Rebuilt Engine with No End Play?

[Geezer]

New engine rebuild. With the Scat crank pulley installed I have .03" end play at the crankshaft fly wheel end. I install the flywheel without any shims "0" end play. I have a dial indicator mounted to the case.
I remove the crankshaft pulley and have .03" end play both ends.
I thought the distributor drive gear was maybe loading the crank, but no it isn't. I was hoping for .003 to .006 end play with the 3 shims. This is not happening. I have .01" shims.
I have a lightened flywheel. Counter weighted crankshaft. 8 dowels.
I think maybe the mounting area depth in the flywheel is to deep? I will mic it against a stock flywheel and see if there is a difference.
Never had a no end play problem before. I know the flywheel is bottoming out against the front bearing. I will contact the fellows I got the flywheel from. I think it could be machined down, but is that a correct fix?

[bluebus86]

make sure the flywheel is really wrongly made before you alter it. as you say, check against a stock flywheel, or simply bolt a stock flywheel to the motor and see what kind of clearance there is.

there could be lots of reason why the crank is not moving, other than a bad flywheel, poorly installed bearings, dirt, broken parts, out of tolerance parts, etc....

So don't alter the flywheel unless you know it is the problem, else you could be hiding the real fault, which could result in motor destruction.

If worse case, you will need to split the case and check the guts for problems.

you say the problem goes away with the crank pulley removed. could it be the crank pulley is interfering with something?

get a stock pulley and see if that improves the situation.

as I recall, (I might be wrong, but I am pretty sure I am right) the pulley does not effect the endplay normally. The pulley does NOT have a thrust surface. sure you can measure endplay at the pulley end, but the pulley should not be altering endplay.

At this point I'd suspect the aftermarket pulley is hitting something it shouldn't

I one time had a noisy motor, drove home about 20 miles, found the pulley had lots of endplay, thought my flywheel came loose, pulled the motor, and found that when I yanked on the flywheel it moved in and out a whole bunch, but the pulley didn't move with the flywheel. I had a two piece crank, broken in a bearing journal, it was a jagged break, so the broken crank pieces meshed together, enough to get me home. Different situation, but it does show you never know what you may find.

good luck
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[vwsteve]

If you can set the end play correctly with no pulley installed, the problem is not on the flywheel end. Try a different pulley. I am not sure, but you may get this problem if the oil slinger was installed backwards on the crankshaft.

[Geezer]

I guess I didn't explain everything. The pulley is a Scat full size. I have used them before. There is a steel spacer that goes in between the oil slinger and the pulley. The oil slinger is tapered toward the pulley. I have always installed them in that direction according to the book. Otherwise the oil would come out the shaft hole.
Next I thought possibly the distributor drive gear and the brass crankshaft gear were preloading the crank. Not. The distributor drive moves with the end play with the flywheel off and the pulley off. It also moves with the pulley installed.
If the mounting area depth in the flywheel is correct I am leaning toward one of the counterweights connecting the bearing support inside the case. I have not used this brand of crankshaft before. If the flywheel is correct it means disassembly of the engine to located the problem. I am retired so time is not important and I figure it as the school of hard knocks.

[williamM]

Just add the tin or paper gasket to the crank shaft and start over.
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[KTPhil]

It's not really a "hard knock." Most of the time, engine assembly is done two or even three times to make sure all is well, especially if there has been machining or non-stock parts installed. Consider it part of the normal process toward a 100% correct and reliable build.

[Geezer]

This is not my first engine build. It is the first for this problem. I am using a 8 dowel crank and flywheel. The paper and tin stock shim is only 4 dowels. I figure it will have to come apart unless there is a problem with the flywheel.
First engine build was a 36 horse in 1969 on my 57' Oval. There have been a few since then. Biggest was a 2165 44 IDF engine. That said I am still learning new tricks.
In my manual the cut away view shows a stack of three shims against the front main bearing. I must assume if the crank counterweights are not rubbing the bearing supports the depth of the flywheel must be to deep. I am gong to the machine shop and checkout other flywheels. I will post what I find. I was a machinist for 45 years so I can measure things.

[williamM]

You might have some case issues with the balanced crank. I've also run into the "no O ring " flywheels that have been forced on causing clearance issues.

3 shims are the rule, but have taken apart long milers with 2 thick shims.

Love the retired aspect of engine building- no pressure and time to "blueprint" everything. AND nobody looking over your shoulder "are we there yet"
_________________
some days I get up and just sit and think. Some days I just sit.

opinion untempered by fact is ignorance.

Don't step in any!

[Geezer]

There seems to be a slight difference in the end of the crankshafts where the O ring seal in the flywheel goes around the end of the crankshaft.
I tried a bored out flywheel with no O ring and I have end play. I measured a few flywheels and the depth of the counter bore that mates to the end of the crankshaft seems to be a standard .375" deep.
The fix will be to open up the counter bore on the flywheel maybe .010" and retain the O ring seal, not really important as if you use a large diameter washer with sealer it won't leak. With .030" shims my end play is .005" when torqued to 225 foot pounds. I don't use lock tight, it's not a race car.
If this had not appeared it would be disassemble time to see if the counter weights were rubbing the bearing supports.

[drscope]

[vwsteve]

Something doesn't make sense. You said that without the pulley installed, you have end play and it goes away with the pulley installed.? The only things that affect end play are the crank, flywheel, front bearing, shims between flywheel and bearing, and the gasket between flywheel and crankshaft. The case has nothing to do with setting endplay. You can set endplay before you ever drop the crankshaft into the case.

[Geezer]

I have .030" end play with the pulley installed. I have to relieve the flywheel counterbore in the area of the O ring. I am having trouble locating shims. Seems everyone is out of them. I need a .008" or .007" shim to get my .005 to .006 end play. I suggest that the case does have lots to do with the end play as the main bearing is located in the case. Maybe I'm wrong?

[vwsteve]

Sounds similar to what you have to do to put a common 200 mm flywheel onto a common 64 mm crank.

[57BLITZ]

[vwsteve]

[williamM]

I think you will solve your problem by opening up the bore on the "O" ring flywheel so it mates with the "paper gasket" style crankshaft. I've got one now that will be changed to 6vt flywheel for that same reason and (of course- I need a 6vt motor for my bus.)

Keep us informed- love a happy ending.
_________________
some days I get up and just sit and think. Some days I just sit.

opinion untempered by fact is ignorance.

Don't step in any!