Slowhawk

iTrader: (12)

We used light test springs <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

JF WS6

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Slowhawk:
<strong> We used light test springs <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Hmmm.. well, if you used test springs then it sounds like for some reason you just don't have clearance. That's really weird considering your cam isn't all that big.

My next guess would be that you may have more shaved off your heads than you think you do. Is that a possibility?

rsmith

When checking V/P clearance with checking springs make sure the rocker nut is pulled down to .000 as hyd. lifters will not compress to running height for checking. and will be holding valves open to make up for lifter preload and really throw your check off.

Just my $.02

LS1derfull

Ok this is my break down of where our clearance went, Felpro gaskets; .042" vs. stock :.055"
Decked heads .030", 2.02 valve diameter(o.d. reduces clearance to piston at 15* angle) I reduced margin close to stock valve thickness, to reduce weight, increase flow and increase ptv clearance, both valves are set high on seats to maximize flow other shops must sink valves extensively and it shows in there low flow numbers. Testing PTV with hydraulic lifter is acceptable, solid lifter would possibly reduce test clearance not gain. Also Solid lifter would require adjustable rockers which we do not have.

Brian98

Testing PTV with hydraulic lifter is acceptable, solid lifter would possibly reduce test clearance not gain. Also Solid lifter would require adjustable rockers which we do not have.

R U 110% sure of that???
I'm almost at that stage of the game and the engine shop that are doing my heads told me i had to use a solid lifter like the other said in this post...

LS1derfull

You will need method to keep lifter at 0" lash to use solid lifter. That is best way but you must either shim rocker or have adjustable valvetrain to get this. My method showed us we did not have adequate clearance, this is not because we used hydraulic lifter. Hydraulic lifter in our case has plenty of tension to bleed out fluid,we are seeing running clearance with this method.

dand35th

yes that is 110% true.. As long as the pushrod is not being plunged into the lifter...thus causing the lifter to essentially shorten..less lift value.. That is why the use of test springs are needed. and making sure the hyd. lifter is kept up all the way..at full height

JohnR

iTrader: (1)

"That is why the use of test springs are needed. and making sure the hyd. lifter is kept up all the way..at full height"

I'm confused about why you want the lifter to be at full height? Normally, when installing the rockers, the lifter will compress about .060-.100. This would be where the valve train normally runs. Test springs might not be strong enough to "Preload" the lifters and thus the valve will lift higher than normal.
When I installed my cam, I rotated the crank to a position where I knew the piston was on the compression stroke. I noticed that when I tightened down the rocker bolt, the VALVE lifted a little. This scared me into thinking "WHAT DID I DO WRONG?" I let the rockers rest in the loaded state and after about 15-20 minutes the lifers compressed down to their normal state, all was fine.

Is my theory way out there? Just my .02
Please explain.

Thanks,
John

-Joseph-

iTrader: (12)

You can't get accurate results using the "light" test springs with hydralic lifters, unless you get an adjustable test pushrod, or adj. rockers. The adj. pushrod being the cheaper way. You need as close to 0 lash as possible with the valves closed, you can adjust the lash at TDC firing position for the cylinder you are checking.

What your doing is adding whatever lifter preload you have to your max lift (preload x 1.7 rocker ratio). Watch the valve/test spring as you tighten the rocker arm down, if your valves are open all the time with the test spring how can you measure proper p/v clearance?

Ryan K

iTrader: (11)

How about a head gasket? I didn't see anything about that...

Are you running the stock gaskets?

Ryan K.

PAULJ99Z

I recently installed a set of LS6 ported heads with Ferrea 2.02" intake valves, stock head gaskets, no surfacing, with a 220/220 .564 115 Comp Cam. Installed on a 112 LSA I had .085" of P to V clearance at the minimum point. I would consider .080" an absolute minimum, so I don't know how some of the more radical setups are getting by without machining the pistons. Stock intake valves with a thinner margin would probably give .020-.030" additional clearance.

Paul J.

LS1derfull

Joseph, you are correct, we retested PTV with adjustable pushrod and 0 lash. The LS6 intake ptv was .050" at minimum clearance and .105" on exhaust. I purchased Isky notch cutting tool and added .050" to intakes. Tool worked very well and our method was within .010" accuracy piston to piston, with minimal clean up required afterwards. Piston deck thickness was .250" for anyone interested(stock) meaning .090" was possible notch depth leaving .160" left. I figure that would be min. safe thickness N/A application.

1991ls13

iTrader: (1)

im getting ls6 stage 2 heads and confused on a custom grind set up. tsp said the tsunomi would fit(235/240 .654 .609) and i want a custom grind, 236/240 .612 .609 or 236/238 .602 .605, but they said that would be too big? and told me to get the off the shelf cam...why is it too big if its smaller then one they recommended?
how big can i go without fly cutting the pistons with a 113 or 114lsa for a smoother idle???


searching for hours.. . n` hours lol

1991ls13

iTrader: (1)

another queston and statement, why the hell wouldnt you have clearence on that small of a cam? im most likely going to go with the v2 witht the same heads, and TSP said there wouldnt be a problem at all(232 234 .595 .598)

Damian

iTrader: (89)

Dude. Seriously? You just brought a 7 year old thread to the top?

1991ls13

iTrader: (1)

i could make a new thread and get bitched at for not searching ahaha
but that would be to easy.
its either i get, use the search button!!! or wow,why would you search and search like we expect then. you bring up a thread thats old...wtf???
lol

shot yourself? shoot yourself maybe? good one.
my point has been proven, thanks

built408

iTrader: (10)

shot yourself