Shawn MacAnanny

iTrader: (12)

So from what i read i install the cam and springs but the #1 cylinder valve springs.

I rotate the crank to #1 TDC dot to dot.
I let the valves drop down.
I install the rockers, pushrods, and rocker rail.
I measure between the intake rocker and the top of the valve with a feeler gauge.

And thats how i do it right? I measured mine today and i watched as i tighened it down it touches on the last 1/2 turn of the rocker bolt. This is with the stock lifters and stock 7.4 pushrods. Now i will be installing 7.45 as that is what i measured i needed with my setup. How do i figure in my lifter preload and all to this? I know my springs will keep plenty of pressure on the preload which i figured for about .60 with the 7.45s.

So how does that translate my 7.45s and .60 preload to my .000 of clearence between the valve stem?

8a8mfh

iTrader: (3)

You need to check with a solid lifter. The valvetrain geometry has to be close at least.
Most important you need to rotate the engine because piston to valve contact never happens at tdc.

What I do is set it up with a solid lifter, zero lash, checking springs weak enough to push with your hand, an old head gasket or one thinner than what you plan to use.
Turn the engine clockwise by hand while pushing down on a rocker, when (if) the valve touches the piston turn real slow and let it take up the slack til about .010 is left.
then loosen the rocker at the tightest point and insert feeler gauges between the rocker and valve.
Keep the feeler gauges in and turn it over. If you're looking for say .080 PTV clearance subtract your feeler gauge from .080 and thats what you cut.
Triple check, cut one, check with .080 of feeler gauges.
This is one way to do it.

Shawn MacAnanny

iTrader: (12)

By the time i sold my harness and intake and all i bought this LS1 longblock for $200 so really its a template for the swap and to make way for my 408. If it runs for 1000 miles i would be extremely happy. Nothing binds up with the engine turning over so i think it will be ok. Engine is on an engine stand in my dining room and im really not wanting to take it apart and buy headgaskets and all. Using cranes charts and all it should clear fine. I have both cam cards here from this cam and from the HPE S cam i had and the HPE S cam had less clearence but still cleared in my LS6 that had ET 2.055s so i think I'm safe just was wondering if i was doing it right.

8a8mfh

iTrader: (3)

No you're not.
PTV contact will never happen at tdc, you're measuring PTV clearance at tdc which is useless.
As long as you're going to be happy doing whatever it is you're doing to have it never run, then you're just fine. And by doing it wrong whatever time you spent with that was wasted, why bother.

PREDATOR-Z

You need a dial indicator, degree wheel, modified solid lifters and light springs.
PTVC is measured 10* BTDC and 10* ATDC

BOWTIE

And either an adjustable pushrod or adjustable valvetrain.

Damian

iTrader: (89)

What he said.

Checking PTV @ TDC does you absolutely no good.

ssheets

iTrader: (1)

This was the best lesson I learned out of my build. I never worked on an non adjustable valve train. Predator has it down. I made an adjustable pushrod and used my stock lifters, they were fully pumped up and my test springs barely held the locks in place. I ended up with .100"/.180" and used 7.40" pushrods. It took me a day to learn about it, but when I turned the key I knew it was right. I also knew I wouldn' likely destroy the motor the first time I spun it up to 6800rpm (I've since set the rev limit at 6400).

So either you do it right or you just leave it to chance...chance never did make it on the list of great engineers.