Machining will be done with a torque plate installed as well.
Weisco recommends 0.0025 measured at bottom of skirt.. Im thinking I want to run these things looser, at 0.0035. Its not really a 'street' motor... It will see some street driving, but primarily track once the new setup is in.
What are you guys running who are making big power? I would really like to get some feedback on this. I know its very common to run upwards on 0.0040 on a honda, but I have no experience with DSM's.. yet...
I definitely wouldn't run .0025 on your motor. It opens up to .003 after the coating wears off the skirt, but that's still too tight.
I won't comment on what to run, since I don't have anywhere near 650hp. Call Brian Nutter at Wiseco on Monday after you get all the opinions from here.
See I am on the opposite side of things on my end. I trying to figure out what piston to wall clearance to run with my Wossner pistons. The spec sheet that comes with the pistons reccommends .007 but to me that sounds too loose from what i have read. This is still somewhat new to me.
-wes
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projectGSX is underway
It has to do also with what the piston is made from and how it will expand under heat.. but when an engine is cold its cold, and at 0.007 you would think there would be lots of slap untill it gets warm.
I'm stupid! I went back and looked at my spec sheet. Mine is not .007 it is 0.07mm which when converted to inches is 0.0028in which is tight. I wasn't thinking that my spec sheet would be in metric since my wossners are made in Germany.
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projectGSX is underway
You do not provide us with the proper information to give you an accurate suggestion on piston to wall clearance. Pistons expands with different fuels under different amounts of pressure. You should be telling us how much you drive the car and what type of fuel and turbo you are using. When you call up wiseco they will ask you the same thing and give you a measurement based on there tests and estimates on the expansion rate of there pistons and rings.
You do not provide us with the proper information to give you an accurate suggestion on piston to wall clearance. Pistons expands with different fuels under different amounts of pressure. You should be telling us how much you drive the car and what type of fuel and turbo you are using. When you call up wiseco they will ask you the same thing and give you a measurement based on there tests and estimates on the expansion rate of there pistons and rings.
100-200km street driven per month... 2-3+ track visits per month (seasonal only)
s366 ett
e85, q16 or c16.
thanks for the info guys, prob just run this thing nice and loose at 0.0040 i will call weisco tommorow
I am running .0025 and plan on 500 whp with wisecos(still on break in right now). If the pistons are measured properly per wiseco's directions that come with the pistons, you shouldnt have an issue but then again, if you can run looser why not I guess. My car is street driven everyday and I dont plan on running 500whp more than oonce a month at most at the track. I have seen others run the same PTW clearance at 650whp, but there are plenty of people that have failures as well. I think some people just measure the pistons improperly or their machine shop measures it improperly. Best thing to do is to micromanage the build with your machine shop.
I have seen others run the same PTW clearance at 650whp, but there are plenty of people that have failures as well. Best thing to do is to micromanage the build with your machine shop.
Agreed!
If I'm not mistaken, jeffgst on the Link forums cracked his cylinder wall from too tight p/w clearance on Wisecos. I can search later today, but I think I remember a few guys over there complaining of skirt issues with too tight p/w clearance. I have mine at .003 which is why I remember reading those threads and wishing I went a little looser on my build.
Your Piston to Wall clearence really depends on a number of things. Wiesco's paperwork recomends .0025" for most applications but I would venture to say that clearence is more geared towards near stock power levels.
If you will be producing anything near 650hp you should really start to think about partially filling your block. Anything above this number without a filled block is playing with fire IMO. With a partially filled block and the power level you are targeting, I would shoot for .00375-.00425" PTW with Wiesco's pistons.
If you do not fill at all, and run a full water jacket, I would stay in the .00325-.00375" PTW range.
Full filled block, I would be up there in the .0045-.0055" range, but this would be for a dedicated track car.
These are numbers that I would reccomend for Wiesco's piston material.
Your Piston to Wall clearence really depends on a number of things. Wiesco's paperwork recomends .0025" for most applications but I would venture to say that clearence is more geared towards near stock power levels.
If you will be producing anything near 650hp you should really start to think about partially filling your block. Anything above this number without a filled block is playing with fire IMO. With a partially filled block and the power level you are targeting, I would shoot for .00375-.00425" PTW with Wiesco's pistons.
If you do not fill at all, and run a full water jacket, I would stay in the .00325-.00375" PTW range.
Full filled block, I would be up there in the .0045-.0055" range, but this would be for a dedicated track car.
These are numbers that I would reccomend for Wiesco's piston material.
Good luck.
Why would you have to partially fill your block? I thought these blocks didnt need to reinforced till over 1000whp? There are alot of guys running in the 700whp range with out a partially filled block.
I'm wondering about this too. Not arguing one way or the other. Jsut seen too many unfilled 4g63 blocks daily beaten with 700-800whp. And those who've advised me on my eagle/wiseco build for my hx40 goals, everyone says that filling the block is for +900whp.
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Matt
dd '90 GST, Holset H1C
