Converting Auto to a Manual (Crankshaft Pilot Bearing)
January 19th, 2011, 11:53 PM
#1
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Converting Auto to a Manual (Crankshaft Pilot Bearing)
Quite a few questions in one big thread. 
Has anyone here converted their Olds factory Auto engine to a Manual ??
I'm looking for insight on the Pilot Bearing adaptors that don't require crank drilling for the input shaft depth.
I'm debating what flywheel and pilot bearing adaptor to go with.
I'm reading this Olds FAQ site on Pilot Bearings.
http://www.442.com/oldsfaq/ofcrk.htm
There's a few choices I'm seeing.
SuperCarsUnlimited site with their Pilot Bearing Adaptor for $39
Dick Miller Racing site with their flywheel, bolts, and Pilot Bearing Adaptors
Mondello, which I probably won't even bother with.
Dick Miller sells the flywheel, bolts, & pilot bearing adaptor in a package. My biggest concern is what I've read that the majority of Olds motors were made with automatics and don't have a drilled out crankshaft for the input shaft depth of a manual trans. Putting this pilot bearing adaptor in, plus shortening the input shaft looks like the simplest approach to turning my Automatic vehicle into a Manual vehicle. I was hoping someone might have done this or at least might have pics or references to consider.
Has anyone here converted their Olds factory Auto engine to a Manual ??
I'm looking for insight on the Pilot Bearing adaptors that don't require crank drilling for the input shaft depth.
I'm debating what flywheel and pilot bearing adaptor to go with.
I'm reading this Olds FAQ site on Pilot Bearings.
http://www.442.com/oldsfaq/ofcrk.htm
Our pilot bearing adaptor allows the use of an "automatic" crankshaft with a manual transmission. (Who is the company that posted this FAQ??) Factory automatic cranks are not machined with the step required for a pilot bearing. And they lack the depth required for the manual transmissions input shaft. The adaptor bearing addresses these issues by using the torque converter ring of the crank for centering and mounting of the bearing.
A self-aligning ball bearing (Not a bushing) is encased in a hardened steel case that has a knurl on the outside that provides a VERY tight fit in the crankshaft. Installation only requires a hammer and a socket that fits the O.D. of the adaptor. As noted, the automatic crank also lacks the depth required for the manuals input shaft. To accommodate this depth, the input shaft must be shortened by approx. 1/4" to 3/8". This can be done with a hacksaw or a disc style grinder.
A common misconception with this modification is that it will somehow weaken the input shaft. Actually, it is quite the contrary. Because, the pilot bearing is now closer to the transmissions front bearing, this will reduce flex in the input shaft. Think of a piece of tubing, say, 10 feet long, supported at the ends. This will flex in the center more so than a piece of tubing 5 feet long. An alternative to cutting the end of the input shaft, is to drill the existing hole in the crank deeper, while using the adaptor to support the input shaft.
A self-aligning ball bearing (Not a bushing) is encased in a hardened steel case that has a knurl on the outside that provides a VERY tight fit in the crankshaft. Installation only requires a hammer and a socket that fits the O.D. of the adaptor. As noted, the automatic crank also lacks the depth required for the manuals input shaft. To accommodate this depth, the input shaft must be shortened by approx. 1/4" to 3/8". This can be done with a hacksaw or a disc style grinder.
A common misconception with this modification is that it will somehow weaken the input shaft. Actually, it is quite the contrary. Because, the pilot bearing is now closer to the transmissions front bearing, this will reduce flex in the input shaft. Think of a piece of tubing, say, 10 feet long, supported at the ends. This will flex in the center more so than a piece of tubing 5 feet long. An alternative to cutting the end of the input shaft, is to drill the existing hole in the crank deeper, while using the adaptor to support the input shaft.
SuperCarsUnlimited site with their Pilot Bearing Adaptor for $39
Dick Miller Racing site with their flywheel, bolts, and Pilot Bearing Adaptors
Mondello, which I probably won't even bother with.
Dick Miller sells the flywheel, bolts, & pilot bearing adaptor in a package. My biggest concern is what I've read that the majority of Olds motors were made with automatics and don't have a drilled out crankshaft for the input shaft depth of a manual trans. Putting this pilot bearing adaptor in, plus shortening the input shaft looks like the simplest approach to turning my Automatic vehicle into a Manual vehicle. I was hoping someone might have done this or at least might have pics or references to consider.
Last edited by Aceshigh; January 20th, 2011 at 12:10 AM.
January 20th, 2011, 03:23 AM
#2
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Join Date: Feb 2009
Posts: 2,257
I did it.
The conversion bearing lasted about 500 miles, then it spun in the I.D. of the crank.
The tranny was hard to get into reverse, and I attributed that to misalignment of the bearing to the input shaft.
The conversion bearing is really a cheesy part, looks like a low quality chineseum part.
I pulled the engine, and had the crank drilled for a BCA7109 bearing.
Works 1000x better.
My .02 is to avoid the conversion bearing.
The conversion bearing lasted about 500 miles, then it spun in the I.D. of the crank.
The tranny was hard to get into reverse, and I attributed that to misalignment of the bearing to the input shaft.
The conversion bearing is really a cheesy part, looks like a low quality chineseum part.
I pulled the engine, and had the crank drilled for a BCA7109 bearing.
Works 1000x better.
My .02 is to avoid the conversion bearing.
January 20th, 2011, 04:06 AM
#3
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Join Date: Oct 2009
Location: Erie,PA
Posts: 3,814
Do not cut the end off the shaft.That is half-***. "IF",and I mean "IF" you decide to use the adapter bearing,drill a relief hole in the crank,to give the input shaft somewhere to go,once it passes through the adapter bearing.
I have one of those adpater bearings that I used for awhile,in one of my 70's,so I could move the car around & such.I did very little driving with it.If you look at the bearing itself,it is a thin ball-bearing style sealed bearing.I doubt it was ever intended for this type of load. I think when these companies decided to make an adapater,they researched the bearings,and found one with the correct inner diamater,then made a shell for it that would press into the end of the crank.The better way would be to machine a piece of bronze,much like they did originally,to fit the end of the crank.
The best way,and the correct way,would be to have the end of the crank machined to the factory spec,and put the correct pilot bearing in it.You might get lucky & have a crank that is.
I have one of those adpater bearings that I used for awhile,in one of my 70's,so I could move the car around & such.I did very little driving with it.If you look at the bearing itself,it is a thin ball-bearing style sealed bearing.I doubt it was ever intended for this type of load. I think when these companies decided to make an adapater,they researched the bearings,and found one with the correct inner diamater,then made a shell for it that would press into the end of the crank.The better way would be to machine a piece of bronze,much like they did originally,to fit the end of the crank.
The best way,and the correct way,would be to have the end of the crank machined to the factory spec,and put the correct pilot bearing in it.You might get lucky & have a crank that is.
January 20th, 2011, 04:24 AM
#4
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Did you cut the input shaft length into the crank when installing this ?
If you didn't, did you cut the input shaft shorter instead??
Which route did you go initially that failed??
I was also told, to use the adaptor pilot bearing,
A] I can hand drill the crank while IN the engine for input shaft depth.
B] Cut the excess off the input shaft by 1/4" to 3/8"
But NOT for a crank fitting pilot bearing, that has to be removed from the engine, and put on the lathe.
To me this sounds like a project tearing the lower half apart......
The best way,and the correct way,would be to have the end of the crank machined to the factory spec,and put the correct pilot bearing in it.You might get lucky & have a crank that is.
Last edited by Aceshigh; January 20th, 2011 at 04:29 AM.
January 27th, 2011, 10:53 AM
#5
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I would love to see a pic of the crank drilling for the "more correct" method. Not sure where it would be on the crank and what the specs are either? I'll be looking into this as well in the near future. Interested in this thread for sure.
January 27th, 2011, 11:08 AM
#6
Ben
Join Date: Mar 2009
Location: Snohomish, WA
Posts: 1,824
Here is a thread discussing the drilling specs...
https://classicoldsmobile.com/forums...-question.html
January 27th, 2011, 02:24 PM
#7
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Posts: 2,257
I bought the bearing from Dick Miller, but I believe all the Olds vendors sell the same one.
A friend of mine made a fixture to drill the clearance hole in the crank.
With a 1/2 HP drill and a new bit, drilling the hole was an absolute bear. The crank material is hard as hell. Took 45 minutes to drill into the crank 1/2".
Based upon how the correct bearing works, I would not do it any other way.
"Doing it the wrong way means that you will have to do it again the right way"
A friend of mine made a fixture to drill the clearance hole in the crank.
With a 1/2 HP drill and a new bit, drilling the hole was an absolute bear. The crank material is hard as hell. Took 45 minutes to drill into the crank 1/2".
Based upon how the correct bearing works, I would not do it any other way.
"Doing it the wrong way means that you will have to do it again the right way"
January 27th, 2011, 02:57 PM
#8
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Join Date: Apr 2008
Location: Dallas TX
Posts: 5,656
Whose adaptor bearing did you purchase??
They are all the same piece of junk. Mine came from Super Cars Unlimited. I did not have a failure but I never had any long term plans to keep using mine.
Did you cut the input shaft length into the crank when installing this ?
If you didn't, did you cut the input shaft shorter instead??
Cutting off the end of a input shaft is the last thing I would ever do.
Which route did you go initially that failed??
Has nothing to do with the failure. The tinker toy bearing they use does
I was reading that this is the easiest method , but I'm not sure it will yield the greatest result.
I was also told, to use the adaptor pilot bearing,
A] I can hand drill the crank while IN the engine for input shaft depth.
B] Cut the excess off the input shaft by 1/4" to 3/8"
took me about an hour to drill mine with a HD 1/2" drill and machine shop quality bit.
They are all the same piece of junk. Mine came from Super Cars Unlimited. I did not have a failure but I never had any long term plans to keep using mine.
Did you cut the input shaft length into the crank when installing this ?
If you didn't, did you cut the input shaft shorter instead??
Cutting off the end of a input shaft is the last thing I would ever do.
Which route did you go initially that failed??
Has nothing to do with the failure. The tinker toy bearing they use does
I was reading that this is the easiest method , but I'm not sure it will yield the greatest result.
I was also told, to use the adaptor pilot bearing,
A] I can hand drill the crank while IN the engine for input shaft depth.
B] Cut the excess off the input shaft by 1/4" to 3/8"
took me about an hour to drill mine with a HD 1/2" drill and machine shop quality bit.
January 27th, 2011, 04:28 PM
#9
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Join Date: Nov 2007
Location: Charleston, West Virginia
Posts: 1,190
I did it.
The conversion bearing lasted about 500 miles, then it spun in the I.D. of the crank.
The tranny was hard to get into reverse, and I attributed that to misalignment of the bearing to the input shaft.
The conversion bearing is really a cheesy part, looks like a low quality chineseum part.
I pulled the engine, and had the crank drilled for a BCA7109 bearing.
Works 1000x better.
My .02 is to avoid the conversion bearing.
The conversion bearing lasted about 500 miles, then it spun in the I.D. of the crank.
The tranny was hard to get into reverse, and I attributed that to misalignment of the bearing to the input shaft.
The conversion bearing is really a cheesy part, looks like a low quality chineseum part.
I pulled the engine, and had the crank drilled for a BCA7109 bearing.
Works 1000x better.
My .02 is to avoid the conversion bearing.
I considered using an adapter myself until I saw one. Looked pretty flimsy.
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