Question:

If everyone is having to buy custom pistons than why not build a LONG ROD j35 motor? The benefits of LR motors are thoroughly discussed here:

http://www.motoiq.com/MagazineArticl...part-deux.aspx

And

Building the Long Rod Nissan SR20VE Engine

Also LR builds have taken over the evo world it seems when building stroker motors. Typically a 2.4L stroker motor on an evo was good to rev to 7200-7500 or so. Now company's are offering in stock shelf long rod builds that are said to be good to 8,000 rpm with most people atleast revving them to 7800 or so. Here are my thoughts:

The difference between J32 rods and J35 rods is 5mm. If your ordering custom pistons anyway, why not see if they could offset the pistons wrist pins 5mm and run the longer rod J32 rods on the J35 crank? You would essentially build yourself a LR motor and gain all the benefits that come with it.
Thoughts?

 

I thought it was only 3mm difference - 162mm for J32 and 158mm for J35.

Related to this, I was wondering if perhaps the recent J35 failures were due to the lower rod ratio and increased side loading.

 

A J35 has a 1.7 rod ratio and that is about as good as you get from what I remember looked into that when building our J35a8

 

Its true it is good. But when honda made the High Revving F20C in the S2000 they gave it a rod ratio of 1.82, so my thinking was this:
If you can get on the shelf J32 rods, and your having to order custom pistons and pay the custom piston tax.......then why not order long rod pistons and loose a little torque in favor of a much more rev happy motor with less side loads and smoother revving?

PS you are right its not 5mm the difference is actually 3.3 mm

I am only suggesting this since we have access to j32 on the shelf rods as is. If you had to pay custom prices for both the rods and the pistons than it probably wouldn't be worth discussion, but if your already paying for custom pistons and your there than why not right?

 

Ya'll are dissing the J32 - its rod ratio is 1.88 - closing in on some motorcylce territory there, lol.

I never understood why it was such an oversquare motor with such a low redline. My only thinking is that Honda designed the bottom end first - then got the top end to make the power and torque they wanted. If they didn't have to rev it more - why do it.

It would be interesting to see just in general the effect on the torque curve of a long rod J35.

 

Who want's to do the math ? what would the ratio be with J32 rods in a J35.
We used JE piston with offset pins this also helps rod ratio I'm not sure how much ?

 

Using a 162mm rod with 93mm stroke gives you the optimal 1.74 rod ratio.

I don't see how the offset pin would change the rod ratio since its merely rod to stroke ratio. With a stock length rod, it shouldn't change it.

My understanding is that an offset pin moves the pin laterally in the piston bore. How are yours offset? To the minor thrust side or major thrust side? I believe an offset towards the minor thrust results in less friction, but more noise, like piston slap. The opposite is true - towards the major would be more friction but less noise.

 

The pin is moved toward the major thrust side, I thought that changed the angle of the rod ? maybe not

 

So you basically go from a stock J35 rod ratio of 1.70 to a rod ratio of 1.74. Like I said. If you were going to be building the motor anyway and had to order custom pistons, it is my opinion that it just makes sense to order J32 rods and do a Long Rod J35 build. With that rod ratio, forged bottom end with good hardware, and spring and retainers up top......I don't see why the J35 couldn't rev to 7800-8000 all day long. For anyone going the N/A route, we already know that the way to do it is displacement and revs. The obstacle would be getting a good cam in there that makes power up into the 7k range, but companies are doing it so the option is there. For the turbo guys, picking a much larger turbo with a much larger exhaust wheel and housing, freeing up some of the motors VE and getting it farther away from detonation due to cylinder reversion of hot exhaust gasses is a huge plus. Yes that ads lag, but you have more power band to work with anyway. Also having a 7800 redline would make it so having a turbo not come online till 4k wouldn't be such a big deal with another 4k in revs to go.

Thoughts?

 

HERE IS AN EXAMPLE OF OFFSET PISTON PINS AFFECT ON PISTON TRAVER MUCH LIKE A LONG RODS
Created by Camtasia Studio 6

 

Well whoever pops the next motor I would hope you go with a LR motor build with piston pin offset as well. What a nasty motor build that would be. Big torque yet still the ability to rev to 8k. I think we know someone that has built many of these motors before and can put it to the test so it looks like we all vote........yungone501 Build it! :-)