Brand new GM shortblock (12556121) 4 bolt, cast crank, pm rods, -13cc dish pistons, roller. I built my new motor from this assembly with trickflow (3030005) alum. heads, stock L98 cam w/ summit 1.6 rr's.new gm roller lifter kit, Big mouth,edelbrock runners, ported plenum and 52mm tb. Runs very well, pulls hard, idles nicely BUT....Since I first fired the motor after about 2 minutes of heat it developes a valvetrain niose like a lifter tick. I've adjusted the valves 5 times at different settings with no change in the sound. It sounds like a badly adjusted SOLID cam! Yesterday I even went so far as to swap the steel 1.5 rockers back on. Nothing. The sound is solid at the back half of the motor, directly under the center of the plenum, just in front of the dizz. This motor is suppose to take my wife and I on our honeymoon on the fotrod power tour in 2 weeks! So....I pulled the intake back off last night and all LOOKS ok except that I have some lifter bores at the rear of the motor that the lifter catches the edge of the bore on the way up and down. If I take ONE lifter and install it in all of the bores it works great until I get the the rear of the motor ( particularly # 5 cyl.) then the sticking starts. I can easily see this sticking lifter issue causing a valvetrain noise. So do I take this turd on the trip and hope it survives? I will not be happy if this thing comes apart 1500 miles form home. Do I call summit? Do I call GM and bitch about thy're POS made in mexico shortblock? See what happens when you don't cheap out on stuff! Anyone ever seen this before. Solutions anyone?

 

Inspect the lifters closely to make sure there are no problems with them. If exchanging lifters in the suspect locations doesn't improve the situation, I'd be calling the supplier and relating my disappointment to them. Beyond that, I'd consider honing the offending lifter bores a few tenths, then washing the area down with cleaner/solvent and changing oil before even moving the engine. Ideally, an expansion reamer set to 0.843" would be used, but a hone and careful measurement should suffice. A reamer will only produce some fine metal shavings, while a hone may also introduce abrasive grit. Either way, you'd need to clean thoroughly abd change oil immediately afterward. If you do this, rotate the cam so only the base circle portion of the lobe is exposed before reaming or honing.

If you're sure the problem is not with the lifters themselves, there's not much else to do short of changing the block.

 

Thanks for the reply Vader....I should title this...what I did on my 40th birthday!! I reinspected everything again sunday morning (as saturday was a LONG day) and still found absolutely no physical flaws in either the roller lifters, roller rockers, or pushrods. Of course in removing the stock rockers I galled a thread as the gm locking nut came off! So now I have to track down one single screw in stud, order new hi flo runner gaskets etc. I re assembled the top end and in doing so I have swapped the d/s lifters to the pass. side and visa versa. I also swapped them front to rear. So if I have a lifter issue the noise should now be in the d/s front, not the pass. rear. Sounds good in theory! If I still have the noise in the same spot then it pretty much points at the new shortblock is the issue. That will teach me to buy brand new instead of rebuilding my origional, whisper quiet valvetrain, L98! I'll let you know how things go....