WeirdRich

OK, just assembled my first motor. 383 Stroker

-16CC Inverted Dome pistons
CC306 Cam
Crane Gold 1.6 RR's
CM 612 Springs
Stock Pushrods

Now everytime I try to fire it up...I bend all the exhaust pushrods. Thought it was timing...and it was fine. Thought it was me adjusting the rockers wrong...and its not. Thought the springs were bottoming out...and they arent. What the hell is going on. Im open to ANY suggestions, knowing that this is probably just some stupid newb mistake. HELP!!!

WeirdRich

Anyone? I kinda want this thing running....

Dave89IROC

valves hitting the pistons?

does stock pushrods mean stock, or stock length?

if stock, get some aftermarket hardened pushrods

WeirdRich

usually thats what happens when the pushrods bend....but why

Dave89IROC

huh?

WeirdRich

they are stock, but arent stock push rods still strong enough to push open the valve without bending? Im not going to buy hardened push rods and then bend those too...

WeirdRich

usually the valve hits the piston when the push rod bends, but why are they hitting.

Dave89IROC

no, a bent pushrod can be caused by the valve hitting the piston, unlikely for a bent pushrod to make the valve hit the piston though


what valve springs?
any deck work done to the block/heads?
was the valve to piston clearance checked on assembly?
valve train geometery ok(no binding)?

94 NO TOP Z

You probably have the timing chain installed wrong (cam to crank sprocket orientation is off).

Dave89IROC

quite possible, I'm trying to get some more info then he gave, see if the easy stuff is good

WeirdRich

like I said, CM 612 springs
no deck work done
didnt check the valve/piston clearance because my machinist said it was fine
no idea what your talking about with the binding...

this would be my first time here, so please forgive the newb mistakes.

EDIT : timing chain is not off...I checked it 4 times now

blackztpi

your valves will not hit the pistons with a cc306. not even on stock pistons. since you have forged pistons, you are definately fine. most all forged and aftermarket pistons have much deeper valve reliefs allowing bigger cams without PtoV clearnance issues.

1racerdude

Go to the hardware and get a pair of springs that are 3-1/2 to 3-3/4 long and 7/8"-1" in dia. Install them on one cyl with the rest of the exhaust push rods left out. Roll the engine and check your p/v clearance by pushing on the valve anywhere from 70*BTDC to 75*ATDC and see if they are hitting. Do this several times to make sure. They will be the closest on the overlap cycle. This will rule out or in that problem.
If that's not it ya need to look for coil bind,retainer hitting the guide or seal from the underside. That's all I can think of that would cause push rod bending.
Do this with the pushrods and rockers installed and adjusted and ya may have to make your lifters on that cyl solid to check with.

blackztpi

it is not PtoV clearance. he informed me that he changed to 1.5 rr's and the same results.... the exhaust lift on the cc306 on 1.5rr's is .540". the intake lift on the 1.6 is .544" and he is having no problems with the intake pushrods oin the 1.6rr's, and the intake lift on 1.6 rockers is higher than the exhaust lift on 1.5 rockers. this rules out PtoV issues.

1racerdude

The ex pocket may be shallower than the intake or to small.
Check coil bind or the retainer hitting the seal or valve guide. Check also to see if the rockers have a long enough slot to handle the lift but the intake is working if they are the same rocker's.