streetknight2

iTrader: (10)

I have a LQ9 in a fox body. I had to fly cut the pistons .100" for the cam. The machine shop that cut the pistons said I probably shouldn't spray the motor. Just wanted you guys $.02


The car is only 60' in the mid 1.60's with a 4.10 gear and TH350 trans. But its running 6.90's @ 102 in the 1/8
Converter is tight and I think some spray would wake it up.

Sales@Tick

iTrader: (3)

Are you mainly worried about the integrity of the piston now that it has been fly cut?

I'm pretty sure there are guys that do it all the time, the stock pistons weak points are the rings and ring land area anyways not the actual piston itself although they aren't that strong anyway.

streetknight2

iTrader: (10)

Yes, the integrity of the piston. I didn't open the ring gap any. Was just thinking a 100 shot though.

Chris@NitroDaves

Sticking around 100hp will put in the safe zone but you should be able to spray that without a problem. We have had customer spray with flycut pistons before and have had good luck with no problems.

Sales@Tick

iTrader: (3)

As Chris said you will be fine.

Sam88Gta1

iTrader: (13)

I have cut twice that out of a stock piston and turned 7400 rpm on a 250hp nitrous without a problem. I'm not saying its completely safe to do but it will work.

tittan1500

iTrader: (8)

I broke my flycut piston after a month of spraying a 100 shot. Plugs looked good and it actually broke on a NA pass.

In the Fbody club in MN there are 2 other people that broke there flycut pistons in the same place mine gave out, right at the pocket of the cut.

Sales@Tick

iTrader: (3)

Very interesting.

How much was fly cut from the piston?

streetknight2

iTrader: (10)

I'd like to know as well. I was leaning a little closer to spraying after my last outing at the track. Got to make a couple 1/4 mile passes and now I know converter is a little tight. She went 10.70's @ 127.35 mph.

fergymoto

iTrader: (129)

The broken pistons were likely caused by detonation, and the spot where they were flycut was the weakest part.

Chris@NitroDaves

Agreed...

tittan1500

iTrader: (8)

I dont know how deep it was but this is the picture, plugs looked good I was pulling them when tuning the 100 shot

JRracing

iTrader: (35)

Mine broke also. On a 100 shot. I think it went on a na pull street racing on a hot summer night. The piston was cut .130" and made 471 whp na and 572 on a 100 shot.

I would play it safe and not spray it. But I think it will be fine once in a while.

JRracing

iTrader: (35)

I think this is totally the cause of my failure.

fergymoto

iTrader: (129)

Detonation can do a lot of damage on stock/cast components. It can fracture crankshafts, distort rods, crack pistons, break ring lands, and sometimes beat the bearings up without visibly hurting other parts. I recently bought a stock LS1 that had been sprayed and was removed from the car because it was smoking. Many of the pistons had broken ring lands. Bad tune up and detonation.

PACKETFOCUS

iTrader: (2)

Im in the middle of this right now. Built my 98 ls1 and swapped in a MS4. Went to check PTV and both valves are hitting. So I have to flycut to make it work, but was worried about piston integrity.

Wanting to spray 200 on it wet through a plate.

Also gapped my rings at .022 and 0.24 so was even thinking about opening them up a little since I was initially only going to spray 100 on this motor.

Pete91

iTrader: (4)

I sprayed a 100-150 shot on .80 fly cut ls1 pistons for a couple months. The pistons took the hit, but the motor did spin a bearing.

tittan1500

iTrader: (8)

I would say your going to be on borrowed time. My pic above shows how close the deep portion of the cut is to the ringland. there is not much metal left at that point.

98blueSScamaro

iTrader: (14)

Bad fuel and or knock. All the pistons I seen do that where n/a with 29 to 31 deg of timing on pump gas. It detonated for sure. Running better fuels like race gas or E85 help a lot in thes areas.

Ksths2

iTrader: (1)

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