No shim in flywheel housing

Kevin - Illinois

Kevin - Illinois

Senior Member
Unless I'm reading it wrong there should be a couple of horse shoe shaped shims between the block and flywheel housing. When I removed my housing I found no shims. If I understand correctly the risk is breaking the housing during installation if the shims are left out. Well the housing was on there tight and nothing was cracked or broke. Was this just luck by the last person working on it? Should I buy and install shims when I put it together?
 
If everything was lined up correctly during set-up for boring the last time around, the shims should be in place to maintain paralism of the flywheel housing to the back mounting flange of the engine block. These brass or stainless steel shims are the same thickness as the half moon gasket between the flywheel housing and the engine block.
 
Its good to dial in the flywheel housing from the crankshaft; it may take more than 1 shim on each upper bolt ? This process is to keep everything in line with the crankshaft including flywheel cover, bell housing, transmission, and u-joint. Can solve vibration problems.

Ron
 
Was there a gasket between the housing and the block? If not, the builder probably used a thin layer of RTV instead of a gasket and deleted the shims.

As Glenn says, there should (typically) be shims equal to the gasket thickness. Note, though, that gaskets thicknesses vary widely.

Joe
 
The lack of the two shims can throw the clutch out of alignment and contribute to early clutch failure. It can also cause the transmission to jump out of gear. Bratton's sells the shims, they are each .010 thick. They should match the thickness of the paper gasket when crushed down that is placed between the clutch housing and the block. However, the thickness of the gasket is all over the map, depending on who is selling them. The thickness of the gasket Henry perscribed is a debatable subject.

It is best to check the alignment of the clutch housing across the top 180 degrees of the clutch housing after the gasket has been installed, the shims in place, and the all the bolts torqued down, including the two that hold the accelerator mechanism. I believe the spec is within .006. The bottom 180 will be pulled into alignment when the bell housing is installed. Some clutch housings have been whacked out of shape and cannot be aligned.

Tom Endy
 
To answer your question, I suggest that you clean the two surfaces where the shims normally are found very well before assembly of the flywheel housing to the engine. Once the four bolts are installed and torqued, use a feeler gauge to determine the thickness of shims that are required. Install the shims and then check the assembly with a dial indicator. Adjust the shims as necessary. Gar Williams
 
One of our local club members didnt put in the shims after his $3500 engine rebuild. the result was after 450 miles the oil was spraying out the rear main and it was knocking. Now, i cant blame it all on the shims not being there because there were some problems with the engine builder, but the fly wheel was not dialated in before instal. So after talking to other people in the club, we think this caused the problem.
 
Pics attached. No sealant or shims. The engine leaked oil and knocked. The clutch failed a month ago. Thanks for your comments, they make a lot of sence as to what I've been dealing with on this car. ;)
 

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Kevin - Illinois said:
Pics attached. No sealant or shims. The engine leaked oil and knocked. The clutch failed a month ago. Thanks for your comments, they make a lot of sence as to what I've been dealing with on this car. ;)
Click to expand...
The pictures reveal worse than the sealant or gasket problem. The main bolt says a lot about the rebuild. Did it even have a gasket? Where are the pins for the crank? did it have the plate under the flywheel bolts?
 
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The clutch housing shown in the right photo. Clean up the two very bottom mounting holes on both sides. Polish them with emery paper and you will more than likely find a hair line crack around one or both. This does not mean you can't use the housing, unless they are really bad, it just means it has the normal cracks. Most are found that way. My theory is that they are caused by people changing out a timing gear. They jack up the front of the engine to get the timing cover off. If the car has solid motor mounts the engine can't bend, so something has to give.

Tom Endy
 
Kevin - Illinois said:
James, I'm new at this. What is it about the main bolt that concerns you?
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The main bolt on the left is correct, the one on the right is a center/front that has been cut and re-threaded to use in the rear. Says a lot about the competency of the re-build. This is why I ask the question about the gasket and flywheel bolt plate. I believe there may be other issues here.
 
I agree with James. When I see something like that wrong bolt stuck in the rear main it tells me I'd have a cobbled together engine. For sure look everything else over and check the clearance on the front and center mains also. I took an engine apart once that had 3 of the dippers facing the wrong way.
 
I'm new at this too. Indicate what to what? Put the indicator on the back of the crank (magnetic base) and spin the crank to check the surface where the bell housing bolts up to? If you know of any pictorials of this being done, please provide me the links. Thanks
Terry


Aerocraft said:
To answer your question, I suggest that you clean the two surfaces where the shims normally are found very well before assembly of the flywheel housing to the engine. Once the four bolts are installed and torqued, use a feeler gauge to determine the thickness of shims that are required. Install the shims and then check the assembly with a dial indicator. Adjust the shims as necessary. Gar Williams
Click to expand...
 
Terry said:
I'm new at this too. Indicate what to what? Put the indicator on the back of the crank (magnetic base) and spin the crank to check the surface where the bell housing bolts up to? If you know of any pictorials of this being done, please provide me the links. Thanks
Terry
Click to expand...


tom w had some good pictures showing this. he just had them up on a previous thread. maybe try doing a search
 
Do a search in this forum for "dialing in flywheel" and the first one to appear will be by D J Moordigian on 9-9-10 at 1:15 PM.

There you will see me dialing in my flywheel housing using my K.R. Wilson crankshaft turner. Before I found this tool I made my own from a 2 foot length of flat bar stock.

If the engine isn't standing on end, you will have to be sure to push the crankshaft forward throughout the measurement (or pull it rearward)or you will mess up the numbers with the crankshaft end clearance.

Measure the top half of the housing and get it within .006" maximum. I also use my magnetic mount on the flywheel housing and put the dial indicator tip on the outside of the crankshaft flywheel flange, then turn the crank over to measure flywheel mounting runout. This should be zero if the crankshaft was correctly ground.
 
You also want to be sure you torque down all six mounting bolts, and with whatever shims you think you need behind the ears of the two mounting holes. These are the two bolts that hold the accelerrator mechanism. You will have to mount it temporarily or find shorter bolts. If you leave these two bolts untorqued, you will get a false reading. The whole effort is to find out the shim value needed. If you leave the two bolts untorqued the shims become moot.

Tom Endy
 
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