New engine flywheel from old doesnt fit coupler?

[LAC_STS]

I was trying to swap out my OMC 5.7 engine with a new one today.

The guy at the place I bought my engine said the old flywheel would fit but I think that the old engine is a car engine and thats why it has a different flywheel on it.


Anyways the old flywheel was too big. I went and got a new flywheel from Napa and it fit. the new one (the one that fits) has a 2" hole in the middle. The bolt pattern is around the whole but Im talking about the hole in the center of the flywheel.


Since I cant use the old flywheel and the coupler bolts to the flywheel the coupler doesnt fit now either.

So I need to get a coupler. I have found a bunch online but they dont say what the bolt patter is. Here on Iboats I have found two different ones for my year style OMC Cobra engine.

This is the one we pulled off the old engine. I know because it looks brand new and has the number on it.

http://www.iboats.com/Engine-Coupler-Sierra/dm/*******.254080367--**********.703697158--view_id.270543

http://www.iboats.com/Engine-Coupler-for-Volvo-Penta-3858437-1-3853917-OMC-Sterndrive-Cobra-984290-986120-Sierra/dm/*******.254080367--**********.703697158--view_id.270574



The part numbers are the same but one ends in a 1 and the other in a 2.

Does anyone know if the second one that ends in a 2 is the right part? I need one that bolts up to a flywheel with a 2" center hole and a Cobra outdrive on the other side.


Thanks

 

[Bondo]

Re: New engine flywheel from old doesnt fit coupler?

Ayuh,... The 2" hole in the middle is meaningless...

Chevy flywheels come in 2 bolt pattern,... 3" for 86,+ Newer,+ 3, 1/2" for 85,+ Earlier...
They also come in 2 sizes,... 12",+ 14"...

Now,... What have you got,+ what do you Need...

 

[zbnutcase]

Re: New engine flywheel from old doesnt fit coupler?

Does the new engine have a 1 piece or 2 piece rear main seal?? That is the only thing that determines what coupler you need.

 

[zbnutcase]

Re: New engine flywheel from old doesnt fit coupler?

If one piece seal you need #984290, two piece#983902

 

[LAC_STS]

Re: New engine flywheel from old doesnt fit coupler?

I will be at my house where the paperwork on the engine is which says if it is 1 or 2 pc.

Which one is 983902?

Is it one of the ones I linked?

The 984290 one is the other one that I dont have right now so I was thinking it was that one because those are the only two on here that say they are for my engine.

This one is the one I have now.
http://www.iboats.com/Engine-Coupler-Sierra/dm/*******.254080367--**********.703697158--view_id.270543

I will measure the flywheel when I get home.

 

[LAC_STS]

Re: New engine flywheel from old doesnt fit coupler?

Oh yea,

I looked all over the new engines block trying to find a serial number or model number.

All I found was 10054727 On the back of the block above where the flywheel goes.

I googled it and it appears to be a casting number.

Where do I look for the model and serial numbers?

 

[Alpheus]

Re: New engine flywheel from old doesnt fit coupler?

10054727 = 350, 86 and up, 2 or 4 bolt main, one piece rear main seal, some made in Canada.


You got a 1 piece rear main seal. Now what came with your boat? This is most likely your problem. Need a coupler for new style flywheel...

 

[LAC_STS]

Re: New engine flywheel from old doesnt fit coupler?

Ok Here are the flywheels and the coupler I got off the boat.

I measured them both and both of the flywheels are 14". You can see how the bolt pattern is way different though.

The old flywheel would not fit the new engine but the new flywheel fit the new engine but now the coupler wont fit the new flywheel so I need to get a new coupler.

 

[LAC_STS]

Re: New engine flywheel from old doesnt fit coupler?

Sorry if this is a dumb question but since they are both 14" flywheels how do I measure the bolt pattern?

If I can measure the bolt pattern to the new flywheel that fits the new engine then I will know what the bolt pattern of the coupler has to be.

 

[Bondo]

Re: New engine flywheel from old doesnt fit coupler?

Chevy flywheels come in 2 bolt pattern,... 3" for 86,+ Newer,+ 3, 1/2" for 85,+ Earlier...

Ayuh,.... I gave you that answer at the top of this thread...

 

[LAC_STS]

Re: New engine flywheel from old doesnt fit coupler?

But how do I measure the bolt pattern? And both engines are newer than 86.

The old one is an 89 and the new one is a 88.

 

[LAC_STS]

Re: New engine flywheel from old doesnt fit coupler?

Disregard everything everyone has said except Bond-O. He gave you the correct answer.

Ok I'm just gonna go to a marina that is local and deals in OMC stuff and give them the part number for the coupler that I linked and see if they have one in stock.

I think the price here on Iboats is pretty good but I have borrowed a forklift and A frame and have to give it back soon so I need it ASAP.




Thank you everyone.

 

[LAC_STS]

Re: New engine flywheel from old doesnt fit coupler?

The new one in the pics is the one that fits the new engine crank.

the old rusted one in the pics is the one I took off of the old engine that fits the coupler.


The coupler does not fit the new flywheel which fits the new engine.


Sucks too because it looks brand new (coupler).


So basically I need to make sure I get the right coupler that fits the new flywheel.

I assume the new one is the smaller bolt pattern since the center hole is smaller.