engine GURU qestion....vortec....

[RED71CHEVY]

currently set up:
--12513151 GM crate engine (minuns the heads, i have them and they are for
sell)block modular crank, roller cam, powered rods.\
--electric fuel pump [5-6psi]
--zz4 roller cam lift[.474I, .510E] dura[208I, 221E]
--crane valve kit 10309-1 [good for .550+ lift]
--zz4 take-out 1.5 stamped rocker arms w/ poly locks
--stock push rods that came with the 12513151 [melling mpr373 from
autozone]
--'97 truck vortec heads w/cut down valve boss[height only], new viton seals
--elbrock 1405 no choke
--power wind rpm air gap nock off
--proform hei dist, with vac adv.
--ram horns
--8mm accel wires
--bosch 2 prong plugs
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whew!!!!
ok now that's out of the way, i am having trouble setting the vales, they are noisy like they are not adjusted corretly. they have been re-adjusted [4] time and they still sound the same. are therer any diff in the push rods for a vortec head vs. push rods for ,say 442 fuelie heads if they were on the same block and with all parts listed above [except vale guide plates]. could the stock lifters be not handling the lift/crane spring combo? are they leaking down..?
I AM OPEN FOR ALL IDEAS, SO LETS HEAR THEM.
THANKS FOR THE HELP.

[gmc67swb]

Were The The Holes Where The Pushrods Go Through The Head Clearanced? I Heard Somewhere That If Your Lift Is Too Much You Can Make Contact In This Area If Not Clearnced. Also, Unless Machined, These Heads Are Made To Except 1.25" Valve Springs. If Yours Are Bigger, This May Cause A Problem.

[neonlarry]

Do you have long slot rockers? ^Are they making contact? Whenever you put other than a stock engine combo together you need to check to make sure the pushrods are the proper length. There is no way of telling from here whether they are or not, each individual combination has too many variables thats why they need to be checked.

[Dual quad]

You need to check that the rocker is acting upon the central section of the valve stem. The rocker actually wipes across the valve stem tip as the valve operates. If the pushrood is either too long or too short, this valvetrain geometry is compromised.

One of the ways you can do a quick check is remove a rocker and mark the valve tip with a black marker. Reinstall the rocker and turn the motor over by hand (might want to remove some plugs first). You can then remove the same rocker to see the witness marks. The marks should show action centered around the middle of the tip.

You also might want to take close look to see that the rocker is actually pushing down on the stem tip only and not part of the retainer.

BTW, I'd like to see a pic of your truck with the wheels and drop.

[Litdave]

Not to steal your thread but I have the same problem.

I have virtually the same engine setup and I can't get my valves to stay quiet either.

How much oil do you have coming out the top of the pushrods when the engine is idleing.

My engine has good oil pressure, it almost pegs the stock oil guage at idle. I am begining to think that I have a oil supply problem to the lifters. Maybe a pluged lifter oil galley.

Also, I did clearance my pushrod holes so I don't think that is my problem.

BTW the pushrods for the roller lifters are shorter than for the flat hydraulic lifters.

[bigjimzlll]

are the zz4 rockers self aligning? are the polylocks interfering? Check your pushrod length..I use an adjustable crane unit...less than 20 bucks