xtreme1604

what is the correct pushrod length for a MS3 cam?

Greekey

iTrader: (3)

Must Measure.

xtreme1604

someone that has put a ms3 in must know

xtreme1604

i have a slight ticking noise and i have the 7.400 push rods. just wondering now if that is to big of a lengh. dont really wanna rip it apart to measure if i dont have to. some one that has a ms3 must know.

Whiteaw57

iTrader: (2)

you could always put 7.425s in to see if it quiets up. If you have low mile hardened 7.4s and the .425s work id buy the 7.4s from ya. and the $109 from texas speed would be cheaper than all youd have to buy to measure and that doesnt include the time to pull the head

xtreme1604

wouldnt i need smaller than 7.4s since cam lift is bigger? dont understand why 7.425s would be quieter? wouldnt it be louder?

Whiteaw57

iTrader: (2)

no. your noise now is coming from slack in the valvetrain due to a smaller base circle on the cam. 7.35s would be louder if anything. if you do end up putting in the 7.425s keep the 7.4s handy in case the .425s are holding the valves open. if the .425s dont quiet the thing up though then its just the ramp rate of the cam slapping the valves shut. youll never get it out. Im pretty sure people have gotten ms3s pretty quiet though, its been around a while

Sales2@Texas-speed

iTrader: (5)

Same as already stated, if you've got more noise than you like, you really have to measure. There are tons of guys running the MS3, but every engine is different and one length pushrod will result in different preload on two different engines.

xtreme1604

yeah the guy that help me put it in said that is common to have a little noise like that. its nothing real loud and bad sounding but you can hear it if your standing on the driver side fender. just thought it might be that i had got the wrong push rod size. so its nothing to worry about?

xtreme1604

what do you mean by this? are you saying different springs will make the size different?

Greekey

iTrader: (3)

Every engine is not the same. Just because Joe Schmo runs an ms3 with 7.4 pushrods, does not mean you will run an 7.4 pushrods.

Sales2@Texas-speed

iTrader: (5)

There is different machining on the blocks, heads, etc brand new from GM. Then you have the variable of one camshaft to the next (even the same grind) from Comp that throws another variable into the mix. The valve springs actually don't affect preload at all!

xtreme1604

even is it is the same set up? ms3 7.4 rods stock rockers dual springs?

xtreme1604

o ok so every engine will be slightly different. thanks for the info

Whiteaw57

iTrader: (2)

the spring size shouldnt make a difference but simple factors such as head gasket thickness, wear on valve tips, rocker tips, even some wear on pushrods. The main place is the lifter preload though. thats what you adjust with the different sizes of pushrod. Preload is how far you push the plunger into the body of the lifter initially. that preload is your play range or the sponge of the valvetrain stress. if you have ticking your pushrods are lightly touching the sponge an theres still some play. with a longer pushrod you get down to the meat of the sponge and it can absorb the valve train actuation. it gives extra push when needed and also gives up a little when needed. Sry thats so long and I hope it makes sense. Idk really how else to put it. another question is does it sound like every valve is ticking or is it just one? If its just one you may have a weak lifter (lifter is going out) do you know what lifters youre running? Stock?

xtreme1604

thanks you this is exactly what i needed to hear! makes perfect sense now. yes lifters are stock. and it only seems to be coming from driver side.

Whiteaw57

iTrader: (2)

thats what somewhat worries me if you do end up taking the head off to measure someday go ahead and install LS7 lifters. theyre relatively cheap compared to most LS parts