valves hit pistons!!!

[stangster50]

ok, so i got some new gt40x-303 heads, b-cam, and scorpion 1.6 pedistal rr's installed, i went to clay the piston, and it wouldnt make a revolution, i then took the clay out, same deal, just stops part way, and the clay says it hits.. i tried using a stock pushrod out of the old engine, just to see if thats just what i needed to buy. i made a solid lifter, and thats in there.. so, after i spun the engine, and it stopped, i looked at the mark on the intake valve, and it is pretty centered but maybe 1/8" wide? also... when tightening the rocker arms down, they seemed to compress the valvesprings a good bit... that supposed to happen?
exhaust seems to clear..


(intake)

so, do i need to change my cam, or could it be the wrong size pushrods? thank you.

 

[jtfairlane]

If when you are tightening your rocker arms, your valve springs are compressing, than you are setting up your rockers WRONG!

That would mean that your cam lobe for that valve is NOT on the base circle where it needs to be, but rather somewhere between part and full valve lift.

What rocker arm installation procedure are you following? The installation procedure for pedestal rocker arms calls for ensuring that you go one piston at a time, ensuring that the cylinder you are working on has its piston at Top dead center, which will ensure that the cam lobes for that cylinder are on their base circles and the lifters are fully seated, then and only then do you tighten down your rockers to spec.

There are a lot of variables that could be causing your problem:

improper cam indexing in relation to crankshaft. Did you install it dot to dot at least?

Are the lifters fully seated in their bores (all the way down) when you are tightening your rockers? If not, make sure they are.

Have you verified whether or not you need to use shims on top of your pedestals?

If you need to redo your work, follow these instructions:

http://cranecams.com/pdf/453e.pdf

 

[capri debris]

Too much cam or your pistons need notched.

What pistons do you have?

Also, are you positive you got the timing gears in correctly?

The cam isn't indexed is it?

 

[stangster50]

If when you are tightening your rocker arms, your valve springs are compressing, than you are setting up your rockers WRONG!

That would mean that your cam lobe for that valve is NOT on the base circle where it needs to be, but rather somewhere between part and full valve lift.

What rocker arm installation procedure are you following? The installation procedure for pedestal rocker arms calls for ensuring that you go one piston at a time, ensuring that the cylinder you are working on has its piston at Top dead center, which will ensure that the cam lobes for that cylinder are on their base circles and the lifters are fully seated, then and only then do you tighten down your rockers to spec.

There are a lot of variables that could be causing your problem:

improper cam indexing in relation to crankshaft. Did you install it dot to dot at least?

Are the lifters fully seated in their bores (all the way down) when you are tightening your rockers? If not, make sure they are.

Have you verified whether or not you need to use shims on top of your pedestals?

If you need to redo your work, follow these instructions:

http://cranecams.com/pdf/453e.pdf

the piston was at top center, it is timed correctly...
how would i go about determining when shims are needed?

 

[jtfairlane]

If you had read the link I provided you in my last post:

From Crane Cams install instructions:

"To check and adjust the lifter preload, turn the bolt by hand until
there is no clearance between the front roller and the valve stem
and the pushrod is seated in the rocker arm pushrod seat. Slowly
torque the bolt to 18-20 ft/lbs. Since you are pushing down the
plunger in the hydraulic lifter as you torque the bolt, it will probably
take a minute or two for you to get the correct setting. You
should be able to turn the bolt between 1/4 & 1 turn before you
reach the correct torque setting. This will give you the correct lifter
preload of .020" to .060". If you can turn the bolt more than one
turn to achieve the proper torque, you will have to shim the
pedestal. Two different thickness shims are provided for each
rocker arm to assist you. A thick shim represents approximately
one turn."

 

[Fast63]

jtfairlane, I don't think your instructions are proper for what he is doing.

stangster50, you said you made a solid lifter in order to check piston to valve clearance? That means you should NOT tighten down the rocker bolt all the way. You need to only tighten it down until you close the gap between the rocker and the valve stem and the rocker and the pushrod. That is why your valvespring is compressing. By tightening it down further, you are effectively giving the valve that much more lift. So only tighten it down to where all the slack is gone, then clay the pistons and tell us what you have. Does that make sense? Let me know if you need more clarification.

 

[347HO]

jtfairlane, I don't think your instructions are proper for what he is doing.

stangster50, you said you made a solid lifter in order to check piston to valve clearance? That means you should NOT tighten down the rocker bolt all the way. You need to only tighten it down until you close the gap between the rocker and the valve stem and the rocker and the pushrod. That is why your valvespring is compressing. By tightening it down further, you are effectively giving the valve that much more lift. So only tighten it down to where all the slack is gone, then clay the pistons and tell us what you have. Does that make sense? Let me know if you need more clarification.

I agree with Fast63.
On your PTV issue, I would suspect you're not at TDC when you set your camshaft, or you have indexed your camshaft incorrectly. Either or both of these will give you this problem.
You should have no issues with this install except maybe the need for different length pushrods. Can't go by your witness picture because you haven't spun a few full 4 cycles.

 

[PUNISHER RACING]

I am running Gt40Y heads on a customers car with the same 1.94/1.54 valves and an F cam with no interference problems at all. What length pushrods are you running you should have a 6.250 p/r with around .030/.050 thousandths shim when done.

 

[stangster50]

jtfairlane, I don't think your instructions are proper for what he is doing.

stangster50, you said you made a solid lifter in order to check piston to valve clearance? That means you should NOT tighten down the rocker bolt all the way. You need to only tighten it down until you close the gap between the rocker and the valve stem and the rocker and the pushrod. That is why your valvespring is compressing. By tightening it down further, you are effectively giving the valve that much more lift. So only tighten it down to where all the slack is gone, then clay the pistons and tell us what you have. Does that make sense? Let me know if you need more clarification.

im sorry, i dont fully understand the point of making a solid lifter, if it only creates piston to valve problems. i understand that is to check pushrod length, but if so, then how could i make a full revolution to check pushrod length, if it makes the valves contact? or dont you tighten the rocker down all the way then either?

so, are you saying, if it tighten it down, just to when the points contact, and the clay says i have enough clearance, then i can just tighten down the rocker and be fine with the hyd. lifter?


once again, the piston was at tdc, and the cam was indexed correctly. it did run, at one point with that cam in it.

 

[jtfairlane]

The purpose of using a solid lifter when you are not running a solid roller cam is only for checking pushrod length, so the plunger in the hydraulic lifter does not depress while measuring. You then take that pushrod length and add whatever lifter preload to determine the final length of the pushrod, typically between .020-.060

Saying that he made "a solid lifter" leads me to believe he is running a hydraulic roller, and only using the 1 solid lifter for measuring pushrod length. The instructions I gave him from Crane are correct for setting up his hydraulic roller cam/lifters/pushrods/rockers once he has determined the correct pushrod length.

 

[stangster50]

The purpose of using a solid lifter when you are not running a solid roller cam is only for checking pushrod length, so the plunger in the hydraulic lifter does not depress while measuring. You then take that pushrod length and add whatever lifter preload to determine the final length of the pushrod, typically between .020-.060

Saying that he made "a solid lifter" leads me to believe he is running a hydraulic roller, and only using the 1 solid lifter for measuring pushrod length. The instructions I gave him from Crane are correct for setting up his hydraulic roller cam/lifters/pushrods/rockers once he has determined the correct pushrod length.

yes. only using that 1 solid lifter to measure pushrod length.

 

[Fast63]

im sorry, i dont fully understand the point of making a solid lifter, if it only creates piston to valve problems. i understand that is to check pushrod length, but if so, then how could i make a full revolution to check pushrod length, if it makes the valves contact? or dont you tighten the rocker down all the way then either?

so, are you saying, if it tighten it down, just to when the points contact, and the clay says i have enough clearance, then i can just tighten down the rocker and be fine with the hyd. lifter?


once again, the piston was at tdc, and the cam was indexed correctly. it did run, at one point with that cam in it.

Right, DO NOT tighten down the rocker all the way when checking piston to valve contact using a solid lifter. There is no preload, so tightening it down furthur just compresses the valvespring and opens the valve. When you install the hydraulic lifters, you need to use the method shown by mr. fairlane to make sure you have the right pushrod length, and then the preload will not make a difference on your piston to valve clearance because you checked it with the solid lifter.

 

[stangster50]

Right, DO NOT tighten down the rocker all the way when checking piston to valve contact using a solid lifter. There is no preload, so tightening it down furthur just compresses the valvespring and opens the valve. When you install the hydraulic lifters, you need to use the method shown by mr. fairlane to make sure you have the right pushrod length, and then the preload will not make a difference on your piston to valve clearance because you checked it with the solid lifter.

ok. thank you all. im guessing i will need a shim kit since the rocker is about 1/8" from being seated once both points touch, and if i shorten the pushrod, its at a weird angle on the valve tip. that would mean i need to shim right?

its just weird, i put a stock head on for the hell of it with a rr, and everything was fine.. i didnt think there was much of a difference with the gt-40x? theres really that much of a difference?