jerr6

iTrader: (1)

So I was able to get some work done today. Turned hydro lifter into a solid lifter and got adjustable pushrod. Last time when I tighten down rocker arm i had timing dots set at crank at 12 and cam at 6 o clock. I noticed today in that position the intake on no1 cylinder is opening. So I tightened the rocker today with both dots at 12 o clock. Idk if that made the difference or what but now I have a lot of clearence. At the edge of the piston I have about .090 intake valve clearence. About .125 on the dished part of piston.

I adjusted pushrod to zero lash. The math comes out I need a 7.33" pushrod. Do I need to add a certain amount for preload? On the previous test I was using 7.4 pushrod.

Does all this seem right? I didn't do the exhaust. Ran out of time. I have exhaust valve reliefs in Pistons so I don't think I ll have problem. I didn't last time.

Having both timing dots at 12 o'clock to get both valves on cam base circle really confused me. When dots are at 12&6 I should be check no 6 cylinder

speedtigger

iTrader: (16)

I would make extra sure that intake piston to valve measurement is correct. It is hard to believe you have .090" with the set up you described.

TXsilverado

iTrader: (18)

quit looking at the dots when torqueing rockers. stick the push rod in and press it down with your thumb and stop once you feel the cam on the base circle. the base circle is large enough that you won't miss it. this point should also be where you find zero lash. not sure how the hell you went from 0 ptv to .090.

dogsballs

Dots are there to line up cam and crank. As above find base circle and get your pushrod length right. With head and head gasket on, couple bolts nipped up check that it clears either with clay or a dial guage. The lowest ptv won't correspond to dots at front due to Cam grind and usually not close at tdc either

TXsilverado

iTrader: (18)

if you have a good dial caliper to measure with, I prefer that method. much more precise than trying to measure a piece of playdough.

Doug G

With the piston at TDC, drop on the heads (no gaskets/bolts needed), do as Tiggs said with the drop test. (measure VERY carefully) and add the gasket thickness you plan to use to your measurement.
This should give you a ballpark close figure....it it's close to being or under the safe zone....you'll need to test again with clay.

jerr6

iTrader: (1)

i talked to Martin at tick today. he spec the cam for me. i told him everything i did ,what i did before,and the clearences i got. he thinks the clearences sound right. he thinks before the lifter was completely compressed/collapsed and that made the valve open further and maybe it didnt even close. i did everything the right way this time and got good results.

jerr6

iTrader: (1)

i measured valve drop on flat surface and got .131''

speedtigger

iTrader: (16)

That sounds about right for the drop.

Doug G

OK, now subtract the gasket thickness you plan to use and the amount the piston is out of the hole....

.131
.051
.005 ?
---------
.075


IDK ....how does the notch and valve sizes fit ?

speedtigger

iTrader: (16)

I think his .131 is measuring the valve drop of the head alone on a flat surface Doug.

I would like to know the assembled valve drop with the head and head gasket on the engine, head bolts lightly snugged and the piston at top dead center.

That is the measurement that really counts. This would also let us know how much additional valve clearance is being gained with the LY6 dished pistons.

jerr6

iTrader: (1)

i might of figured out what went wrong on my first test when valve hit piston. i noticed the lifter i was using would not compress at all, as if it was fully pumped up and the pushrod cup was up against the clip that holds it all together. all the other lifters i can easily compress them a little bit.

so it be like that lifter is acting like a solid lifter and that combined with the right length pushrods(which i used) would hold the valve open more,alot more.

i measured that i needed a 7.33 pushrod with the adjustable pushrod,solid lifter,and checker springs. if i was using 7.4 rod that is .070 too long.

i was trying to think if maybe the check valve in the lifter is bad but you wouldnt want the lifter to be able to compress under the valve spring load.

so am i correct in thinking that the way a hydro lifter works is if everything is correct length instead of the lifter pumping up to it hits the e clip that holds it all together the pressure from the valvespring and pushrod will only let it pump up the right amount?

i wouldnt think any of these lifters are bad. the motor ran fine when i had it pulled. no ticking,noises, and good oil pressure.

i did measure the valve drop on a flat surface not on engine. wouldnt you have to add gasket thickness and then subtract piston out of hole?

Doug G

....you are correct

speedtigger

iTrader: (16)

I would love to see you do an assembled valve drop measurement after knowing your head only valve drop. It would be good information for the community to know just exactly how much extra clearance the dished pistons afforded you.

jerr6

iTrader: (1)

I'll do assembled valve drop soon. Have engine masked off for painting right now.

Doug G

Yes....please

Prorac1

iTrader: (4)

FWIW, when I was putting my LY6 together, the valve was so big that it almost reached the outer edge of the piston. So the fly cuts I made actually went into the flat edge out beyond the dish. Does this make sence? LOL. Eric L

Doug G

YES, since the LS3 valve is HUGE @ 2.16



As compared to my old SBC 2.05/1.6 heads

dogsballs

These are 70 thou cuts for ls3 valves

Doug G

DB, that's yours with the .100 shave ?

Not near as bad as I thought it would be...Almost makes me want to pull a head and look at mine....almost