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Aluminum Main caps from one block to another??? #2597818
12/28/18 12:04 AM
12/28/18 12:04 AM
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Btween a rock and a hard place
moparlulu Offline OP
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I have a set of bcr aluminum main caps in 1 block that's damaged. I don't want to mess with it. I'd like to use them in a different block. is this even feasible? Other than having a line bore done, would they fit the cap registers ok? I realize only the shop will know for sure, but was just wondering if anyone had reused a set???

Re: Aluminum Main caps from one block to another??? [Re: moparlulu] #2597825
12/28/18 12:28 AM
12/28/18 12:28 AM
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Bend,OR USA
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Try fitting them on the new block to see if they fit or not scope twocents


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Aluminum Main caps from one block to another??? [Re: moparlulu] #2597841
12/28/18 01:11 AM
12/28/18 01:11 AM
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Warren, MI
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Jerry Offline
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depends on what kind of damage the block sustained? as long as the edges of the caps are damaged that interface with the block you're good


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Re: Aluminum Main caps from one block to another??? [Re: moparlulu] #2597844
12/28/18 01:25 AM
12/28/18 01:25 AM
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Salt Lake City
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camastomcat Offline
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No matter what, they will need to be fit and align honed for the new block.

Re: Aluminum Main caps from one block to another??? [Re: moparlulu] #2597845
12/28/18 01:25 AM
12/28/18 01:25 AM
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gulfport, ms, west mi
rowin4 Offline
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The only reason that I can see why they wouldn't fit if when the damage occurred it may have damaged the caps. Other had that probably a slight clean up with a align bore. The caps are made to fit any block of the same main journal size.


it's ok to butt heads, just don't do it with a butthead
Re: Aluminum Main caps from one block to another??? [Re: moparlulu] #2597870
12/28/18 03:02 AM
12/28/18 03:02 AM
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Fancy Farm Ky
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Jim, should be fine, Im sure they will need a light cut and line bore, but should be fine after that.

Re: Aluminum Main caps from one block to another??? [Re: moparlulu] #2597877
12/28/18 03:37 AM
12/28/18 03:37 AM
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Btween a rock and a hard place
moparlulu Offline OP
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The old block developed a crack in #8 cyl bore. that's the main reason I'm changing blocks. I knew I'd have to have the other block aligned bored was just wondering about the fitting of the cap from one to the other, as I was under the impression it was a block specific kind of thing.

Re: Aluminum Main caps from one block to another??? [Re: wyoming] #2597879
12/28/18 03:43 AM
12/28/18 03:43 AM
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Btween a rock and a hard place
moparlulu Offline OP
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Hey Glenn! How's Kentucky treating you? Bet the winters not like Wyoming's!!! Miss seeing your car at Firebird...

Re: Aluminum Main caps from one block to another??? [Re: moparlulu] #2597930
12/28/18 11:11 AM
12/28/18 11:11 AM
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Washington
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Originally Posted By moparlulu
The old block developed a crack in #8 cyl bore. that's the main reason I'm changing blocks. I knew I'd have to have the other block aligned bored was just wondering about the fitting of the cap from one to the other, as I was under the impression it was a block specific kind of thing.


As long as they fit tight in the registers you'll be GTG. You may have to cut a bit off the caps to get something to work with. I've done it may times.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: Aluminum Main caps from one block to another??? [Re: moparlulu] #2597985
12/28/18 02:40 PM
12/28/18 02:40 PM
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Aurora, Colorado
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Can't you sleeve the cylinder? It would be less expensive.
Should be able to fit the caps to the new block, shave a bit off and resize (bore, hone) for the new block. If using the girdle, would need to machine the oil pan rails to the caps again.

Re: Aluminum Main caps from one block to another??? [Re: moparlulu] #2597998
12/28/18 03:10 PM
12/28/18 03:10 PM
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NW Indiana USA
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I had that done with my recent 440 build. Mine were 440 source caps though.
They said sometimes they have to weld some on the side of the cap to center it over the bore. Keith

Re: Aluminum Main caps from one block to another??? [Re: moparlulu] #2598001
12/28/18 03:15 PM
12/28/18 03:15 PM
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Bend,OR USA
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Did it crack the cylinder wall only or is it cracked down in the main webbing ?


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Aluminum Main caps from one block to another??? [Re: Cab_Burge] #2598252
12/29/18 06:06 AM
12/29/18 06:06 AM
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Btween a rock and a hard place
moparlulu Offline OP
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It cracked the wall vertically. On the non thrust side. the thing always ran warm. Non fill. I'm thinking it has some thin walls. -8 on the block. The machine shop I was using didn't sonic check it. The block I'm going to hopefully use after it gets checked for thickness is a -2. We'll see if it's any good. Thanks for the info fellas!

Re: Aluminum Main caps from one block to another??? [Re: moparlulu] #2598470
12/29/18 06:30 PM
12/29/18 06:30 PM
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Val-haul-ass... eventually
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I think my level of confidence in reusing aluminum main caps in a different block would have a lot to do with how long they've been in service. It would have to have been a pretty limited amount of prior usage for me to consider it, given I've seen a few broken aluminum main caps from more than one brand (including the ones my fresh block is machined to use).

Re: Aluminum Main caps from one block to another??? [Re: moparlulu] #2598828
12/30/18 03:23 PM
12/30/18 03:23 PM
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Warren, MI
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Jerry Offline
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7075 aluminum has a higher tendency to crack since they are harder. at bcr we have had a few caps crack from guys really pushing the envelope over the years, but the percentage of caps that cracked vs the percentage that we produced is down around .1%


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Re: Aluminum Main caps from one block to another??? [Re: Jerry] #2598920
12/30/18 07:31 PM
12/30/18 07:31 PM
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Posts: 771
Btween a rock and a hard place
moparlulu Offline OP
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Originally Posted By Jerry
7075 aluminum has a higher tendency to crack since they are harder. at bcr we have had a few caps crack from guys really pushing the envelope over the years, but the percentage of caps that cracked vs the percentage that we produced is down around .1%
Nice! This motor is and was a fairly mild engine compared to most street/strip motors on here. Really, did I even need them??? I'm not concerned in the least about breaking a cap, I just liked the idea of "Lessing the load on a block"...... Hindsight........ should of went to a different shop that checked thickness in the first place. lesson learner!!! Thank again everyone







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