Clean94Z

iTrader: (5)

Im curious if flycutting the pistons would in any way weakened the stock lq9 pistons.

rsz288

Yes.

RARON455

iTrader: (35)

Anytime you remove matierial from a finished part you weaken it, alot of folks do this, I would not do it if you plan on running any spray or power adders.

IHEARTLS1

iTrader: (1)

that is like saying pistons with valve reliefs are weaker. sure they are weaker, but it's not a meaningful difference.

rsz288

Pistons with valve reliefs generally add material to maintain piston crown thickness under the reliefs. Plus flycutters generally dont leave a nice radius like a factory or aftermarket valve relief which drives up the stress profile considerably. Its a crap shoot. Minor flycuts like 0.30-0.40" will probably live within the factory engineering margin but the piston crown is not as fatigue resistant.

JFM-jr

iTrader: (23)

I ran .080 flycuts on my LS1 and currently have .060 on my LS2 without issues. I never used nitrous tho. The stock piston is either 220 or 250 thous thick there have been guys running flycuts exceeding 100 thous but that's pushing it IMO. The Lindy cutting does indeed provide a nice radius in the cut and is worth the money.

Camaro_Zach

iTrader: (19)

I am a self titled garage mechanic. I am a computer programmer by profession and schooling. I personally fly cut my pistons in my last vette, on an engine stand in my garage during december in chicago. It was freakin -10 and I had a space heater. I did it little by little by little, cause Ive never done it and I didnt want to ruin my motor. It was a low mileage LS6 short block. Long short, I sold the car to my buddy, and hes driving the HELL out of it 2 years later. Runs like a top, hes road raced it with me many times (5-6 30 minute sessions of 4000+ rpm, super hard on the car/motor). The car is starting out season 3 of flycut pistons, no excessive oil burn, no nada, and sincerely....he/I drive that car HARD. So I say do it, if a computer programmer can do it by himself in a garage and have zero issues in over 15k miles and 3 years, anyone can.

(no comments on nitrous though)

silver-mod-o

iTrader: (15)

I'm considering doing this to my L92 motor... planning on .010 reliefs and maybe a small shot down the road???

kelp

I have 12:1 pistons which weigh a lot more than their 11:1 pistons, so I can weigh and also observe directly that they added more mass there.

I conclude I should be safe then having my engine builder machine some thousands off the top of the 12:1 to decrease my compression ratio. I was worried about upsetting the metallurgy or crystalline structure or something. I think I was getting too theoretical, but want to be careful.

chrs1313

iTrader: (24)

.110 cuts here...we will see how long she stays together...

05blackgto

i juat asked matt this from tsp. he said "yes, but they have ran flycut pistons with a 150 shot". i wouldn't do it but many people do.

subhumanzz

iTrader: (46)

spraying 100 for now on my car and it has .080 cut out. never hade a problem.

IHEARTLS1

iTrader: (1)

making a mountain out of a molehill.

SOMbitch

iTrader: (8)

Even with a generous flycut generally speaking it seems to me the ringlands are the weakest point in a stock piston.....

Erik@Lashway

iTrader: (14)

We avoid it when possible. Run a combo that does not require it and call it a day. Problem is, for every success story there are many more failures and or mess ups. If you do not do it right, you can really screw yourself. Also, I have seen some flycut pistons actually develop hotspots which caused detonation.

Just my $0.02- if you do it, take your dam time and make sure you use a trash head you'll never use again.

JFM-jr

iTrader: (23)

I used the cutting tool from Lindy tools. It worked very well provided a clean well radius'd cut and .045 radial clearance . I used an old head as suggested above but have been told by more than one person they used their current heads with no ill effects.

Here are my 2.08 / .060 deep cuts on my intake side pic


Here is the cutting tool