flywheel housing shims? late production diamond block.

[mike657894]

When I took my motor apart there were no shims between the housing and block. I have seen them advertised. When Putting the motor back together I had heard about aligning the flywheel housing but I saw these large locator pins that made it so the fly wheel housing would not be able to move around on the bolts.




Were all fly wheel housings located by pins? Should I have some shims between the block and housing? Is there a general or regular amount of shims needed? If this is a problem can it be fixed with engine in car or do I need to pull it out?

[rotorwrench]

I would put a dial indicator on it just for my own curiosity. I like things to be properly aligned. If it needs no shims then that's a big Yippee!

[Patrick L.]

The shims go in the top bell bolt holes. As RW said, a dial indicator or other indictor should be used to check for straightness. The measurements at 12:00-3:00 and 9:00 should be within about .006-.007".

[Railcarmover]

Dial the flywheel housing to the crankshaft..it insures the trans input shaft and crankshaft are parallel,helps stop clutch chatter

[Mulletwagon]

Dialing in the flywheel housing is a must. Do not omit this critical check. Clutch chatter after installing a new disk/pressure plate is very disappointing.

[Bob C]

Sponsored Links (Register now to hide all advertisements)

Don’t forget to account for crank thrust. Better if engine sitting with front pointing down.

[Kohnke Rebabbitting]

9:00, and 3:00 should read alike.

12:00 and 6:00 should read a like.

All 4 points have to be a like.

This is all accomplished, with shims on the two top bolt holes.

Set 9 & 3 first, and 12 & 6 next.

Shim amounts on both sides will likely, not be the same, but all for points will be square, and that is what your after.

You also should be using shim thickness, as littled as .001, to .002 thousandths.

Herm.

[mike657894]

The clutch doesn't chatter. Does this mean Im ok...for now? herm am I correct in saying that you are using head shelac as the shim? how thick is pressed head shellac? and are within .0002 on that gauge it looks like your splitting the thousandth? Is that block straighter than a standard one because of machining? my block is stamped 40 or 41. Were late crate motors straight enough? On some motors is this more for modern amounts of balanced smoothness? And am I ok to leave it till I do my bottom end rebuild down the road? I dont think my car vibrates too much for the design.




Edit: winters coming . probably should do it then

[Railcarmover]

If you're careful you can do it with the engine horizontal,truck engines have been done like that for years..you rotate the crank slowly..

[mike657894]

my engine comes out easy. no pinch. taking the trans back might be more work.

[Mulletwagon]

Originally Posted by Kohnke Rebabbitting

9:00, and 3:00 should read alike.

12:00 and 6:00 should read a like.

All 4 points have to be a like.

This is all accomplished, with shims on the two top bolt holes.

Set 9 & 3 first, and 12 & 6 next.

Shim amounts on both sides will likely, not be the same, but all for points will be square, and that is what your after.

You also should be using shim thickness, as littled as .001, to .002 thousandths.

Herm.

Understand how the shims affect 1200/0600 tolerance, not sure how 0900/0300 is adjusted. Thinking the shims are only placed on the upper through bolts and not the side bolts. Welcome clarification since I expect to do this drill when the cooler weather makes it to Florida.

[Kohnke Rebabbitting]

Originally Posted by Mulletwagon

Understand how the shims affect 1200/0600 tolerance, not sure how 0900/0300 is adjusted. Thinking the shims are only placed on the upper through bolts and not the side bolts. Welcome clarification since I expect to do this drill when the cooler weather makes it to Florida.

Ok, again, you have to adjust 9 & 3, first. More then likely you will have a different thickness of shims under each bolt. What you are doing is twisting the housing casting, to get the same reading, on each side.

Then you use plus, or minus shims, in equal amounts to get 12, and 6 to read the same.

Top, and bottom may, or may not read the same as either side, but what your after is 4 level points to bolt to, so the bell housing bolts square, and the pilot is straight, and NO bind in the pilot shaft.

Now, all good out comes depend on cranks where they belong.
Flywheels ground correctly.
Pressure plates rebuilt, surfaced, and bolts adjusted, ect.

Herm.

[Kohnke Rebabbitting]

Originally Posted by mike657894

The clutch doesn't chatter. Does this mean Im ok...for now? herm am I correct in saying that you are using head shelac as the shim? how thick is pressed head shellac? and are within .0002 on that gauge it looks like your splitting the thousandth? Is that block straighter than a standard one because of machining? my block is stamped 40 or 41. Were late crate motors straight enough? On some motors is this more for modern amounts of balanced smoothness? And am I ok to leave it till I do my bottom end rebuild down the road? I dont think my car vibrates too much for the design.

Edit: winters coming . probably should do it then

1. The chatter may, or may not come later.

2. No shellac for shims. The shellac is for the gasket, and the 4 flywheel bolts, as the threads go into the crankcase, they would leak oil into the flywheel housing.
3. The dial indicator is in .001 increments. Yes you can split in 1/2 thousandths.
4. I am not sure what you are asking, but I would think all factory pour, and aligned blocks, would be the same.

Thanks,

Herm.

[john charlton]

On the production line the shims were fitted to compensate for the housing gasket thickness I doubt they were dialled in they relied on uniformity of manufacture . I have changed out cracked housings over the years without dialling as I do not have the equiptment . I bolt the housing hard up with gasket and goo installed .I then fit the shims they are generally a tightish slip fit sometimes a gentle pry with a large screwdriver assists I know dialling in is the way to go preferably but in practise I get no chatter even with the old style "spoked" clutch disc .

John in sunny Suffolk County England .

[Tom Endy]

As mentioned above the purpose of the two shims is to compensate for the thickness of the gasket located at the lower portion of the clutch housing where the other four mounting bolts are located.

The two shims as provided by most suppliers are .010 thick. However the gasket thickness is less than that and the actual thickness is all over the map depending on the supplier.

My theory is that the gasket should be thicker than the shims as it will crush down when the bolts are torqued, the shims will not. For this reason I purchased a roll of gasket material from NAPA that is .015 thick and made my own clutch housing gaskets.

Another thing to consider if you are going to check housing alignment with a dial indictor gauge, it should be done with all six bolts evenly torqued. This becomes difficult because generally when this is done the top two bolts at the ears are not installed because they also hold the accelerator mechanism, and the mounting bolts are too long to be installed without the mechanism. For this reason I have a set of shorter bolts I use.

Attached is a document that describes clutch housing alignment.

Tom Endy

[5lugnuts]

Is it possible to notice an out of alignment condition by measuring the torque needed to turn the tail shaft of the transmission in high gear with the clutch disengaged in the car and not under engine load as opposed to the torque necessary to turn the tail shaft in high gear when the transmission is out of the car on the bench?

If the alignment were not correct would there be a noticeable difference?

[Mulletwagon]

Originally Posted by Tom Endy

As mentioned above the purpose of the two shims is to compensate for the thickness of the gasket located at the lower portion of the clutch housing where the other four mounting bolts are located.

The two shims as provided by most suppliers are .010 thick. However the gasket thickness is less than that and the actual thickness is all over the map depending on the supplier.

My theory is that the gasket should be thicker than the shims as it will crush down when the bolts are torqued, the shims will not. For this reason I purchased a roll of gasket material from NAPA that is .015 thick and made my own clutch housing gaskets.

Another thing to consider if you are going to check housing alignment with a dial indictor gauge, it should be done with all six bolts evenly torqued. This becomes difficult because generally when this is done the top two bolts at the ears are not installed because they also hold the accelerator mechanism, and the mounting bolts are too long to be installed without the mechanism. For this reason I have a set of shorter bolts I use.

Attached is a document that describes clutch housing alignment.

Tom Endy

Interesting !! The attached article suggests only the 0900/1200/0300 reference points need to be within .006 inch. The 0600 point will be pulled into alignment by the clutch housing is the suggestion.

[mike657894]

.010 is the standard thickness? do you have to sand them down or add more if your not at the correct position with those?

[Railcarmover]

you can use what you need,no gasket with sealer and horseshoes,horseshoes and gasket,gasket and no horseshoes,sealer and no horseshoes..went through five housing before I found one uncracked and true.