Engine: Aceeptable Tolerances for Bell Housing Dial in?

[GBC]

I recently completed dial indicating a V8 engine bell housing. I used the process found on Bob Johnstone's Resource Website following the instructions and pictures from Allan Anderson's "Dial In Procedure". I did not put the dowel pins in yet to secure the bell housing to the back of the engine block. I wanted to make sure that I was in the correct and/or acceptable tolerance range for the crankshaft to bell housing position before proceeding with that last step. I am having difficulty finding a reference for the correct/acceptable tolerances between the crankshaft to bell housing. I used the 12 o'clock, 3,6,9, markings on the bell housing. I got .004 at 12 o'clock, 0 at 3, 0 at 6, and .004 at the 9 o'clock position. If anyone is familiar with this procedure, I want to know if I should readjust the 9 and 12 o'clock positions or leave it alone? I would appreciate any advise or direction to complete this process. Thanks in advance for any assistance!

Garth Collins,
San Francisco, CA.

[DEEPNHOCK]

If you are .004" out at 9 o'clock and zero at 3 o'clock, you are within spec's ( I do not have them in fromt of me).
Same goes for 12 o'clock and 6 o'clock.

Sounds like you need to move it toward the 4 o'clock position exactly one whack with a rubber mallet.
(A scientific engineering technique)
But....
You 'should' run the indicator around with the pins in first, just to see if it is within spec's.
(about half of the dial-in's I have done over the years were within spec's without doing anything...)
If it is good, then you are done (don't re-invent the wheel)..
If it is out, then you pop out the pins, move the bellhousing around until it is perfect, tighten the bolts, drill and tap the old pin hole for a bolt, and drill out the other 2 holes for the pins (in the new spot).
The service manual goes over this procedute quite well.
HTIH
Jeff

I recently completed dial indicating a V8 engine bell housing. I used the process found on Bob Johnstone's Resource Website following the instructions and pictures from Allan Anderson's "Dial In Procedure". I did not put the dowel pins in yet to secure the bell housing to the back of the engine block. I wanted to make sure that I was in the correct and/or acceptable tolerance range for the crankshaft to bell housing position before proceeding with that last step. I am having difficulty finding a reference for the correct/acceptable tolerances between the crankshaft to bell housing. I used the 12 o'clock, 3,6,9, markings on the bell housing. I got .004 at 12 o'clock, 0 at 3, 0 at 6, and .004 at the 9 o'clock position. If anyone is familiar with this procedure, I want to know if I should readjust the 9 and 12 o'clock positions or leave it alone? I would appreciate any advise or direction to complete this process. Thanks in advance for any assistance!

Garth Collins,
San Francisco, CA.

[GBC]

Thanks Deepnhock for your advice. Just for a couple points of clarification, could you refer me to the section and page number of the service manual you mentioned in your response. I have several manuals but looked through the 1956 Service Manual. I am working on a super charged V8 for a 57 Golden Hawk. I am not sure what section of the manual to look at for the procedure for dial indicating a bell housing. I know it must be there, but I could not find the right section to locate it. The other point is drilling of the holes for the dowel points. Are you advising to drill two new holes for the pins or just enlarging the existing holes once the correct specs. are maintained by tightened the bell housing bolts and then proceed with installing the dowel pins? I am slightly confused about this part of your recommendation. Your advice has been helpful to get me moving again - thanks again!

GBC

[Warren Webb]

In both my truck & 59-64 car service manuals its on page 3 under new clutch housing installation. There it states a max allowance of .006" runout. I'm sure that spec has not changed.

[Tom Bredehoft]

If you can get it down to .006, you can get it down to.002. go for it, the closer you get it , the better is it is for the car.

Instead of Jeff's big rubber hammer, I used a 24 oz brass hammer, very gently.

[DEEPNHOCK]

My vintage big rubber hammer has been retired
Jeff

<snip>
Instead of Jeff's big rubber hammer, I used a 24 oz brass hammer, very gently.

[studebaker-R2-4-me]

My vintage big rubber hammer has been retired
Jeff


[ATTACH=CONFIG]9481[/ATTACH]

Just as well Jeff. When I did that dial-in that is on Bob Johnston site I found the rubber hammer just bounced off... maybe you have a bigger hammer.

Garth, Glad to hear that you dialed in you bellhousing successfully, ...quite easy wasn't it?... BTW Bob got my name spelled wrong.


Allen

[DEEPNHOCK]

Just verbalizing what the service manual says.. Check it for the exact procedure.
Jeff

Thanks Deepnhock for your advice. Just for a couple points of clarification, could you refer me to the section and page number of the service manual you mentioned in your response. I have several manuals but looked through the 1956 Service Manual. I am working on a super charged V8 for a 57 Golden Hawk. I am not sure what section of the manual to look at for the procedure for dial indicating a bell housing. I know it must be there, but I could not find the right section to locate it. The other point is drilling of the holes for the dowel points. Are you advising to drill two new holes for the pins or just enlarging the existing holes once the correct specs. are maintained by tightened the bell housing bolts and then proceed with installing the dowel pins? I am slightly confused about this part of your recommendation. Your advice has been helpful to get me moving again - thanks again!

GBC

[Dan Timberlake]

If I was checking bellhousing bore alignment with the crank horizontal (like in the car) Before I messed with dowels to achieve much better than 0.006" TIR I'd check (measure) indicator sag of my set up to prevent finding something unpleasant or unreal about the bellhousing.

http://www.graphicsgrotto.com/animatedgifs/scary/images/agscary9.gif

All indicator brackets sag. The only real question is how much. half thou, who cares. But it might be more.

http://www.reliabilitydirect.com/alignmentproducts/Dial%20Indicator%20Procedure.htm

http://www.stiweb.com/appnotes/rdia.htm

http://www.maintenancegeeks.com/installation-a-removal-methods/167-coupling-alignment/220-correcting-indicator-bracket-sag-strain

I also would check the runout of the face that the trans mounts to. That would likely require applying forward or backward pressure on the crank while rotating the crank to sweep the indicator.

Dan T

[Tom Bredehoft]

Very good point, Dan, when I did my 289, it was standing on its' nose. Crankshaft vertical, no sag. Ditto face sweep.