LSXNV

iTrader: (1)

so, i just finish changing head gaskets, a job i never want to do again. and i am still chasing a few bugs down, but nothing too big. i head out to the "street warriors" thing at bristol and a car that repeatedly goes 13.8-13.9 runs a blistering 14.6.

anyway, during the run i notice that right at 5k rpm the thing stumbles. it comes right back to life though, it feels more like a "bump" at 5k. every time, run after run, on the interstate, hot, cold it doesn't matter. at 5k, it just "bumps". all i can think is it is electrical/ignition. have any of you LT1 folks ever came across something like this?

the car;

'97 T/A w/ 106000miles
SLP cold air and LM exhuast
4:10 gear
head gaskets replaced
heads trued w/slight shave.
93 octane

LSXNV

iTrader: (1)

i have searched the forums and can't find much at all on this.

96capricemgr

iTrader: (1)

How old are the cap and rotor. They are often neglected on this motor. While guys would replce them with maybe every other set of sparkplugs on other engines they expect the Opti cap and rotor to last indefinetely BUT they are still wear items.

LSXNV

iTrader: (1)

well, i thought of that but i didnt really have the problem before. i will try the idea out though.

BALLSS

how tight did you lash the valves??

by 'shaved" heads....how much was taken off?

I would think not enough to alter valve train geometry and if you still have stock cam and head gasket thickness and 1:5 rockers geometry should still be fine...but worth checking. A quick check on one valve will show a "witness" mark on the valve stem tip.

Like Dwayne said...very possible cap/rotor are wearing.

96capricemgr

iTrader: (1)

The valve lash is a good point too as from what I have seen MOST guys will get it wrong the first time.

What method did you use to find zero lash?

LSXNV

iTrader: (1)

i went with what the book said. tighten right to the point of no play and go another 3/4 turn. i havn't felt comfy with setting the preload on these (my other vehicle has solid lifters). i was wanting to check it one more time to be sure. how do you all set preload on hydrualic lifters?