Cutting a 1990P6

Skidude

Skidude

Member
How much can you cut off the top of a Wiseco 1990 piston before having issues with thickness or top land burn through? I want to run a .060 piston in my .200 stroker and the .540 deck height piston isn’t available in .060 over. I’d have to go .120 over to use a 1982 series. It’s a brand new Raptor 4 block and I hate to resleeve it right off the bat.
 
I just looked at a couple of my 1990 pistons .
There not much room there .
If you went half you would be at around .030 on the land .
That seems too thin .
Ihave some hortsman pistons i could look see whats there .
You want something with .540 deck hieght ?
 
I’ve not bought the piston yet. My last .200 I used a 4.375 H-beam rod with a 1985 series, .590 deck height. Since that piston is no longer available I’ve opted for a 4.425 rod. So theoretically I need a .540 deck height piston. I’ve not purchased the piston yet. Also, the block hasn’t been decked yet. I prefer to run mine about .020 in the hole with a thin gasket. If it’s safe to cut up to .025 off I’m good, I’ll just buy the 1990P6 and fit it up.
 
flattop1 said:
I would wait and see what Brian says .
I had a clements piston that was real thin .
Click to expand...
It's too early for math!

LOL
The old style Wiseco, you could take .050" off and still be alright in a limited. The new style, I would be hard pressed to take any off...maybe .020" at most. We used to mill a slot on the underside of the piston just to lighten them...haven't done that in years.

We might have some pistons here in stock that will work, I'll have to do some looking.

Skidude, have you cut the eyebrow down in the cylinder, or why are you wanting to run the piston .020" in the hole?


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No, I’ve not cut anything yet. I run .020 in the hole with a .010 copper gasket. That gives me .030 between the top of the piston and the head.
 
These may help someone .
 

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flattop1 said:
Piston crown thickness .
I had a brainstorm .using my 3-4 mic and a 3" gauge .
A stock full skirt piston is .165
1990 i had 2 handy .144 and .122
One piston thats cut it is .095
The 1980 was .228 which fit with you can cut .100 off them .
Click to expand...
Thanks for that. Now that my memory is jogged a bit it seems like .100 to .120 thickness is what I used to look for when cutting a top or lightening from the under side. It’s been 26 years since I was doing this kind of stuff.
 
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