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HEAVY DUTY BILLET MAIN CAPS???

Posted By: Labratt

HEAVY DUTY BILLET MAIN CAPS??? - 11/07/11 09:32 PM

Randy Johnson(Dartin)and I pulled the engine and trans out of the GTX last weekend,and I was wondering what would have to be done to replace the factory main caps with some good after-market replacements? Would everything have to come apart...and the block/caps be line bored?...or just swapped,and clearances checked? Thanks in advance! Randy B.
Posted By: BradH

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/07/11 09:46 PM

If you want "bolt on", get a $300 girdle. If you want new caps, it'll require additional machine work for the installation that will about double the price over the girdle kit. I'd think the girdle will be all you need at your power level.
Posted By: CompWedgeEngines

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/07/11 09:54 PM

Randy,

ANY change of caps typically requires a new align BORE, and then an align HONE. Most caps are undersized to the point where they are intended to be bored first. Some of the newer computerized equipment like a Rotller F series may be able to bore to size. Make sure what ever you do, save your #1 and #5 cap for reference points for the machinist.

Its common to have anywhere from about .060 +/-plus .125 that needs to be bored out depending on whose and what caps you are purchasing. Boring and honing are two seperate process' for the most part.
Posted By: Performance Only

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/07/11 10:34 PM

Quote:

Randy,

ANY change of caps typically requires a new align BORE, and then an align HONE. Most caps are undersized to the point where they are intended to be bored first. Some of the newer computerized equipment like a Rotller F series may be able to bore to size. Make sure what ever you do, save your #1 and #5 cap for reference points for the machinist.

Its common to have anywhere from about .060 +/-plus .125 that needs to be bored out depending on whose and what caps you are purchasing. Boring and honing are two seperate process' for the most part.



as usual, good advice Todd. we use the F series Rottler and we do bore to size, no honing needed. we would not need the old main caps however. we routinely do that job and yes, anywhere from .060-.125 comes out of almost any new cap.
Posted By: Labratt

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/08/11 12:46 AM

Thank You guys! We are VERY LUCKY to have you guys around for your knowledge...and valuable time that you share with us! I just might go the girdle route,since it's a simple bolt-on! Thanks for the idea,Brad! Randy B
Posted By: WILD BILL

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/08/11 12:51 AM

Wouldn't installing a girdle require changing to studs in the mains resulting in the mains needing line honed at a minimum?
Posted By: nss guy

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/08/11 01:27 AM

this is just a thought,
due to the integrity of a 'stock' block are these mods needed?
How much $
Is this cost effective?
After x amount of runs buy another stock block and swap rotating assy.
or buy an aftermarket block and be done.

I'm in the same situation, I am keeping a count on the runs of the block and it's condition, especially in the main cap webbing.
If cracks are starting I switch to another block and keep going.
Done this for about the last 10yrs now on my 2nd block 400-500 runs each block
before the cracks start to appear
Posted By: WO23Coronet

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/08/11 01:33 AM

A technical question for the machinists here (I'm a machinist by trade but not an automotive one). What is the process for line boring the mains? I mean do you dial in the front and rear main and go from there? How much material do you take off of the block portion of the mains?
Posted By: 440Jim

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/08/11 01:36 AM

Your thinking is correct.
But there is no way to know for sure if any particular block will hold up for any particular number of passes, at any particular power/rpm level. That block and mains could come apart at 5 passes or 500. And if it does it could take out a lot of expensive parts around it.

IMO, if you are pushing things (and I am); you need to reduce your risk by careful inspection of parts (block sonic check, magnaflux mains, etc), setup, assembly, and routine inspections to hopefully catch any developing issues before you waste the whole thing. Or pay the big bucks up front (which is no guarantee of not blowing up for other reasons).

You make your choices, and take your chances.
Posted By: 383man

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/08/11 03:01 AM

Randy I went with the steel main caps and ARP main studs on my 493. I also had the caps line honed. I only race my car and run it hard a few weekends a year so I felt I should be good with that as the rest of the time I just cruise in my car so its not like I race it every weekend and I think you do about the same as a street/strip car ? Ron
Posted By: Labratt

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/08/11 03:45 AM

Ron..you are correct! I only race 3-6 times a year...but,once in a while...I do hammer it on the street! ...LOTS of paved country roads and corn fields out here in Memphis! I'm just going to pull the pan,inspect the lower-end,including the main and rod bearings...and go from there. As Brad H. suggested,I'll look into the bottom-end girdle set-up.

Attached picture 6908894-ENGINEANDTRANSOUT-11-5-2011006.jpg
Posted By: WILD BILL

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/08/11 09:42 PM

Quote:

Wouldn't installing a girdle require changing to studs in the mains resulting in the mains needing line honed at a minimum?




Posted By: JohnRR

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/08/11 10:23 PM

Quote:

Quote:

Wouldn't installing a girdle require changing to studs in the mains resulting in the mains needing line honed at a minimum?








If the gridle uses studs and he doesn't have studs already then yes he should have it line honed .

Randy also realize that pan gets 1/2" to 3/4" closer to the street and you have to extend your pickup back to the bottom of the pan.
Posted By: 383man

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/08/11 10:51 PM

Any time I change anything in the main bearing area I have it lined honed. Ron
Posted By: BB Dart 69

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/09/11 03:30 PM

alum mains from Best in mine No gridle, nine seasons and you know how i drive it
Posted By: fourgearsavoy

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/10/11 01:36 AM

Hi Randy I really think at your power level just put some new ARP studs in it and have it honed If your caps are going to break then most likely the block will crack as well So I figure use it until it breaks then call Koffel's and get a new aftermarket block.Don't waste your money on a band-aid
Now that being said the next time I take my car out and beat it my caps will break
Gus

Attached picture 6911754-burnoutpicturegus.JPG
Posted By: Labratt

Re: HEAVY DUTY BILLET MAIN CAPS??? - 11/10/11 01:46 AM

Hello,Gus! Thanks for those "words of wisdom"! So,I'll just BEAT ON IT until it decides to "give up the ghost"!
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