BrandonSS

iTrader: (1)

Why do the rods bend if you bounce the rev limiter? I would have imagined the rev limiter being at a "safe" point to where it would protect everything. I know they are soft and that is a good thing to prevent valve and other damages. I've just always wondered this.


Thanks!
Brandon

PS... yes I searched.

LS1s R US

iTrader: (1)

Well its usually when ya engine is turning faster than the valve spring can keep up with. The push rod will actually becoming back up and the rocker arm will be coming back down because the spring can't close it fast enough!

Tony Mamo @ AFR

iTrader: (13)

Usually when the valves are BANGING into the pistons....probably due to valve float (loss of valve control) at high RPM. Its better the pushrod bends than the valve but sometimes its both.

prostock_bigblock

iTrader: (11)

Thats a very good safety feature that GM done to this engine . I think its beter to bend one thing instead of braking your engine.

BrandonSS

iTrader: (1)

I agree and understand why its better. But missing a shift and sending the rpms to 6-6200 just doesnt seem like it should bend a push rod. So the stock rev limiter is useless? Well I wouldnt say useless b/c if it were to go higher then a lot more problems would happen... but you get what I'm saying.

LS1s R US

iTrader: (1)

The stock springs are crap I upgraded to LS6 springs and it solved my problems. If ya got a stock cam that would be a good investment if ya ain't going to do any heavy moding soon!

jrp

iTrader: (16)

the rev limiter wont save you in a mechanical over rev (i.e 3rd to 2nd shift).

P Mack

iTrader: (6)

He's asking why pushrods bend when you bounce off the rev limiter, no mechanical overrev and no valves hitting pistons. That's a good question. I guess the stock valvesprings aren't good enough for the stock rev limiter?

LS1s R US

iTrader: (1)

Yeah this is a very common problem with the stock springs it will make ya want to after ya bend several! Upgrades are nice!

GuitsBoy

iTrader: (4)

Ive run headlong into the revlimiter dozens of times without bending a pushrod. In theory, the rev limiter should be at a safe point before damage occours from valve float. If you truly bent pushrods without mechanically over-revving the motor via missed shift or other error, then there is a problem with your valvetrain besides the anemic pushrods. My guess would be that if youre really hard on your valvesprings, taking it up into the high RPMS constantly, driving the car hard when its cold, etc... My guess is that the valvesprings have lost some seat pressure and are not able to close the valves quickly enough, causing the valve float and thus bending your pushrods when the piston taps the valve. Just one possibility though...

LS1s R US

iTrader: (1)

If it hit the valves he would know it would probably bent the valve a little! It doesn,t have to hit the valve to bend a push rod. I always run a compression check when I used to bent a lot of push rods and the compression on every cylinder was the same!

Boostaholic

iTrader: (4)

I agree, I've hit the rev limiter in my stock TA a few times after being so used to spinning my 408 so high rpm, but have not bent any pushrods.

BrandonSS

iTrader: (1)

I havent bent a pushrod yet that I am aware of. I am going to pull them when I get the car back b/c I have never checked them out. But some good info thus far.