1978 Oldsmobile Omega

So I have recently realized there may be an issue with my 4 speed to olds 350 mating. This is my first project and I tend to avoid transmission talk because its often complex, anyway, what are my options to make it work? My cranks are both automatics I believe because they have the center hole that comes to a funnel like shape, I assumed this was a common issue considering it's a common engine to an extent and many run a standard trans, what's the deal!!!

CRUZN 66

You will have to find a crank which has been drilled to accept the pilot bushing/bearing for the output shaft of the standard transmission... Or you can have your crank machined.....

joe_padavano

Or, you can use the aftermarket conversion pilot bearing, which requires you to either trim the end of the trans input shaft or to drill a clearance hole in the end of the crank (which is much less critical than the machined bore required to use the factory pilot bearing). Be aware that some folks here have had problems with these aftermarket bearings. I have no first-hand experience so I can't comment either way.

1978 Oldsmobile Omega

I deleted my post as I went back and found some old threads, so really, dont I just need to either make the hole deeper or cut the shaft and install the bearing?

svnt442

Bottom of the page.

http://www.mondellotwister.com/Transmission.htm

1978 Oldsmobile Omega

Like I said (before deleting the post) I dont want to pay what I did for the engine in a bearing, once I ship that to Canada it's alot more that $69, summit has about two pages of pilot bearings under oldsmobile, if I check measurments, will I have any issue? I have heard bronze bushings being used, any thoughts?

svnt442

Nope. It's either use this and cut down the input shaft, or modify the crank.
What you have to remember is that Oldsmobile was primarily into luxury and not performance so automatic transmissions were the norm for them. That's not to say that they didn't make performance cars, but it wasn't their main concern.

joe_padavano

To clarify, the factory manual transmission cars had the crank bored with a precision hole to accept the factory-style pilot bearing. The aftermarket conversion bearing fits in the shallow recess that normally accepts the pilot on the AT torque converter. This provides the proper centering accuracy for the manual trans input shaft, but the recess in the crank is not deep enough for the input shaft. This is why you either need to cut about 3/4" off the end of the input shaft or bore a non-precision clearance hole in the crank. People have manually drilled this hole, but it's not easy with a hand-held drill, as you need to work your way up in a lot of steps and can easily spend the money in buying drill bits. Personally I don't like the idea of shortening the input shaft as it prevents using that trans in a normal application.

My442

I tried the conversion bearing....and it failed within 500 miles.


The bearing was not concentric to the crank, and ate itself.


Could not shift into reverse either.


Drilling the crank for clearance is harder than picking fly crap out of black pepper with boxing gloves.....that material is harder than anything metal I have come across.


Best bet is to have the crank drilled properly, and install a BCA7109 bearing.

CRUZN 66

Like I said, it's most likely best to machine the one you have or find one already drilled... Can't hurt to get an estimate from a machine shop and then weigh your options against some real money numbers.....

1978 Oldsmobile Omega

I really wouldn't trust any machine shop in my area and have heard bad things ,certainly none here with olds experience. And I have an assembled engine that I can't just hand to a machine shop so for this one I will need a bearing that converts, is there any other options part-wise, I need to find one that won't cost a lot for part+shipping+conversion to the lowly Canadian dollar. When I build the more powerful engine for my car I can either find a crank or find a machinist or use a bearing again
Still, how is this not a perfected conversion, someone wanting a standard trans isn't that weird, for there to be only one option seems odd

1978 Oldsmobile Omega

i have read about using a bushing, is there a process to that or is that just impossible?

svnt442

The crank just is not machined for it. You have two options as already outlined in this thread.
Unfortunately no matter how much you may want a third option, it's just not there.

So here's how I see your options....
1. Get the conversion bearing and cut down the input shaft
2. Disassemble the engine and have the crank machined to accept a factory bearing/bushing
3. Find a crank that is already setup for a manual transmission
4. Use an automatic
5. Find a Chevy.

Not sure what else to tell you.

1978 Oldsmobile Omega

So the answer I was looking for is no there is not a bushing to use, I understand the previously mentioned options. What I do need to know is all of the places where I may find it, aside from the previously mentioned mondellos
And a Chevy certainly isn't an option

joe_padavano

There is solid metal in the end of the crank where any normal, factory-style bushing would go. No one has yet invented a bushing that takes up negative space. I don't know how to say this any other way. The conversion bushing/bearing uses the available recess in the end of the crank. Without machining metal, how would one do anything other than that?

kevdog442

Supercars Unlimited has the conversion bearing, price is less than mondellos. I've used one for years with no issues, and I just ordered another one for my new 455. I did have to buy a good drill bit from lowes. Wasn't hard to do. This is going to be your cheapest option as machining for a pilot bearing isn't cheap especially if it's not dead nuts on.

RetroRanger

what size bit did you use? I would guess its just a little larger than the input shaft dia ?

how deep ?

Octania

Correct on the diameter
deep enough to allow pilot shaft to reside [measure it]

for sure stop before you drill into the oil passage around the main bearing