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Bell Housing dial in

31K views 23 replies 17 participants last post by  v8440 
#1 ·
This is no fun at all doing by yer lonesome. Especially since it was .023 out from perfect and I only had .007 offset dowels. At least I had the motor out and and on hoist and blocks.

That's what happens after line honing the block I suppose. The offset was such that I needed to raise the housing strait up.

Long story short, I ended up with a 7/16-20 shoulder bolt drilled and tapped through the Lakewood Housing into the top block bell housing boss.

After blocking and shimming the housing up from the bottom I was able to get it dialed in at .001 and drilled a pilot hole followed by the the proper bit for tapping.

Buttoned it all up and I got lucky. The .001 didn't change.

The story ain't over. I ordered the .021 offset dowels from http://www.robbmcperformance.com/products/dowels.html
which are much better than the .007 style that I had.

A 2 hour job crammed into 12...and I still have to redo the whole thing after the new offset dowels get here.

BTW - GREAT CUSTOMER SERVICE FROM robbmcperformance.com and on SUNDAY , NO LESS.
 
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#3 ·
Thanks,

I haven't seen the parallel spec tolerance or the method to measure it.

Do you have the specs or a link to them?

How do I correct it if out of tolerance? Machine shop?
 
#4 ·
Here is a picture reference for checking the parallel alignment. Parallel alignment is corrected by installing shims between the bellhousing and engine block.

Standard Automotive Bellhousing Alignment Specifications:
Concentric: +/-.005” or .010” TIR
Parallel: +/-.001” or .002” TIR

Hi-Performance 7,500+ RPM Bellhousing Alignment Specifications:
Concentric: +/-.0025” or .005” TIR
Parallel: +/-.0005” or .001” TIR
 

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#5 ·
Thanks Jody. It's a great confidence builder to be able to nail these specs down and achieve them on my projects.

From the pic it appears that the mag base is mounted on the flywheel which is rotated do perform the check just outside the opening in the bell.
 
#6 ·
Here is a 5 page bellhousing alignment procedure I wrote up for the Legend700 transmission warranty. Anyone can print these 5 pages and use them for any manual transmission install.
 

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#13 ·
lots of things! premature clutch failure, excessive pilot bear wear, ruined trans input bearing, difficulty shifting under load, vibration, and broken transmission case. ever seen a trans at a swap meet with the ears broken off? this is why.
 
#16 ·
Hey guys I've got a bell housing clutch fork question, 68 chevelle 454 4-speed, I grenaded my bell housing ,m20 tranny, clutch n driveshaft, I have the new clutch 11" with the truck bell housing for a large flywheel the clutch fork / throw out bearing does not line up to the alignment tool when I installed the clutch, I've read I need some adapter plate to make a Muncie tranny fit to it as well, but do I need a different clutch fork , here's my part #"s on the bell an fork 460486 bell and fork is14066235
 
#22 ·
Google is your friend.

 
#24 ·
I've had problems with clutch disengagement on my dodge dually diesel for more than 10 years. Has a southbend dual disk sintered iron monster. This is the only thing I haven't checked. I guess when I pull it out to replace the clutch, I'd better check this. It sure would be great to find this was the problem all along, then I could solve it once and for all.
 
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