Marine Camshaft???

[Ostsideend]

Hy guys,
i'm still working on my reversion problem.

Got a brand new First Mate MARINE 5,7 roller camshaft longblock and assembled it with my "old" parts.

The engine is still revesing water through the exhaust.

I did change everything of the attached components. Manifold, elbow, reiser, ignition complete, intake manifold (fresh to raw water cooling) from other boats or got it new.

There is now only left the First Mate marine longblock as the problem maker.

Pulled the camshaft out.

It shows following casting number: 471 4 YA and it shows C1 D1

Is this a camshaft for marine use?
Where can i compare casting numbers of camshafts?

Thanks a lot
Oliver

 

[WizeOne]

Re: Marine Camshaft???

Best to call your engine supplier. Who knows what camshaft they used. The numbers you posted are probably from a specific cam supplier with no way to tell by the numbers.

 

[Ostsideend]

Re: Marine Camshaft???

Best to call your engine supplier. Who knows what camshaft they used. The numbers you posted are probably from a specific cam supplier with no way to tell by the numbers.

I dont think that First Mate will say: Oh sorry put the wrong type in we'll send a new block to germany...

Oliver

 

[WizeOne]

Re: Marine Camshaft???

I dont think that First Mate will say: Oh sorry put the wrong type in we'll send a new block to germany...

Oliver

Well of course it is not easy to give usable advice when we do not even know from where you hail! Be that as it may, they might not admit to a wrong cam but you are certainly within your rights to ask what the specific specs are on the cam they gave you.

You could then take those numbers and compare them to marine suitable cam specs and possibly get a proper one on your own.

 

[Ostsideend]

Re: Marine Camshaft???

You are right.
I'll ask.

But to what i can compare the dats if i'll get them?

Is there a data sheet available to compare marine camshafts with?

Best regards
Oliver

 

[WizeOne]

Re: Marine Camshaft???

You are right.
I'll ask.

But to what i can compare the dats if i'll get them?

Is there a data sheet available to compare marine camshafts with?

Best regards
Oliver

Unfortunately I have not yet learned to speak cam-ese. Just get all the numbers (like lift, ie exhaust and intake, duration, lobe seperation angle, etc, and post them here. Someone will either have the knowledge or be able to get it.

No doubt, with all you've said, you've got big time cam overlap reversion.

 

[CharlieB]

Re: Marine Camshaft???

I've been reading all of your postings from the beginning.

Reversion problems, different engines, different exhaust manifolds, in the water, or on the hose.

It's NOT the cam.

Start looking at the attitude/mounting angle of your engine.

The exhaust elbow mounting flange to the exhaust manifold is to be at a slight angle with the rear of the flange slightly lower than the front, making the distance that the water must travel slightly higher before being able to go over back into the manifold.

Has the boat been refitted or weight added to the front enough to change the position in the water?

 

[WizeOne]

Re: Marine Camshaft???

I've been reading all of your postings from the beginning.

Reversion problems, different engines, different exhaust manifolds, in the water, or on the hose.

It's NOT the cam.

Start looking at the attitude/mounting angle of your engine.

The exhaust elbow mounting flange to the exhaust manifold is to be at a slight angle with the rear of the flange slightly lower than the front, making the distance that the water must travel slightly higher before being able to go over back into the manifold.

Has the boat been refitted or weight added to the front enough to change the position in the water?

There is nothing in his post that indicates any changes in the configuration of his boat/motor positition. If that is the case then shame on him, otherwize, the cam remain highly suspect.

 

[Ostsideend]

Re: Marine Camshaft???

....Start looking at the attitude/mounting angle of your engine.

....Has the boat been refitted or weight added to the front enough to change the position in the water?

Hi CharlieB,
everything i added to the boat is sitting in the back. (2 additional battaries, larger charger and fresh water heater)
The reiser-elbow is the design with an downangle of 13? or so with a small hink in it before the water can rund down into the manifolds.

All the last test have been done with the motor sitting on a wooden frame on the floor with the same effekt. I took care about that the position of the motor will be slightely down angled. (the frame was used for many other engine tests before with no problems)

With best regards
Oliver

 

[Ostsideend]

Re: Marine Camshaft???

There is nothing in his post that indicates any changes in the configuration of his boat/motor positition. If that is the case then shame on him, otherwize, the cam remain highly suspect.

Hi WizeOne,
I would be pleased if there is something stupid i did not recognize what will blame me. Yust stopping me from assembling and dissassembling all the time.

Hope i can dig in here on comming thuesday all camshaft datas i can gauge.

With best regards
Oliver

 

[CharlieB]

Re: Marine Camshaft???

Perhaps I misunderstood your postings.

The reversion began with THIS engine and NOT the original that has been replaced?

Then yes, I would suspect the cam.

Pull one exhaust out or off, and remove the rocker cover, install degree wheel and measure the opening and closing, calculate the centerline of both then calculate the separation

 

[Ostsideend]

Re: Marine Camshaft???

Perhaps I misunderstood your postings.

The reversion began with THIS engine and NOT the original that has been replaced?

Then yes, I would suspect the cam.

Pull one exhaust out or off, and remove the rocker cover, install degree wheel and measure the opening and closing, calculate the centerline of both then calculate the separation

Hi CharlieB,
The engine before could have had the same problem. But it was the same maker and the same model.

The reversion was recognized in detail at this engine first due to checking carefully in detail before placing it back into the boat.

All things we could check on the old engine seems to come from reversion.

It's not a small spray back we are talking about, it's a quater of a waterglass full of water per manifold after ideling for 1 or 2 minutes.

I cant tell you how this pi...es me off after weeks of working on this iron pig.

I'll check the camshaft. She's already out. And compare her with an mercruiser marine shaft. Will put the datas in here and hope to your recommondation.
Oliver

 

[CharlieB]

Re: Marine Camshaft???

Also check what ratio rocker arms are installed.

If someone installed 1.6's in place of 1.5's to gain a little more valve lift it would also have the effect of increasing flow at overlap, fine above 3500 but could create your reversion at lower RPM.

 

[Mkos1980]

Re: Marine Camshaft???

Its going to have to be a pretty big cam for reversion. I'm running 218/228 525/525 112 LSA which is "alot" bigger then stock and I'm having no issues at idle or cruising. And I'm running stock manifolds and risers! I'd look into something else.

 

[Mkos1980]

Re: Marine Camshaft???

Are you positive your riser to manfiold sealing surface is true?

 

[Ostsideend]

Re: Marine Camshaft???

Yes sealings are all fine. Changed to several different manifold makers always the same effekt on both sides.

I checked 3 camshafts Merc, first mate and Federal mogul. Firstmate is a lot different. Ich check in detail the merc again today. Let you know what i did find out.

I'll check the leaver ratio as well. Good idea!

Oliver

 

[Ostsideend]

Re: Marine Camshaft???

Also check what ratio rocker arms are installed.

If someone installed 1.6's in place of 1.5's to gain a little more valve lift it would also have the effect of increasing flow at overlap, fine above 3500 but could create your reversion at lower RPM.

Rocker arms are 1:1,5
The exhaust camlift is 7,9mm on First Mate and 7,35mm on Mercruiser. Overlap guaged directly on the camshaft is 55? on Firstmate and 40? on Mercruiser. Cam distance I/O is 112? on Firstmate and 109? on Mercruiser.

Federal Mogul (speed pro) is not identical but very close to Mercruiser
Got a second Mercruiser camshaft. Its almost identical to the first Mercruiser shaft.

I'll change the shaft to Mercruiser and test it.

Oliver

 

[CharlieB]

Re: Marine Camshaft???

Overlap guaged directly on the camshaft is 55? on Firstmate and 40? on Mercruiser.


Overlap and LSA (Lobe Separation Angle) are two different animals.

While LSA is the current technical term for figuring overlap, two camshafts with the same LSA but different valve opening duration, a longer duration cam may exhibit reversion and the shorter duration cam will not.
Is this the First Mate engine?

5.7 Liter GM 350
"Stroker" 383
Peak HP: 405 Torque: 450ft/lbs
Roller
.503 intake .510 exhaust lift, 224 intake 230 exhaust duration at .050

224/230 may be fine in a high perf application jet boat with water cooled 28 to 30 inch tube headers, but may have reversion problems with stock replacement manifolds.