Interested in knowing how many of ya'll measured your bellhousing alignment during assembly versus just bolted right up. I recognize it's obviously better to be precise and measure and if necessary use the offset dowel pins however I also would bet GM didn't do this in the old days on the assembly line. Granted I recognize all parts were new and freshly machined and further that GM was likely willing to fix the few that wore prematurely due to poor alignment. Interested in what you guys are doing today.

Thanks,
Chris

typically i bolted it up,
this last engine i had the bell checked while at the machine shop.
it was off some,(lakewood-bell).
it would not be very easy to do with the engine installed in a car..........

Never, ZERO problems with the tranny neither! ;)

Stock bellhousing...No. Aftermarket...Yes.

If you use an aftermarket scatter shield YES. Lakewood has this in their instructions for a reason. Mine was off quite a bit, not sure what the measurement was but I think I purchased .060 offset dowels and rotated them down and to the pass side. If you can afford the scatter shield you can afford a dial indicator and offset dowels.

Jerry

I just installed my lakewood scattershield and a TKO600 on to my 505, I checked mine with a finger indicator and it was .002 off, so well within reason. After the amount of money I have spent on this new trans and 505, I would be an idiot not to spend a an hour to make sure everything is spot on.

Jeff

I didnt have to in my Chevelle as I run an auto in it. I did however, align the scattersheild in my last Mustang just because it was an aftermarket piece and I understand it to be a "must do" when installing an aftermarket bell/scattersheild.

We always do a bellhousing alignment check before any transmission installation.

We also measure the flywheel thickness and set-up the clutch pivotball height in relation to the flywheel thickness.

Got it to zero~! :D

I did the alignment with a stock BH when I installed a new clutch and a rebuilt trans. I used the Centreforce clutch specs. Turned out that the trans had a flaw and having done this procedure went a long way to convincing the trans builder that it was not my screw up.

A necessity for a Lakewood, not so much for stock. My Lakewood was off .050", more than enough to cause problems.

Tom

A necessity with a TKO.

I have heard but have no proof that Mcleod has better tolerances than Lakewood. Just from what I have heard here. I have launched my Richmond as high as 6K and it is still living without being aligned. My bell was used when I got it and the register is so scratched up it was impossible to dial in.

We always do a bellhousing alignment check before any transmission installation.

We also measure the flywheel thickness and set-up the clutch pivotball height in relation to the flywheel thickness.

I did both as Jody stated with my lakewood.

We also measure the flywheel thickness and set-up the clutch pivotball height in relation to the flywheel thickness.

Any instructions on how to determine proper pivotball height with relation to flywheel thickness? I don't think I've ever seen this discussed in any detail.

Is it safe to assume that a muncie will be perfectly happy running at factory tolerances w/ a stock GM bellhousing and factory dowels? Has anyone used a GM bell and found it to need major adjustment?

Any instructions on how to determine proper pivotball height with relation to flywheel thickness? I don't think I've ever seen this discussed in any detail.

The instructions came with my CF DF clutch. It is the measurement from the flywheel friction surface to the tip of the pivot ball. Mine was off due to the difference in the new Hays flywheel and the Lakewood bellhousing. I used a McLeod adjustable ball stud to correct mine. I can't remember the exact measurement off hand though.

With all GM factory stuff you should be fine.

My Mcleod was off enough to make a difference with my TKO. All I know was it was a paint to do with the car on jackstands.

I have heard but have no proof that Mcleod has better tolerances than Lakewood. Just from what I have heard here. I have launched my Richmond as high as 6K and it is still living without being aligned. My bell was used when I got it and the register is so scratched up it was impossible to dial in.

McLeod's bellhousing are machined to tighter tolerances than any Lakewood. But, if you have an engine that has been line bored then, most likely the alignment will be off with a McLeod too.

Any instructions on how to determine proper pivotball height with relation to flywheel thickness? I don't think I've ever seen this discussed in any detail.

Is it safe to assume that a muncie will be perfectly happy running at factory tolerances w/ a stock GM bellhousing and factory dowels? Has anyone used a GM bell and found it to need major adjustment?

A flywheel thickness of .950" will have a pivotball height of 4.750". If you have a flywheel that measures .900", the pivotball height would be 4.700". This precision method will also give you the same results as the 5-7* fork tilt forward.

My stock 621 bellhousing on my '70 Chevelle was out .014" on the parallel, not every stock bellhousing has a perfect concentric reading either.

Bellhousing Specs:
Concentric: +/- .005" or .010" T.I.R.
Parallel: +/- .001" or .002" T.I.R.
T.I.R.= total indicator runout

On the flip side, many bellhousings are a perfect match to an engine with the alignment. But, we do not gamble with the bellhousing alignment and every vehicle gets checked.

I'm glad I checked mine, this is a used McCleod and I had to do some adjusting to get it within spec for a TKO600. The car works very well, no vibrations at all from the driveline.

http://i418.photobucket.com/albums/pp264/gotago396/IMG_4489.jpg

http://i418.photobucket.com/albums/pp264/gotago396/IMG_4490.jpg

My stock 621 bellhousing on my '70 Chevelle was out .014" on the parallel, not every stock bellhousing has a perfect concentric reading either.



Parallel seems like a tougher one to fix. I guess you machine the rear face of the bellhousing?

Here are the instructions for setting the pivot ball stud depth that comes with a CF Dual Friction.

http://www.centerforce.com/mediafiles/I93GM002.pdf

Parallel seems like a tougher one to fix. I guess you machine the rear face of the bellhousing?

Yes, you can machine or shim the bellhousing to correct the alignment.

I did it with my Lakewood and TKO 600 it was off quite a bit.

I'm glad I checked mine, this is a used McCleod and I had to do some adjusting to get it within spec for a TKO600. The car works very well, no vibrations at all from the driveline.

http://i418.photobucket.com/albums/pp264/gotago396/IMG_4489.jpg

http://i418.photobucket.com/albums/pp264/gotago396/IMG_4490.jpg

It appears you were .010 out at the furthest point which is within specs for the TKO. .010 is actually only .005 out, which is the worst they want it to be.

Jeff

I I also would bet GM didn't do this in the old days on the assembly line. Granted I recognize all parts were new and freshly machined and further that GM was likely willing to fix the few that wore prematurely due to poor alignment. Interested in what you guys are doing today.

Thanks,
Chris

GM supposedly attached a bell housing to the block when the crankshaft mains were line bored and bored through the bell housing to have it in perfect alignment. This may or may not be true as I have never seen any proof.

I checked the McLeod on my Nova and it did not need any adjustments. It did need the coating cleaned off the bore to get a decent reading, before cleaning the numbers were all over the place.

GM supposedly attached a bell housing to the block when the crankshaft mains were line bored and bored through the bell housing to have it in perfect alignment. This may or may not be true as I have never seen any proof.

I checked the McLeod on my Nova and it did not need any adjustments. It did need the coating cleaned off the bore to get a decent reading, before cleaning the numbers were all over the place.

If GM did it this way in the 1960s, I'd be surprised, as this hardly seems practical for a production environment. Not saying it's impossible, but it seems like an awful lot of work when you are cranking out hundreds of units per day.

I would think that they designed the block dowel locations, and input retainer hole to have a worst case tolerance stack-up that was acceptable to get the trans through the 3yr/36k warranty period.

It appears you were .010 out at the furthest point which is within specs for the TKO. .010 is actually only .005 out, which is the worst they want it to be.

Jeff

It was .014 out when I started, when I got it to .005, I thought I'd better leave well enough alone:)

When I bought my car it was known for being hard on clutches and I blew the center clean out of an almost new cf clutch,then one of the gears lost a couple of teeth.It was another year or two before I learnt about bellhousing indexing,and after I had the Lakewood bellhousing properly indexed,it made a huge difference.I went from pulling the tranny every year,to over 5 years trouble free driving.
Guy

I always do it. It is very cheep insurance.
I have a lot of machine shop experiance so it is very easy for me to do it.

Just stick a magnetic base indicator stand on the crank, set the dial indicator on the hole, and rotate the engine.

I may be a little nuttie but also check brake rotors, bicycle wheels, (almost anything that rotates), with a dial indicator.

If you have the right indicator set ups, it only takes a few minutes, and I feel better knowing if something runs true vs has a lot of run out.

Thanks for all of your thoughts, votes and responses. Well - yesterday was the day. Attached bellhousing to block and then tranny to bell. Based on the information you guys provided and my specific situation ('66 396 with 621 Bell and '67 Muncie M-21 4 speed), I did not dial this in. Bolted right on and afterwards we installed the engine and tranny back in the engine bay without incident (even with headers)! Took a few images while we were working yesterday and will post later today after I get home from work.

Chris

Stock bellhousing...No. Aftermarket...Yes.

I agree... I swapped my Muncie out for a 5-speed and a a scattershield... Had a little trouble shifting, so I pulled it apapt and it was off...

I find it ironic that a 40+ year old piece (and machining techniques) are still that much better than modern methods...

I'm wondering, how are the repro 621 bellhousings?

I would guess they're no better than the Lakewood and others, but I don't know. Anyone have experience with checking them? I'll have to start hunting for one soon if I'm looking for an original.

I've had the same lakewood scattershield for about 15 years and my cars had plenty of WOT abuse. Never checked it. It has always worked great and never any clutch or trans problems.

But if I were purchasing something new, I would check it. I just figure that in my case, if it ain't broke, and has worked for 15 years, why mess with it.

if your not going to put out the effort to dial in then at least use a modern roller pilot bearing.
the gm-diesel part has more rollers than the Moroso unit..... :)

I just finished doing my Lakewood. I first checked it with the factory dowls and it needed to go .005 to the 11 o'clock position. Since I had already purchased .007 dowls in anticipation of the Lakewood being off, I put those in figuring I would then be .002 off. After installing them I was now .012 off! Damn, must have put them in wrong. Hammered them out, turned 180 degrees and hammered them back in. (like you can really turn them with that screwdriver slot) It was now off .010 to the 5 oclock positon. WTF!!! Reinstalled stock dowls, rechecked - .005 off. Good enough for me.

I just finished doing my Lakewood. I first checked it with the factory dowls and it needed to go .005 to the 11 o'clock position. Since I had already purchased .007 dowls in anticipation of the Lakewood being off, I put those in figuring I would then be .002 off. After installing them I was now .012 off! Damn, must have put them in wrong. Hammered them out, turned 180 degrees and hammered them back in. (like you can really turn them with that screwdriver slot) It was now off .010 to the 5 oclock positon. WTF!!! Reinstalled stock dowls, rechecked - .005 off. Good enough for me.

Went through he same thing, until I cleaned the inside bore of the bell housing. Then it dialed in almost perfect with stock dowels.

I'm wondering, how are the repro 621 bellhousings?

I would guess they're no better than the Lakewood and others, but I don't know. Anyone have experience with checking them? I'll have to start hunting for one soon if I'm looking for an original.


Follow up on dmuller's comment -- Can anybody chime in here? Would be good to know if the answer is out there.

Chris

I just finished doing my Lakewood. I first checked it with the factory dowls and it needed to go .005 to the 11 o'clock position. Since I had already purchased .007 dowls in anticipation of the Lakewood being off, I put those in figuring I would then be .002 off. After installing them I was now .012 off! Damn, must have put them in wrong. Hammered them out, turned 180 degrees and hammered them back in. (like you can really turn them with that screwdriver slot) It was now off .010 to the 5 oclock positon. WTF!!! Reinstalled stock dowls, rechecked - .005 off. Good enough for me.

These dowels make aligning a bellhousing much easier:

http://www.robbmcperformance.com/products/dowels.html

I've used the RobbMc dowels... they are nice and work great !
Gary

Jody and Tom are right. Doing it by the numbers, the alignment check should be done with a steel bellhousing or a stock GM bell. My machine shop recommended exactly what Jody does. I have an OEM stock 621 bell and did not bother with alignment, mostly because I didn't have the money to buy the tools. No problems after about 10K miles. The repro 621 bells have worse alignment problems than the Lakewood. I tried one. It wouldn't even fit over the dowel pins.

The repro 621 bells have worse alignment problems than the Lakewood. I tried one. It wouldn't even fit over the dowel pins. I bought a OEM 621 on eBay. Probably paid too much, but needed it right away to get my car back on the road. No problems.

The repro 621 bells have worse alignment problems than the Lakewood. I tried one. It wouldn't even fit over the dowel pins. I bought a OEM 621 on eBay. Probably paid too much, but needed it right away to get my car back on the road. No problems.

My repro 621 was spot on. I got it from GU. My Quicktime scatter shield needed .007 offset dowels

I put a used Lakewood in my 78 Malibu, never checked it and it worked fine.

Had minor shifting problems and serious reverse-grinding problems after installing the Lakewood...2000-'08. Used McRobb dowels last time I had it out in '08. Dialed in to zero, not problems since.

This is next on my list..have a new quick time bell for a T 56..never did check a stock bell and never had any issues..but I will check this one..anyone have a copy or lnk on how to go about it..thanks

YouTube - How to Dial In a Bellhousing