Any Quality Difference from Main Girdle To Main Girdle?

[90lxcoupe]

there is a support system that i just saw a week or two ago that looks like it is more usefful than the standard girdles. it ties the main caps together and from what i remember it also uses the blot holes where the oil pan connects. if i was to go with a main support thats the one i would choose.

there is someone using that setup and a mexican block, and is at somewhere around 800 hp.

o think it was a thread started by tt91 if i remember correctly.

 

[txstang84]

yeah, ck out: www.prcinc.com

it's just like what you said, main caps tie to each other with a big tie over to the oil pan rail. I remember doing that search. but here's where the whole mexican block thing get's confusing...after making calls to tech support lines, looking at junk yard blocks, and many other research stops, I've noticed that the only difference between the pre-'74 blocks and the mexican/289Hi-Po blocks was the caps...that's it, nothing more, nothing less. All of them have blind tapped bolt holes in the mains and the deck, all of them have the same block thicknesses-not accounting for core shift-and all of them were better alloy than the newer blocks. So, that's why I mentioned just taking an old block-of which there are thousands available-and putting some good caps on it with a line bore, and some new studs.

 

[65ShelbyClone]

With all the trouble people go to building block supports and whatnot, I'm surprised nobody has made a one-piece main cap assembly. I think Nissan's RB26DETT is that way and its a 2.6L I-6 that can be built up to around 1200hp.

 

[CoupedUp1]

.... I'm surprised nobody has made a one-piece main cap assembly.

Sounds like the way to go.

Just a couple of thoughts though:
The manufacturing tolerances would have to be controlled to ensure that from the fore cap location to the aft is within acceptable parameters and ... and each in between.
The idea may have been thrown around, but the cost associated in cast/forged units, the success rates and QC'ing them may be more than most companies want to get into.

 

[txstang84]

the biggest problem isn't the caps on the block though, putting on the new caps can help you, but the primary problem is the way the stock blocks are cast and machined. obviously, cap walk is bad, but even if they don't move, the block still doesn't have the beef to handle the abuse that they are commonly subjected to. compare a windsors mains to a SBC's main webbing...it doesn't taper off like a windsor, the bolt holes are not tapped through a bulkhead-they are blind. This is why blocks like the R, A4, Dart or WP can handle the power levels exceeding 1000.

 

[65ShelbyClone]

Just a couple of thoughts though:
The manufacturing tolerances would have to be controlled to ensure that from the fore cap location to the aft is within acceptable parameters and ... and each in between.
The idea may have been thrown around, but the cost associated in cast/forged units, the success rates and QC'ing them may be more than most companies want to get into.

Keeping tolerances is no problem in the CNC age. The difficulty is convincing customers that cap walk is a problem when its actually the block that is a problem. A one-piece main assembly might be a consideration on something like a Dart or World block, but even they dont have walk issues at 1000+hp & 10,000rpm. It just wouldnt be cost effective with a stock block. I was just poking fun at the aftermarket and all the block supports that dont help.

 

[CoupedUp1]

Keeping tolerances is no problem in the CNC age ...

I wasn't saying it could not be done ...
Just with a cast/mold setup, the one-piece main cap would require additional machining or CNC work.

Additional machining and the tooling to make it happen would incrue additional cost and is probably the main reason it isn't done more often.
The poor harmonics of the rotating assembly in a 5.0 is another reason they are prone to splitting.

 

[pb_paulie_b]

yeah, ck out: www.prcinc.com

it's just like what you said, main caps tie to each other with a big tie over to the oil pan rail. I remember doing that search. but here's where the whole mexican block thing get's confusing...after making calls to tech support lines, looking at junk yard blocks, and many other research stops, I've noticed that the only difference between the pre-'74 blocks and the mexican/289Hi-Po blocks was the caps...that's it, nothing more, nothing less. All of them have blind tapped bolt holes in the mains and the deck, all of them have the same block thicknesses-not accounting for core shift-and all of them were better alloy than the newer blocks. So, that's why I mentioned just taking an old block-of which there are thousands available-and putting some good caps on it with a line bore, and some new studs.

Is there a main support like this available yet?