help with 82 5.7 to vortec upgrade, flywheel question

capitan828 · Nov 29, 2012

Im upgrading and old 5.7 to a newer vortec and im not sure as to which flywheel I need to use. I know I cant use the original flywheel from the old 2-piece engine because its completely different. So can I use the flywheel that came with the vortec when it was in the pickup truck? Autozone says that its 14.13" OD. Will that fit in the old 82 housing when I drop the engine in? I already ordered the necessary coupler it needs when upgrading from 2-piece to 1-piece but I just dont wanna get stuck having to stop and order another flywheel when it makes contact with the bellhousing.

Dogdave · Dec 2, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

I went through a bit of this with my rebuild. I did not go to a vortec but I can tell you from the auto world I am used to the newer vortec fly wheel has a diferant bolt pattern. As for the bell housing and transom plate. If you are changing from the log style manifolds ( pre alpha) to the new center dump you will need all alpha parts from bell housing to transom plate or the exhaust will not line up. This is not directly on your topic but I thought I would bring it up. It took me a while to compile all the right infor from everyones opinions.

81 Checkmate · Dec 3, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

I would like to know the answer also!

What is the O.D. of your old flywheel?

RogersJetboat454 · Dec 3, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

capitan828 said:
Im upgrading and old 5.7 to a newer vortec and im not sure as to which flywheel I need to use. I know I cant use the original flywheel from the old 2-piece engine because its completely different. So can I use the flywheel that came with the vortec when it was in the pickup truck? Autozone says that its 14.13" OD. Will that fit in the old 82 housing when I drop the engine in? I already ordered the necessary coupler it needs when upgrading from 2-piece to 1-piece but I just dont wanna get stuck having to stop and order another flywheel when it makes contact with the bellhousing.

You need to use the flywheel that matches what your block will accommodate for a starter. GM used both 153 tooth, and 168 tooth flywheels. A starter with its mounting bolts in a strait line is for the 153 tooth. A starter with its bolts staggered at an angle is for 168 tooth flywheels. Some blocks are drilled for both starters. Others are only drilled for one style. Both flywheels should fit in the housing, and the truck flywheel you have is no different then what Mercury would have gotten from GM.

13crazyhorse · Dec 4, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

The center holes are probably a different size. If you call Michigan Motorz they can tell you exactly what you need before you make an expensive mistake. 1-877-666-8679. They do this stuff every day.

RogersJetboat454 · Dec 4, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

13crazyhorse said:
The center holes are probably a different size.

What center holes are you talking about?
Unless he bought the engine from Michigan Motorz, they probably aren't going to be too keen on being his technical assistance help line. That's what Iboat's is for....

81 Checkmate · Dec 4, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

Rodger - I measured my flywheel last night, 1981 - 305 SB and it is a 153 tooth at 12.75 O.D.

I dont think the 14 1/8" O.D. flywheel will fit in the old housing!...... Not for sure as i could not find my housing to measure.

Thought i would throw that out there.

13crazyhorse · Dec 4, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

RogersJetboat454 said:
What center holes are you talking about?
Unless he bought the engine from Michigan Motorz, they probably aren't going to be too keen on being his technical assistance help line. That's what Iboat's is for....

I meant center hole, not center holes, my mistake excuse me. The older ones have a 2 inch and the newer ones are 2 1/2 inch. As far as Michigan Motorz is concerned they are real nice people and would probably help since they sell new flywheels also. They can tell you which wheel and which starter will work. Not everybody is a know it all like some on this site. Just trying to offer some assistance.

RogersJetboat454 · Dec 4, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

81 Checkmate said:
Rodger - I measured my flywheel last night, 1981 - 305 SB and it is a 153 tooth at 12.75 O.D.

I dont think the 14 1/8" O.D. flywheel will fit in the old housing!...... Not for sure as i could not find my housing to measure.

Thought i would throw that out there.

Yep, see if you can chase down the housing, and take a measurement. If it's not going to fit, you're gunna have to cross your fingers, and hope your block will accept a starter for a 153 tooth flywheel.

RogersJetboat454 · Dec 4, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

13crazyhorse said:
I meant center hole, not center holes, my mistake excuse me. The older ones have a 2 inch and the newer ones are 2 1/2 inch. As far as Michigan Motorz is concerned they are real nice people and would probably help since they sell new flywheels also. They can tell you which wheel and which starter will work. Not everybody is a know it all like some on this site. Just trying to offer some assistance.

Easy there buddy.... no need to get all worked up. :yield:
I asked about the "holes", because maybe you knew something we didn't.
As far as Michigan Motorz is concerned, they may be willing to answer questions, and tell him exactly what he needs. But... if it turns out his 14" flywheel fits, they probably won't be making a sale. The OP just needs to do a little bit of homework first.

Mdinz · Dec 4, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

If you look up a flywheel housing for a 1982 350, they are the same part for a 12.75 or a 14 inch flywheel. The difference is in the cover on the bottom. I presume that is for the different starter mounting locations for the two different sized flywheels.

vznx1w · Dec 4, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

I am in the middle of a similar engine swap on my 1984 Glastron.

The flywheel fits the bell housing just fine, the need to change bell housings is caused by engine coupler issues:
your old ball-shaped coupler will not mate to the smaller bolt circle of the Vortec crankshaft. If you buy the Mercruiser coupler that is designed for the new engine you will find it is a large triangular shape that will not fit in the old bell housing. Furthermore, to use the triangular coupler you not only have to buy a bell housing but also a longer driveshaft yoke in order to achieve proper spline engagement. (The triangle coupler has much shorter splines than the older model.)

The best way to avoid all this is to purchase an aftermarket coupler that is designed to couple the new crankshaft bolt circle to the geometry of your old drive. That way you can reuse your existing bell housing and driveshaft yoke.
The Sierra part number is 18-2172 http://www.marineengine.com/parts/sierra_marine/index.htm?gclid=CI3cuMzWgbQCFVCd4Aodnj8ASQ]Sierra Marine Engine Parts Catalog[/url]

Steve

81 Checkmate · Dec 5, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

Yes Steve is correct.... Found my bell housing....it will excepet the 14 1/8" flywheel as it measures 14 1/4" I.D. and the coupler is the round/bell shape.

The part number stamp on it is Mercruiser 59823

Inner Transom Plate number is 5472693 With 5402375 Stern Drive numbers......but i am having a hard time looking up those mercrusier numbers. By the pics i have a MC-1 Drive

Bondo · Dec 5, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

vznx1w said:
I am in the middle of a similar engine swap on my 1984 Glastron.

The flywheel fits the bell housing just fine, the need to change bell housings is caused by engine coupler issues:
your old ball-shaped coupler will not mate to the smaller bolt circle of the Vortec crankshaft. If you buy the Mercruiser coupler that is designed for the new engine you will find it is a large triangular shape that will not fit in the old bell housing. Furthermore, to use the triangular coupler you not only have to buy a bell housing but also a longer driveshaft yoke in order to achieve proper spline engagement. (The triangle coupler has much shorter splines than the older model.)

The best way to avoid all this is to purchase an aftermarket coupler that is designed to couple the new crankshaft bolt circle to the geometry of your old drive. That way you can reuse your existing bell housing and driveshaft yoke.
The Sierra part number is 18-2172 http://www.marineengine.com/parts/sierra_marine/index.htm?gclid=CI3cuMzWgbQCFVCd4Aodnj8ASQ]Sierra Marine Engine Parts Catalog[/url]

Steve

Ayuh,.... Welcome Aboard Steve,... Good post, 'n some Good info,... But,........

The Hi-lighted line is Bad info, 'n is Wrong...

That Only applies if yer talkin' 'bout an ole In-line GM motor, 'n drive....
The 2.5l, the 3.0l, 'n the I-6 motor... 'n only with the old MC-1 drives,...

Sometime 'round the R, or MR drive, they All went to the long input shafts...

All the other motors, 'n drives still use the 9" input shaft on the Alpha series of drives...

capitan828 · Dec 5, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

Thanks everybody for your input. My block is drilled with the staggered bolt pattern starter and im pretty sure gm only made those two options for starters. Either streight or staggered, neither is intended for a certain flywheel size. That would be up to the starter manufacturer. Im gonna measure my flywheel to see exactly what it measures.

Bondo · Dec 6, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

capitan828 said:
Thanks everybody for your input. My block is drilled with the staggered bolt pattern starter and im pretty sure gm only made those two options for starters. Either streight or staggered, neither is intended for a certain flywheel size. That would be up to the starter manufacturer. Im gonna measure my flywheel to see exactly what it measures.

Nope,... That's Wrong,....

The Staggered pattern starter will fit up to the 14" flywheel, ONLY....

'n the Straight pattern starter will marry up to the 12" flywheel, ONLY....

vznx1w · Dec 6, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

Bond-o said:
Ayuh,.... Welcome Aboard Steve,... Good post, 'n some Good info,... But,........

The Hi-lighted line is Bad info, 'n is Wrong...

That Only applies if yer talkin' 'bout an ole In-line GM motor, 'n drive....
The 2.5l, the 3.0l, 'n the I-6 motor... 'n only with the old MC-1 drives,...

Sometime 'round the R, or MR drive, they All went to the long input shafts...

All the other motors, 'n drives still use the 9" input shaft on the Alpha series of drives...

**************
Ahoy Bondo,
My boat is a 1984 Glastron 260R: it has a 5.7L GM V-8 engine, R-Drive, the short input shaft and the bell-shaped coupler. The engine has never been out of the boat before, so I am confident this is the stock configuration.

Bondo · Dec 6, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

vznx1w said:
**************
Ahoy Bondo,
My boat is a 1984 Glastron 260R: it has a 5.7L GM V-8 engine, R-Drive, the short input shaft and the bell-shaped coupler. The engine has never been out of the boat before, so I am confident this is the stock configuration.

Ayuh,... If yer drive has the 8" input shaft, it's Not original....

RogersJetboat454 · Dec 6, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

Bond-o said:
Nope,... That's Wrong,....

The Staggered pattern starter will fit up to the 14" flywheel, ONLY....

'n the Straight pattern starter will marry up to the 12" flywheel, ONLY....

+1^^^^

That would be up to the starter manufacturer.

The starter manufacturer that GM would use if this engine would be going in a car or truck would be Delco.... A division of GM...
Trust us... there is a difference.

vznx1w · Dec 6, 2012

Re: help with 82 5.7 to vortec upgrade, flywheel question

Bond-o said:
Ayuh,... If yer drive has the 8" input shaft, it's Not original....

Bondo,
The Sierra the part I recommended (above) is in their catalog described as:
"18-2172 Engine coupler: Used when replacing V6 or V8 engine with 2pc rear main seal with 3-1/2” crankshaft bolt pattern to a newer 1 pc rear main seal engine with a 3” bolt pattern."

Since the description matched what I (and Capitan828) are trying to do, I bought it. Upon arrival I have verified that it fits my new crankshaft and is otherwise dimensionally identical to my old coupler so it mates with my R drive perfectly.

It works as advertised, I don't know what else to tell you.

Steve

help with 82 5.7 to vortec upgrade, flywheel question

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