Bellhousing Alignment Readings

[cv2065]

Hey guys. Getting some Saturday morning bellhousing alignment action going and needed to get some advice. Once completed, my readings are as follows:

12 o'clock = 0
3 o'clock = +4
6 o'clock = +4
9 o'clock = 0

I ran this twice to ensure that I ended up at zero and could duplicate my readings without error, and was good to go. My 12 o'clock zero was actually 3 o'clock, but I don't think it matters where you start. I've tried to find some info around the TKO600 tolerances, but am finding some conflicting stuff so thought I'd ask you guys. Are these readings good to go as is or do I need some kind of offset dowels?

101278

[Sigurd]

According to the article here you are OK. I assume 4 is 0.004". It states: If your number is greater than .005”, you’re outside of the tolerance allowed by Tremec.

https://shiftsst.com/articles/bellhousing-dial-in/

[cv2065]

According to the article here you are OK. I assume 4 is 0.004". It states: If your number is greater than .005”, you’re outside of the tolerance allowed by Tremec.

https://shiftsst.com/articles/bellhousing-dial-in/

Thanks Sigurd! Was just reading the same that you take half the distance of your readings, which I would be at 0.002" if I'm reading this correctly.

[OnlyAndy]

I would say you are golden. I am trying to get my bell dialed in for TKO 600 on SBC and cannot get close. I am old school and have never heard of this requirement before and none of my "old friends" have either. They say "Just Bolt It On...." It must be my old man technique or cheap indicator,, likely both. I have the off set dowels and a new indicator coming so I hope to solve this one soon. .005 is a pretty small tolerance.

[cv2065]

I would say you are golden. I am trying to get my bell dialed in for TKO 600 on SBC and cannot get close. I am old school and have never heard of this requirement before and none of my "old friends" have either. They say "Just Bolt It On...." It must be my old man technique or cheap indicator,, likely both. I have the off set dowels and a new indicator coming so I hope to solve this one soon. .005 is a pretty small tolerance.

I think its because the old Muncie 4 speeds and bronze bushings did not need the tighter tolerances of roller bearings. I think they were a little more able to adapt to minor slop in the rotation. When rotating the crank, I took it real slow as to not risk moving the magnet off point and screwing up the readings.

[OnlyAndy]

I thought I had it a couple weeks ago and told a couple buddies via text... "I Got It"..... Was ready to button everything up and put engine trans in for last time until one of them said "Are you Sure"? Then,,, I wasn't. All apart to check it AGAIN and could not get consistant numbers. I walk away for days and even weeks at a time when I get to the dreaded "Frustration over Load Level". I know its the mag base and indicator,,,, lots of trouble getting it right. Spent 2+ hours out there today ( with new .021 off set dowels ) and got the vertical 12-6 axsis to .004 ,,, and the horizontal 3-9 axsis to .005. I am ready to call it DONE.... But, have a new ( better? ) indicator and base coming next week to check One,,, Last,,, Time.... Good thing I have no deadline like SEMA to get this done.

[cv2065]

I thought I had it a couple weeks ago and told a couple buddies via text... "I Got It"..... Was ready to button everything up and put engine trans in for last time until one of them said "Are you Sure"? Then,,, I wasn't. All apart to check it AGAIN and could not get consistant numbers. I walk away for days and even weeks at a time when I get to the dreaded "Frustration over Load Level". I know its the mag base and indicator,,,, lots of trouble getting it right. Spent 2+ hours out there today ( with new .021 off set dowels ) and got the vertical 12-6 axsis to .004 ,,, and the horizontal 3-9 axsis to .005. I am ready to call it DONE.... But, have a new ( better? ) indicator and base coming next week to check One,,, Last,,, Time.... Good thing I have no deadline like SEMA to get this done.

Took me a while to get the base right as well. That has to be the most frustrating part. I was looking at one of those Browell alignment tools as a backup, but one, its expensive, and two, you have to unbolt the flywheel.

[CraigS]

CV in another thread you mention an aluminum bell. Do you need to check that? I am aware that the steel safety bells need to be checked mainly because they are kind of crudely made. While it can't hurt to check, I didn't think it was needed w/ an aluminum bell.

[cv2065]

CV in another thread you mention an aluminum bell. Do you need to check that? I am aware that the steel safety bells need to be checked mainly because they are kind of crudely made. While it can't hurt to check, I didn't think it was needed w/ an aluminum bell.

Wasn’t completely sure, but thought I’d check anyway. I had read that if you upgrade anything in the sequence, new engine, flywheel, trans or bell, that you should check.

[edwardb]

...I am aware that the steel safety bells need to be checked mainly because they are kind of crudely made...

Maybe that was true in the past, I don't know. But wouldn't say that at all for the QuickTime bells I've used. They're nice quality and very cleanly made and finished. Should be for how much they cost. :eek: The three I've used all measured easily within spec. But still doesn't hurt to check. Haven't had to find out for myself, but apparently Tremec won't honor their warranty unless the bell alignment is confirmed in spec.

[NAZ]

Part of assembling an engine and trans is to ensure concentricity specs are met. Doesn't matter the material the bell housing is made from. Everything that is machined is manufactured to a +/- tolerance and these variations around a nominal value can stack up and make the overall variation larger than any one single component.

This is especially true if you are using a remanufactured engine as one of the common machining steps is line boring the mains which can significantly shift the crank center-line in relation to the dowel pins that align the bell housing. Tremec has a fairly tight alignment spec so it is prudent to check.

[CraigS]

Thanks CV and EdwardB. I learned something here for sure.

[OnlyAndy]

I am learning TOO. Everything I am working with is NEW. Everything. But I did buy an aluminum GM "621" bell housing which is probably a china knock off. I noticed after MANY tries and many on-off's with bell housing that some of the mount holes were different size. Why would they do that??? The smaller holes prevented the off-set dowels from doing what they are supposed to do. I have struggled way too long on this and if I don't get it today, Really get it, I'm going to order a GOOD Lakewood or Quick Time bell and be done with it.

[NAZ]

This is a performance car that you will push hard at times even if only traversing a freeway onramp. A scatter shield is a great investment in safety even if you don't plan to race. Look how close that clutch is to your body parts (and your passenger's) and think about what might happen if the clutch failed during a one to two shift at WFO playing with your new toy.

And don't tell us that you won't drive it hard even if only just from a stop light -- you're not building a Prius so don't expect us to believe you're only going to putt around the block and never get after it.

[OnlyAndy]

Busted..... While I DON'T intend to get wild and crazy, not to say I would not jump on it from time to time..... Went to order a Lakewood Bell and now I don't know which # to get..... GMPP L31 350 w/ Tremac 600 11" clutch... Hate to order wrong one,,,, need to do more research....

[NAZ]

I didn't realize this is a SBC application. If so, I have a Quick Time that was test ran only and now setting in my swap meet parts storage. I swapped the TKO 600 for a Powerglide so won't be using it. I'll make you a great deal on.

[OnlyAndy]

NAZ, would be interested in your Bell. I need to buy one and a good, barely used one could be a good deal for me. Now, I hardly know how to post a comment on this forum so not sure how to como with you outside this site.