I stripped a bolt earlier today trying to put my flywheel on.

The engine is a zz454 crate motor and I am trying to install the recommended flywheel (GM 14096987 specific to the one piece seal ext balance).

Crank collar seems to be too tight. When I removed the Flex plate it took me several hours, lots of cussing, and a big pry bar.

In my earlier attempt to install the flywheel, I thought I would use the bolts to pull it onto the crank. It seemed to work for awhile; but then I stripped a bolt.

Lucky for me I was not using the high strength bolts and did not damaged the threads on the crank. I ran a tap thru the hole and tried another bolt. All seems to be good.

Does anyone know what the clearance should be on the Flywheel to crank for a GEN VI BBC?

I am thinking maybe I should try sanding/grinding the flywheel hole a bit.

Any ideas other than using the bolts (do not want to press my luck)?

TIA

 

Whatever you do DON'T grind the inside flange of the flywheel to make it fit! They are a snug fit on purpose, that way the flexplate/flywheel is properly centered with no slop. That said, it should go on with just a little effort by hand. This is probably obvious, but are you getting the dowel pin and corresponding hole in the flywheel lined up correctly?

If so, time to get the micrometers out and take some measurements on the crank flange and flywheel. It sounds like you narrowly averted disaster the first time. I wouldn't try the bolt trick again.

 

I'm thinkin' there has to be a slight high spot.

 

Get a little bit of heat in to the flywheel immediately before putting it on?

 

Pre-heat oven to 250 degrees. Put the flywheel in the oven 10 minutes one side then turn it over and repeat for additional 10 minutes.

Seriously; heating the flywheel will expand the metal. You should be able to re-install by hand. You should also use a thread locking compound.

 

100% good advice - in an ideal workshop enviroment it would be great also to pack ice around the end of the crankshaft to achieve a 1/10 of a thou' or so of additional shrinkage

 

Good advice.

Unfortunately, I do not have access to an oven where the engine is.

I will mic the crank and flywheel.

If I find any high spots I will polish them out with some emery cloth.

Otherwise, I think I might try and polish .001 - .0015 off of the flywheel flange.

I wish I knew what the Clearance specs are.

It seems to me that in the past I had no trouble putting the flywheel on my 427 and other engines; but that was a very long time ago. Red Line on this engine is only 5500 so is this that critical?

I will also try some ice on the crank collar and some silicone spray on the flywheel flange hole.

Once I get it lined up with the dowel pin and the bolts started, I will try to tap it on with a 4x4 centered over the flywheel flange. Periodically I will torque the bolts to 20 ft lbs. This should help pull it on and let me know if I am making progress and or getting skewed.

I would hope that 20 ft. lbs. of torque would not strip any threads. I will use some low grade/strength bolts again. Once on and seated, I will replace with ARP flywheel bolts and use LocTite.

I am getting anxious to just slam this on at all cost; but I guess I will think about it over the weekend and keep checking back for other's thoughts on my flywheel problem.

Thanks again for all of the input.

 

I found a High spot on the back side of the flywheel flange hole. There was about .032" lip that went about 40% of the circumference.

Don't know how that made it thru GM's quality control. It was a brand new GM flywheel.

Anyway, I was able to polish it off and install the flywheel.

tip: easy way to locate high spots is to use your finger nail and run it over the surface. Once you find one you can use a mic to measure it.