Z.E.R.O.

anyone know what type of forged rods will work on cast pistons?

omniman

Oddly enough, no one makes a shelf rod that has press fit pin ends. you have to custom order it from a rod manufacturer. One would think with the advent of cast pistons being so popular someone would have a shelf stock fittment for it.

d15Beta

is it possible.. say on the more common Hbeams like eagle rods
to have them rebush the small end for press fit appl. ?

omniman

you can have the pistons cut for C-clips and shorten the wrist pins a little and have a full floater set up.

d15Beta

interesting.. as i was thinkin of that as the possible "other" solution...

is it the safer route? cutting a ledge on the cast pistons for the C clips , i know the pins wouldnt mind a few mm off it hehe

Z.E.R.O.

hmmm.... :S i remember from somewhere that i does work just forgot which forged rod will... but basically if i want it to work then both the rods and pistons must be machined to work? hmmm so should i just stick with shot-peened and polish rod w/arp bolts... trying to built a ls/v for auto-x, don't really know if it will hold on the long run, been searching but most of them are like 6 years ago which building the ls/v use to be harder...

racebum

if you're making so much power that you can snap a GSR with upgraded bolts..do you really think cast pistons are a smart idea??

lluks_844

RS machine works makes cast pistons that will accept aftermarket rods. Check performance in the marketplace.

ZC1.8crx

Eagle ESP H-beams. I put them on my P29 pistons and the pins needed to be pressed on. I've been running this set-up for a while now. But I had these rod for over 5 yrs or so before using them this summer.

d15Beta

the pistons (p29) are press fit pins on rods...

but did u mean ur EAGLE ESP, came as press fit application?m or did u have them rebushed?

thats sum good stuff indeed

omniman

An interesting little tid bit of info.........

The newer rods and pistons ( OEM) found in K20 type-s engines for example are full floater. However they differ from conventional forged pitsons in design slightly. The clearance for the pin and piston is a slight press fit at room temp. So when you assemble them you have to heat the piston up to 180 deg F.they do this to probably reduce vibration or maybe for another reason. when the motor is cold the pin rotates only on the rod and as the engine/piston heats up the pin can now rotate on the piston and the rod. aluminum expands about 3 times more than steel per degree of temp.

in comparison to a b-series piston the k-series piston will have a much tighter clearance between the piston and the wrist pin at operating temp. This probably helps reduce vibration and also could possibly extend the life of the piston in someway.

ZC1.8crx

let me clarify, the Eagle ESP H-beams was not rebushed, and the P29 pistons were not touched either. Just let me reiterate that the Rods were purchased some years ago at least 5yrs or so. I don't know if Eagle changed anything in years since, but here is the part# of the Eagle ESP H-beams Part# CRS5394H3D with pics.

d15Beta

wow interesting! thanks for the clarification..

i wonder if eagle ESP still offers these kinda rods... hmmm i better shoot them a mail

vinuneuro

97+ OEM H22 pistons are the same. They are full floating, but must be heated to 158* to remove and install the pins.

racebum

talk to your local machine shop. the machines they use to press fit pistons basically drive in a pin and expand it. if the rod has a bronze bushing the only thing i don't know is if they would leave it in place and just expand the pin or remove it to expand. switching this around i'm using full floater mahle pistons press fit on gsr rods. rather than using the locks to hold the pin it was just set and expanded since the GSR rod does not have a bushing and installing one would mean removing material from a rod that already has a small top end.

p.s. i still think it's nutty to be making so much power that you're worried about the factory rods but want to use cast pistons.

Z.E.R.O.

i'm actually gonna be running rs machines pr3 82mm pistons... but from reading from previous posts/threads the ls r/s ratio isn't too good for high revving, although i'll be using stock rods w/ shot-peening, polish (if necessary), and arp rod bolts (which i have)... just don't wanna do this a second time :wink:...

racebum

how much power your making has a very large impact on how long the engine will live. the RS pistons are used often in builds and do not have the annoying piston slap that forged pistons do. the drawbacks of course are that the RS pistons weigh more than forged and are much weaker. high oil temps from boost, really high compression or road racing tend to worry me if the engine has cast pistons. if anything goes wrong they come apart. if you're going to 11k i would spend the money on a real balance with the pressureplate and flywheel. i only spin to 8500 and the motor is balanced within half a gram along with pistons that weigh 40g less than stock. slightly larger than average bearing clearances are also going to keep this motor alive. same with the piston to wall. whatever you do, DO NOT BUILD THIS THING TIGHT if you're going to 11k. something like .0020 on the RS piston to wall, .0020 to .0025 on the rods and mains will live a lot longer than people who tell you to build to factory specs. when you get this engine hot racing the last thing you want to do is croud out the oil.

Z.E.R.O.

probably trying to rev'd to 9-9.5k only (not a goal, but would just like to) and probably auto-x the car once awhile... also trying to reach a goal of 200+ whp on the ls/v, still debating on which cams to use though... probably buddy club 4's...

4g hatch

rpm's kill motors,not hp.

mightyjoecivic

Im in the same boat. So a machine shop can slide the pins in and THEN expand the pins in the rods? This wont affect the piston will it?

Fixxe2

i mounted oem PCT pistons on eagle H rods for my LS/vtec...
later, I also lightend the piston and rod a bit..

did a jig so that I was abel to put the pistons in the turner? machine..
ended out like this:
(dont mind my english.. I´m swedish )

d15Beta

anybody have any comments on these?

machining the cast pistons for pin locks/spiro etc?

Fixxe2

worked fine for 6000 km...

then my fuelpump dropped 1.5bar between 7500-9000rpm witch did alot av damage..

TorganFM.

I'm sure the fact you were using PCT's had something to do with it too.

Fixxe2

why??

the fact that i ran on ethanol with 4bar fuelpressure, and the wires to the fuelpump made too much resistance so i dropped fuelpressure...