Hi all,

The stock 400 engine from my 1969 442 is at the engine builder and I'm replacing the cast automatic crankshaft with a forged manual transmission crankshaft. The engine builder is having trouble locating suppliers who sell the 400 crankshaft for a manual transmission. I've only found one so far...

http://www.rpmmachine.com/crankshaftkitsoldsmobile.html

Can you guys let me know of some more suppliers that offer this crankshaft?

I sure appreciate your help!

 

I also read in another thread that the crank in the '69 Olds 400 is identical to the 1969-1976 455 crank. Is that correct? I am looking for one that is set up for a pilot bushing and the increased length of the input shaft.

 

Factory forged crankshafts were only used in some 1968 455's so they're hard to find. Depending on what your plans are, factory cast cranks are pretty good and have been used in pretty tough applications. You can find one that's drilled already and use a bushing or have a good machine shop cut it out for you. Here's a reference where it was discussed in a previous thread.

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

 

You can use a nodular 455 crank (1" high N or smaller CN on the edge of the first counterweight) but I would get it balanced to the rest of the engine. There were very few forged cranks, as noted above, and they would be only in early 1968 455s. The 65-7 forged cranks had a shorter stroke, 3.975" rather than 4.25" of the late 400 and 455.

 

For most applications your cast 400 crank can be machined for a pilot bearing a lot cheaper than buying a new forged crank. What kind of HP is the build?

 

That's what I mentioned to the engine builder, but he is strongly against machining the crank. He said that it could affect the balance of the crank. Is that correct? I'm having it rebuilt to stock specifications.

 

I have gotten automatic cranks bored in a lathe so the hole is perfectly centered, for about $100 at my auto machine shop. For the earlier cranks, up to about 1970, the stock hole for an AT application is shallow, and I get them bored .55" deep for a Chevy bushing-- Dorman 690-014. You could also get them bored for the Olds bearing or its replacement Dorman bushing, 690-023.

 

Unless the crank is damaged there no reason not to use the original one. Machining for a pilot bearing isn't going to effect the balance. The auto crank and MT are identical except for the pilot bearing machining.

 

If the above quote is an example of this machinists knowledge you should see the writing on the wall & find another machine shop to handle this for you. There are plenty of Olds experienced vendors out there. This person obvious is not one of them. Spool your rags & go.

 

You need to find another machine shop, don't walk, run the other way.

 

I'd think more he's never done one, and trying to talk you out if it, rather than take a chance of messing it up.
If you don't learn something new, every day, you become stagnant.

 

I agree. This is something a competent machinist should have learned to do a long time ago. And if he isn't willing to learn on something this simple I would have to wonder how skilled he is.

 

You really don't want him learning on your crank. Find a shop with some intelligence. . .geez, he thinks balance will be upset, what a moron.

 

I was really wondering about what he said too. To clarify, the engine builder is sending the work out to be machined, so they aren't doing any of the machining. I've been dealing directly with a rep at the engine builder (rather than one of the laborers), and I am starting to question his experience, although I really can't talk considering I've never built one.

BTW... he said that my crank was not useable, as I had 3 spun bearings. I sure appreciate the feedback, as you guys have a ton of knowledge. I'm going to take a hard look at my options at this point.