Oversize OD main bearings

[Walt Dupont--Me.]

I don't care how long you build flatheads you find something new. A friend called me, he's been building engines all his life, he doing a 40-41 flathead, installing a new crank 2.498 2.499 mains, std bearings, torque the mains and the crank was loose, plastic gauge, never touched it, pulled the crank, mic the housing bore, .015 overbore. He's found a set someplace. As most of you know I've been building these thing for over 60yr's and never found a block with factory over size main bearings. I've found quite a few with over size cam bearings. Has anyone found block with over main housing bore? Walt

[cmbrucew]

Walt
Could this be caused by align boring the block?
Bruce

[Walt Dupont--Me.]

Originally Posted by cmbrucew

Walt
Could this be caused by align boring the block?
Bruce

When they align bore the block they usually machine the caps so the bore is smaller then align bore back to std bore. I cain't see .015 over them making oversize bearings. But everdently Ford did. Walt

[Ken/Alabama]

Walt, I have some Ford literature somewhere explaining how to identify those blocks with oversized housing bore. But I thought it was only on the rear main. Ill have to see if I can dig it up.

[Pete]

I have never seen one but knew they existed. Apparently the factory had enough blocks that wouldn't clean up that they could afford to make over size OD bearings.
Same with cam lines. I have seen those.

[Flathead]

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Ford did it, I got stuck with one of these blocks on a rebuild many years ago. I think the block is supposed to be stamped ERP somewhere as a warning. I have heard it was done on rebuilds as a quicker way to line bore if needed. Those bearings are listed in the Green Book, and on the Ford bearing box the crankcase dia. is shown as .015 oversize. They did all three mains the same on the motor I had. This was all well and good back when you could get those bearings, now not so much.

[GEOFFNZ]

I heard of an English 6 cylinder Ford Zephyr engine out here which was like that .Apparently it was done to some blocks at manufacture that had to be over bored in the mains to clean up the casting.Cheers.

[big job]

I agree with Pete I have seen that before. This has been written in ink. Chrysler
was notorious with this practice back in the 30's. That caused us re builders
crazy back then, cause no one had service parts. Not sure how Ford did this, I do
know Chrysler would send these (screwed up blocks) to another Dept. Other words,
a new Plymouth came with a rebuilt engine. I know cause my father had a new
DeSoto that had one cyl. liner and a turned crank, that blew up one mo. old. Dealer
made good with another car, my father was friends with the dealer and I with my father saw the engine apart and this was in 1951. "so they were still doing this practice" sam

[Mart]

I knew of this and had a similar experience with core plugs years ago. I had a small ford sidevalve (100E) motor and the new core plugs I has bought were loose. One Ford main dealer still had dusty nos oversize core plugs in stock. Same as with the mains and cam bores, Ford (and others I suppose) would go oversize to enable otherwise scrap blocks to go out the door.

Interesting stuff.

Mart.

[Walt Dupont--Me.]

That's why I learned years not to through anything away until the engine is done. I align bored engine for 28 years with a big Tobin Arp machine, I did a lot of vintage engine Packard ect, couldn't get mains for a lot of those engines, I'd send the old brg. to Rons Con Rod Service, he would rebabbit the shell to semi then I would bore to crank size. Where there's will there is a relative. Walt

[jake197000]

just sent a set of early packard mains to effingham cams to get rebabbited

[NealinCA]

My dad has one of these engines. Back in the 60's, he rebuilt the engine with new bearings and then promptly broke the crank. When they tore it down they discovered the oversize mains. Luckily he had saved the old bearings, so they put those back in, along with another crank. We still have that engine...not sure what to do with it though.

Neal

[Walt Dupont--Me.]

Originally Posted by Walt Dupont--Me.

That's why I learned years not to through anything away until the engine is done. I align bored engine for 28 years with a big Tobin Arp machine, I did a lot of vintage engine Packard ect, couldn't get mains for a lot of those engines, I'd send the old brg. to Rons Con Rod Service, he would rebabbit the shell to semi then I would bore to crank size. Where there's will there is a relative. Walt

I ment (Paul's con Rod Service) Walt

[barnfind08]

Neal I have those oversized bearings.

[NealinCA]

Ok, I'll let my dad know. Thanks.

[russcc]

I knew Fred would have them.

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Hi, I have one of those blocks. It has a plate on the front right to say that it is 0.015” over on the main journals. Also has 015 stamped on the sump mounting face at the rear of the block.