Flywheel question

texasrebel75

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Apr 6, 2009
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Need some help identifying my flywheel. On a 1984 mercuiser 350ci I/O. Books seem to indicate two different flywheels, a 14in and a 12 1/2 in.
Question is is there a way to tell which I have without pulling the engine? IE can I roll it over and count the teeth? anyone know the teeth count between the 2? in any case if you were to buy a new flywheel the only one available anymore is the 14 so I think that is it. I need to get a new starter but have to know which flywheel I am dealing with. Any help or advice is much appreciated thanks guys.
 

dubs283

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Jul 27, 2005
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Re: Flywheel question

you have to pull the motor to replace the flywheel anyways. do that and be sure of what you need instead of guessing
 

mylesm260

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Re: Flywheel question

Yup,

Go grab the serial number off you're starter and cross reference it.

The starters are different for each flywheel.
 

TilliamWe

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Dec 21, 2004
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Re: Flywheel question

rebel, the smaller diameter flywheel came into use in 1987 when GM switched to a one piece rear main seal. I believe it is a 154 tooth ring. Your engine, provided it has not been changed has the larger 168 tooth wheel.
 

Bondo

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Re: Flywheel question

Need some help identifying my flywheel.

Ayuh,.... What bolt pattern is your Starter,..??

If it's Striaght across,... You have the 12" flywheel which takes the 153 tooth ring gear...

If it's the Staggered bolt pattern,... You have the 14" flywheel with the 168 tooth ring gear...

It's the Starter mounting holes drilled in the block that determines which diameter flywheel you can run...
Some blocks are drilled for Both,... Many are Not...
 

gbeltran

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Re: Flywheel question

If you wanted a new flywheel I'd pull it anyway to see what you have, I think that's the year that Chevy changed to the one piece main seal, I don't know if it was a mid year thing or not but it would be a good idea to have the old one for comparison.
 

mkast

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Nov 6, 2002
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1,934
Re: Flywheel question

Casting number on the back of the block the flat area, top rear.
Take that number, go to www.mortec.com
 

TilliamWe

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Re: Flywheel question

..Quote:
Originally Posted by TilliamWe
rebel, the smaller diameter flywheel came into use in 1987 when GM switched to a one piece rear main seal..

not true, he could have either or......
...


Okay, then, when did the smaller flywheel come out? And in what applications is it used? And is it correct that now (since 1987 one piece rear main seal) they only use the smaller one?
Rather than just point out something you think is inaccurate, take a minute to expand and educate. Like bond-o tries to do (in his weird "ayuh" sorta way! :) ). That's what we are all here for. At least that's what I was lead to believe.
 

Rat Capri

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Re: Flywheel question

Okay, then, when did the smaller flywheel come out? And in what applications is it used?

1962, non performance style vehicles with 8",9",9 1/2" or 10" clutch

And is it correct that now (since 1987 one piece rear main seal they only use the smaller one?

no, I've seen more 14" flyweels/flexplates than 12 3/4"

Rather than just point out something you think is inaccurate, take a minute to expand and educate. Like bond-o tries to do (in his weird "ayuh" sorta way! :) ). That's what we are all here for. At least that's what I was lead to believe.

I dont think it's inaccurate , I know it is. The best way to determine what flywheel you have is to check the starter bolt pattern as noted above, if the starter mount bolts are in line with each then you need the smaller flywheel if they are staggered then you need the larger flywheel
 

TilliamWe

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Re: Flywheel question

Well, other than your holier-than-thou style, thanks for the education.
So what do most boat engines have?
 

Bondo

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Re: Flywheel question

So what do most boat engines have?

Ayuh,... Up to around the early 90s it was pretty much Either,.. Or....

14" has become the More common...
But the starter still tells the story...
 
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