Question : Problem after LIM change

Nick-G · 10-26-2008, 02:32 AM

Ok so just last week I discovered my 3400 grand am had a LIM leak.

Anyways while I was changing the LIM gasket I decided to put new heads on which are ported with SI valves and ls6 springs. Now after all new gaskets new heads p&p LIM 3500 UIM and new plugs/wires I started the car and it doesn't run very well and their is allot of noise coming from the valve train.

I know other people have said that ls6 springs do make a lot of noise but can some one maybe explain in more detail how loud they really are? I have worked with the 3400 quite a bit but this is the first time I have actually ran any of this stuff on my car.

And besides the valve train noise the car has started to run a little better after letting it run but it still seems to be running pretty bad.

So is this all normal?

EDIT: could having a couple collapsed lifters cause this? I know new valve springs will make more noise but this has to be something else.

Superdave · 10-26-2008, 01:14 PM

are the rockers torqued to spec?

the valve springs put alot of load on the lifters, if the lifters aren't in the best shape then there will be some noise for sure. I'm sure you don't want to take the LIM off again but if you do then pull out a few lifters, take them apart and see if they're full of sludge, and if they show lots of wear.

i've seen some that are all full of crud, the checkvalve leaks a little and the lifter dosen't fully pump up. Also after alot of miles the lifter core to outer clearance can let oil past it and not pump up fully.

Nick-G · 10-26-2008, 02:47 PM

Yes I did torque all of the rockers using the specs on this site and I also used red thread locker on them.

I just pulled the front valve cover and all of the rockers seem to be tight. I would like to fix this because this car is loud when I start it. You can clearly hear the ticking from inside the car. If this is from the lifters could it cause any damage if I keep the engine running? And would it cause the engine to run bad?

**SappySE107** · 10-26-2008, 03:18 PM

Are the pushrods in the right location? That can make it run bad and cause noises.