CI GS

BTW: the Comp instructions tell you to tighten the rockers down, with the lifter on the base circle, mark the pushrod, and then back it off slowly until you can turn the pushrod between your fingers, make another mark on the pushrod, and then measure the distance between the two marks for preload. That would be a great way to do it, IF you had decent access to make an accurate mark each time.

realcanuk

I cant see getting an accurate number that way, at least not on an LS. Too hard to get in there. Strange cause everything Ive seen from comp suggests using a measuring pushrod, which is really the best way other than a dial indicator.

realcanuk

For some reason, as simple as it sounds.... I fail miserably at measuring for pushrods.....

I measured for mine 10 times. Settled on a number, ordered the pushrods, and ended up throwing away 180 bucks, because in the end I used the ones I had, with some shims.

CI GS

Sorry, my misquote. They said stock LS lifters.
I would love if the covers can work somehow. I'll take a look at it again tomorrow. Maybe it's not as bad as I think.
I'm almost tempted to rip the heads off, throw some Johnson lifters on there and some CNC heads back on top of them...

CI GS

Good idea. I'm going to dig a dial indicator out tomorrow and use that. No more 'screwing around" with preload.

realcanuk

I probably should have done that too ..... but all worked out in the end.

CI GS

Tell me about it. I probably have had every type of adjustable pushrod and pushrod measuring fixture ever made for big block chevys, and I still ended up with a whole drawer full of brand new pushrods before I settled on the right ones. Good thing I still have two big blocks, one in the race car (565) and another (540) in my boat, neither if which gets used as much as the vette, which has a whopping 3949 miles on it, as of today.

old motorhead

Do you lack clearance due to valve cover's height? If so, I'm guessing they still make those spacers that raise the valve covers about a half inch.

Oh, and if you didn't live on a postage stamp, you'd have more miles on your Vette. It is a pretty postage stamp though

CI GS

LOL.
Yes, the covers won't sit down on the rail. The baffle inside is resting on the rockers. I've seen the spacers. I think they're made by yella terra? But I would rather just get the taller covers and throw the existing ones on my old truck, or sell them.
It is a postage stamp. But there's lots of roads here and we have some unbelievable infrastructure works going on down here as we speak. I think we probably have the highest per capita and per square mile amount of vehicles of any country in the world. There's even one billionaire developer who's building two tunnels, from the ground up , to put two major public roadways in, so that he can build over the highway!
It's certainly not as big as Texas! Hell, NOTHING is that big!
But, the good thing is that I get to say that I have the only GS in the country!

CI GS

Here's a link to the Comp instructional video I referred to above:


I've since noted that she says "much less than one turn means you need a longer pushrod".

irok

Texas is only 695,662 km squared and Ontario is 1.076 million km squared.thats 1 1/2 times the size of Texas I think.Quebec is 1.667 million km squared.I can't count that far

CI GS

Yes, but Texas is measured in miles, TEXAS miles!
You ever heard the joke about the Canadian and the Texan, who were bragging and trying to outdo each other? The Canadian takes the Texan to the Niagara Falls and, pointing to the falls, says, "I betcha you don't have anything like THAT in Texas, aye?" To which the Texan promptly replies, in his deepest drawl, "Yeah, maybe not, but I bet we all got a plumber that kin fix it!"

CI GS

Geometry looks good, I think? This is on the right cylinder head. I'll probably check another pair of rockers on the driver's side too. I'm glad that I don't have to mess with shimming it.

realcanuk

Looks like s touch to front side but I think I'd call it good.

CI GS

So, I figured out a better way to find zero lash with these rockers than wiggling the rocker body, which is not the best way, or spinning the pushrod between your finger tips, which is impossible with these fat *** rockers on the LS head.
What I did was hold the rocker body very slightly against the pushrod, but not so hard as to depress the plunger in the lifter (which is very easy to do, at least for the first ~0.010" or so) and gently spin the roller tip with my thumb whilst using an extension and hex socket in the other hand to gently tighten the rocker bolt, until I start to feel resistance on the roller wheel. At that point, I know that I have reached "zero lash", and I can then check the number of turns until the bolt is tightened to 22 ft. lbs. It couldn't be simply than that, could it? If only I had figured that out a little sooner, I would've saved myself a lot of screwing around, literally, with these rockers.

CI GS

Thanks Jody. It is a little bit to the inside, but I don't think that will hurt. From the markings on the valve stem tip, it looks like the stock rockers were a touch on that side too.

CI GS

Just checked the preload on the rockers again - one pair on each side, and found out that I don't really need longer pushrods, at least not for the intake valves. On the intake rockers I tested on each side, both took between 1 1/2 to 1 3/4 turns of preload before the bolt was tight. On the exhaust side on both rockers tested, it took roughly 7/8 of a turn.
So, my thinking is that the only explanation for this is that my cam is ground with two different base circles on the intake and exhaust?
This is the VR PD-1 grind, with 223* / 238* duration and .610" / .623" lift, so this may be possible.
In any event, I'm going to order a set of 7.425" pushrods and run those on the exhaust only, and leave the 7.40" on the intake. That's the plan for now, anyhow.
BTW: I checked the valve covers again, and they are standing off the rail by about 3/16" to 1/4", so a thicker gasket might work, but I still think I'll just order the taller covers, since I have to fly in a set of pushrods anyways.

realcanuk

Strange to have different base circle...I think. Lol

I would run what you have and see how it sounds. 7/8 ish is like .045-.050 area which many say works well.

irok

I would run it the way it is also

CI GS

Thanks guys. I checked it again and it literally takes just under one full turn to torque it to 22 ft. lbs. on the exhaust and the intake is somewhere between 1 & 1/2 and 1 & 3/4 turns. I've torqued them all down and all I need is the taller covers to throw on them.
They look so damn good I wish I could get some clear valve covers, LOL.