Jeff Smith

iTrader: (44)

Subscribing...

ramdaspadhye

iTrader: (3)

How are you at 11:1 compression? Is that calculated SCR with the cam or just a piston/combustion chamber calculation?

PREDATOR-Z

IIRC, dish in LQ4 pistons are ~6.7cc can anyone confirm please.

NemeSS

iTrader: (127)

10.8:1 scr with dished lq4 .060 over pistons and 4cc valve relives
milled 243 heads .030.
4.085 bore .051 compressed gasket
+.015 deck
stock crank,rods, .060 over 8cc dish piston
if i would not have machined in the vr's it would be right at 11:1 even with dished pistons and the milled 243 and .051 gasket.
the piston protrudes .015 out of the bore.
SD tune
mostly weekend and gtg car. i dont dd as much anymore, but i use dd it for about a yr after i built engine. engine has around 40k miles now.
avg. about 23mpg with t56 full weight and 18in wheels

pistons used are Speed Pro part number:
H857CP (8) 99-02 VORTEC 364CI (6.0) 250.00$
1.5/1.5/3.0MM Sealed Power Rings (4.00-4.06) bore 100$
coated skirts, press fit stock rods.

99 Blue Bird

iTrader: (3)

does anyone else have any good rods and piston brands to reccomend?

elias_799

iTrader: (8)

i got coated wiseco pistons and compstar rods in my turbo motor, and no problems yet

ramdaspadhye

iTrader: (3)

So 11:1 compression on a stock LQ4 would be 59cc chamber heads with a .041 gasket, correct?

NemeSS

iTrader: (127)

a stock lq4 is around +.010 deck, a .041 gasket would net .031 quench.
perhaps a bit on the tight side. i try to keep it around .035-.040
u will have to verify ptv for sure with that gasket. even though the spherical dish does allow for some valve clearance,

with a .041 compressed gasket (assuming the bore is around 4.08) and 59cc chamber heads, SCR will be at around 11.31:1 with a lq4

ramdaspadhye

iTrader: (3)

and the GM 6.0 MLS gasket is how thick?

NemeSS

iTrader: (127)

ls3 is around 4.085 .051 compressed

novaflash2002

iTrader: (51)

lq4 head gaskets are 4.045 bore compressed .051 compressed thickness

NemeSS

iTrader: (127)

i measured them at same bore, but iirc the compressed thickness was .055

Sales2@Texas-speed

iTrader: (5)

We also have a 227 runner with a small chamber in the new PRC castings! It's available with small chambers for kicking the compression up!

NemeSS

iTrader: (127)

any more info?
chamber bore? cc? valves? flow?

Kory 88Iroc Lt1

iTrader: (7)

great info.
bookmarking for future project.
Thanks,
kory