LS1 Valve train rebuild

[Theodore K.]

A friend of mine has a 1998 LS1 engine (stock) that has developed a definate click in the valve train. The valve cover was removed on the driver side and it is reported that the back two valves are not getting oil via the pushrods. It is unknown if the problem is the lifters, the pushrods or the rocker arms. My question is this: What has been the experience of people with this LS1 problem. Do they typically need lifter replacement, rocker arm and push rod replacement, or do the rockers survive or the push rods even if the lifter fails. I would appreciate some technical comments on this matter outlining what the experiences have been. Further, are these replacement parts available from parts stores or do they have to be bought only from GM. thanks in advance for your help.
Ted von Kampen

[Joseph S.]

Re: LS1 Valve train rebuild

Theodore, There are plenty of reports of LS motors eating cams and lifters just like the old flat tappet motors. Some of the other discussion boards and forums have plenty of info about this. Funny timing, one of my guys in the shop was just discussing this with me today.

Joe

[Theodore K.]

Re: LS1 Valve train rebuild

Joe,
Thanks for the quick reply. How do you determine if the cam is bad or the lifter without tearing out the cam. Can you measure push rod lift and compare or is there some other way. Trying to help this friend out before a huge amount gets spend just invetigating.
Thanks
Ted

[Theodore K.]

Re: LS1 Valve train rebuild

Another question Joe, can the valve lifter be removed without removing the head and intake plenum?
Thanks,
Ted

[Clem Z.]

Re: LS1 Valve train rebuild

Another question Joe, can the valve lifter be removed without removing the head and intake plenum?
Thanks,
Ted

no they can not and the early LS series engine had some hyd lifter noise. if it goes away in a few seconds after start up i would not tear the engine apart.

[Theodore K.]

Re: LS1 Valve train rebuild

Thanks for your comment Clem. No in this engine, the noise increases as it warms up. I heard it yesterday. It was commented that the back two pushrods on the driver side were not oiling. I have not witnessed this myself but am trying to help a friend out.
Ted

[Clem Z.]

Re: LS1 Valve train rebuild

valve train noise would be at 1/2 engine RPM. these early engines also had carbon knock which sometime be corrected by a top engine clean up. the carbon knock would at full engine RPM not 1/2 engine RPM like valve train noise.

[Edward J.]

Re: LS1 Valve train rebuild

Thanks for your comment Clem. No in this engine, the noise increases as it warms up. I heard it yesterday. It was commented that the back two pushrods on the driver side were not oiling. I have not witnessed this myself but am trying to help a friend out.
Ted

Ted, check the push rods and make sure they are not blocked with sludge or abnormal wear at the bottom ot top of the pushrod , if they are not, a lifter replacement may be necc. (generally the lack of routine oil changes cause sludge,(with the extended mileage mobil one it may create sludge problems as cars get higher in mileage. ). cylinder head removel is needed to replace the lifters. And GM also has has a TSB on rocker arm problems with the roller needles falling out and causing valve train noises, (they do say to remove lower part if oil pan to remove the needles.)