HamadUP

I spent the whole afternoon adjusting the bellhousing using the offset dowel pins, and this is how it measures now :

1- 12 o'clock : 0
2- 3 o'clock : +.008
3- 6 o'clock : +.008
4- 9 o'clock : .0

So based on what I read here in this forum I'm .004 out of round (.008/2=.004) which should be OK for a Tremec TKO, but when I read a PDF document made by Tremec, they are calling for .0025 maximum, so which one of them is correct?

I spent around 6 hours of work just to achieve these numbers, so I hope I'll be good to go!

GT's 78

According to what I understand about it you have .008 vertical run out and .008 horizonal run out. The formula is 12 o'clock - 6 o'clock = run out and 3 o'clock - 9 o'clock = run out. Your tolerance is max .005 run out.

73, Dark Blue 454

I assume you're negative at either the 3 or 6 o'clock postion,..right?

FKING1

My TKO 600 install tolerance was +or - .005.
As I interpret your readings from the center you are + or - .004 and are good.
I was + or - .006 and installed that way. Wasn't going to mess with .001.

GT's 78

I humbly disagree. If there was a way (which there isn't) to perfectly center the dial indicator to the pilot bushing you could only be .00025 max out on top and .00025 max on bottom which would be a total of .005 run out. You can't perfectly center the dial indicator with the magnetic base to the crank but it doesn't really matter, when you spin the crank (as long as you dont move the base) your just measuring the difference between top and bottom which would give you your total run out (max .005). Also I'm guessing that he may have zero'd his indicator for each measurement when you probably should spin the full 360 when taking the measurements. Lets say you mount your indicator and zero it in with about .002 measurement at the 12 0'clock position. If the bellhousing was perfectly centered you would get a .002 all the way around. The part about dividing by 2 is the amount of correction needed to move toward center. If you are .008 out to the bottom side then you would need to move .004 to the center to be perfect.

HamadUP

OK, I did some further adjustments to the offset dowel pins and now I have :

1- 12 o'clock : 0
2- 3 o'clock : 0
3- 6 o'clock : +.005
4- 9 o'clock : +.004

Thats the maximum I can do, thats for a total runout of about .0025 which should be OK according to Tremec's manual, that 5 sp. conversion job is really taking A LOT of my time and effort!

HamadUP

No, both positive figures.

73, Dark Blue 454

Ahh,..should have read closer,..I thought yoou were positive at both the 3 o'clock and 9 o'clock positions.

gkull

So you are at .002 left and .0025 down. Are your offset dowels orientated the same? If they are I would loosen the 4 bell housing bolts and rotate the dowels both less than 45 degrees to lift towards 12 and right towards 3:00. retighten the bolts and re zero the dial and measure again.

Once you understand the relationship of the offset being just another cam lobe and always moving them together it is easy.

I did a post on how I bent the magnetic base arm to easy position the dial when locked onto the flywheel.

Just because something says the max allowable is 2.5 out I would not do it. It loads the tranny input staft to the pilot bearing.

Shark Racer

Thinking about swapping the 700R4 in the 78 for a T45 or TKO... maybe I'll have to do it at your place.

pws69

Modern math.......

HamadUP

I've been fighting it for few days now and I'm spending 4-5 hours on it almost daily!, doing the whole thing alone is also a pain. I'll just leave it with what it is right now as long as I'm with in the recommended tolerances, I just don't have the talent (nor the physical ability!) to get that thing exactly on the centerline of the crankshaft.

TPIShark

gkull

If you are doing it by yourself I totally understand! For doing it at all and not paying a guy like me $85 per hour

To the jerks that can't see why it is 1/2. You have to set the dial to "Zero" as a reference point. When it actually is .0025 down at the top (12) and down .0025 down from exact center of the crank shaft at (6)

Shark Racer. Come on over I would help you do the swap. I did mine here at home.

Shark Racer

It's probably been a while since you've seen one of these with a full interior.

I'm going to take you up on that. Might be next year. Going to overhaul third member this year.

The only things that really scare me on the job are hanging the pedals and dialing in the bellhousing.

GT's 78

If I didn't have the correct understanding of it why do you feel the need to be a ***** about it.

pws69

Wasn't being a "*****" - and nothing about the understanding - just questioning the incorrect math....

69 Chevy

The TKO and more modern trannys have a tapered roller bearing front bearing that has no side to side tolerance and therefore is much less forgiving than a Muncie which has a ball bearing front bearing.

redvetracr

are you using a new reproduction #621 bellhousing?

GT's 78

I put in to many zero's I see that now. Sorry for pricking you.