[PunchT37]

Does the beveled side of the teeth on a flywheel go towards the engine or the trans?


I just realized my old engine with the factory wheel has the bevels towards the trans. I have had no trouble with starting of this motor for 30 years. Factory and IMI starter.


New engine has PRW wheel. Bevel is towards the engine. I have had nothing but trouble with intermittent clashing with a RobbMc starter. No matter the shim pack. Hmmm. What gives?

[steve25]

The bevel goes on the motor side to allow a smoother engagement and release of the starter drive Teeth and far less ware to both gears!

[Gary H]

Also, in addition to what Steve 25 said, the flywheel won't go on backwards. The holes won't line up.

[steve25]

Well, you mean atleast a stock one and some aftermarket ones with the flare around the mounting hole lip, since it will not sit flush.

[b-man]

Those clever Pontiac engineers.

The one offset bolt hole in that six bolt flange always does the trick.

[1968GTO421]

Originally Posted by PunchT37

Does the beveled side of the teeth on a flywheel go towards the engine or the trans?


I just realized my old engine with the factory wheel has the bevels towards the trans. I have had no trouble with starting of this motor for 30 years. Factory and IMI starter.


New engine has PRW wheel. Bevel is towards the engine. I have had nothing but trouble with intermittent clashing with a RobbMc starter. No matter the shim pack. Hmmm. What gives?

Originally Posted by steve25

The bevel goes on the motor side to allow a smoother engagement and release of the starter drive Teeth and far less ware to both gears!

Sounds like OP has the beveled teeth correctly facing the engine. Sounds like the starter may need to be checked for appropriate dimensions, alignment or bolts. A better mind than mine needs to chime in on this.

[adynes]

How far is the starter pinion from the ring gear in the 'at rest' position? For instance, Summit mini starter instructions specify 0.100" +-0.040.

I have a billet flywheel that positions the ring gear .200" further away compared to the OEM, and caused some issues.

[Sirrotica]

Originally Posted by Gary H

Also, in addition to what Steve 25 said, the flywheel won't go on backwards. The holes won't line up.

The ring gear can absolutely be installed backwards on a manual flywheel if it were changed sometime during the life of the car before the OP bought it. And yes the bevel should face the front of the car.

I would hazard a guess that the PRW flywheel is out of spec as far as diameter, or pitch of the ring gear teeth. Even though the chinese can copy our engineering, and machining, doesn't mean they can copy it correctly.

I have no idea of why you went with a PRW flywheel, but it may be time to put the two side by side and really compare if they are in fact the same, I'd be willing to bet the problem lies in the execution of the manufacturing/engineering of your new flywheel.

FWIW, is if your starter is an OEM style, be sure it has the block to starter brace installed. It safeguards the block casting from snapping off the bolt bosses and rendering the block useless, as well as stopping the starter from trying to twist off of the axis of the crankshaft. Starter bolts can, and do snap off on GM cars. The hard fragile cast iron bolt bosses can also snap off without the starter brace. Removing a broken starter bolt out of the block isn't usually high on the priority list of jobs I'd like to do. Fixing someone else's failed attempt of re drilling the hole off center is even worse, been there, done that.

Below is a failed GM starter boss that snapped off because someone didn't bother to re install the starter brace:



Is it common, no probably not common, but it does happen. No more Pontiac blocks are going to be made by GM, so for the little bit of work required to use the brace, I feel it's worth the effort to use it, YMMV.

[Entropy11]

I have the PRW flywheel on mine. I couldn’t get my Summit mini starter to engage enough of the width of the ring gear no matter what. Engagement was less than 1/4 of the ring gear width. I read of others having issues on other forums with Summit starters possibly having less travel so I deceived to swap mine out.

I did try slightly machining the aluminum block that the starter mounts in so it would mount “deeper” into the aluminum block to give more depth, but there wasn’t enough meat in that block to make enough of a difference.

I grabbed a Powermaster XS starter and that solved my problems. Well, it at least gave me the minimum engagement I wanted.

[PunchT37]

The point is, either flywheel goes on 1 way. BUT, one has the bevels one way and the other the opposite. I got my buddy toinite to take some pics of his `78 400 wheel and his PRW wheel. Both of those don`t appear to have the beveled teeth.

[adynes]

Looks like the RobbMC instructions specify 1/16 - 3/16 end gap.

My Powermaster/PRW billet flywheel combo had ~.25" end gap until I removed the starters internal 1/16" spacer, which brought it to ~3/16". It would intermittently grind, even with proper gear tooth backlash, so I tried an extra starter to block shim, and it hasn't done it since, fingers crossed. If it happens again I'm going to take the starter apart and try to space the pinion out closer.

[adynes]

My thinking is that 'End Gap' is a fairly critical dimension, and the acceptable range probably varies depending on starter type/design. If too large, the pinion may be spinning too fast to engage by the time it reaches the ring gear. Check yours and let us know what you find. Aren't aftermarket parts great?