Main Caps: stock or aftermarket?

[ereckerdeet]

Hi, I'm building up my 4g63 with a stroker crank. With ARP main studs, what kinda horsepower will the stock main caps be able to hold down. Is there an aftermarket set of caps which will hold up better? I'll refrain from posting my 'bench racing' estimates but we'll say it's an all out drag motor, just don't wanna see these things coming apart.

Thanks for any insight!
~Eric

 

[sho_tyme_psi]

There are a few differnt places that have these. I know jackson machine has some @$500. And I recently found these and will be buying them for my RACE motor.

http://cgi.ebay.com/ebaymotors/ws/e...d=1,1&item=8041558544&sspagename=STRK:MEWA:IT

I think if your not exceding the 800hp mark I would leave it stock. But allways nice to have the peice of mind when you cranking the hell out of it. Where is lebanon located in indiana at?

 

[fourreGsixty3]

Check these out>>>http://www.slowboyracing.com/shop.p...40&PHPSESSID=be7e121f756c6239263a3c1ea1cea613
Those are real nice ones, tested at 90k psi compared to 30k psi stock ones are tested at and they come with ARP bolts and all for 500$, damn good deal if you ask me. Ill be putting those in my engine winter of '06 when I pull it and completely work it over with internals.

 

[ereckerdeet]

Hey great links, thanks guys I really appreciate it!
~Eric

 

[project_tsi]

This is all you would ever need. Kiggly himself runs stock mains (low 9 sec fwd 1) and uses his main girdle.

http://www.kigglyracing.com/Main_Girdle.htm

Besides that, how many engine failures have you seen b/c a main has broken??? Exactly. Plain and simply, these bad boys are not needed unless your shep, and honestly, I'm not so sure that he even runs them.

But if you do decide to get these main caps, hopefully you know the mains have to line honed.

 

[kiggly]

I've never seen a main cap break. That happens at some level beyond when people start breaking cylinder walls. I've seen problems with stiffness and the caps fretting where they contact the block, as I have a picture of. The caps seem to flex front-back in the motor (side-side car reference), pivoting on each cap's bolt axis. The Pro Gram caps alone do not address any stiffness problems without their girdle (with their girdle is the nearly $1k version). I don't know if you can use their girdle and still bolt the oil pan on with a transfer case under it. That is one reason my part is designed to fit inside the OEM oil pan.

Now, the Pro Gram caps will get rid of all the fretting problems because they are a different, harder alloy than the OEM block. Whenever there are 2 similar hardness surfaces working against each other, there will be fretting and galling. This is what happens with the OEM caps and block that are cast of the same alloy. With the Pro Gram caps alone, it won't fret or mess up the surfaces no matter how much it is working the parts against each other. The fretting is a symptom of the flexing problem. The caps treat the symptom, the girdle treats the problem.

Although I don't particularly recommend it, I have installed my main girdle in my race engine without line honing it. It hasn't ever been line honed, but if you were to install it in a motor that has been line honed, it would need to be line honed with the girdle installed (the caps end up at different heights after line honing and would probably pull around with the girdle).

Kevin