Anyone spraying stock pistons that are fly cut?
09-07-2012, 11:27 PM
#21
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This is interesting, I flycut mine 2 years of drag racing ago .100" deep, I spray 150hp every pass right from the hit, this weekend going 175hp..... on stock bottom end & its tuned by Speed inc 
I guess i didnt' think this would have any issues of the strength, i figure as long as it is a good tune I can't imagine that being the problem.
I'll report back with results Monday, hopefully I won't need a shovel to pick up the broken flycut pistons
I guess i didnt' think this would have any issues of the strength, i figure as long as it is a good tune I can't imagine that being the problem.
I'll report back with results Monday, hopefully I won't need a shovel to pick up the broken flycut pistons
09-10-2012, 10:06 AM
#22
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X2 on the sharp edges = bad! & yes, Jim is the man!
I sprayed 175 to it Friday night several times and it loved it, it needed one step colder plugs but new personal best 1/8th mile 1.45 60', 6.49 @ 106.21
I sprayed 175 to it Friday night several times and it loved it, it needed one step colder plugs but new personal best 1/8th mile 1.45 60', 6.49 @ 106.21
09-11-2012, 12:28 PM
#23
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Well, I remembered that I have an extra piston the machine shop fly cut for me "just in case" lol.
Here's what's in my motor and now I'm really hesitant about spraying it. There's only .055" to the edge of the piston, not sure if that matters, but I finally mic'd the depth of the valve reliefs and they're .208" NOT .100" like they were supposed to be. I had .010" clearance on the intake valve (told them to cut .090") and had .050" on the exhaust (told them to cut .050")
UGH!!!!!!!!!!
Here's what's in my motor and now I'm really hesitant about spraying it. There's only .055" to the edge of the piston, not sure if that matters, but I finally mic'd the depth of the valve reliefs and they're .208" NOT .100" like they were supposed to be. I had .010" clearance on the intake valve (told them to cut .090") and had .050" on the exhaust (told them to cut .050")
UGH!!!!!!!!!!
09-13-2012, 10:58 AM
#26
Damn man.....what cam do you have in there ?? Wow....I mean I know they screwed up but wow.....can you mic the total thickness left in the crown (from bottom of flycut to bottom of crown) ??
09-13-2012, 11:10 AM
#27
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Ok guys I forgot to add some info lol.
I have LS3 heads so the valves are 2.16, 1.59
The cam isn't that big at all. 230/238 .600 .615
But they're definitely cut too deep. They are already installed in the engine and it seems to be running fine on motor.
As far as checking to the crown, I have no idea what that means lol.
This piston in the pic is a .020" over piston that was sent to me by mistake and I didn't realize till after the machine shop fly cut it. So, it is no good to me and I can cut it up or what ever I need to do.
I have LS3 heads so the valves are 2.16, 1.59
The cam isn't that big at all. 230/238 .600 .615
But they're definitely cut too deep. They are already installed in the engine and it seems to be running fine on motor.
As far as checking to the crown, I have no idea what that means lol.
This piston in the pic is a .020" over piston that was sent to me by mistake and I didn't realize till after the machine shop fly cut it. So, it is no good to me and I can cut it up or what ever I need to do.
09-14-2012, 03:47 AM
#28
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theres a video of my stock pistons fly cut on a 150 load i sprayed it three times pulled the plugs out to find out number 7 to be melted... my pistons are fly cut .100 after the pass didnt feel right was poping and sounded weird babied it home 60 miles made it ten miles from home exploded the ten bolt got it fixed and went to do a wot pull on motor and smoked pulled the head off and found the valves on number 7 were bent machine shop said from extreme heat but idk lol...... btw that car i raced in the video went 10.78 at 128 last night so im looking for a 10.50s pass next week
