So I've got 2 diagrams for modifying a crankshaft for use with a manual tranny (pilot bearing/bushing).

pretty much the same, only one has a deeper narrower void beyond the bushing for the input shaft, the other has a wider shallower void.
1.56 total depth on one, 1.75 on the other.

Which should i tell the machine shop to go with. Need to get the correct specs dropped off so the machine shop can finish up my crank work.

here are the two diagrams i've found/recieved. Just not sure which to go by or if that extra bit of depth/width for the input shaft matters.

olds-crank-pilotbearing-diagram.jpg

crank20dimentions1.jpg

Thanks for your input

 

I used the top drawing (it is from the Mondello Manual)

It takes the BCA 7109 bearing.

Works perfectly in my 442.....

 

You need to know which crank you have,Auto, or manual? If it is the auto crank, use the photo, and if a manual,use the manual photo.

 

Not trying to be a smart *** but the manual crank is already drilled. The only cranks you need to drill are the auto cranks.

 

If you was to opt out of drilling the crank . you can cut off 3/8 inch of the input shaft on the trans. and install a bronze bushing in the crank where the torque convertor hub rides. (Dorman) part # 690-035 or use the self aligning bearing that mondello sells in place of the bushing. I did this and it worked fine . I would think drilling the crank would me better though . Just my 2 cents worth .

 

I'm already doing machine work on the crank, so drilling it out for the proper bushing & clearance is the smart thing, in my mind anyway.
But if it were already installed in the block, i might look at the other options instead.

Both diagrams are for modifying an auto crank for use with manual transmission.

With no other input, i'll likely go with what my442 said. I'd rather it be a little deepr than not deep enough.

heading down to the machine shop tomorrow morning with the diagram and the bushing.

 

I have a factory 4-speed crank I could measure but it would take a week to dig it out of my garage right now.

 

When using the aftermarket "conversion bearing", an alternative to cutting off the tip of the input shaft is to simply drill the crank out for clearance. This need not be a "precision" drilling, rather the crank can simply be drilled out deep and wide enough to accomodate the length of input shaft that extends past the bearing (which is knurled on the edges and tightly seats into the recess on the outer part of the crank). This is something I read many years back on the 442.com tech board (possibly came from the fingertips Joe P.). Anyway, I actually did this on a '65 425, and it worked great and to my knowledge (I since sold the car), the conversion continues to work fine to this day, 9 years and untold miles afterwards). I will say that I destroyed many a drill bit and used a lot of drilling oil and may have caused premature arthritis in my wrists from this procedure (it was slow going and took DAYS of drilling with successively wider bits and LOTs of exerted pressure required).

The nice thing is that this also avoids any issue of "run out" caused by improper centering when drilling the crank, as the bearing seats itself in the factory machined crank recess, automatically centering itself. And if you drill for clearance instead of "circumcizing" the tip of the input shaft, you can still use the trans with another motor (which I am not sure would be the case if you "snipped" it).

BTW, I MAY recall hearing of one of two guys who did have problems when using this piece, don't recall the nature of the problem (may in fact have been runout?!)

 

The conversion bearing from Supercars or from mondello is like $65-$75 + shipping- and as you say still requires drilling the crank, or cutting the input shaft on the trans.

Or... The machine shop will just drill it out to spec for the correct bushing/bearing for $100

So kind of a no brainer since the crank is out of the block.

I can see wanting to use the other method if the engine was assembled though. I saw the photos of the process Richard used on his assembled 330 to drill it, and its pretty crazy.

 

I would ONLY use that adapter bearing,IF the engine is assembled,and in the car,and I would drill a relief in the crank,and NOT cut the tip off the input. I did do this to a 455 that I had in one of my 70 442's,so I could move the car around,on-off trailers,bodyshop,etc.Most people I have talked with,that used this for a permanent application,said they didn't get very many miles out of that adapater bearing,like 500 miles or less,so I would be weary of trying that.I do not know if they trimmed the input or drilled the crank.Maybe neither.I don't think that bearing was designed to handle this type of use.I think it is for a light-duty application.
Just drill the crank,especially if the engine is apart.It's the only chance.

 

Good reason NOT to use it. It probably doesn't work in Supremes...

Seriously, either one works fine. The recess forward of the bearing is simply clearance for the input shaft. Either one shown will clear.

 

The adapter I used lasted about 500 miles.

It spun in the crank bore.

The conversion bearing is really cheap chineseum junk.

 

I used the adapter bearing and had good luck but it was never planned as a permanent use part. It was very cheap looking light duty piece.

 

Well,you'll be at least 500 miles from Mondello's when it fails.HAHA!

 

I use to sell bearings for a living way back when , I could get top notch bearings for 5 or 10 % over cost....I still talk to those guys over there and still get good deals , maybe shoot me some bearing #'s and let me check. we sold Fafnir and *** and Timken , SKF , Consolidated and many more top notch bearing names. radial bearings , sphericals and angular contacts also ....Gears too from Martin and cant remember the others, been 10 years since i worked there. I may even be able to get timming chains too, I beleive that is just leaf chain , not to mention o-rings , steelies and almost forgot , national oil seals

 

My understanding is that most bearing failures are caused by not centering the bellhousing or scatter shield correctly which may of may not require offset dowels. This happens most often when the conversion is done from auto to manual. Just a thought

 

I have one of the Supercars conversion bearings that I never used or even opened the baggie. $25 shipped if someone wants it.

If the crank is an older one, up to 1969 and maybe 70 or 71, the factory automatic drilling is shallow enough that you can bore the crank .55" deep for the Chevy Dorman 690-014 bushing that has a nice rolled chamfer at the entrance. Late cranks would put the bushing too far from the trans and need the Bower 7109 bearing or dorman 690-023 bushing.

Use the upper drawing. If using the conversion bearing, you can just use a big drill bit (the nose of the shaft is .59" because it doesnt' have to be dead straight, it is just a relief so the trans doesn't hit the crank.

 

My 442 crank that is factory drilled has a clip to hold the bearing in place, I suspect that is the bottom drawing. I had others drilled with the top drawing.

 

The bottom drawing is one person's way of doing it, not the factory way. Olds used a snap ring beginning with 1970 models, according to the service manuals. Before that, the bearing was staked with a center punch near the edge of the hole.

 

That started in 69 or 70. The 68 Factory Service Manual has the bearing "staked" into place with a punch at the edge of the bearing

 

I noticed the .060 to .064 measurement on thre bottom drawing. Wouldn't that be for the clip?

 

From what I can remember , there are way better bearings then a Bower , those were our cheaper end bearings....unless things have changed in the last 10 yrs . I could have that matched with a better bearing manufacturer possibly.

 

These days tranny inputs are expensive and we don't drive our Oldsmobiles for 100,000 miles, so a bronze bushing is good.

 

No,Bower is even "cheaper" now. Now you're updated.

 

So whats the best bearing? I am in the process of this on my 48 Olds build right now. I received a bearing with the TKO 600 kit I bought

 

SFK , Fafnir and *** are all quality bearings .... I tried to croos match the 7109 Bower , but every site I was on wanted me to register and all this other jive. I wish I kept all those bearing catalogs from when I worked there , but I can just call or email...The place was called Wisconsin Bearing Co.which was bought about 13yrs ago by Motion Industries, im guessing there are branches in your neighborhood possibly too. Wisc Brg and Motion are all over the world in every state to.

 

Im really curious to see a picture of crank for a manual, thanks in advance!

 

https://classicoldsmobile.com/forums...ans-crank.html

 

After talking with several hotrod people in my area i went with the bronze bushing. Nothing to go wrong with it and several have been in cars for over 50 years. Proven method

 

Hey pat, is your engine still out of the car? I need to find another 455 block that has the zbar stud hole that i can take some measurements off of. Does yours have that mounting boss? Maybe i could swing by and make some notes.

 

Ben,

Yes it its still out of the car and yes it has the stud hole. Your welcome to stop by anytime. I work from home call before you come as I do go to meetings from time to time. If you've lost my number PM me

 

Make sure the bronze bushing is a true bronze oilite bushing,and not the immitation with the bronze appearance.I've seen both.

 

Trying to prep for a automatic to muncie four speed swap. Read most of the post on the subject. Pulled up the Dorman pilot bushing for a 70 455. As noted in the thread part number 690-023. $20.97 at Summit. Went down to O'Reilly--Dorman part number 690-023 $3.25. Now with that said, I also called Dorman wanting to check what this part was made of since the thread mentions an oilite bronze. The guys at Dorman were clueless. Summit has it down as powered metal. This is what the guy at Dorman tech said.

Question: Is this Dorman piece I have 690-023 going to do the trick for my auto to four speed conversion. Color is kind of a bronzy/gray. Pics below.

Just as follow up on using a pilot bearing instead of a bushing. I looked at a couple of these on Summit site and they did not seem to be sealed bearings. If these are not sealed how does a pilot bearing get lubrication? Possibly Summit had the wrong pictures. I looked at a Timken 7109 and a BCA 7109.

 

The bushing is oil-impregnated bronze. The bearing is packed with grease when it is installed, just like a front wheel bearing. Keep in mind that the only time the pilot bushing/bearing is rotating is when you have your foot on the clutch. During normal operation, the clutch is engaged and the trans input shaft is spinning at the same speed as the crank.

 

Auto Gear in NY state makes real oilite bronze bushings. We are told if the bushing is attracted to a magnet, it has iron in it and is low quality.

 

Thx Joe and Run to Rund. Just put a small business card sized sheet magnet on the Dorman 690-023 clutch pilot bushing. You can see by the pic that there is a lot of iron in the Dorman piece. It held strongly to that thin sheet magnet. I will be contacting Auto Gear as Run to Rund suggested. (315) 471-8141 or 1-800-634-3001. autogear.net.

 

Thanks for this info. I need to do a 350 crank for my hi-revving ramrod? Which approach is best for 7500-8000 rpm racecar? Bearing or bushing? I have a stick shift std crank from a 330 that has a bearing , (not a bushing) in it. Been contemplating just swapping the 330 crank into the motor? Any suggestions JOE. RUN T RUN?

 

Just ordered oilite bronze pilot bushing from Auto Gear. $13.50 approx. 1/2 inch thick, 1.378-1.377 OD, .592-.593 ID. Talked with Nathan. Very helpful. Would have never found them except for ClassicOldsmobile.com.

 

Tweed,

The 330 crank is forged, the 350 crank is cast. For a high-rpm race car, this is really a no-brainer. Obviously you need the flywheel that matches the 330 crank bolt pattern, and the 330 crank will want to be rebalanced for the heavier 350 pistons, but that's the right answer for your application.

 

How about a GM part?

They are probably around. I bought 3-4 clutch assemblies off CL a while back, they came with NOS GM bushings and throwout bearings.

try
3752487

or

907321

aha
http://www.ebay.com/itm/NOS-GM-PART-...p2047675.l2557