norris_83

iTrader: (4)

Hey all,

I've installed wats in the title and I seem to be getting a constant tapping/rattling noise from the valvetrain... Heard I would need to change my pushrods but unsure of what length to go for... any ideas? stock is 7.4, if there is some play would I need to check or should I get slightly longer ones?

viciousknid

iTrader: (8)

most people buy some hardend 7.4 pushrods. If you feel that it has idled long enough to refill the lifters I would double check the pushrods to make sure none are bent. Go ahead and put some hardened push rods put in. And if that checks out and it isn't very loud pour in a little Lucas.

viciousknid

iTrader: (8)

also. Do what weight oil do you use?

JakeBrakeIH

iTrader: (22)

depending on what kinda noise it is it might be normal...when i did my cam and spring swap i was scarred shitless because they do 'sing' alot more than the stockers...a lot more audible with the radio off and windows up but again just throwing this out there...

00ChevyScott

iTrader: (10)

I agree with Jake. The valvetrain is MUCH louder with aftermarket springs/rods.

trever1t

iTrader: (14)

mine click tick tick rattle and ring. don't worry, it get's louder over time

norris_83

iTrader: (4)

see thats the problem, its a very small cam with not much lope at all.... I mean i shouldn't even be hearing anything, the car is a brand new Yukon, it sounds like a 20yr old suburban :/

if I tightened up the rockers u guys think that would help? Ill get some pushrods in but really just want the noise to go

hirdlej

iTrader: (31)

Tightening up the rockers will do you no good, the valvetrain in non-adjustable. You either need a pushrod length checker or what I do for the poor mans valvetrain checker is to rotate the engine over until the cam is on its base circle then tighten down the rocker until there's zero lash in the pushrod (meaning you cannot move it up and down and everything is making contact gently). Then for every full turn of the bolt it is .049" compression of the lifter plunger (this is your preload). Hopefully you already have your torque wrench set to 22 ft lbs so count how many revolutions it takes you to get to 22 ft lbs after you reach zero lash. For me it was 1 3/4 turns so this is .8575 lifter preload. You want your preload between .060 and .100 thousandths. Less preload gives you better performance but more noise, high preload is quieter but you run the rish of lifter pump up under high RPM's and float your valves and run the risk of piston to valve colission under high RPM's.

FL.04GMC

iTrader: (1)

i put in the same cam same springs and the hardend 7.4 push rods and my trucks audible valve train noise has gone up significantly. i think that problem is something you might have to get used to.

sickREDsierra

iTrader: (17)

get a cut-out

problem solved

it is very normal though, like a sewing machine.