hi guys

i am rebuilding my engine with all these parts in the pic.my question is
i am using 85.5mm bore with over wiseco pistons ,spec sheet says .0025 ptw
what do you guys recommend i am gona be boosting til 25-30psi.
2) i have resurfaced my block to .0002 i will be doing the same with the head to 0002 , i am using cometic mls which is .051 will it seat perfectly n this case the repair manual says i cannot go beyound .0008 with both the resurface of block n head .

thanx

Its best to go to a good machinest, and tell him what kind of power you plan on making. He will usually determine how "loose" to setup the motor.

machinist here dont know nuthin they have no knowledge this is uae
i need experienced person sugestion

Well, if you won't take a machinists advice - you can search around for what PTW other people used on their Wisecos and formulate an opinion from there. Your missing a spark plug btw.

I would use .0055 PTW. It's huge but forged pistons like to swell under boost. Piston slap, oil consumption, and such aren't really an issue either then. That is with a torque plate bolted to the block and without using a torque plate, walls become distorted a few thousandths and you won't be able to get the correct PTW clearance.

I would follow what the spec sheet says. When I had my 2.3 done a few years back, the machinist took it upon himself to NOT follow the Wiseco sheet, and I had a nice case of piston slap. His reasoning was..."..well, .0025 seemed a little too tight, a lot of 'em I do are around .0040 or so, so I just split the difference...".

Anyway, after the re-do, with my insistence in following the Wiseco spec sheet, everything has been fine, and it's been over 40k.

I think .0055 is a bit large, once the coating wears off, it'll be even looser.

I'd go with .0045, then once the coating wears, you'll be about .0050.

If you have access to the ECMLink forums, this is a good thread to check out. ECMTuning User Support Forums

well diference of opinion on all of them i found .some say .0040 and they run fine,some say they dont .
how about .0030 with the coating of wiseco. i am planning to boost 30 psi
today i will buy all the head internals .so i want the car to make 500-550hp
and drivable everyday .
thanx all of you for sharing experiences

My engine running with 0.001 extra from what written on the wiseco piston spec sheet no slap or blow by... that for race application. For daily used and weekend warrior i used .0005 extra. Most of the engine stand the abuse for more than 2 year already and counting.

You should shoot for 0.0045. I run 0.0045 PTW clearence. I know that 0.0030 and lower can cause damage.

Mine were at .0028" and i just did a teardown, they looked fine no scuffing, no audible slap at cold startup, and a very small lightening of the coating. The w is still extremely pronounced in the coating. They look almost brand new. This is after a solid year of 30+ psi, on e85. Anyone that knows me, knows how hard i am on my car also. Easily hundreds of launches, and wot pulls. For people running gasoline fuels, a couple .0001" more might be a good idea if you are pushing it. I have never seen any problems with their recommended .0025", on a typical 400ish hp build.

I run and alway run .0040 and has never had a problem. Putting out over 500 lets me know that its good

what would you put you ptw clearences at if you was runing around 500 crank hp?on ,manley 8:5:1 coated pistons .0035 or .004?and how about ring gaps does .020 top and .0022 or .0023 second ring sound good?

helpfull people needed