H-beam rods, billet cranks and Forged pistons for F motors? (1 Viewer)

[stereophile33]

So I have been into FJ's since my grandfather first took me out as a young 4 year old in his.

I have been slowly getting my cruiser to a stage 0 steup that is both reliable and enjoyable.

Well for the last few years, I own and drive/race classic Volvo's. I own R-Sport International, a performance Volvo company that designs and manufacturers performance and restoration parts.

Well I am looking at taking what I have learned and the contacts I have made and start doing stuff for my FJ.

Would there be any interest in Forged H-beam long rods, Billet cranks, or Wiseco forged lightweight pistons.

My goal with my personal Volvo was 400hp with 100,000 miles reliability. So not all out performance, but performance that lasts.

Is there interest in doing some fun motor work with FJ's?

Rods are $100 a rod with ARP2000 bolts. 4340 Billet cranks are $600-700 and pistons would be around $140 a piston.

Take a look at our website, even though it hasnt been updated lately, but let m e know if this sort of thing interests anyone besides myself.
Thanks,
Jonathan

www.r-sportinternational.com

 

[agent orange]

600 bucks for a billet f motor crank? Thats cheap for billet.

 

[bjowett]

I might be, or know of some folks that would be interested in the crank.

My local Volvo dealer got rid of some very rare Volvo's about 6 years ago. I don't recall the exact models.... I know one of the 240's had something to do with the touring car circuit.

 

[Uncle Ben]

I would probably be interested if those are close in pricing.

 

[Mace]

cranks typically hold up,

The rod bolts stretch and the main webs die..

how many HP are you expecting to get out of these motors??

 

[Mark W]

Seems kinda steep for pistons.

The stock cranks are stout as hell. They are the strongest link in the bottom end.

Biggest gain for this engine would be lighter rods (and pistons). I've yet to see a stock rod fail unless the rod bolt has failed first.

#1 upgrade, rod bolts.
#2 upgrade, lighter rods
#3 upgrade, lighter/stronger pistons (lighter more important than stronger).

The head won't support real high rpm use anyway and 5000-6000 is about as high as there is any point in pushing it.


(I have not encountered any engines which have suffer main bearing cap failure. Just rod caps.)

Keep an eye on oiling. Achilles heel for this engine.

And I assume that you are actually talking abut the 2F, not the F engine. Really no reason to start a high performance build with smaller bore and an archaic oiling system.


Mark...

 

[Moby]

I thought about parts like these for my ongoing rebuild. Priced custom lightweight pistons and rods. Looked into Man-a-fre's forged piston as well (basically the same price as custom JEs). In the end for the rpm range that my motor is going to see I decided that it wasn't worth it. I did ask for upgraded rod bolts though. Now if these parts had been available off the self without having to go custom when I started my rebuild my geekier side might have been able to convince me that I really needed this kind of stuff

 

[stereophile33]

sorry guys, I have been in Minnesota at St. Olaf for my brother-in-law's graduation.

As for all the questions. The reason the pistons are so much is that they are designed by Larry Widmer, of NASCAR fame. www.theoldone.com

I offer them just because he does an amazing job, I don't try and make any money at all...like $50

As for motors, yes I was actually referring to the F series of motors, not the actual F motor.

The rods would be longer/lighter/and stronger, and allow the pistons to be much lighter.

As for performance goals, the older Volvo motors are a non-crossflow design as well and we can reliably get 220hp out of 4 cylinder tractor motor that revs to 6500.

So I would expect that out of a 6 cylinder F motor that revs to 6k that 200-250 would be extrememly possible with lots of torque, and still be reliable.

Check out some of Larry;s piston info as he would take a head and flow the head, computer model the flow through the head, and then make pistons that optimise that flow.

Let me know if you have any more questions.
Thanks,
Jonathan

 

[Mark W]

Yep, those power levels should be very do-able.

How much longer are you talking about on the rods and how much lighter on the rods/pistons?


Mark...

 

[Moby]

The rods would be longer/lighter/and stronger, and allow the pistons to be much lighter.

I'm curious - why longer? The 2F already has a 1.88 rod ratio which seems pretty close to optimal in terms of peak loads on the other bottom end components and cylinder walls (especially compared to a 3F). Not trying to be argumentative, I think that it's great that this family of engines is getting some options for the bottom end, I'm just curious. Are you moving the pin up to give the piston more stability and therefore need a longer rod or is there something else you're going for here?

Have you considered stronger bearing caps or a girdle for 6K+ rpms?

Is the crank that you mention only for a 2F or do you have one for the destroked 3F as well?

 

[stereophile33]

though I have long revered the 1.75:1 RS ratio....our recent dyno data has shown that longer rods do not reduce the detonation threshold, and can run the same amount of timing, while at the same time cutting down on reciprocating mass.

The idea is to get longer rods to get that lead weight of a piston to a reasonable weight and size and get the pin in a more stable location in relation to the rings.

As for caps/girdle, that is something to consider...I will have to look into that.

 

[Moby]

though I have long revered the 1.75:1 RS ratio....

Isn't the stock R/S ratio 1.875? Stock 2F rods are 190.5 and the stroke is 101.6? Unless that's a stroker billet crank that you've got. That would be intriguing

our recent dyno data has shown that longer rods do not reduce the detonation threshold, and can run the same amount of timing, while at the same time cutting down on reciprocating mass.

Interesting about the detonation threshold, I guess that is related to the piston speed being slower at TDC/BDC with a higher R/S ratio? Is it common that a nomial R/S ratio increase introduces detontation problems?

The idea is to get longer rods to get that lead weight of a piston to a reasonable weight and size and get the pin in a more stable location in relation to the rings.

Makes sense, that does seem like the primary reason to move to a longer rod in a 2F.

 

[agent orange]

If anything i would think the best thing to do would be too make some shorter pistons to use with stock length rods or even a shade shorter to go with a stroker crank. Otherwise i doubt it would make a difference at all.

BTW why did you think that R/S ratio would make a difference in detonation or need different timing stereophile? The way you talked about your tests it seems like you were suprised.

 

[Moby]

BTW why did you think that R/S ratio would make a difference in detonation or need different timing stereophile? The way you talked about your tests it seems like you were suprised.

This is just speculation on my part based on reading but with a longer R/S ratio the piston speed is slower at TDC/BDC. This is why, in theory at least, a longer R/S will impart a lower peak load on the other bottom end components. In regards to detonation there is more time for a second flame front to start and spread because the piston is moving slower just before and just after TDC. But there are a lot of other factors at work. For example 3FE have a tendency to detonate and they have a really short R/S ratio (1.55). Anyway that's my understanding based on absolutely no first hand experience Maybe someone else can confirm.

 

[Logan]

Digging up a 10 year old thread here, but did this ever happen?

 

[stereophile33]

Just now seeing this. I actually just wound up offset grinding the factory crankshafts and having custom rods/pistons made. The goal was to get the compression up without taking so much meat off the deck of the head...though it does help with high lift head flow...just not worth it for relaibility.