Connecting rod Bottom end width.

[Plechtan]

I was looking at getting some special rods made, I can't seem to find the spec for the Jeep rod connecting rod width anywhere. I fould the Chevy 6, It's 1.029, but wb=hat is the jeep size and can you use the chevy rod without modification?

[Muad'Dib]

You did check the FAQ right??

viewtopic.php?f=27&t=53

[Plechtan]

Yes, i had previously read that thread after doing a serrch for "connecting rod" on the forum. It still does not answer the question i posed.

[John]

1.060 for one laying on my bench.
John

[Plechtan]

I found a spec, sort of, the crank journal width spec is 1.070 to 1.076 The rod clearance spec is .010-.019 So a 1.060 width rod with would give you .010 clearance if the crank was at the minimum spec and .016 if it was in the high side, but the rod needs a tolerance too, so 1.059 +- .001 looks like a good spec. you need this number if you are getting custom connecting rods made. Using chevy 6 cylinder rods @ 1.029 width, you end up .020 short on width or .041 side clearance, more than double the .019 spec.

[Alex22]

i just measured an extra 4.0 rod I had laying around and I got 1.055.

If you look at page 7 of the SCAT catalog it lists the Chevy I6 rod with a big end width of 1.050 which would give .001 extra side clearance from the stock spec.
http://scatcrankshafts.com/PDFs/ScatCrank07.pdf

I found this set of Eagle connecting rods that are meant for a 4.2 with a 6.125 c-c. Big end width of 1.063 and they use a .912 wrist pin (SB Ford) Interesting combo.
http://www.cnc-motorsports.com/product. ... CtgID=8081

Last time I tried to order a set of the Eagle connecting rods, the H-beam rods built to the stock 4.2 specs they had been discontinued, about two years ago. Maybe Eagle started producing them again, but thats a hefty price tag.

~Alex

[John]

I don't think they started producing them again, but they are still to be found, at a premium. I know of properly prepped 4.0 rods dealing with 400 HP + turbo motors without issues.
John

[seanyb505]

505 Performance sells forged stroker kits on ebay for 1250. That includes Ross pistons and the eagle rods, among a couple other things. Id like to think that they could sell just the rods themselves.

[Alex22]

I don't think they started producing them again, but they are still to be found, at a premium. I know of properly prepped 4.0 rods dealing with 400 HP + turbo motors without issues.
John

In the end it comes down to how much time you have Vs. how much money you have. Not saying that i'm loaded by any means, but I'm going with the SCAT rods because I just don't want to put that much work into a set of stock rods and I'll have a 2.000 rod journal with more stroke than before.

~Alex

[John]

Alex, what is the performance goals you are building for? Yeah prepping rods is time consuming. But takes less time that cleaning up after a 3" X 4" jagged hole I put in one block......I do like the idea of 2" journals.
John

[Alex22]

Alex, what is the performance goals you are building for? Yeah prepping rods is time consuming. But takes less time that cleaning up after a 3" X 4" jagged hole I put in one block......I do like the idea of 2" journals.
John

I haven't set any real goals yet, This has become a side project I work on after hours when I have time for it. I'd like 300ft-lb at the flywheel and whatever HP comes allong with it, but that isn't set in stone yet. Another less important goal of this build is to figure out how to get a part from every major manufacturer into this engine.

~Alex