6 Bolt 4G64 Main Caps Question

[Ninety7GSX]

I just picked up a 92 4g64 6 bolt today from a mitsu van. Upon pulling it apart I found that the main caps are all separate. 1G's have the outers and inners bridged (combined) and 2g's have a full bridge setup. I was under the impression that this is done to allow a motor to rev high more safely.

Are all the 6 bolt 2.4's like this and should I be worried about revving it high like this?? The plan for the motor is to destroke and use stroker pistons for a 162mm long rod setup.

I was thinking about swapping the main caps from a 2.0 6 bolt and having an align hone done. I test fit a set of main caps from a 6 bolt 2.0 and the caps seemed to fit correctly. Whats you guys' opinions??

[James92TSi]

Originally posted by Ninety7GSX
I was thinking about swapping the main caps from a 2.0 6 bolt and having an align hone done. Do that, with ARP mains.

[TEC]

Originally posted by Ninety7GSX
I just picked up a 92 4g64 6 bolt today from a mitsu van. Upon pulling it apart I found that the main caps are all separate. 1G's have the outers and inners bridged (combined) and 2g's have a full bridge setup. I was under the impression that this is done to allow a motor to rev high more safely.

Are all the 6 bolt 2.4's like this and should I be worried about revving it high like this?? The plan for the motor is to destroke and use stroker pistons for a 162mm long rod setup.

I was thinking about swapping the main caps from a 2.0 6 bolt and having an align hone done. I test fit a set of main caps from a 6 bolt 2.0 and the caps seemed to fit correctly. Whats you guys' opinions??

Yep. I found the same thing on a block that I picked up. It should work out fine with the seperate caps, just make sure you use new main bolts or ARP hardware.

Switching main caps from one block to another can give your machinist hell. If I were your machinist I might charge you the normal fee, plus additional shop hours to even attempt to align hone the block. Discuss what you are thinking on this with your machinist, if he doesn't shoot you first for suggesting this, he can at least let you know if it is possible.

[redawdturbo]

Originally posted by TEC
Yep. I found the same thing on a block that I picked up. It should work out fine with the seperate caps, just make sure you use new main bolts or ARP hardware.

Switching main caps from one block to another can give your machinist hell. If I were your machinist I might charge you the normal fee, plus additional shop hours to even attempt to align hone the block. Discuss what you are thinking on this with your machinist, if he doesn't shoot you first for suggesting this, he can at least let you know if it is possible.

The 2.4 mains have been used pretty sucessfully in engines producing in excess of 600whp. The 2.4 block is cast with extra webbing in it that helps to compenate for the lack of bridging in the maincaps.

Depending on the machinists experience and skill, swapping the mains may prove to more of a problem for you than a benefit, and could ruin the entire block if it isn't done perfectly. It is highly recommended NOT to interchange main caps from other engines. Doing so would be playing russian roulette with your block imho.

[Ninety7GSX]

Sorry my post wasn't in the proper section. Figured I'd get more intelligent responces in there.

Originally posted by James92TSi
Do that, with ARP mains.

That was my thinking. The 6 bolt I had dowel pinned and was running arps, so only the block side would need to be reemed for the pins then of coarse the align hone.

I was worried about the mains working properly. I'm not a fan of switching caps, but figured if the extra strength was worth the hassle I'd go for it. I talked to the machinist that will be doing the block. He seemed to be gungho about it. But, if its working for everyone else I don't see why I should go messing it up. :)

Has anyone seen block girdles or anything of the sort for this motor?

[High Booster]

Leave well enough alone. The 64 mains are strong as hell. Also a van engine may or may not bolt on a dsm transmission case. The tranny bolt pattern on truck blocks are 13 1/4 inch or so. The 2.0 awd/fwd tranny case it is about a inch narrower. Measure to be sure ok.

[Ninety7GSX]

I was told its the same.
I have a broken trans that the case is apart I will check it first.

Thanks didn't think to make sure. Would been sucky to spend money on the block and find it doesn't work.

Thanks for everyones help

[Ninety7GSX]

the bellhousing fits

I was under the impression people were running into probs with the rwd 2.4's?

[Boosted3000GT]

The 4G64 is the same as the 4g63 only with a taller deck height and slightly larger bore in the cylinders right? If that's the case, why NOT take the main caps and girdle out of the 2.0 and place it int he 2.4. I think it's an awesome idea. It's a mronic and impossible thing to do if you're not align honing it, but you are, you could pust any main caps that fit on there, as long as it's properly honed it's not a problem. The honing cost should be roughly the same either way. And if your machinist is loving the idea, why not give it a shot?

I'd never given it much thought really, but if they just bolted right up and it was only a matter of getting the journals perfectly round, I'd do it in a heart beat...


Good luck with wichever method you choose...

Mike

[redawdturbo]

http://www.jacksonautomachine.com/images/products/2-0billetcaps.jpg

Jackson Auto Machine (http://www.jacksonautomachine.com/html/shopping/list_section.cfm?sectionId=2) makes these billet main caps for the 4g63. Scroll down ~5 items on their webpage.:)

[DJpowerHaus]

So if the "upgrade" solution is non-bridged caps, then we can infer that the difference between bridged and non-bridged caps is nominal.