I have searched threads and online regarding bellhousing alignment for manual transmissions and also watched a couple of You Tube videos on how to perform.
All of the articles deal with aftermarket bellhousings, and don't offer much on the original bellhousing. So I am going to put it out here for discussion. My setup is a mildly modified SBC with less than 400 Hp, plan on using the original bellhousing (with starter mounting) with front stock motor mounts and a newly rebuilt M20 Muncie transmission.
Is it necessary to check bellhousing alignment for this setup?
How did the factory ensure bellhousing alignment on the 60's muscle cars?
The problem that I am experiencing the setup of the dial indicator and trying to configure the dial indicator to check the readings . I am using this type of dial indicator. (Which was recommended on the Summit You Tube).
Hopefully someone has used this setup and can shed some light for me, this my first time attempting left me quite frustrated but today is a new day!!
I've done this application many times without complications. The alignment pins that are standard on the block is all you should need. If everything is in alignment the four speed should slide completely in the pilot bearing without having to draw up using the four bolts into the bellhousing
When using all original type parts especially, we just assembled them together and went on with it. Unless there was a problem after that for some reason, which would be pretty rare, we were good to go.
I've used both the dial indicator and the Browell tool. Personally I prefer the indicator. So it can go either way.
Just because the factory didn't use a dial indicator doesn't make it right. They relied on whatever tolerances were in machining the individual parts. And there was some kind of quality inspection on the parts, maybe not 100% though. You're not talking just the bellhousing, it's the block and the crankshaft too.
The reason that indicator checking of the assembly became common for hot rodders was because Lakewood bellhousings are so much worse than stock bellhousings due to the way they are manufactured. Factory bellhousings have all the holes 100% machined - a Lakewood housing does not! The big hole is just a precision flame cut, but that precision flame cut is far from the accuracy of a boring bar in a milling machine.
Years ago when Detroit Diesel was part of GM, I was involved as a customer on a run of several dozen bellhousings on new engines that were far beyond GM specs. Also found out that GM specs were not as tight as SAE specs. GM and the DD dealer fixed them all at their expense - but they didn't pay for the broken hydraulic pump gearboxes their problems caused. Luckily we found the problem in time to limit that to a half dozen. So GM doesn't/didn't always make and check things to their specs all the time.
Well with a little help from a friend we managed to get the dial indicator setup and took the following readings.
We first made a couple of trial readings and we found that at 11' o clock was our negative reading and we set the Dial to zero and made that our starting point. 2 o'clock reading was 23 thousandths, 5 o'clock read 54 thousandths
and 8 o'clock read 28 thousandths.
Besides the readings here is what I found, the one bellhousing pin was damaged. Even though the damage is on the tapered end of the pin, it appears that it is deformed. I am thinking this might be causing me my problems. I am first going to try and get a OEM replacement pin and re-do the readings.
I have no idea why this pin was damaged or how it happened, and I am a little disappointed that I wasn't informed by the engine builder who did not point this out to me.
If you are using factory parts than all you need to do is bolt it together,. You would never see a dial indicator on a production line.
I have a 56 Belair 2 dr HT. I removed the 265 ci engine and 3 speed manual and installed a 61 348 Tri-power stroker. The original cast iron bell housing, 168 tooth flywheel, clutch and pressure plate, starter and a M-21 Muncie all bolted right up to the engine. Everything was aligned, no pressure required to stab the tranny. I bought engine front side mounts, which positioned the engine/bell housing in the original position. I had to change only the worn-out pilot bushing and adapt the clutch cross shaft tube mounting on the engine, a simple 1" alum plate. Chuck