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My flywheel has had worn teeth in certain areas around the circumference since day one. I got tired of the sporadic chattering when starting, so I found a replacement flywheel last spring and had it blasted and resurfaced. It is 146 tooth, has 8 mounting holes and a thicker outer area on the engine side, but no thicker than the center area where the flywheel mounts to the crankshaft. The flywheel I'm removing is also 146 tooth, has 6 mounting holes but is thinner on the outer engine side. Anyway, I attempted to install the replacement and encountered a great deal of difficulty-it didn't rub anywhere but was extremely difficult to turn the engine by hand in order to tighten the flywheel bolts. Once I got those tightened, I decided to engage the starter before I moved on to installing the clutch. The starter didn't engage, but locked in place and flamed out! Not good, so I pulled that flywheel back out, thinking it was not for an M37, and ordered a new one. That one arrived, NOS 1968 still in Cosmolene, and the NSN matches, so I know I've got the correct flywheel, right? Well, comparing flywheels shows the NOS wheel matches the replacement that I was installing to begin with, with the thicker outer area on the engine side, which again, doesn't appear to be rubbing anywhere in the bellhousing. I will mention again that my M37 was converted to 12v in order to pose my question: Has anyone else had this experience with replacing the flywheel, or when converting to a 12v starter? Perhaps the starter nose cone is contacting the thicker outer surface of the flywheel?

I will give it another go this weekend-any and all brainstorming is appreciated!
Thanks,
Gary

The first thought that comes to mind is why did you replace the flywheel if you only had a bad ring gear? You are aware that a new ring gear can be installed on your original flywheel I guess.

Hey Crew! New Guy here. I too would go the ring gear route. Being a truckdriver and a cheap one at that, this is the way I would try and go. Any good machine/speed/custom shop can do this for you!!

Hey, Charles! We have to remember that some of our friends on this forum are young whipper-snappers with full heads of curly hair who have never heard of press-fit ring gears. It's those of us whose hair has either turned white or fallen out that know about things like that.

One of my funniest moments at work was when this young guy( a friend of the shop's owner) was trying to get a ring gear on a flywheel. He was beating it, pushing it around the work bench and sweraing a blue streak "they gave me the wrong one, it doesn't fit!". I just looked at him and very calmly said "you know you have to heat it up first, right!" Needless to say he was quite red in the face for a while. You gotta love those people who think they know everything... except for some common sense.

Lifer wrote:Hey, Charles! We have to remember that some of our friends on this forum are young whipper-snappers with full heads of curly hair who have never heard of press-fit ring gears. It's those of us whose hair has either turned white or fallen out that know about things like that.

Well I know what group I fall in, I always tell my barber just to do the best he can with what he has left to work with, it's getting now where I think he should give a discount cause his job is getting so easy.

flobble wrote:One of my funniest moments at work was when this young guy( a friend of the shop's owner) was trying to get a ring gear on a flywheel. He was beating it, pushing it around the work bench and sweraing a blue streak "they gave me the wrong one, it doesn't fit!". I just looked at him and very calmly said "you know you have to heat it up first, right!" Needless to say he was quite red in the face for a while. You gotta love those people who think they know everything... except for some common sense.

We heat the ring gear in an oven & cool the flywheel in the fridge. Have a good spot cleared on the bench so you can work fast when both are ready. Drops right on, it's really quite a simple job to do once you learn how.

Thanks for all the replies-I wish I WAS a young whipper snapper, and yes, I know about replacing just the flywheel teeth. I'm not a skilled welder, still getting up to speed with my MIG, so I decided on a new flywheel to make absolutely sure I had the correct one, instead of trying to heat and MIG a new ring into place (apartment living, you know).

I'm going to try again-this time w/o the starter mounted. If all clearances are ok, then I'll see if I can drop in the starter and go from there. I just can't see that the flywheel is the real issue here based on all my measurements and comparisons-it could be the 12v starter.
Stay tuned....
Gary

Gary,
From what I understand there is no welding involved. It is just a tight fit. By heating the ring in an oven it expands some and by putting the flywheel in the freezer it shrinks a tad and then they are assembled. When both come to the same temperature... they won't come apart.

Good luck with the swap.

My 2c
Mark

No welding involved, after heating the new ring in an oven along with cooling the flywheel, you can drop the new ring right into place. When it cools, it will be tight as a banjo string.

Do you have the original engine and trans combo? Or has your been replaced with say an automatic? If so you have a flex plate inplace of the flywheel, inwhich case the ring gear is welded to the plate. If in fact you do have the original flywheel you simply cut the old gear off . Heat up the new gear and drop it on to the flywheel. Let cool and instal the flywheel. Very simple process. I am concerned in that you stated the one removed had six bolt where as the new has eight bolts. Sound to me like someone has replaced the engine.

Thanks again. My last response wasn't too clear. I understand the heat-ring process but thought some tack welds would also be required. Original equipment all, as far as I can tell. The lone oddity is the 6-hole flywheel that needs attention-the crankshaft end is 8-hole.
More to follow,
Gary