Choice of pistons..

[UndergroundR32]

I'm curious so know everyones piston of choice is and why. Also what you think about JE.

 

[L2RTSiAWD]

My choice is Weisco. I dont' like JE for our cars.

Later,

 

[RocketDSM]

I've never heard anything bad about JE. I was planning on using 9.3-9.5 custom pistons from JE when I do my engine rebuild. My theory on things, make a stong all motor setup and use the turbo as a quick burst on top end. Hence my higher than normal compression. Most people I talk to say to use 9.0.

 

[UndergroundR32]

I may use 9:1. I'm most likely going to use 8.5:1

 

[L2RTSiAWD]

I"m going 9:1 also. I have heard people having piston slap problems on startup while cold with JE's and some other issues.

Later,

 

[NosLaser]

Just about any forged piston..wait, I take that back..EVERY forged piston when installed to the proper clearances is going to get piston slap to some degree when cold. That's a pretty silly reason to discount a particular product. That aside, the Ross pistons are about the best off the shelf offering you can get.

Regards,

 

[swordfish]

I have a 9.0:1 engine. Stay at 8.5:1. Less detonation prone, less finicky with timing, more boost on pump gas. If I had it to do over again I would have just stayed at 8.5:1

jeff

 

[UndergroundR32]

Originally posted by NosLaser
Just about any forged piston..wait, I take that back..EVERY forged piston when installed to the proper clearances is going to get piston slap to some degree when cold. That's a pretty silly reason to discount a particular product. That aside, the Ross pistons are about the best off the shelf offering you can get.

Regards,

That's what I'm getting. Ross 8.5:1. Crower rods most likely.

 

[L2RTSiAWD]

Originally posted by NosLaser
EVERY forged piston when installed to the proper clearances is going to get piston slap to some degree when cold.

Regards,

That's odd. I had only heard that about JE not about ROSS,Weisco, or Arias.

Later,

 

[NosLaser]

What you are battling is expansion rates. JE's are a zero silicon forged piston. Basically, to not put it into technical terms, when you change to a forged piston, the idea is you are planning on making a good amount of horsepower; read, a good amount of cylinder pressure and heat. You set the piston to wall clearance more on the loose side, because you have to worry about expansion as to not score the cylinder wall under power. Take a forged piston, and measure it (with a precision measuring tool that gives to the thousandths of an inch) then put it in the freezer for a while, and measure it again. Notice a difference? Now heat it up a bit; measure again, and compare to the room temperature measurement. Once again, things like piston slap, etc. are all prices you pay to make power and go fast. (loud fuel pumps, loud exhaust, worse gas mileage, and the list goes on)

Regards,

 

[UndergroundR32]

Originally posted by NosLaser
JE's are a zero silicon forged piston.

And what are the levels of a ross? If any.

 

[L2RTSiAWD]

This is very interesting. I didn't know this about all pistons. I know piston slap was not good. But can you explain what it exactly is and can it kill an engine?

Later,

 

[RocketDSM]

Isn't 8.5:1 stock?

 

[L2RTSiAWD]

Originally posted by RocketDSM
Isn't 8.5:1 stock?

Yes on a 2G. I think it's 8:1 on a 1G.

Later,

 

[RocketDSM]

Anyone know how fast Ross can do custom jobs? I know JE can pump out anything in about two weeks regardless of compression ratio desired.

 

[swordfish]

Originally posted by MuttedTSiAWD


Yes on a 2G. I think it's 8:1 on a 1G.

Later,

7.8:1 on a 1G

jeff

 

[L2RTSiAWD]

Originally posted by swordfish



7.8:1 on a 1G

jeff

My Bad I forgot.

Later,

 

[cmc]

I use ross pistons in my motors. All forged pistons expand, cast do not. I think ross spends extra special care w/ their pistons. I've had some JE's that were messed up, but were replaced at no extra cost. Always inspect a part to make sure it is at manufactorers specs!
I use Eagle rods, they are very well made!

 

[UndergroundR32]

I don't have a tool to measure size if you are referring to that. I could get one no problem though.

 

[rdrkt]

Originally posted by RocketDSM
Anyone know how fast Ross can do custom jobs? I know JE can pump out anything in about two weeks regardless of compression ratio desired.

What type of custom work are you looking for exactly?

Originally posted by RocketDSM
I've never heard anything bad about JE. I was planning on using 9.3-9.5 custom pistons from JE when I do my engine rebuild. My theory on things, make a stong all motor setup and use the turbo as a quick burst on top end. Hence my higher than normal compression. Most people I talk to say to use 9.0.

I'm sorry the jerk in me just can't let that go. Quick burst of top end? Dude what are you talking about. 9:1 is nothing. That is an ideal CR for a forced motor going a third or a half a point higher is not going to get you a strong “all motor” car. If you want to go crazy Magnus sells 10:1 Ross pistons. I'm sure that would spool a big turbo great. However I think it would be almost impossible for the average guy to make “good” power on pump gas with a 10:1 or higher motor. So that pretty much makes it a race gas only car. Is that what you are looking for?

 

[RocketDSM]

Gee, what a concept (since we seem to starting a pissing contest). I can't afford to run race gas everywhere I go, who can? So in order to maintain pump gas I plan on keeping it down to 9.3-9.5. My point being that 7.8 or 8.5 don't make a good all motor engine. In fact it's pathetic. Take off the turbo and what does our engine do, didly squat. Now, build a stroker engine (I favor the Crower setup) with 9.5:1 pistons. Now it is a decent engine that can run without hiding from Kia's. Now throw the turbo back on top and you have yourself a nice engine that can thrash just about anyone on the street. Track is still another story, but what do you expect. My term - "quick burst of top end" - is referring to the fact that turbos do NOTHING for bottom end power and the bigger turbos don't spool until the very end of a normal RPM range. So what use does it make in the real world (non-track)? Instead, build up a good bottom end and use the turbo as a kicker, not your sole source of power. Does that explain it a little better? Silly me for not wanting to type an entire essay and trying to paraphrase myself.

 

[NDgsx]

Cast pistons don't expand? Haha um ok, what evidence do you have of that? Any metal expands when it is heated, forged pistons simply expand more because they are denser.

The piston does not expand the same amount across the face of the skirt either. There is less metal in the skirts, so they do not expand as far. That is why the skirts taper from the bottom to the top.
That is why it is important that your machinist talks to whatever company makes your pistons so they measure the piston at the right height on the skirt. On stock pistons it is measured on the skirt bellow the pin.

When your machinist hones your block they set the piston to wall clearance (boring sets the rough clearance, the last .006 inch of removal is typically done during honing). Each bore should be sized for it's own piston.

JE's seem to need a lot more clearance than other forged pistons, I've heard of anywhere from .0040-.0055 of an inch. Ross and Wesicos seem to do well at .0035". Not sure about arias. Stock pistons are good at .0015-.0020" (factory spec ).
That is in GENERAL though, every car is different. If you are running nitrous you will create more heat in the combustion chamber, so you will need looser clearances. If you are running a small turbo there will be lower cylinder pressures and temps, so you could run tighter. Talk to your machinist.

Oh and one more thing, this is for everyone, pick up a couple books about bluepriniting engines before trying to rebuild yours.

 

[RocketDSM]

I can attest to that last part. I blew up a lot of engine in my beginning days from not following the book. I had it, my dad made sure of that, I just didn't follow it until I blew three engines in a row and killed the block beyond machining (it was an old Chevy SB). Definitely have a blueprinting book and follow it.

 

[RocketDSM]

As for my "custom Ross pistons" - I was only referring to the compression ratio. As I stated, not many people I know of opt for 9.5:1. Usually 9:1 (pump gas) or 10:1 (race gas). Any thoughts?

 

[rdrkt]

RocketDSM: I kind of understand what you are saying but I just don’t think you are thinking it all the way through. My turbo (Br57) is a bit bigger then a FP Red but I am still getting full spool by 4500 with 95 pistons (8:5:1).

Why in the world would I take off my turbo in my turbo car and go try and race people? Off boost and on boost are not that far apart as long as your have a decent sized turbo. Personally I think my Br57 is a pretty decent street turbo albeit you need a lot of supporting mods to make it run well. That turbo is just about as big as anyone would want to go anyway and it spools great around town I don’t see why your are focusing on such a narrow part of your powerband.

Which brings me to my next point if you want a stronger bottom end why not just get a stroker? You say you prefer the Crower stroker setup. I believe that is a 4g64 crank in a 63 block with crower rods and custom pistons. Why not just go with a 4g64 block? Its just as much effort and I bet you will get better results with the 64 block anyway. I have a Maguns prepared 4g64 on order so I am bit biased towards it.