whiteseven

iTrader: (8)

I built this motor about 3000k miles ago, I used red loctite when I installed them and torqued them to 22Ft-lbs. It sounds like it's constantly getting looser and I need to re-torque them again, it's only been about 100 miles since the last time I torqued them.

I'm going to pull them this weekend, clean out/chase the threads to get all of the old loctite out and re-loctite them in. Is there something I'm missing here? I bought them second hand, but they've been fine for 3000 miles until now.

Specs on the motor is just a stock rebuilt short block with PRC 2.5 5.3 heads, 233/239 cam, 7.400 Pushrods, PRC double valve springs. Brand new LS7 lifters.

ae13291

iTrader: (8)

have you cheked the preload on the lifter? i think with those cam specs you have a smaller base circle and you should be using a 7.425 pushrod

vettenuts

iTrader: (4)

Do you know for a fact they are backing out?

Has your torque wrench been calibrated?

Did you clean the threads prior to using loctite (no oil)?

Do not use a tap in the threads, use a thread chaser. The tap will alter the thread class of fit by removing more material from the tapped hole in the head.

whiteseven

iTrader: (8)

Kinda confused, what else would they do? The bolt was loose on one of the rockers on the passenger side head by several turns, this happened specifically after a WOT run, immediately returned to the garage to fix it.

Threads were clean.

I'm leaning more towards this being a pushrod length issue as the rockers are noisy in general. I was actually consdering using brake cleaner to clean out the threads. I upgraded my cam/changed heads when I re-built the motor. For whatever reason I ended up re-using the 7.400 TSP pushrods I had from my previous cam kit from TSP.

I ordered a tool this evening, I'll check 'em and order the new ones probably next week.

ae13291

iTrader: (8)

check the preload. you shouldent go past 2 1/4 turns i think after zero lash

Reckless

iTrader: (9)

In my opinion, you wasted your money and gave yourself something else to worry about. I have seen engines make 1000hp on the dyno with GM factory rockers with no problems. I have also had a car's engine completely destroyed while I was running it on the dyno due to an aftermarket rocker backing out. This caused a valve to collide hard with the piston...next thing you know, I am mopping up coolant and oil from the shop.

I classify most LS aftermarker rockers as "snake oil". They aren't going to do anything positive for you, and chances are they will upset your stomach.

whiteseven

iTrader: (8)

I understand your position, but I disagree with you. My factory rockers had quite a bit of miles on them, my stomach was already upset waiting for one of the rockers to puke some bearings out. I got these for a decent deal, probably less then a new set of factory rockers.

Once I get the proper length push rods and put them back down to torque with some fresh red loctite I don't think I'll be worrying about it anymore.

PREDATOR-Z

Get yourself a p-rod guage and check your pushrod length. It is possible also the threads in your head bolt hole going bad, not allowing the bolt to "grip". Double check things carefully, inspect the bolt holes for unnusual wear.

Reckless

iTrader: (9)

Is it a good deal if your engine eats itself? Not saying it will happen, but it has happened.

vettenuts

iTrader: (4)

Try tightening a bolt by hand until you get to zero lash and then count turns to reach 22 lb-ft on the bolt. Also, do you bring piston for each rocker pair to TDC for that cylinder prior to tightening the rocker?

ae13291

iTrader: (8)

^^ there is a GM sequence for tightening them up, i remember i did that for mine. somebody hAd posted it up here.

vettenuts

iTrader: (4)

You can't use that for Harland Sharp rockers.

02*C5

iTrader: (1)

Harland Sharp = Fail. I have seen them cause more catastrophic failures in LS engines than any other rockers combined. I have a set of low mile (32K) stock rockers from an engine swap that I just did if you want them pm me Ill sell them to you cheap just to stop your head aches.