Sleeveing a block
 

I am having problems with my 307 Olds. The problems are #1 keep loosing ring seal. Number 2 the block is flexing and killing bearings. After the Baton Rough race,I noticed the oil pressure was starting to run at a lower pressure at idle. So I cut the filter apart and found bearing material. So out comes the motor and here is what I found. The center three main bearing bad, and the center three cam bearing spun. The main and cam bearing at each end of the block were good except were trash went though them. Rod bearings good except for trash. The 307 block has what they call windowed mains on the center three mains. The block was hard blocked and has about 75 passes on it. My question is can I use a 350 block and sleeve it down to a 307. Also I run solid motor mounts, they bolt to the center of the block. Could they be trying to pull it apart. Thanks for any info

Re: Sleeveing a block
 

If it is legal, and they are dimensionally the same, (I think they are dimensionally the same and it's legal, but I haven't looked close at small block Oldsmobiles in Stock) I'd say sleeving a 350 down to make it a 307 would work well. I like the Melling flanged sleeves, yes, they're more expensive, and more expensive to put in, but they do not move. They're made out of the same material as severe duty diesel sleeves. I'd piour it up to the water pump holes, put the sleeves in, and then do the rest of the work. If you're running a hydraulic roller and 0.921" lifters, don't forget you'll have to have the lifter bores done.

I'd never put solid mounts on an Oldsmobile, ever. Rubber or urethane and a torque limiter is way better, the Oldsmobile blocks just aren't rugged enough. I don't really like solid mounts anyway, but especially never on an Oldsmobile.

Re: Sleeveing a block
 

Kip Martin tells a story that a Ford engine was on a dyno, running. I think it was an automotive class and I can't remember if it was SBF or FE Ford. But he takes a breaker bar between the motor mount and applies pressure to the block. The engine slows down. A lot.
Just goes to show you cast iron isn't as tuff as you think!

* besides the normal align bore / hone to the mains, I would recommend the same to the cam tunnel. And always make sure came is straight.
I can hear the cash register now...:D

Re: Sleeveing a block
 

Yes, you can sleeve a Olds 350 block to an Olds 307. Use the 1969 to1971 high nickel block. Also, you will need to use the early style Olds head gaskets on the early block too. After sleeving, use Embecco Epoxy instead of Hardblok.

Re: Sleeveing a block
 

fwiw, i've heard that 76ish caddy sevilles had the "good" block, too.
what about the 350 olds diesel blocks?
they legal?

Re: Sleeveing a block
 

On another subjet a little known fact on Small bolcks Ford the vertical intake manifold bolts do more to pull bores out of round that the head bolts. Saw a study from Ford Engine Eng. back in the lat 60's when I was working there. Also when you lose # 2 & 4 main bearings it is usually due to crank bending.

Re: Sleeveing a block
 

Alan,

Our blue SS/NA has a sleeved 350 block, NO FILL, and mounts on the side with welded stock mounts. We have over 300 passes on it, with the same bearings. We found a lifter going away, so we're going to freshen it again, but there is zero bearing material in the oil. It's not as fast as the purple car, but it's not nearly as trick either and it'll run 11.00's in good air, so it's no pooch. The point is, if your chassis is stiff enough, you won't have block problems.

I might add, the blue car has no bars forward of the firewall either, and we have never lost a bearing in that car in 13 years except for one mental lapse on my part -- got interrupted and forgot to put all the oil in. Whoops! But that block is still being used.

Jerry

Re: Sleeveing a block
 

Can you sleeve all the bores in stock?

Re: Sleeveing a block
 

Yes. Some of the older small bore stuff is impossible to find.

Re: Sleeveing a block
 

If you pick the right sleeves and rings, it will actually pick up measurable H.P.