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View Full Version : Choice of Pistons ROSS or JE



supraguy31
January 28th, 2008, 09:38 AM
Well, I have a friend of mine that has a Set of ROSS stock bore pistons for sale and I have a Current forum member that has a Set Of JE .040 overbore pistons for sale also. Both are asking the same Price but I want to know what you forged internal guys think is the better Piston or Option. Ive never ran Forged internals so this would be a great help in Decided what way to go.

Thanks
Robert

Mr.PFloyd
January 28th, 2008, 09:40 AM
Aren't Ross's the ones with the super high comp ratio?

jdub
January 28th, 2008, 09:55 AM
Cyro - Ross are 8.5:1 - JE are 8.4:1. You might be thinking of Wisco...they are a 9.0:1 CR.

Both are excellent pistons.

The JE's will require the max over bore you can safely do...it will be the last time that block will be bored.

To use the Ross, you will need to check your cyn bores...iirc stock pistons are 83mm...Ross "stock size" are 83.1mm. For Ross pistons you will need 0.0035" - 0.004" piston to bore clearance...more than that and you'll get warm-up piston slap. If your bores can be made true and meet the above spec, I'd use the Ross.

NewWestSupras
January 28th, 2008, 10:05 AM
0.040 is alot of bore on these blocks. They are thin-walled to begin with. If you don't need to bore it, then I would'nt. I don't know the comp. ratio offhand on these Ross pistons I have, but my compression numbers aren't extraordinary with them. You do have to be careful about piston to bore though. They can diesel a bit till they warm up...

oooops, jdub beat me to it while I was typing, what he said...

supraguy31
January 28th, 2008, 10:07 AM
Got this off the JE website.
http://www.jepistons.com/cat/je/sport/toyota/7mgte.shtml

The block that these Pistons are going into has only 68,000 miles on it so Im sure its a good canidate. Do JE pistons Expand that much?

Since these are 83.1mm, How much boring do you need or are you just Honing the Cylinders until you get the correct Clearnace Specs.

jdub
January 28th, 2008, 10:11 AM
So...this is a 2J?
Would have been good to know...esp since this is in the 7M GTE Tech Section ;)

supraguy31
January 28th, 2008, 10:13 AM
So...this is a 2J?
Would have been good to know...esp since this is in the 7M GTE Tech Section ;)

Changed the Link... Try again, Still same Place just didnt click on the right one

jdub
January 28th, 2008, 10:22 AM
Interesting...JE lists the CR at 8.8:1. That's quite a bit higher than what I was looking at (another web site)...you might want to consider how much boost you're planning on ;)

JE pistons are significantly lighter than Ross.

You'll have to take the block to the machinist and have him measure the bores for roundness. The "stock" Ross pistons will require a very small amount of bore to meet piston/bore clearance, but it's going to depend on how much wear is present in the cylinders.

supraguy31
January 28th, 2008, 10:36 AM
Im planning on running just enough boost to get into the Low 12s/High 11s in a MK2. Im running a 67mm Turbo with on it right now so I just want the Issurance that my Internals are going to hold up under lets say as a Guess 18 to 20 psi

supraguy31
January 28th, 2008, 10:41 AM
I have a Block at home what Im going to a few Pics of J and let you see it. It has .040 pistons installed and as soon as I got the engine in the car and started, I instantly got a Very Faint miss like I was loosing compression. I ran it for 300 miles and I started to get Blowby. Pulled the engine out and pulled the head, If you look at the engine from the Side and look down into the cylinders, Everyone of them have about a 1/2" of area that looks like the rings arent even touching. If you look at it from the front of the motor its the east and west side of the Cylinder on all 6.

starscream5000
January 28th, 2008, 11:08 AM
An aquantance who has experience running both of these pistons has advised me that ROSS would be the better route for a DD, high HP street car ;). ROSS are heavier, true, but IIRC, they are lighter than a stock piston as well ;).

jdub
January 28th, 2008, 11:27 AM
The higher compression pistons are great for bottom end, but you risk detonation at boost due to dynamic compression. You'll have to pay close attention to the tune and run premium gas ;)

Sounds like the block was bored without a torque plate and/or without the main bearing caps torqued down ;)
Boring without the timing belt tensioning pulley torqued down will do the same thing to the front of the #1 cylinder.

BTW - that's a case in point...that block is done. Boring it out any more (say for a .050 oversize) will push the cylinder walls way too thin IMO.

supraguy31
January 28th, 2008, 11:47 AM
That block is pretty much toast I agree which is the reason for the 68000 mile block that I have sitting on my stand. It came off a JDM engine and I knew the guy pretty well that owned it.

So from what Im getting, the Ross Pistons would be a great way to go due to not having to bore the cylinder out so much and they are lighter than stock Pistons.

JE Pistons are even lighter but you have to hope that the Machinist does the Job correctly the first time around or your block is pretty much toast.

Robert

jdub
January 28th, 2008, 01:20 PM
Take a look at these specs...take the block to the machinist to make sure the ones you're looking at will work. The 2nd sheet list the piston to wall clearance as 0.006"...that is too large. Use 0.004"

http://www.rosspistons.thinkhost.com/uploads/toyota.pdf

http://www.rosspistons.thinkhost.com/resources/ROSSRACINGPISTONINSTALLATION.pdf

supraguy31
January 28th, 2008, 01:33 PM
Im pretty sure they will work as I have the Stock Pistons that came out of it sitting in the Garage. They have the #2 Stamped on them and Im sure that doesnt mean anything but I just want to let ya Know.

I printed out the Sheets and thank you for the Link. So best recommendation is go 0.035 if Possible but if not, Use 0.004

What about ring Gap, What would be a Recommended ring gap Size based on Boost Pressure as I dont see it in on the ROSS website.

Thanks

jdub
January 28th, 2008, 01:39 PM
I'm thinking the Ross pistons *should* work, but actual measurements will tell-the-tale.

If you plan on coating the pistons, def use 0.0035". If not, I would lean more toward 0.004" to account for expansion. You may get a small amount of slap (Ross skirts are fairly short) at start, but that's better than a locked up piston ;)

supraguy31
January 28th, 2008, 01:50 PM
They are already coated so I will be using the 0.0035 as you recommended. Now I just need to figure out this Ring gap thing and I should be good to go.

supraguy31
January 28th, 2008, 05:25 PM
Jdub.....

Pics from last block
http://img.photobucket.com/albums/v219/supraguy31/6.jpg
http://img.photobucket.com/albums/v219/supraguy31/1.jpg

They are on Every Cylinder the same way, Some wider than others but Im sure you get the Picture

jdub
January 28th, 2008, 09:21 PM
Not good!

No wonder you got blow by so fast.

supraguy31
January 28th, 2008, 10:06 PM
I would say I had 500 Miles on it. Thats why I havent taken anything back to the Machinist that did it. Its all good though as I have another block sitting here waiting to go. Does that look like he bored it wrong or it Cylinder isnt completely round or what?

jdub
January 28th, 2008, 10:35 PM
It's hard to say, but I'll bet he bored it without the main bearing caps torqued down to spec...the cylinder walls on a 7M are on the thin side anyway and can be distorted when you start torquing on it. Especially when you go to the larger oversize bore. Make sure he uses a torque plate and the timing belt tensioning pulley is torqued down to spec too.

supraguy31
January 29th, 2008, 12:06 PM
So you are saying that when I go to get this block bored out to have the front cover on it already. Im going to have it Decked just to make sure and I know you need the cover when you have it decked but I wasnt for sure if it needed to be on when you have the Cylinders bored and Honed

bigaaron
January 29th, 2008, 12:26 PM
Ross pistons are old school technology, unrefined, heavy ass pistons that don't take abuse well at all. I will never use or sell another set of Ross pistons again.

spoolint78
January 29th, 2008, 12:51 PM
i never had a problem with them.

Unrefined? Not sure, but they work.
So why mess with something that works?


just my 2 cents

IJ.
January 29th, 2008, 01:32 PM
Ross pistons are old school technology, unrefined, heavy ass pistons that don't take abuse well at all. I will never use or sell another set of Ross pistons again.
How do you figure that?
(In my experience they hold up really well to abuse due to their mass)

supraguy31
January 29th, 2008, 01:35 PM
Ok, I knew that there was someone that would have a not so Positive comment about them which is fine but Please elaborate on why they are so bad. I see that you have Probe Pistons on your Site so what makes those any better than the ROSS pistons or is there a Piston that you recommend.

bigaaron
January 29th, 2008, 02:23 PM
I have two sets of pistons with the crowns broken in the same place. Neither one was run super lean. I have already posted pics in the past showing how the Ross is an old 2 valve per cylinder casting that they use for the 7m. The Ross pins that come with the set are too weak for the weight of the piston also. A piston that heavy can cause standard pins to flex. I would use CP or JE or Probe or anything but Ross. I have also been warned by several machine shops that Ross makes a habbit of screwing up custom orders. This is not only my opinion, but also several other people I know who have been in the industry for a lot longer then myself. I try not to make claims that are not backed up by personal experience and research.

WhtMa71
January 29th, 2008, 02:24 PM
Ive had good experiences with CP..IF you were buying new..id go that route. 2nd JE.

IJ.
January 29th, 2008, 02:26 PM
I have two sets of pistons with the crowns broken in the same place. Neither one was run super lean. I have already posted pics in the past showing how the Ross is an old 2 valve per cylinder casting that they use for the 7m. The Ross pins that come with the set are too weak for the weight of the piston also. A piston that heavy can cause standard pins to flex. I would use CP or JE or Probe or anything but Ross. I have also been warned by several machine shops that Ross makes a habbit of screwing up custom orders. This is not only my opinion, but also several other people I know who have been in the industry for a lot longer then myself. I would never make claims that are not backed up by personal experience and research.

Got pics of the failed pistons?

Doward
January 29th, 2008, 03:58 PM
Arias pistons ftw. (Having now seen them @ Bryan Maloof's shop)

bigaaron
January 29th, 2008, 04:04 PM
I forgot Arias, I have those in my 7m, they seemed to be very nice, but they did cost over $1k with the custom order.

jonny87turbo
January 29th, 2008, 04:26 PM
I will be rebuilding my engine sometime ive never heard of probe pistons before till a couple months ago. Would those pistons be a good buy?
Or should i just spend the extra $350 on the JE.

jdub
January 29th, 2008, 05:49 PM
How do you figure that?
(In my experience they hold up really well to abuse due to their mass)

:withstupi

;)

Haven't seen a Ross piston fail, unless it was due to the installer or it was run lean and melted the top.



I will be rebuilding my engine sometime ive never heard of probe pistons before till a couple months ago. Would those pistons be a good buy?
Or should i just spend the extra $350 on the JE.

Have a look at CP pistons...Suprarich stocks them. JE's would be my 2nd choice.

MRSUPRA
January 30th, 2008, 05:27 AM
My Arias pistons only cost about $550. The shop that built my 7M which deals with all kinds of forged pistons recomended them because of there tight tolerances. (Maybe they have a special deal with Aria, who knows?).

Ross pistons are heavy and I have heard of them having piston slap when cold.

Doward
January 30th, 2008, 06:11 AM
If you can spring for them, the Arias are super nice (AND CONTOURED TO THE HEAD)

If not, the Probe pistons were 90% of the Arias @ 1/2 the cost, lol

*edit* $550 for Arias? That's a steal. When I was looking into a set of pistons before the Probe GB, I was quoted $735 for a set.

MRSUPRA
January 30th, 2008, 11:39 AM
/\The shop price was $1000 for Eagle rods and Arias pistons together, so I'm just guestimating on the $550 price.

Rennat
January 30th, 2008, 08:52 PM
Ross - 357 Grams
Arias - 312 Grams

According to 935motorsports....
And there the only vendor site i could find that listed piston weights... weird...

Probe - 300 Grams AND there on sale for $395 at Driftmotion! DM FTW!!!!

My point is if your going solely off of weight... the probe are the "best"...

starscream5000
January 31st, 2008, 06:44 AM
... For racing possibly.

92nsx
January 31st, 2008, 07:05 AM
I have used Ross in the past (2001) on one of my 7m builds. Dont know if was the pistons, rings, or the install, But i had a slight tick at first start up. Other then that, they were great, held up to boost i was running at the time, (15-17 psi). How ever this time around i am going with JE 40 over pistons, just because i got a great deal on them, and i wanted to try them out. :)