Bellhousing alignment.
Printed From: TheAMCForum.com
Category: The Garage
Forum Name: Transmission & Drivetrain
Forum Description: If it's between the engine and wheels, it goes here
URL: https://theamcforum.com/forum/forum_posts.asp?TID=89933
Printed Date: Apr/24/2024 at 4:58am
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Topic: Bellhousing alignment.
Posted By: Javelin69
Subject: Bellhousing alignment.
Date Posted: Sep/23/2017 at 11:00pm
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I've got a 390 & T-10 Javelin I've had many years. Put a couple clutches in it no problem. Several years ago I had the motor rebuilt and since have had issues with pilot bushings. Finally figured out the input shaft was worn so I had a custom bushing made undersized and things worked out pretty well. Now I just had the trans gone thru and at this time had the input shaft resurfaced to factory size. I told the guy who is reinstalling it about my bushing issues suggesting he check the Bellhousing alignment. Today he calls Telling me that it's 50 thou out of concentric (he did not check parallel). My questions are these: -how could it be that far out and not give trouble before the engine work? -suppose something could have changed because of the engine rebuild? -the tsm states runout can be changed by changing face alignment as long as .010 isn't exceeded for either. Is it possible shimming could correct my issue? -outside of replacing the bell, any ideas to correct this? -this seems so much more than what others call misalignment should I suspect a flaw in his measuring? |
Replies:
Posted By: purple72Gremlin
Date Posted: Sep/23/2017 at 11:43pm
| have the dowel pins??? |
Posted By: Javelin69
Date Posted: Sep/24/2017 at 8:09am
| The pins are in. If my math is correct 50 thou is 1/20th of an inch. Hard to believe if they were defective it could be out that much. |
Posted By: 1948kaiser
Date Posted: Sep/24/2017 at 9:05am
| is the block plate on when checking this? |
Posted By: Raccoonman
Date Posted: Sep/24/2017 at 9:14am
| I'm thinking in the other direction. My suspicion would fall on the crankshaft being ground off center, throwing the bushing bore out of concentricity. The rest of the physical dimensions can't change as they're never modified. Check the radial run-out of the bushing bore. |
Posted By: Javelin69
Date Posted: Sep/24/2017 at 9:22am
| When you say that about the crank, do you mean when it was turned during the rebuild that the journals somehow were ground offset, or the bushing bore was never properly located? I did notice the bushing bore seemed a little rough. Could that have happened when the crank was turned? |
Posted By: Red Devil
Date Posted: Sep/24/2017 at 10:04am
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Check parallelism first. Paint, debris, surface defects, etc. on block, block plate or bell can throw off the parallel alignment which changes the concentric alignment. Assume the 0.050" was TIR? Check and adjust concentric alignment only after making sure parallelism is in spec.(a good shop would have done this). Mine was out on an aftermarket bell and needed shims to correct parallelism and modified alignment sleeves to correct the concentricity. If parts are still at the machine shop, best to get them to machine the parts to suit, if you're confident in the shop. Hope this helps, RD |
Posted By: Javelin69
Date Posted: Sep/24/2017 at 10:23am
| What did you use for sleeves? |
Posted By: 6PakBee
Date Posted: Sep/24/2017 at 10:26am
That's the million dollar question right there. 0.025" misalignment is still a lot but much different than 0.050". ------------- Roger Gazur 1969 'B' Scheme SC/Rambler 1970 RWB 4-spd Machine 1970 Sonic Silver auto AMX All project cars. Forum Cockroach |
Red Devil wrote:Posted By: Red Devil
Date Posted: Sep/24/2017 at 10:33am
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I ground the stock sleeves on one side to allow the bell to move toward centre until had alignment right with bolts torqued. Then drilled holes in the flange of the bell and into the block to fit smaller dowel pins for easier alignment in the future. Some vendors may sell offset dowel sleeves, but not sure who? Could check with Jody's Transmission? If it's at the machine shop, they should be able to align it and machine for small dowels - but make sure they check parallel alignment first. Parallelism can be corrected by machining the face of the bell or the block, depending which is off. There is some variation block-to-block, so always best to check. Hope this helps,RD
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Posted By: Javelin69
Date Posted: Sep/24/2017 at 10:45am
| I'll check but I think it's 50 total. |
Posted By: Lyle
Date Posted: Sep/24/2017 at 9:36pm
| If the shafts are parallel and concentric you can determine if the block or bell is wrong. For a long term solution it would be best to take the offending part, block or bell, machine oversize, press or thread sleeve and machine the holes in the correct location. Then you don't have to worry about custom step dowels, changing engines/transmissions/clutch or converter in the future. Your machine shop should be able to do this with little expense if they have already determined the offset. |
Posted By: Javelin69
Date Posted: Sep/25/2017 at 7:53am
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It's being done in the auto shop at a tech school, so I'm not sure they have the resources to do that. I also don't know what sort of shop to Inquire about a service like that. |