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Discussion Starter #1
I am chasing my tail tracking a tick. Its not an exhaust leak. I've adjusted the rockers 4x now and the tick is still there. It doesn't do it cold, only once it warms up. Performance is fine, just tick tick tick that follows the RPM's of the car. Oil pressure is good.

You can't really hear it up top, with the hood open, but get under the car and you can hear it well. A stethoscope against the pan sounds normal. Held against the rearmost driver's head bolt and you can hear it well.

Running the LS7 lifters in the car and they have less than 200 miles on them.

Any thoughts that this could be a bad lifter?
 

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Take your serpentine drive belt off to eliminate accessory noise.

Could it be water pump drive or it's coupler making the noise?

I've heard ticking noises from crank dampers before.

And broken motor mounts allowing engine to rock with metal to metal contact.

Once you've eliminated all other possibilities, then bad lifter could be the trouble.
 

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Discussion Starter #3
Update - fifth time adjusting rockers to chase it down. Discovered that cylinder #8 rocker nut polylock doesn't go in the nut as far as the other 15. It sticks out of the top of the nut 3 threads instead of sitting inside it by a couple threads. Meaning the rocker is sitting lower than the other 15 rockers are due to the PR sitting lower.

To me, that says 'collapsed lifter'. Anyone else?
 

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your "discovery" on the one poly not sitting like the rest would indicate a bad lifter or bent PR

if this is a LT1 motor.....many bad stories on the LSx lifters working well

Melling is what I would use vs the LSx lifters

supposedly these are Delphi lifters... but the part # is the same as Melling

Skip White Performance Detail Description
 

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Discussion Starter #5 (Edited)
Those are the exact lifters I bought. I just purchased another GM LS7 lifter from summit. Here's hoping I didn't screw anything up by running it for a few days like this. I didn't notice the difference when I was adjusting & setting lash until this last time through
 

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Discussion Starter #6
Update - so its not the lifter. Turns out that these heads have 15 of 16 rocker studs the same length. The one that didn't adjust down like the others is about 1/8" longer. So there's that mystery solved.

Any ideas what the source of my tick could be?
 

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What was your valve adjustment procedure? I'm assuming that since these are AFR heads, they have 7/16" studs.

Also, what is the history of the bottom end? I know you put a cam in it, but what about the rest of it?
 

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Discussion Starter #8
They're 3/8 studs as-equipped from AFR. I originally set to 0-lash then 1/2 turn. Then went back in after the engine was hot and re-set while running. Bottom end is 100% stock. I am confident its not a rod bearing going out - its a definite "tick" versus a knock. Then again, with this engine anything is possible.

I pulled all the lifters last night and checked them, as well as all the cam journals. The cam looks perfect. 15 of 16 lifters look "new", but one looked like this:


The grooves in the roller are deep enough to where you can feel them with your fingernail. These lifters were run for 200-300 miles. Again, the corresponding cam journal looks perfect. Zero grooves or damage.

I have purchased an entire set of new lifters and will be installing them today.
 

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Wow... 3/8" from AFR, huh? They must use 3/8" on the smaller heads. My AFR 210's came with 7/16". No matter... I just needed to know the thread pitch of your rocker studs. Yours are apparently 3/8"-24. This is important for adjusting the preload on your lifters.

When I worked at a large Chevrolet dealership in the 90's, we used to do valve guide seals on the 5.0L and 5.7L truck engines on a daily basis...literally hundreds and hundreds of sets of them. Of course, you would have to pull the rockers to change the seals, then readjust the valve on the way back together. I have tried pretty much EVERY method of adjusting SBC rockers, as well as pretty much EVERY amount of preload. With stock 1.5 rockers, and stock 3/8"-24 rocker studs, I found 3/4 turn past zero lash to work the best. I had them start clattering after a test drive at 1/2 turn, and I had them hang valves open after a test drive at 1.0 turns. I never had any problems at 3/4 turn past zero lash. Now, this if for 1.5:1 rocker arms on a 24 thread/inch rocker stud. With 7/16"-20 studs, and/or 1.6:1 or 1.7:1 rocker ratios, you'll have to do the math to get your lifter preload correct. I always set up hydraulic lifters (roller or flat tappet) at appx. .050-.060" preload, unless otherwise specified.

I asked about the bottom end because the LT1's were notorious for coming in with an upper end tapping/knocking sound that sounded for all the world like a lifter tick, except that it was at crankshaft speed. Almost without fail you would find a spun rod bearing on either #7 or #8 to where the rod would let go of the bearing shells, and they would both end up stacked together in the big end of the rod. So you had the empty rod cap on one side, and a double-stack of bearing shells on the other side riding against the crank journal. Oil pressure would read normal, but you had this tick/knock sound that was actually the piston lightly kissing the bottom of the head on that cylinder due to the extra bearing shell in the big end causing the piston to come out of the hole at TDC and hit the head. I've seen this literally dozens of times with these engines. That's why I have such a hate/hate relationship with the rods in a stock LT1. They're heavy, weak, and don't hang onto their bearing shells well at all. ANY build should include a new, decent set of rods...
 

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Discussion Starter #11
Dynamic396, thanks for your input. Hand's-on tech experience is a valuable thing to have.

I am inclined to think that the stacking bearing issue isn't my case here as it only happens once it is hot, and even then - only after running for a while. I have just bought and thoroughly cleaned a new set of GMPP lifters, and I'll be slapping them in later.

Out of morbid curiosity, I took a can of brake-cleaner to the lifter pictured above. It had been sitting out on its top all night and the oil had all drained out of it. I stuck the tube in the oil bleed hole and gave it a squirt and it was completely plugged up. It took a while to blow through whatever was in there, so I think I've found my ticking lifter. Time will tell, though.

Those bearings may just get me yet.

Thanks
 

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So, what do you consider to be a decent set of rods for a lt1.
Any decent forged rod, really. I use a lot of Scat for their quality/price value, but Eagle has a much better reputation now, Callies/Compstar, K1 (Wiseco), Carillo (if you've got the checkbook for them).

Like I said, I've used a TON of Scat lately, with great results. They are very consistent, and are accurately machined right out of the box. I used Scat H-beam rods and stroker crank in my LT1, Scat H-beams in my circle track engine, Scat forged I-beams in my wife's Hemi, and now I'm using Scat H-beam rods and stroker crank in my Hemi that I'm building right now. And these are just my own personal projects...!
 

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Discussion Starter #13
Well, new lifters installed and all lashed correctly. Still have the tick. So I suspect there are much deeper, and more expensive things afoot. Time for a rebuild.

Outside of Karl E., any other good builders? Golen has a 383 shortblock for a decent price...
 

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You can just buy mine...

Brand new, never fired, professionally built, lots of goodies...and it comes with a FREE CAR...!!
 
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