing order, the cap has cross overs molded into the cap. This keeps the wires neater and shorter. each side wires would be 1.3.5.7 or 2.4.6.8 this link shows the cap molded paths. http://www.summitracing.com/parts/ACC-120141/?rtype=10 Its possible to retro fit some distributers to different caps. They made a cap awhile back that fit HEI and some older GM units that looked "normal" but were molded to keep wires on each side. The only give away was color. http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=180594212308&viewitem=#ht_500wt_1182. As the op said he found the issue. could be he has v drives and what is port and starboard are swapped.

I`ll try to simplify this, but this only only for GM v8`s
For a standard rotation motor ,Using the round dist cap and looking down at it ,locate #1 (if marked on the cap) going in a clockwise direction 1,8,4,3,6,5,7,2
for counter-rotation , locate #1 (if marked) ,going in a clockwise rotation 1,2,7,5,6,3,4,8,
both dist turn in the same direction, clockwise. Only the crankshaft turns reversed

Sorry to revive this thread back from the dead, but it's about the only one I can find online that relates to the situation that I'm in.

Quick back-story: bought a '64 Hatteras 34 Sportfish with non-running engines. Engines are not original to the boat and appear to be ~1975 Pleasurecraft 454 big blocks (GM). Engines were partially dismantled when I got them with random parts missing...such as spark plug wires. Rebuilt starboard cylinder heads and was in the process of trying to fire up these old engines when I came across a bunch of things that don't seem to add up.

My port engine is LH (CW) rotation. The Pleasurecraft model/serial number tag states that it has a 1-2-7-5-6-3-4-8 firing order. This contradicts EVERYTHING I have ever read about a GM 454 engine - marine or automotive.

My starboard engine is RH (CCW) rotation. The Pleasurecraft model/serial number tag states that it has a 1-8-4-3-6-5-7-2 firing order. Again, another contradiction.

The third contradiction is this, and I believe it makes the above two "issues" go away. My distributor rotates COUNTER-CLOCKWISE, which contradicts every service manual I have ever read on the GM 454 engine - marine or automotive. Since I have just about gone crazy with this I believe that since my distributor rotates in the opposite direction than it should, my LH and RH engines should have reverse firing orders (the ones I stated above) to what every manual and mechanic has told me.

Does this seem accurate?

Note: All rotations were viewed from the rear of the engine looking forward. Distributor rotation was viewed standing at the rear of the engines looking down.

If your reference is correct, your descriptions are contradictory: a LH engine has the flywheel spinning CCW, a RH engine spins CW....and to clarify - when viewed from the flywheel , looking towards the balancer.

Regarding the distributors - do both rotate CCW or just one? normal builds for the reverse rotation (RH) use gears between the cam and crank so that both distributors spin CW.

Pleasurecraft is relatively new in association with Crusader - maybe you have newer repowers?

Based on your history, it is possible somebody hacked up something somewhere - not likely but possible....

Another tidbit that could help - what are the model numbers for the gears?

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

It would be best to start a new and fresh thread regarding your topic.

terrawombat said:

Sorry to revive this thread back from the dead, but it's about the only one I can find online that relates to the situation that I'm in.

Quick back-story: bought a '64 Hatteras 34 Sportfish with non-running engines. Engines are not original to the boat and appear to be ~1975 Pleasurecraft 454 big blocks (GM). Engines were partially dismantled when I got them with random parts missing...such as spark plug wires. Rebuilt starboard cylinder heads and was in the process of trying to fire up these old engines when I came across a bunch of things that don't seem to add up.

My port engine is LH (CW) rotation.
A Std LH Rotation engine turns CCW when veiwed from the flywheel end.
Most straight shaft Port side engines are Std LH Rotation.


The Pleasurecraft model/serial number tag states that it has a 1-2-7-5-6-3-4-8 firing order. This contradicts EVERYTHING I have ever read about a GM 454 engine - marine or automotive.

My starboard engine is RH (CCW) rotation.
A REV RH Rotation engine turns CW when viewed from the flywheel end.
Most straight shaft Stbd side engines are REV RH Rotation.

The Pleasurecraft model/serial number tag states that it has a 1-8-4-3-6-5-7-2 firing order. Again, another contradiction.

The third contradiction is this, and I believe it makes the above two "issues" go away. My distributor rotates COUNTER-CLOCKWISE, which contradicts every service manual I have ever read on the GM 454 engine - marine or automotive.
The companies that Marinized GM's V-8 engines did not re-design the oil pumps, nor did they change the oil pump direction.
So..... in order to operate the oil pump, both the RH and LH engines turn the distributor in the same CW direction.
This is achieved by the design of the camshaft "drive" gear and the distributor's "driven" gear helical gear cut.



Since I have just about gone crazy with this I believe that since my distributor rotates in the opposite direction than it should, my LH and RH engines should have reverse firing orders (the ones I stated above) to what every manual and mechanic has told me.

The standard LH rotation engine firing order is simply reversed for the REV RH rotation engine.
Either begins with #1 cylinder.

Does this seem accurate?

Note: All rotations were viewed from the rear of the engine looking forward. Distributor rotation was viewed standing at the rear of the engines looking down.
That would be correct!

Click to expand...

As said, it would be best if you were to start a new thread in the appropriate forum.
Copy this over to the new thread if you want to.


.

Sorry - you are both correct. I mixed up my CW and CCW.

Port engine CCW/LH. This matches up with the engine model number.

Starboard engine CW/RH. This matches up with the engine model number.

BOTH distributors rotate counter-clockwise. No clue if the distributors are original to the engine or not. All I know is that they're electronic (no points) Prestolite-type.

Started a new thread in the Pleasurecraft forum: http://www.marineengine.com/boat-fo...ng-CCW-Opposite-of-normal&p=531453#post531453