Nimitz87

iTrader: (17)

ok I'm putting together a 6.0 lq4 w/ PRC LS3 heads milled 0.030", 0.040" cometic gaskets and going to flycut.

my question is to correctly measure the pushrod length don't I have to crush my gaskets? can I reuse them if the motor was never fired?

and I obviously have to have the correct pushrod length to even begin to flycut...

thanks

Chad

vettenuts

iTrader: (4)

Here's what I did. I took the original GM MLS gaskets and drilled out the rivets. Then use the thick center and one thin outer and it came out to around 0.040".

jasonsnova

going through the same thing myself(lq4/ls3 heads) i was planning on useing my old lq4 head gaskets for mock up, then measure differance between the gaskets and plan accordingly....
how are you planning to flycut? are using your heads for that? doesnt it mess up your guides?

Nimitz87

iTrader: (17)

sad thing is my mother threw out the old gaskets

Jason I'm going to use the Lindytool it is the identical size to the valve/stem of the heads and fits right in, just going to put some motor oil on it, suppose to be fine and not damage the heads.

measuring both using the clay and dial method, first however I need to measure for pushrod length...all a learning process for me.

Chad

69LT1Bird

iTrader: (1)

All head gasket thicknesses are based on their compressed thickness (stock GM 1.33 mm, .052 in compressed). If you have an adjustable pushrod checker, you can set the head on the block without the gasket, do your measurements and then add the .052 or whatever you are using to your measurement.

I want to correct the above, if you are zero decked this will work, if you are above the deck, you will push the piston up against the head. My error.

jasonsnova

exactly,
how much did you mill off your l92'S?? gonna get mine milled next week, also got new cometic .045 gaskets.....

69LT1Bird

iTrader: (1)

I took .030 off mine. I ran .045 Cometics with my last cam 222/238 XER 114+4 with no issues. I now have a 234/246 in my sig but I went back to the GM L92 gaskets. I calculated that I lost .2 CR but I will be able to run more timing to make up for any loss.

You need to accurately measure how far above the deck the pistons are, measure all of them. Mine are out .010 in. You don't want the quench under .035 for a street car. The OP would be too close if he was out .010 and ran a .040 gasket. Just more to think about and calculate.

The dish in the LQ4 pistons helps with the PTV clearance.

SweetS10V8

iTrader: (4)

Im not sure they are large enough for a 2.160 valve.

chrs1313

iTrader: (24)

why do you need a pushrod made to check ptv clearance...I just used a pushrod checker and made my own solid lifter using washers...order your pushrods last after everything is bolted up and complete...

I would not check ptv without some type of gasket or taped deck...the piston comes our of the hole and will make contact with the head...

vettenuts

iTrader: (4)

If you need an old MLS gasket, give some of the local FL vendors a call. I am sure they have them to be throw away. Not sure where you are located but there are several LSx type of shops in FL.

69LT1Bird

iTrader: (1)

I would have 8 bent valves by now if that was the case. My old 222/238 was fine and so is a 234/246. There are plenty of flat top piston LS2 and LS3's running around with big cams to prove there is not an issue. Yes, valve events dictate if they will be problems so each engine is a bit different. Your S10 is the only one I have ever heard of with PTV issue with a small cam.

WKMCD

iTrader: (2)

FWIW: At one time I ran a cam with 19* of overlap with L92 heads milled .030, LS2 2cc pistons .005 out and had no problems. It's always good to check though.

SweetS10V8

iTrader: (4)

I wasnt saying anything specific or that you do or dont have PTV issues, I was just saying the valve reliefs cut into those pistons were intended for 2.00 valves.

Aftermarket pistons make have standard LS reliefs(2.00" Valves) and different reliefs L92 reliefs (2.160 Valves). Although I think at this point most aftermarkets have jsut started using the L92 on enverything.

69LT1Bird

iTrader: (1)

LQ4 pistons do not have valve reliefs. A 6.7cc dish is all they have.

redsilv

if he crushes his head gasket from torquing it down to check piston to valve and pushrod length
will he be able to reuse his head gasket, since he didnt fire up the motor

as i am also curious

SweetS10V8

iTrader: (4)

They have to have different pistons then form year to year. The ones Ive worked on have a dish and valve reliefs.

69LT1Bird

iTrader: (1)

Here is what my 2002 has.

SweetS10V8

iTrader: (4)

Ill get pics that I took, just for future reference, tommorow if I didnt delete them.