Venolia piston to wall clearance 2.2/2.5

[Shadow]

Saw the thread on JE's and figured it was a good idea to have this info easily seachable so decided to start one on Venolia's. I get several PM/emails a year asking this Q so maybe if it's already out there it's just difficult to find?

Venolia calls for .005-.007 thou and I have always stayed on the tight side of this going .005 with all 2.2/2.5's I've put Venolia's in. They are a noisy piston on start-up and hearing them at .005 I couldn't imagine how much louder they would be at .007!

Couple funny things about Venolia's, one is the clearance they call for which is quite a bit more than other forged pistons. (I'm guessing different metallurgy?) the other is the Two piston clearances that they give? I've always only payed attention to the one, assuming that if the mtr was bored right, the second one will be what they ask for.

So, let's hear what everyone else is running and IF anyone is having any success running tighter than .005.

[turbovanman²]

Set mine to .0035, no issues. .005 is too noisy.

.007 is the extreme end of the spectrum, way too much and noisy as hell.

Not sure why they list .005-.007.

[trannybuster]

^^Ditto, I ran mine to what they suggested .007....too stinkin loud. The weisco's I run at .0035, nice and quite, and I have been told/read they are made from the same material. In fact I just had an engine/hybrid punched out for Venoilas and set clearance at .0035, so I pratice what I preach. Will be awhile before its done sadly...

---------- Post added at 05:48 PM ---------- Previous post was at 05:47 PM ----------

BTW the weisco didnt have any skirt scuffing after 5000 miles of LOTS of detonation and heat..... in fact they look brand new yet.

[jonnyb]

My machine shop was concerned about that much clearance and they wanted to go with .0035, but I asked him to go with .005 just in case. I don't recall what the clearance ended up measuring, but I recall it was a "tight" .005. The motor is definitely a little noisy at startup, but not too bad.

[zin]

Once I get to the point of having to set clearances, I think I might put on my geek hat and try measuring them at operating temp. Just gotta get a good thermometer and fire up the "fry daddy".

Kind of extreme, but it would bug me not knowing...

Mike

[GLHNSLHT2]

JE's have a tighter tolerance because they have a higher silicone content and don't expand as much as venoilias when they warm up.

[turbovanman²]

I set JE's at .0035 too.

[Shadow]

I set JE's at .0035 too.

So you've set Venolia's at .0035 with lots of miles and zero issues?

[turbovanman²]

So you've set Venolia's at .0035 with lots of miles and zero issues?

Yep, until I do something dumb like ignore my gauges,

[johnl]

Cast pistons, of course, have more silicon (sorry Jay, no "e") and that's why they expand less, and suffer from cracked ring lands and skirts.

Forged pistons, have less silicon and therefore are more pliable, don't crack but instead get bent ring lands and collapsed skirts.

[GLHNSLHT2]

Cast pistons, of course, have more silicon (sorry Jay, no "e")

knew I'd seen it spelled with an E. Just a different thing all together though. ok when talking about the metal I'll remember it's silicon

[trannybuster]

Cast pistons, of course, have more silicon (sorry Jay, no "e") and that's why they expand less, and suffer from cracked ring lands and skirts.

Forged pistons, have less silicon and therefore are more pliable, don't crack but instead get bent ring lands and collapsed skirts.

Mainly the steel strut cast into the piston controls expansion.

[ajakeski]

Tis is an older thread, but I'm putting Venolias in a TII block.
What's the verdict on .035 skirt clearance? Does it work or should I live with the noise?

[acannell]

Tis is an older thread, but I'm putting Venolias in a TII block.
What's the verdict on .035 skirt clearance? Does it work or should I live with the noise?

I have basically a similar question, since I'll be putting in Venolias and will need to pick a diameter.

Ajakeski, how are you ordering your pistons from Venolia? Or are you getting them through FWDP?

I am considering forged pistons a consumable that I will replace sooner rather than later. In my case I think Im going to go on the big side of clearance so that I dont have to worry about them seizing. One way or another they will almost certainly end up as scrap anyways, either because I need to change the design for a different dish or valve relief, or because they eat when I see how far things can go.

Venolia told me they have a +0.001" / - 0" manufacturing tolerance.

Also, how are you measuring your bores? Its tricky to get a measurement that is really accurate to 0.001". Id say a 0.0005" dial bore gauge could probably do the job, but it should be calibrated using a micrometer or ring gauge first. Measuring the piston is tricky since the surface is at an angle.

[ajakeski]

Correction .035 should read .0035.

I bought the pistons from another Turbo-Mopar.com member a few years ago and had them on the shelf when this build came up.
The spec sheet calls for .005-.007 skirt clearance. I called Venolia and they reccommend staying with that spec, but going to the tight side is OK.
The machine shop doing my work suggested .0045 based on their experience. They are doing all the measuring they have the proper tools for that.

[acannell]

Correction .035 should read .0035.

I bought the pistons from another Turbo-Mopar.com member a few years ago and had them on the shelf when this build came up.
The spec sheet calls for .005-.007 skirt clearance. I called Venolia and they reccommend staying with that spec, but going to the tight side is OK.
The machine shop doing my work suggested .0045 based on their experience. They are doing all the measuring they have the proper tools for that.

I think Im going to shoot for 0.005" clearance. Doug @ Venolia told me they go for 0.004 to 0.006". Im not surprised you've heard differently. I got the impression things were pretty informal @ Venolia.

[Lotashelbys]

.0045 based on their experience.

This is where I have put every Venolia piston motor I have built at for clearance.

[Shadowv4l]

Mine came with a paper saying .004 so that's what my machine shop did. Car has no piston slap sounds to be heard.

[Shadow]

I have also tightened up to .004" recently, but I would say .004-.0045" is where you want to be. No need to go as tight as .0035" unless you are not planning on high boost/ high cyl temps. (wouldn't want to risk scuffing a piston over .0005")

[wallace]

I was going to use venolias when I built my 2.5 but machinist steered me away from them stating the size from piston to piston varied based on his experience necessitating sizing each bore to suit the piston. I'd like to know if you who have bought and measured venolias if you saw a significant difference piston to piston?