View Full Version : Transmission: Bellhousing dialling

Steve Winzar
07-03-2016, 05:14 AM
I have taken the opportunity to check the register between the crank and the Bellhousing for my Flightomatic trans. I had assumed I had the original Bellhousing buttoned on, but was pretty dismayed when I recorded just under 22 thou of runout (exactly 12 o'clock to 6 o 'clock). Geeze, I must have cleaned up and painted one of my spare ones all those years ago- how silly, oh well better find the other one, I was pretty sure I had the original up there.....
I found another one- with remnant silver paint on it too (its for a '61 Hawk) but I was again surprised to find close to twenty thou runout on this one as well (11 o'clock to 5 o'clock).
Am I kidding myself or did I expect far too much accuracy here ? What is the consensus out there ? BTW can anybody give me the maximum accepted runout, because I haven't spotted it in the shop manual. I will be making up some stepped dowels to fix this problem. Just in case anybody is wondering, the Flexplate on this trans came out of it with no damage, so what gives with this runout?

07-03-2016, 07:11 AM
.004 register total run out, .006 total face run out. per the Avanti shop manual. BTDT and Good Luck, fixing this can cause loss of hair and Religion,Doofus

07-03-2016, 07:14 AM
:) Mike Myer gave a seminar at the Warwick International Meet last week, during which he dial-indicated a bellhousing to a V8 block.

He agreed with the factory specifications (.004-.006) but said he has seen runout as high as .010 with no seemingly ill effects. I'd agree that ought to be as far as one dared to go, especially on an automatic transmission car where the flex plate takes the brunt of any excessive runout. :cool: BP

07-03-2016, 07:17 AM
According to the experts, the runout should be between 4 and 6 thou.

07-03-2016, 05:44 PM
Do what Mike did at the Warwick show. Pull the existing dowel pins. Bolt the bell housing on with 3 or four bolts. Tap the bell housing with a lead, brass or rubber hammer until you get the correct reading. Tighten the bolts up. Recheck your readings. Drill 1/4 inch holes above the existing dowel pin holes and install 1/4 inch roll pins. Mike said there is plenty of meat above the original pin holes.

Steve Winzar
07-03-2016, 11:05 PM
Hi all, thanks for the advice. I will be machining a pair of offset dowels to eliminate the runout or reduce it to under .004" .
Not having access to specialised setting tools, I plan on dial indicating the nose of the torque converter to getting it to run true in the front pump bearing. Still finding myself bemused at the lousy runout, but I have to wonder whether that might be a consequence of CKD'ing studebakers to Australia- maybe it was set lousy here and not at the factory in the US. I'm absolutely convinced that this car was unmolested when I received it.

Steve Winzar
07-04-2016, 01:00 AM
I gotta say something- Clocking the bell housing runout at less than .001" on first attempt!
Time to leave well enough alone.....

07-04-2016, 02:36 AM
I gotta say something- Clocking the bell housing runout at less than .001" on first attempt!
Time to leave well enough alone.....

Daaang Steve, maybe we oughta send all our blocks and bell housings out to you? ? ?
But I've always kept mine at max of .010" and never had a problem. I've been lucky a few times to make a lucky hammer strike to get it in at .005 or .004, but sheesh... .001 is incredible.

Steve Winzar
07-04-2016, 04:11 AM
I reckon the neighbours might object to all the blocks and bells lined up:o. I thought that this job was going to be the tough one but I lucked-out. NOW I have a bigger issue in that the torque converter and flywheel are running WAAAAY out. Given the pilot stub of the Flywheel and crankshaft bushing are locating the whole shebang, I'm wondering what to do next. This thing is running out over forty thou.

07-04-2016, 07:09 AM
Steve,gotta wonder how you are checking run out now. maybe a "Dummy" front pump would help center that TC now the bell housing is spot on? Cant call you a "Shade Tree" any more LOL. Luck Doofus

Steve Winzar
07-04-2016, 09:32 AM
Thanks Doofus- I have an engineering trade background, so its familiar territory for me. I'm hanging a magnetic base and dial indicator off the end of the block and the indicator registers runout on the Torque Converter nose. Given that the flywheel pilot stub is engaged neatly in the bronze bush at the end of the crankshaft, it appears that the the TC was welded onto the flywheel way out of center- so merely thumping it with a mallet is ineffectual.The only cure for this is another unit or get this one recoed, centered up and rebalanced.

07-04-2016, 04:12 PM
Just have to ask. How many miles do you think that Flightomatic has been driven with those wrong offsets? Maybe 100,000 or so?? Guess it really wasn't that important after all! Bet that torque converter was welded up poorly- but it worked anyway. I think we are trying to perfect things that never were.

07-04-2016, 06:34 PM
Just gotta do the best job you can in all things,it will pay off,,,,,eventually. take it from a dyed in the wool "Shade Tree"mechanic,not a "Technician". Doofus

Steve Winzar
07-04-2016, 07:05 PM
This car would likely have done 160,000 miles- based on what the odometer reading when I first obtained the car (and the engine wear on disassembly). That, plus what I think is 'Victorian Western Districts' yellow dust all under the vehicle and trans, lead me to think it is totally unchanged since new. Every thought I have about this runout screams "don't re assemble it as-is". I think I have another TC buried amongst my spares and if so, will give it another go for comparisons sake. I wonder if I've managed to install the wrong one? If I've managed to perfect the bellhousing runout, and recoed the transmission, it seems seems a pity to to reinstall this TC in it's known condition.

Steve Winzar
07-04-2016, 10:34 PM
After checking out another TC I'm ready to bite the bullet. Neither dial up anywhere within a bulls roar so I'm going to hold my breath and accept it as the norm. It all comes down to the spigot bearing centering the whole flywheel. I can't see the front pump seal lasting at all well.

07-04-2016, 11:56 PM
I always understood that the Nose of the Converter merely rests in the opening of the Crankshaft bushing or not at all, and it can actually be removed with no harm because only the Standard Trans. Input Shaft actually goes INTO that bushing and hole in the Crank.

The Converter Centers with the "Centering Tool" into the hole in the Converter Housing just like the Dial Indicator pointer does when Dialing the Housing, then the Converter to Flex plate Bolts are tightened.

In the absence of the "J" Tool, rotating the Engine and Converter with the Bolts not quite tight should accomplish close to the same thing

Someone correct me if that is the incorrect procedure, Please. :)

07-05-2016, 06:17 AM
That's how we used to do it, two full turn with plugs out of course gets all bolt installed then tightened ,use a deep offset wrench for this task and you are home free,,,, eventually. Luck Doofus

Steve Winzar
07-05-2016, 09:45 PM
Thanks Rich- I was wondering about moving that bush. In doing that, the only limiting factor would be the clearance in the Flexplate holes. I could dial the TC nose closer in that case. I have actually fitted the Flightomatic up but I have no problems dismantling it again. Short of 'splitting' the bush carefully with a hacksaw blade- what is the best way of pulling this out?

07-05-2016, 09:53 PM
A dedicated bushing puller, or a cape chisel and hammer with caution. Doofus

Steve Winzar
07-06-2016, 09:44 PM
I decided to pull the installation apart again. My Lathe is out of action and I couldn't use it, but I made up a basic test rig by filing a hole in a big thick lump of chipboard and plugging the pilot stub of the TC into it for a firm fit. I could then rotate the flywheel flat against the board and dial indicate it with the magnetic base clamped to the board. This gave me a surprise result- The ACTUAL runout is only .008". this is within the realms of reality considering the whole shebang is a fabricated product. However, this situation now necessitates the realisation that the pilot bushing at the center of the crankshaft is nowhere near concentric. Once again I'm telling myself- "geeze this is rough". Stude Rich has suggested removal of the bush, so I reckon that's the next move; another choice is a bit of filing with my big bastard cut rat-tail file to bring everything over a bit more.

07-06-2016, 11:01 PM
The purpose of the crankshaft bushing is not to control the centering of the torque converter. It is a support for the nose only. A resting place. When the TC is installed into the splines of the transmission itself it will self center on the input shafts and engage the front pump, etc. The centering for run out occurs when the bell housing itself is installed on the dowels at the back of the block. The tranny will center when it is installed into the housing. The primary controller of centering is the bell housing and the dowels on the back of the engine.

Once the tranny is finally bolted to the bell housing you can go back and torque down the converter to the flex plate.

07-07-2016, 01:34 PM
The crank pilot bushing can be easily pulled with a puller called a "bicycle internal bearing puller". Here in Canada Princess Auto supply a cheap "made in China" version for not much money.

Steve Winzar
07-07-2016, 07:11 PM
Hi Mate, Yes, I agree everything else will self align. The issue I believe I have is that the TC will run eccentrically in the front pump mechanical seal. I have filed out the bushing a bit off center and gotten within 0.009" runout. From what I can find out from seal manufacturers information, runout needs to be no more than .004" in the interests of longevity and oil retention. I'm nearly there.

Steve Winzar
07-09-2016, 02:42 AM
After speaking with a club member respected for his knowledge of the Flightomatic, I have decided that I will replace the pilot bushing with a new one and install it all as it is. I may go as far as machining a centering tool and button the lot up.