How To: Dialing in a Bell Housing

[garyash]

When I dialed in the bell housing on my Champ 6 for the M5, I immediately drilled two new holes for 3/16 roll pins to hold the alignment temporarily. Then, as suggested in the shop manual, I enlarged two of the 3/8 bolt holes with an adjustable hand reamer set to 0.390"-0.3905". The "oversize" dowel bolts will then hold the housing to prevent it from rotating under load. Using a drill just makes the holes egg-shaped. I had been surprised how out of alignment the housing was with the non-original engine, but it was clear that the previous owner didn't address this.

Here's what the reamer looks like:


I doubt that the clamping force available from the other bolts in loose clearance holes and even a couple of small roll pins are enough to keep the centering of a bell housing under severe loads.

An adjustable ream of the correct size (4A) is not something that most of us have in a tool box. However, even the cheap Chinese ones are good enough to ream one bell housing and at about $8-$15, it's a small enough investment for one-time use. Here's one place to buy them:
http://www.wttool.com/category-exec/category_id/14710

[img=left]http://www.studegarage.com/images/gary_ash_m5_sm.jpg[/img=left] Gary Ash
Dartmouth, Mass.
'48 M5
'65 Wagonaire Commander
'63 Wagonaire Standard
web site at http://www.studegarage.com

[bams50]

I'm still not clear on what to drill, or why? If all the bolts are in and tightened, what do the alignment dowels do? I've always thought the dowels were just for initially locating the bell so you could get the bolts started easier.

Are you drilling new holes for the dowels? And what if the alignment means the original holes are half showing thru the bell holes- then what? Or do you drill new holes in both the bell and block? Not to mention what a major PITA it must be, wobbling around with a hand drill[xx(]

Robert (Bob) Andrews Owner- Studebakeracres- on the IoMT (Island of Misfit Toys!)
Parish, central NY 13131

[StudeRich]

Originally posted by bams50> I'm still not clear on what to drill, or why? You drill though the original dowel hole from the block all the way through both.If all the bolts are in and tightened, what do the alignment dowels do? I've always thought the dowels were just for initially locating the bell so you could get the bolts started easier.You have it backwards, the bolts hold center untill you get the dowels drilled then the Dowels hold the dial-in permanently the dowels are what save your front pump and flex plate (or Trans. input shaft & Brg. on Std. Trans.)from self destructing from running eccentric instead of concentric!

Are you drilling new holes for the dowels? And what if the alignment means the original holes are half showing thru the bell holes- then what? Or do you drill new holes in both the bell and block? Not to mention what a major PITA it must be, wobbling around with a hand drill[xx(]The manual says to re-drill the old holes oversize, I have sometimes drilled new ones. You do not "wobble around"if you pilot the holes first and use the thick block surface to keep the drill centered while drilling the Bellhousing. And you will not move it enough that the bolts no longer fit, if so it is junk.Robert (Bob) Andrews

Someone on the forum once said that the early GM Hydramatic and or PowerGlide had the very same situation as Stude. before they tightened up their tooling on later THM's to make them uni-fit but the tollerances are still not as close as Studebaker's custom fitted Bellhousings, the Dealers fixed the Ma & Pa Garage and shadetree mechanic engine swaps all the time, we did some at Frost & French that were so far out there was mass destruction multiple times! [:0]

StudeRich -Studebakers Northwest Ferndale, WA

[bams50]

OK, what I wasn't getting was you drill from front to back, using the original hole in the block as a pilot! I was picturing trying to drill cast iron using the bell as the pilot...

Still, what if the original hole in the bell is only a little off center of the block hole; when you drill, wouldn't you then have a hole in the bell too big for a pin to hold onto?

"the early GM Hydramatic and or PowerGlide had the very same situation as Stude. before they tightened up their tooling on later THM's to make them uni-fit"

Maybe the reason I've never heard of this procedure is my experience only dates back to early 60s cars, and by then it wasn't an issue.

Thank you for your patient explanations[^]

Robert (Bob) Andrews Owner- Studebakeracres- on the IoMT (Island of Misfit Toys!)
Parish, central NY 13131

[studebaker-R2-4-me]

Hey guys thanks for all the great replies to this post. Hope it help all of us from broken Flex plates and chattering clutches. Sorry for the long reply but I wanted to address some of the comments.

Allen

quoteilloCrafter Posted - 02/07/2008 : 12:07:05 PM Allen, where is the dial indicator making contact? At the back side of the dial?


Paul Simpson
"DilloCrafter"

1955 1/2 Ton Pickup
The Red-Headed Amazon
Deep in the heart of Texas

Paul, the dial indicator has shaft at the back of the dial. You set the Dial indicator on the rim of the bell housing, Watch out for the step down on the rim. The shaft can be seen in that little triangle.

quote:Chucks Stude Posted - 02/07/2008 : 11:34:40 AM Great to see this tutorial. Have heard about it for years, and now it makes sense. Eliminating vibration, no matter how minute, is important, especially at high rpm. How did you check the "trueness" of the fixture that the dial indicator is sitting on?

Chuck,

Really good point and I thought about the same thing. When you really think about the trueness of the fixture it really does not matter. I made the fixture square but I wondered how square is square when I was building it. Even if the fixture was at an angle you are really only taking that specific point that the dial indicator is attached to the fixture and the distance to the bell housing. Therefore, that same point is going to be the same distance away from the rim of the bell housing and will travel around circle evenly.

quote:garyash Posted - 02/07/2008 : 9:12:40 PM When I dialed in the bell housing on my Champ 6 for the M5, I immediately drilled two new holes for 3/16 roll pins to hold the alignment temporarily. Then, as suggested in the shop manual, I enlarged two of the 3/8 bolt holes with an adjustable hand reamer set to 0.390"-0.3905". The "oversize" dowel bolts will then hold the housing to prevent it from rotating under load. Using a drill just makes the holes egg-shaped. I had been surprised how out of alignment the housing was with the non-original engine, but it was clear that the previous owner didn't address this.

Here's what the reamer looks like:


I doubt that the clamping force available from the other bolts in loose clearance holes and even a couple of small roll pins are enough to keep the centering of a bell housing under severe loads.

An adjustable ream of the correct size (4A) is not something that most of us have in a tool box. However, even the cheap Chinese ones are good enough to ream one bell housing and at about $8-$15, it's a small enough investment for one-time use. Here's one place to buy them:
http://www.wttool.com/category-exec/category_id/14710

Gary Ash
Dartmouth, Mass.
'48 M5
'65 Wagonaire Commander
'63 Wagonaire Standard
web site at http://www.studegarage.com

Gary is bang on with his reamer tool. Had I known that an adjustable reamer was available for $15 I would have bought one. I did inquire about a 3/8 reamer at the industrial store but they wanted over $40 for a reamer. Ideally I would have liked to drill an undersized hole and then ream it but decided to just drill the bell housing and block with the 3/8 drill bit after checking the size of the drill bit and dowel pin with a digital caliper. I found the biggest problem with drilling the bell housing/block was the drill chuck making contact with the bell housing before dril

[Volstudebaker]

I know that this an old topic but I need help dialing in a bell housing on a Champ 6 in the car. Is there any way to dial in with the clutch installed?

[Pete R]

With the clutch installed, you'll have a hard time attaching any kind of fixture (to hold the dial indicator) to the flange on the rear end of the crankshaft. If you remove the clutch, but leave the engine in the car, you may be able to check the alignment, but it will be tough to fix it, if it's out of tolerance, because it will be difficult if not impossible to re-drill the existing or drill new dowel holes and ream them to size--there probably won't be enough room to fit the drill in the position needed. I just dialed-in the bell housing for the second time on the 289 in my '54 Commander. The information in this thread was very helpful. I checked the alignment with the engine in the car (but not the clutch). But I had to remove the engine to fix the misalignment. I used a fixture that I made just like the one shown here. In the end, one variation I made was to re-drill and ream the existing dowel holes all the way to 1/2". There was plenty of metal around the original holes to allow this. Now, with 1/2" dowels (commonly used on Ford products), I or future owners will have access to off-set dowels made by Lakewood and perhaps others (and marketed as a hot rod part by places like Summit Racing), which means the dowel holes will never need to be re-drilled if the bell housing is ever changed again.