So I did a cam only swap with the MS4 by Texas Speed. I changed out the timing chain to a double roller timing chain set. I have not yet changed out the springs to but I did already put in the new hardened push rods. After I bolted the rockers back in place, I tried to crank the motor with a breaker bar and it cranks about 10 degrees and then it sounds like it hits something on the inside. I don't know what it is or how I could diagnose it. PLEASE HELP

 

Did you make sure the cam was installed dot to dot or measure ptv clearence? Pull the pushrods and rockers and see if it spins.

 

so your turning it over with the stock springs still in place? If so, can you say coil bind?

 

I made sure its dot to dot top dead center. How do you check for ptv clearance? Also, before I put the rockers and pushrods back in, I spun the motor and it spun fine.

 

Well I cant swap out the springs if I cant turn the motor for each piston to be at the top. If I just changed the springs just as it is, I would drop a valve into the cylinder and that would be disastrous.

 

Pull the rockers off

 

The MS4, as I recall, fails to meet minimum PTV. You may also need shorter pushrods. First, how did you measure pushrods? Second, now that the heads are on the only way to measure PTV is with the dial indicator method.

To change the valve springs, pull all the pushrods and the spark plugs. The motor should turn over at this point. Install check springs on cylinder #1 and check PTV with an adjustable pushrod and dial indicator. If PTV is OK, and I suspect it is not, then you may need to pull the heads and flycut. You can change the springs with the pushrods and spark plugs out and then install the new pushrods after the springs are changed.

 

Take the rockers off and see if the engine turns over. The springs are probably going into coil bind since they're not meant for that much lift. With the rockers off, the springs aren't being compressed and won't be put into coil bind.

 

The intake lobe has .650" lift on the MS4.
The stock springs (non LS6) coil bind somewhere around .600"

 

Coil bind for sure. Also, make sure you measure pushrod length.

 

I fixed the issue, it had nothing to do with the springs. I was just stupid and didnt line it up dot to dot properly.

 

Thank you for your honesty! That is how companies and parts get a bad name. You still need to check PTV clearance ETC..

 

Hey man, it happens to the best of us.