Main Caps

[jmwj03]

OK, Since my "difference in studs" thread went so deep, rather than add to it, i am starting a new one about main caps. This one is pretty simple.

I am going to change the main caps to something a little beefier. Up until today, I thought I had 2 choices:

1) Eagle billet steel for about $79. Since it is a BBC, Eacle only makes a straight bolt design...no splayed even on the center caps.

2) Milodon billet steel for $250. These are splayed on the center caps, and Milodon even has a fron cap available for another $100.

Both claim to be billet steel, but Milodon makes a point to indicate theirs are a stronger steel than other manufacturers.

Today my brother in law found a deal on some billet aluminum caps. All 5 of them (although the rear would require me to use a dry sump) and the centers are splayed. My thinking is they are similar to what Pro Stock uses. My original thought was they would be too soft, until I thought about the Pro Stockers using them on iron blocks. I believe aluminum caps were also offer by the DRCE blocks?

What does everyone think of the different versions? I think I can get the aluminums for nothing, and since I have to align hone/bore the mains regardless, the machining costs wont change. Certainly free is very appealing, but I know nothing about them and what to expect.

[jmwj03]

Oh, I would be open to other manufacturers as well, Eagle and Milodon are really the only two I know of.

[rookie]

I'm not sure on BBC but on SBC you have to start with a two bolt block to go splayed,
just FYI.

[jmwj03]

Yeah, I have a 2 bolt block already. I am going to upgrade to 4 bolts, splayed or unsplayed, just dont know which material caps to buy. I can go Eagle straight (steel) or Milodon splayed steel or splayed aluminum.

[Dusty]

Two more possibilities pro-gram engineering and possibly prw used their small block caps don't know if the make bbc stuff

[jmwj03]

Thanks Dusty. I had found the Pro-gram Engineering after I posted and was searching the net for opinions. Looks like they make an identical type set to the aluminum ones I was offered, but they appear to be steel. Over $800 for the whole set. Definately makes the aluminum even more attractive if they're any good.

The PRW seem to be the same encounter I am having between Eagle and Milondon. The PRW are listed as 1020 billet steel. The Eagles are listed as 4130, and the Milodons are listed as "high strength ductile material." Correct me if I am wrong, but the 4130 should be better than the 1020. As for the Milodon, it's anyone's guess.

[Dusty]

i would think it would be easier to get the main bearing shells to the right size with the 1020 vs the 4130

[jmwj03]

Now that I agree with...but what about holding up? I thought the same thing about the aluminum caps...was afraid the hone/bore would favor the soft aluminum and not touch the block.

[old blue 75]

IIRC Oliver makes caps also. Correct me if i am wrong but on MKIV bbc's you can't
use splayed mains because you will hit oil in the pan rail oil galley.

[jmwj03]

Originally Posted by old blue 75

IIRC Oliver makes caps also. Correct me if i am wrong but on MKIV bbc's you can't
use splayed mains because you will hit oil in the pan rail oil galley.

I'll look into the Olivers as well. Thank you.

While it is true that the oil galley is right above the pan rail, I think it's fine. The ones I've now researched with splayed do indicate a number of warnings about the drill depth so as no to hit the galley, but in looking at it you would have to go through quite a bit of iron to do it. I think as long as one were careful (or the machine shop was careful) it would be fine.