Real Fiero Tech

Might be in my future.

If I had to guess I'd say the rods are good for up to 600 tq at the crank. After that you're on borrowed time.

Of course this is 600 tq at 4k rpm. As I understand it, lower rpm and 600 tq is even harder on the rods.

I never dynod higher than 15 psi but did hit 20 a couple of times on the street.

is this the engine something recent, or the one you broke a while ago? looks like the rods I pulled out of one of my 454's.

Recently. I'll post more details later

$1710 plus shipping with about a 10 week lead time. There are a few details I need to finalize with Pauter first before I order but I think this is the way I have to go if I want to make reliable power over 500 whp

Shaun41178(2) wrote: ↑Thu Mar 02, 2023 7:48 pm $1710 plus shipping with about a 10 week lead time. There are a few details I need to finalize with Pauter first before I order but I think this is the way I have to go if I want to make reliable power over 500 whp

I assume you're going with steel rods? stock length?

Yes steal. 4340 I think. They make Ti rods too but I'm not doing that

I'll have pics in 10 weeks

Did you buy these rods for the LZ9 but in the meantime you are swapping everything over to an LZ4?

Also are you going to cut another cam for it? I wonder if there is a way to get blanks of the Equinox cam you have, or even just re-grind it instead of having to install new bearing spacers to run a 3400 cam. But I really want to see what that thing can do with some more cam, it's a shame the seat fell out on your built motor. It is probably better for overall longevity to push the powerband up in the RPMs anyways in addition to making more power.

Yea I'm swapping over to an lz4 for the time being. Maybe I'll have the Pauter rods in a built engine ready to go by the winter or next year depending on my motivation. I am going to use my comp cam in the lz4 too that I had in my built 3.9.

If you order a lnj cam, you might be able to send it off to comp cams, and they might be able to do something for a blank, or get blanks for them. They won't do the vvt cam, but they might do the lnj cam. I have never called to ask or sent them the lnj to find out if they have a blank, or would be willing to regrind it.

I agree though, eliminating the need for spacers with a reground lnj, or even a new blank cut would be the overall best way to go.

Did you check into having 4.3 V6 rods narrowed like Upson (I think?) did? I thought some variation of the 4.3's have the same 2.250" rod journals as the LZ4/LZ9 do. You'd need custom pistons to set the piston deck correctly, but those are cheaper than custom rods.

Going to do an unboxing video?

The Dark Side of Will wrote: ↑Fri Apr 14, 2023 8:39 pm Did you check into having 4.3 V6 rods narrowed like Upson (I think?) did? I thought some variation of the 4.3's have the same 2.250" rod journals as the LZ4/LZ9 do. You'd need custom pistons to set the piston deck correctly, but those are cheaper than custom rods.

Going to do an unboxing video?

5.967" for 2.25" journals, ironically, they're 3800 rods

https://www.summitracing.com/parts/esp-5967b3d

The Dark Side of Will wrote: ↑Fri Apr 14, 2023 8:39 pm Did you check into having 4.3 V6 rods narrowed like Upson (I think?) did? I thought some variation of the 4.3's have the same 2.250" rod journals as the LZ4/LZ9 do. You'd need custom pistons to set the piston deck correctly, but those are cheaper than custom rods.

Going to do an unboxing video?

Upsin used sbc rods of 5.7, and then had the crank offset ground and the journals ground to the 2.0 sbc journal.

I looked at the 3800 rods too. Either too long or too short for off the shelf ls1 pistons I want to use

I also don't want a hodge podge of parts that need machining and the machinist gets it wrong. Upson had got a crank that wasn't machined correctly and had to pay again.

Drop in replacement forged Pistons stock bore. JE 321237. Has a 19cc dish. Compression ratio comes out to 11.1:1. I believe JE says they weigh 421 grams. Not sure what stock is.

.007 overbore is JE 321238 with a 21cc dish. CR is about the same.

$750 at summit with about a 4 week lead time.

These pistons have a 1.34 compression height which puts the piston about .004 out of the hole with the 5.827 Pauter rods if the crank is a true 3.31 and the deck is 8.818.

Are you assuming your block won't need to be decked?

I used the je 321238 overbore pistons on my first build. Block did not need to be decked. But the pistons sat .006 in the hole instead of proud by .004. either due to the crank slightly short of the 3.31 stroke, the deckheight more than 8.818 by a smidge, or a combo of the two.

It didn't matter to me, it was all close enough.

But the JE pistons are a true 100% bolt in piston. I don't recommend forged Pistons if using stock rods. Stock pistons can handle 500 HP just fine.

I have a 130k mile 3.9 here still assembled I'll prob try the stock bore JE pistons with a ball hone only in the cylinders to allow new rings to seat.

Usually we are used to seeing I or H beam connecting rods, so I thought the cruciform section was interesting.

I found this explanation on their website:
https://pauter.com/parts/rods

pmbrunelle wrote: ↑Wed Jun 21, 2023 6:35 pm Usually we are used to seeing I or H beam connecting rods, so I thought the cruciform section was interesting.

I found this explanation on their website:
https://pauter.com/parts/rods

I wouldn't mind reading their analyses of this topic. A column's resistance to buckling is related to the radius of gyration of the cross section... Which I would expect to be larger in an H-beam or I-beam rod than for a cruciform rod, but I haven't done any calculations myself.