Good evening all. I just got done measuring my bell housing alignment and the bore is about .013” out latterly and the face is about .012” out as well. The face I measured just inside the mounting bolt holes as I clearly don’t have the factory disc tool to measure with. I read the manual and it talks about shimming the bell and or the trans to bring back the face into spec of <.007”. Seems doable but wanted to double check if modern tech nowadays has come up with a better method. Also read the lateral alignment can be fixed with custom offset dowles if face alignment doesn’t bring it back into spec. don’t flame me on this as I didn’t even know bellhousing alignment was a thing until last Friday and most google searches just bring up lateral alignment using offset dowls that are common in 1/2” size. bell housing -.012” -.008” .003” 0”
You can shim to correct the face but it is better to have it blanchard ground. Offset dowels are avail to correct being out of concentric. Try to get it within .005 What are those numbers of .012 .008 .003 and 0 at the bottom of your post? Some of your measurements may be due to an out of round bore
I have looked and looked and cannot find 3/8” offset dowels, I checked for .375 too. Guess I’ll keep looking. the numbers at the bottom are the measurements of the face. Zero being the point at which the dial Indicator was zerod and the other numbers are the difference.
Damn, I'm not finding 3/8" either, they can be made on a lathe ez enough though if you know anyone who has access to one.
Blanchard grinding is the way to go for the face, provided you can find a job shop to do it. Clean up the bell and stone off the block mounting face, I think it will take about the same amount of time to do the job as it will to write up the bill and take your money. The register diameter is not that bad, assuming your .013 number is TIR, total indicator reading. TIR should be halved.
Can you elaborate on TIR and what that is? The .013” was the reading I got running the dial indicator around the bore for the transmission. The manual talked about something like that, but I cannot rap my head around what it was trying to say.
Good replies, not a surprise here. But all the years (25+) I’ve been doing yblocks, this is the first time I’ve seen a bellhousing alignment question. I’ve never had a problem. Either with the truck bells or the passenger car. Not to say some weren’t right, I just never heard of it. You might try over at http://forums.y-blocksforever.com/default.aspx. it’s kind of a pain to join, you need to contact Ted Eaton at https://www.eatonbalancing.com/2001/03/20/contact-us/ it’s how he keeps the spammers out. But you’ll get answers there if anywhere for yblocks.
Appreciate it. Had the question because the rebuilt trans I stuck in the car bangs out of second gear when engine braking… and the trans I replaced was doing the same thing. After doing basic external checks I pulled the trans this weekend to measure alignment and you can see what I got here.
Your maximum reading from zero was .013, if you shift the register diameter of the bell half the total indicator reading you will center it. But really I’m not so sure the .0065 that it’s off the c/l is all that bad, of course zero tolerance is the best but I think the ball bearing on the input shaft will tolerate that .0065. Have you looked inside either of your transmissions and checked anything? It could be the second gear synchronizer is warn and causing the trans to pop out of second gear. The photo below is of the inside of the slider that lets you select 1st and 2nd, the rounded teeth are the issue. Next photo shows the teeth on the gear that mesh with the slider when shifting. I can’t say for sure what your problem is but you just might go to the expense of correcting the bell housing and still have your problem.
If you have the transmission out I would pull it apart and check for end play on the main/output and counter shafts, engagement teeth on 2nd gear slider/hub and synchros. If you're not sure of what you replaced then this is the time to make sure once and for all. Make notes, don't expect to remember the details. I would correct the bellhousing because while .0015" more than max spec, it's 30% more than the .005" max recommended runout. You'll only kick yourself if you don't and the problem persists. Do it right and you don't have to do it again!
Here’s what the inside looks like. I need to do some reading because all I can say is “yup it’s all there.” The Input shaft does had a small amount of in and out play, and I can move the 2nd gear on the output shaft a tiny bit forward, but other then that…. How much play should the syncros have? Can can slide forward and back a fair amount.
Well guys I think I found the issue. 2/3 slider and sleeve does not appear to be a proper match. See this link for pictures https://www.jalopyjournal.com/forum/threads/t86-pops-out-of-2nd.1322235/#post-15341780
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