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Looking for aftermarket Rods and Pistons

4118 Views 54 Replies 16 Participants Last post by  UFB
Does anyone know of a company that makes rods and pistons for the 1.5 SOHC alpha motor. Or will I have to get more custom work done? I am building my bottom end for turbo.

<hr noshade width=60% size=1 align=left>"Close with and destroy the Enemy"
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I'm betting you will need to have them custom built; not even Tiburons have the luxury of off-the-shelf parts for rods or pistons.

Crower is probably the only place you will want to make your rods -- you will need to send them a single "donor" rod so they can check it out and make an exact duplicate.

You can pick your favorite as far as custom pistons go: Arias, HKS, Ross, JE just to name a few. I went with Ross just because they weren't expensive and have a great following among the domestic guys here in ABQ. As I understand it, Arias isn't too expensive either and makes good stuff. HKS is pricey, JE are a bunch of pricks AND pricey, neither is probably any better than what you'd get at Ross or Arias.

RPW is fine and dandy, the problem is they will not directly sell to YOU in North America. They insist you go through Phantom Racing, which:

A. Has POOR customer services
B. Has POOR call hours
C. Has UNIMAGINABLE markup ($400 AU = $230 US, but after markup it's back to $400 US <img src=/images/forums/snitz/mad.gif width=16 height=16 border=0>)
D. Charges out the ass for shipping

I've ordered a clutch from RPW, and while I'm VERY happy with the clutch, it wasn't necessarily worth what I paid for it.

I wouldn't go there if I were you...

As usual, JE comes out way more expensive than everyone else.

Ross = $550 for pistons, rings, pins and spiralocks in whatever compression you want -- from 9:1 to 7.5:1

Crower = $675 for the rods INCLUDING shipping.

JE can bite me, expensive pricks.

Whenever you buy aftermarket rods, ALL of them come with a floating pin. Since the stock rods have press-fit bushings, you have to replace the rods so that you get the appropriate floating-pin bushings.

The pistons require an overbore and I STRONGLY suggest that if you're going to do internal work that you do NOT buy a set of drop-in pistons. We've had that discussion before; overbore provides a LOT more than just a small bit of displacement.

Ross can be reached at (310) 536-0100 and ask for Darius (pronounced Der-I-us)

I'm sorry, I wrote my last reply wrong...

What I meant to say was: All of the aftermarket PISTONS available come with floating pins. You will need a rod with a floating pin bushing to use with aftermarket pistons.

Unfortunately, the stock rods use a uni-directional press-fit bushing for the pin. As such, you have to replace the stock rod with an aftermarket rod.

That's not entirely accurate however...

If you send the piston manufacturer a stock rod and pin bushing, there's a almost 100% chance they could build a piston and pin set that would fit. You will of course need a stock rod to offer...

As I understand it from Cheuk, the stock rods are good to around 300FWHP so long as you aren't detonating very much. A good set of inexpensive pistons from Ross or Arias along with the stock rods should be a decent combo.

If you're aiming for any more than 300HP I would suggest just buying the aftermarket rod anyway. <img src=/images/forums/snitz/smile.gif width=15 height=15 border=0>

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$265? What are they made of? That sounds more like a Hypereutectic (sp?) material than a forged metal. What is the forging pressure used to build them? I know both the Ross and Arias pistons use a 1000-ton press to build theirs; JE uses a 400-ton press which could still leave impurities and "bubbles" in the metal. Does that also come with the pins, spiralocks and rings?

There's a lot more to pistons than just the final pricetag...

High compression doesn't necessarily make things detonate more. I can provide at least one instance where raising the compression actually REDUCES detonation... It's called Quench area.

There is a space between your piston and the cylinder head when the piston is fully TDC. That space is called quench clearance and in our motors it's about 0.068" of space. This is a combination of the pistons being ever-so-slightly sunken into the block and the thickness of the head gasket. When the engine is running, that gap serves to "squish" the air fuel mixture, causing turbulence which helps to keep the air and fuel atomized as well as focus the air/fuel mixture into the center of the combustion space.

Honestly, 0.068" is very sloppy -- and putting a thicker head gasket in to lower your compression will actually make it WORSE. Deatomized fuel and inconsistant fuel mixtures can account for lots of detonation and "lacking power" issues.

If you close that quench clearance up to around 0.035" in a BETA engine, you will raise the compression about 0.3 points. HOWEVER, even though you've raised compression, the tighter quench clearance will serve to actually reduce detonation. When the engine heats up and is running at full bore, that clearance will get even smaller (maybe as tight as 0.010" depending...) which serves to make a VERY tight fit between the top of the piston and the flat surfaces in the cylinder head combustion chamber space.

That very tight clearance will serve to create large amounts of turbulence to keep the gasoline fully suspended in the air, as well as to force the air/fuel mixture into the very center of the chamber so you get focused power over a small surface area.

The end result -- an engine that is running higher compression that resists detonation better.

There are other physics principles at work that also dictate higher compression working well, but those are better saved for a later date.

The two things most associated with detonation: heat and too much ignition advance. High compression doesn't directly lead to either of the above, only incorrect fueling, sharp edges in the combustion chamber or BAD tuning. Indeed there are limits, but they aren't at 9:1.

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Ah but you forget, I *do* know this works. We have applied it to three cars now...

Joel's Starion was the first. He dropped a set of Kieth Black 9:1 pistons in the car after the first rebuild, ran it around and got a bit more response out of it but still needed a lot more fuel to feed the 16G he strapped to it (versus the 12A it came with). It would ping at high RPM's + 15psi (that's all the 16G would hold on his 2.7L of displacement) and we ended up having to open the 3rd injector almost to 100% to get it to stop.

We figured it was perhaps the compression raise...

Fast forward about three weeks: he decides to pull the cylinder head to have it ported and cleaned up and decides to also pull the block and have it decked. We remove almost 0.030" from the block deck (which RAISES compression) and removed about 0.005" from the head (just to resurface it so it seats well).

When it was all reassembled? Even with the ported head, we were able to pull fuel to about 65% on the third injector; the 16G would only hold about 14psi because of the better flow in the head. Still with less fuel and more airflow we were able to lean it out without pinging.

We're monitoring pinging via "Knock Linnk" available in AU -- a GM knock sensor attached to it's own indicator black box, somewhat like a J&S Safegard does it.

We've also applied this to my boss's 1984 Celica buildup (he was definately a bit skeptical at first) using a Toyota 2.0L (cannot remember the odd engine code, 2STE I think?)with very similar results. And we've also applied to to one of the local Albuquerque DSM's here in town -- there's a machine shop that actually specializes in headwork and "quench clearance" down by Montgomery and Eubank.

It doesn't only apply to Hondas, and it certainly isn't Larry's original idea. Larry's idea is piston crown design interfacing with the actual cylinder head CC surfaces -- quench clearance is a well-documented principle without him.


<b>Edit - The engine code on that Toyota is 22RE, an electronic injection engine found in his 1982 Celica parts donor car. </b>
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Whoa whoa whoa, wait a minute...


I don't think you understand what I'm talking about, otherwise you wouldn't have made such a remark.

Pull the cylinder head off a BETA (since you have so many) and look at it -- notice how the shape of the combustion chambers in the head is not perfectly round? The head shape doesn't go with the perfectly round cylinder shape. You have two flat spots (top and bottom) in the head...

Know what that is?

Those are QUENCH PADS. These are SPECIFICALLY ENGINEERED to do exactly what I just outlined. The stock quench clearance (not something I made up) is around 0.068" -- bring this down tighter to around 0.035" allows for higher compression and ALSO higher detonation resistance.

Yes, Porsche DOES use this. Yes, so does Ferrari, BMW, Mercedes, Honda, Hyundai, Toyota, Mitsubishi, Subaru, Ford, Dodge and just about every other engine manufacturer I can name.

Care to make a very large wager against me? I could use the money...

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