scuffed pistons, starting over

[highstumpr]

no matter what you use for rods and custom pistons you can only go .050 longer than the 4.2 rod and a 4.0 piston,do to deck height. So at BDC you can only have at most.050 more piston in the bore. The point was .050 more in the bore wouldn't make the piston any more stable. Would having the pin .250 farther in the bore at BDC with the 4.0 rods make the piston more stable? Then again maybe all I needed to change was to notch the rod bearings, don't know. I do know, once you've had a stroker you'll never go back.

[highstumpr]

The new stroker is do, should be on the road in a couple days. Here is where we ended up.
chamber vol. 56cc
deck hght. 9.425
piston to deck -.00
gasket uncrushed .052
piston vol. 22cc
gasket bore 3.995
rod length 6.124
KB 944 forged
crane 753941
If the math is right I come up with scr 9.637;1, and dcr 8.5o4;1

[Flash]

The new stroker is do, should be on the road in a couple days. Here is where we ended up.
chamber vol. 56cc
deck hght. 9.425
piston to deck -.00
gasket uncrushed .052
piston vol. 22cc
gasket bore 3.995
rod length 6.124
KB 944 forged
crane 753941
If the math is right I come up with scr 9.637;1, and dcr 8.5o4;1

Woo Hooo Party on!

I'd really like to get some Cold Hard facts on these piston, so pardon my questions.
How did you come up with the deck hight number
Block is decked .015*?
Piston is truly .000?
Piston was cc to 22cc?
"KB 944 forged piston are the 9.1's right?

A 9.6:1 Compression(scr) should work grate with a .000" deck hight or a quench hight of .051............I might even be temped to go with the .043 head gasket!?????

Will be real interesting to see what kind of octane it will run on (especially at a low altitude that you live at. )
Don't recognize the crane number, will have to go look it up...........do you have the cam card, handy?

Just went in the fact section. Standard deck hight is 9.450 to 9.456 minus Your deck hight Equals .019" to .025" Decking, right?

*From re-reading your post you said that the block had been decked .015 previously, Right?
When i did the math it came up to 9.6:1 Compression, as well.


Flash

[gradon]

Definitely measure deck clearance when the pistons are installed. I went with the stock deck height that the calculator used and mine was .002-.003" taller(or the machinist decked .028" instead of the .030" I ordered). No biggie as the error lowered comp a smidge.

[highstumpr]

Dam, sorry about the deck height, it's .005
If my chambers were a little bigger I would have used the thinner gasket, maybe with a new ported head. It was decked last time. This time we really only changed the rods and pistons plus a rebore to clean the holes. I think my compression is a couple tenths lower this time. I ran on 91 and 89 before. The cam is pretty big but it ran great, a little stumble off idle and away you go. Hope to get an af gauge soon, any preferences?

[highstumpr]

I also used cam saver lifters and drilled the rod bearings. I can still get original delo 400 15-40 in 5 gal pails, not the le. I use alot of oil in my equipment.

[gradon]

I was gonna buy Innovate's LC-1 before I got hooked on the LM-2(can't afford it yet). You can get the lc-1 for under $200 shipped and if you shop around, you can get a gauge(in case you don't have a laptop/want to look at a laptop) for $20 more.

[Flash]

I also used cam saver lifters and drilled the rod bearings. I can still get original delo 400 15-40 in 5 gal pails, not the le. I use alot of oil in my equipment.

A couple more question, I didn't get a complete answer on my first one but............

did you us a standard or a HV oil pump and how is your oil pressure at idle, eng hot or at operating temp.

Flash

[highstumpr]

The deck height was was measured, then a piston and rod were installed to get true compression height. Standard oil pump, had 60 psi before,have not started it yet with the built in oil leaks.

[highstumpr]

40 psi idle, 65-70 at speed. No noises runs great but has a stumble at 3500, like it just misses a beat then back on, only a few miles and computer cycles. I'm smiling.

[SilverXJ]

How do you like the KB944s? what piston to cylinder clearance did you have them installed at?