Flywheel Condition

RonD2 · Post by **RonD2** » Sat Jan 25, 2020 7:03 pm

I have an early bell-housing set-up in my M38 using a 97-tooth flywheel.

The mounting bolt holes are dished (chewed) out. From what I can tell researching this isn't a good thing.

Rookie question please: should I be looking for a new flywheel?

Thank you!

Post by **wesk** » Sat Jan 25, 2020 7:53 pm

I would.

RonD2 · Post by **RonD2** » Sat Jan 25, 2020 8:06 pm

Thanks Wes.

At this point I probably ought to tally the cost and consider switching to a proper M38 set-up.....a 124 or 129 tooth flywheel with the later sealed bell housing and matching rear engine plate. Also means a different starter motor.

I'm pretty sure I'm missing something.....

ChuckW · Post by **ChuckW** » Sat Jan 25, 2020 9:15 pm

Do you think having a machine shop spot-face those areas around the bolt holes would be a viable repair? I don't know how it would effect the balance, bolt torque, etc.

Post by **wesk** » Sun Jan 26, 2020 12:15 am

Chuck I wouldn't trust the flywheel to true up on runout. There's a lot of evidence of loose flywheel there.l That means she waddled around on loose bolts and most if not all the bolt bores are worn as well.

There are quite a few issues to sort out if you start swapping flywheels and bell housings.

Starter drive pinions must match the size and tooth count of the flywheel ring gear being used. Note that the 129 tooth flywheel will not fit all the early bellhousings. It is to large in diameter.

Note starter mounting bolt diameter differences.

4x4M38 · Post by **4x4M38** » Sun Jan 26, 2020 7:50 am

Go for it Ron! 10 bolt bell housing, round nose starter and 129 tooth flywheel!!

jnissen · Post by **jnissen** » Mon Jan 27, 2020 3:08 pm

I agree to look for another flywheel. Even facing off that area it looks like there was enough movement that the bolt holes are starting to look wallered out. Use new attchment hardware regardless. This is one area I would not skimp.

RonD2 · Post by **RonD2** » Tue Jan 28, 2020 8:27 pm

I see my future......sourcing more parts....

RonD2 · Post by **RonD2** » Wed Feb 05, 2020 9:46 pm

Well...I've got what looks like a pretty nice take-off late M38 bell housing inbound along with a NOS 6-bolt inspection cover and a NOS late engine plate. Have to fabricate a cork gasket for the inspection cover.

I've located, have been eye-balling, and almost ready to pull the trigger on a NOS 129-tooth flywheel kit. Will have to take my crankshaft back to the machinist to have the crank flange drilled and reamed for the straight dowel bolts. And because it's a NOS (virgin) flywheel I'm also going to ask the machinist if it should be balanced with the crankshaft.

After that, all that's left is to find a a decent 12V MDU-7004 starter. So far it looks easier said than done.

On second thought, I still have to research if the nearly-new clutch pressure plate and disk that I had on the 97-tooth flywheel will bolt up to the 129-tooth flywheel and do the job.

Also need to find a pair of those special dowel bolts to mate the bell-housing to the engine.

Probably forgetting other stuff too.......

Post by **wesk** » Thu Feb 06, 2020 12:29 am

You know you could have just replaced the ring gear on your old flywheel with a 129 tooth and not worried about drilling and balancing a new complete flywheel assembly! The original basic flywheel without bushing and ring gear is the same WO# A1441, ORD# 8677008. The Basic flywheels only change was the straight dowell bolts.

The ring gears alone usually run around $40

RonD2 · Post by **RonD2** » Thu Feb 06, 2020 8:12 am

Thanks Wes, I wish I was that lucky.

The photo of my flywheel at the top of this post shows the mounting bolt holes are wallowed out and not repairable. Expert opinion said I need a new flywheel.

I'm thinking of recycling the old flywheel into a shop stool by welding a short pipe and old tractor seat on the top and bolting some casters on the bottom.

Just my speed...

Post by **wesk** » Thu Feb 06, 2020 10:58 am

I know your old one was junk. What I didn't make clear enough above is you could have picked up a good used tapered dowell bolt flywheel with any of the old wide tooth counts and then put a new ring gear on it. Would cost a lot less in work & money then avenue you are using. However if the engine is already torn down & getting an overhaul your avenue will work.

RonD2 · Post by **RonD2** » Thu Feb 06, 2020 1:56 pm

In the middle of an overhaul so it's all good.

RonD2 · Post by **RonD2** » Sun Feb 09, 2020 4:48 pm

Received a very nice late M38 take-off bell housing marked 804306 and a NOS rear engine plate and inspection cover from Matt @ QTM:

Any idea what this threaded hole is for? I couldn't find anything about it searching the forum or the M38 Reference Guide.

RonD2 · Post by **RonD2** » Sun Feb 09, 2020 5:00 pm

The backing plate came missing the three pieces of angle iron reinforcing brackets. More parts to search for......