Weiseco's or JE's????

[turbovanman]

Quote:

Originally Posted by DirectConnection I am pretty sure the specs for JE's are .002 to .0035. I remember the .0035 part as I was talking with Mike at FM about my JE's a few years back and he mentioned going up to .004 for added insurance since I was going to be running them hard. Don't worry too much about blowing holes in your's. Remember... Gary ran 2.5 thin skirted JE's in the K-car for quite some time. That was at 35psi, too. The skirts caved in... but I don't recall him torching a set. I do remember a set of torched 2.5 pistons when he upgraded his intercooler and it leaned out for just a tad. I think he may have had mahle's at that point in time.

I called JE and talked to them as there was no instructions in the box. I told them what I was using my van for and he said .0004"
Maybe they changed it recently but I called them 2 weeks ago.

[DirectConnection]

Quote:

Originally Posted by Koreth this thing with piston clearence, does that account for the rings? or do those get pushed far enough inside the grooves in the piston that they are of no consequence provided gaps are correct?

You lost me on that one.
We are talking piston to bore clearances.
I think you are thinking ring end-gaps?
If not, the rings have nothing to do with the piston to bore clearances.
You need a certain clearance between the piston and cylinder bore or the piston will simply seize once it gets up to temp since it will expand in the bore. That's why Venolia's need that .007 (from memory) clearance as they expand alot more than the JE's. This has me thinking that because of this, the quality of the materials in a Venolia may be alot more durable. I thought I read that the JE's have an added material (silicone?) to keep expansion to a minimum??

[mo' parts]

Quote:

Originally Posted by turbovanman I called JE and talked to them as there was no instructions in the box. I told them what I was using my van for and he said .0004" Maybe they changed it recently but I called them 2 weeks ago.

thats .004

should have my wiseco's early next week.
do the clearances need to be increased slightly for more boost(abuse)?
i remember my venoilas asked for a certain amount (per bore size). then recommended the .007 for "racing" use, which was slightly larger than the formula provided for bore size.

[turbovanman]

Quote:

Originally Posted by adam89shlbydayt thats .004

yeah yeah, picky picky, lol!

[john1320]

Gotcha
I miss-understood

[DirectConnection]

Quote:

Originally Posted by turbovanman I called JE and talked to them as there was no instructions in the box. I told them what I was using my van for and he said .0004" Maybe they changed it recently but I called them 2 weeks ago.

Ah, OK. I'd trust JE's reccomendations over what FM told me. We did call
JE when fitting the pistons to my block as I too, had no instructions. We had an issue as to exactly where on the piston to take our measurments from. My machinist told me all JE's are 1/2" up from the bottom of the skirt... and that was what JE told us exactly. Then, I contacted Swain coatings and asked if we use the measurment before or after they did their coating. It was after as their coating is not supposed to wear off like other friction coatings. They told me that their coatings have lasted on diesel semi's with 200k or something like that.

[mopar2ya]

A decent friction coating is so thin it shouldnt effect the side clearance to any appreciable degree. Id go by what the piston mfg recommend for a particular application.

[22dodge]

Quote:

Originally Posted by glhs#064 That what I was going to order, but I just wanted to make sure nobody was having issues with them. I know that with the DSM community they are the worst. They did tests and found that the Weiseco's had a high silicon content and that was causng them to overheat and crack.

hyperuetectic cast pistons have a high silicon content and will grenade with detonation. make sure you are looking at forged pistons for best strength. I actually prefered hyperuetictic pistons in my race cars as they were lighter, and had less piston to cyl wall clearance. the down side was the large ring gap needed on the top ring. I only destroyed one of Keith black hyper piston due to a lean out condition on one cylinder that detonated the piston.

[puppet]

Quote:

Originally Posted by DirectConnection You lost me on that one. We are talking piston to bore clearances. I think you are thinking ring end-gaps? If not, the rings have nothing to do with the piston to bore clearances. You need a certain clearance between the piston and cylinder bore or the piston will simply seize once it gets up to temp since it will expand in the bore. That's why Venolia's need that .007 (from memory) clearance as they expand alot more than the JE's. This has me thinking that because of this, the quality of the materials in a Venolia may be alot more durable. I thought I read that the JE's have an added material (silicone?) to keep expansion to a minimum??

I think he was asking if the ring would bottom out in the groove at a certain point ... which they won't, at least not till they're pased the pistons side face.

[igotaneed4speed]

has any one tired or herd of someone running a low tension three ring piston, maybe top ring like 3\16 and then two 1\16?

would this be over kill or uneeded?

[rwboring]

Quote:

Originally Posted by turbovanman Kind of a shame, TU didn't have Wiseco's when I bought the JE's,

i just got my wisecos in from chris on friday..... 8 WEEKS.... but if it does what i want itto... it will be worth it

I think you mean a 1/16 top and second and a 3/16 oil. That's run of the mill stuff for the V8 guys. Most of them now go for quite a bit thinner than the 1/16 stuff. It would be tough to find a ring set like that for smaller engine bores. If you want less tension but still good oil control go for a 1.0mm gas nitrided top, 1.2mm second with a taper underhook groove (sometimes called napier), and a 2.8mm 3-piece oil ring.

[Reaper1]

Swain reccomends .001" more clearance with the moly coating on the skirts if I remember right. It does add thickness because it is added on top of the aluminum...that's with ANY coating whether its good or not...sommon sense, not rocket science(ok maybe there is some rocket science to it )

[DirectConnection]

Quote:

Originally Posted by mopar2ya A decent friction coating is so thin it shouldnt effect the side clearance to any appreciable degree. Id go by what the piston mfg recommend for a particular application.

Wallace, hate to correct you, but that's not true. The coating is .001" a side, for a total of .002. I work as a machinist and often have prints I have to follow that are listed as dimensions AFTER plating. This makes it hard to calculate in your head the dimension they ask for, and the tolerance they tell you to stay within. Then add in the fact it is to be anodized or plated, etc... Anodizing is .0003-.0004 total (for both sides) and hardcoat is .001 a side (.002 total)

Example... a bore is .1606 +.001/-.002 So, I can make the bore .1616 to .1586 It is being anodized. Now I have to actually make it .162 to .159.

I've seen and measured skirt coatings that were .0005" thick per side, resulting in a total increase of .001". Most coaters can vary the thickness of the coating on the skirt, and can make it extra thick so it is .001" per side. That being said, I've never seen a skirt coating that didn't wear off exactly where the piston skirt rides on the cylinder bore. Be it Swain or an OEM coating on a piston. I would not personally take into account the thickness of the coating for bore clearances.