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Discussion Topic:
LB bearing caps
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thespringman |
03-23-2011 @ 6:50 PM
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Member
Posts: 3
Joined: Mar 2011
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have a 36 lb block without main bering caps. Any chance that caps from another block could be made to fit? I assume that they were assembled at the factory and line bored with the block and caps them being a set.
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supereal |
03-23-2011 @ 8:21 PM
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Senior
Posts: 6819
Joined: Oct 2009
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It is unlikely the a poured bearing block can be salvaged unless the bearings are repoured and rebored. Even if you locate new caps, they would have be at least line honed to fit the crank to the correct clearance. This is also true of an insert block.
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ford38v8 |
03-23-2011 @ 10:02 PM
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Springman, Super is the authority on this subject, but I'll offer my layman take on situation you have: I'd think that assuming you locate substitute caps, the block/cap mating surfaces would have to be milled sufficiently to allow a line-bore that wouldn't go oversize for the new inserts. This should work assuming there isn't a significant sideways shift on the caps as mounted. Super, how'd I do?
Alan
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alanwoodieman |
03-24-2011 @ 6:19 AM
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you have a 36 LB block which is the Liner Bearing block that was first produced that year-liner bearings also known as insert bearing (modern name) you might be able to use the bearing caps from a 37-38 21 stud engine?? Of course some machine work would be necessary. I have some caps off of a 40 engine, maybe you could try them?
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supereal |
03-24-2011 @ 11:14 AM
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Alan: I didn't know I had been elevated to the position of "authority"! Maybe now we can increase our shop labor rate! There are two main (no pun) problems with changing the caps. They must be correct in two dimensions, the linearity of the caps, so all line up in the horizontal axis of the block, and the concentricity of the openings to accomodate inserts. These dimensions are measured in thousanths. It is unlikely that there would be enough stock to re-line bore or hone to fit, and still accomodate even oversize bearings, even if the caps and block were milled. The assembly is bored and honed at manufacture. That is why it isn't usually possible to mix up main or rod caps, as they are mated. When we do cylinder boring, we have to be careful that the main caps are correct so the mandrel in the machine holds the block in alignment.
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drkbp |
03-26-2011 @ 7:51 PM
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New Member
Posts: 180
Joined: Aug 2010
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Alanwoodieman, You are probably correct. I was curious the other day when this thread started and just looked at the inserts I have. I have a '36 LB block as a spare and some NORS Monmouth main bearing inserts for it. The box is marked "'36-'38 Ford Main Bearing". Some of the suppliers show a "'37-'38" cap and inserts @ .20, and so on depending on the grind. Might very well be that the crank caps are the same, late '36 thru '38. I have a '38 engine too that is rebuilt but don't remember the caps. Ken in Texas
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37RAGTOPMAN |
03-27-2011 @ 10:33 AM
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if you had the caps and a set of bearing you could just try them, if the cranks is std. use std bearing, put the bearing in the block, rotate the shaft, if no binding try a center bearing with a cap,if it still rotates with no binding try another, after you have all three in installed and have no binding, now take apart and try using plastic guage and see what kind of clearance you have, You also can do this when you do one cap at a time, it might work, its worth a shot to save the block, a good engine rebuilder should be able to center bore the block, the problem is finding oversize bearing after the block is oversized, 37RAGTOPMAN
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ford38v8 |
03-27-2011 @ 11:32 AM
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Posts: 2762
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37ragtopman, Supereal is "a good engine rebuilder", and he tells us that a block with mismatched bearing caps is probably not salvageable. Perhaps you know of a better engine rebuilder than he?
Alan
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37RAGTOPMAN |
03-27-2011 @ 2:19 PM
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Posts: 1961
Joined: Oct 2009
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ford38v8 all was saying I would give it a try and it did NOT work, Would send out and have it the mains bored out, thowing out maybe salvageable blocks will come to a end one of these days, there are a lot of capable rebuilders still around, you just have to seek them out, I know superreal knows what he is talking about. do you think the guy should throw the engine out and give up without a trying to salvage it.? right now I am sorry I even said anthing about it, I will probably pass next time, just my 3 cents worth 37 RAGTOPMAN, I rebuilt my own 37 motor back in 1976 by myself, a friend worked in a auto machine shop, did the valve seats, and bored the engine out and I had the crank cut,assembled the engine with not problems, I was a auto mechanic for a few shops and had my own business for 15 years, it is really not that hard to do, taking your time .
This message was edited by 37RAGTOPMAN on 3-27-11 @ 2:20 PM
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Stroker |
03-27-2011 @ 4:15 PM
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Posts: 1460
Joined: Oct 2009
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I think this thread has probably gone beyond the original question posed by thespringman. Since he started the thread, he has not enlightened any of us as to how badly he needs to return this block to service. Given enough time and money, new main caps can be carved out of billet stock, as has been done by many a racer that needed a stouter center main for a high powered motor. If that wasn't enough, Don Fergueson of Ardun racing fame will build a full girdle in lieu of the wimpy original 3-main set up. Caps can be made, the block can be salvaged, but without some feedback on the scope of the project on the part of the original poster, this dialog is becoming somewhat hypothetical.
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