Engine Tick When Warm

bytor

bytor

Well-Known Member
Looking for some insight from L98 owners. I have developed a ‘tick’ in my engine that I’m starting to think its lifter related. The tick can’t be heard until the engine is warmed up. After about 3-5 minutes of running, you can hear the tick. It only does it at idle. Sometimes when sitting at idle the tick will go away for a few seconds and come back. The car runs perfect and Idles smooth, with no power loss. I have checked all the usual suspects like flex plate cracked, loose torque converter bolts, exhaust leaks and so on. The only area I can hear the tick is on the #7 exhaust port area on the manifold. This leads me to think the #7 exhaust lifter may be leaking down and causing some valve slap.

The service manual offer a few diagnosis that describes the symptom accurately I think.

1. Intermittently Noisy On Idle Only. Disappearing When Engine Speed is Increased:
Intermittent clicking may be an indication of a pitted check valve ball, or it may be caused by dirt.
Correction: Clean the lifter and inspect. If check valve ball is defective replace lifter.

2. Noisy At Slow Idle or With Hot Oil, Quiet With Cold Oil or As Engine Speed is Increased:
High leak down rate. Replace suspect lifter

Before I yank the intake off to check things out I was curious if any other L98 owners experienced this type of noise and if a lifter was the culprit?
 
approach it in logical stages,
TEST AND VERIFY WHAT,S WRONG BEFORE RANDOMLY SWAPPING PARTS

after its up to temp and ticking pour in a quart of MARVEL MYSTERY OIL and a quart of Rislone
marvel.jpg
rislone.jpg

if its a sticking check valve in the lifter, it should free up,as the varnish, assembly lube, old sludge, or what ever is sticking the check valve, dissolves on the check valve surface, in about 15-20 minutes of idle time with the high detergent additive oil added, Id do that BEFORE pulling it apart, IF that has no effect take it out and run it thru the gears a few times, and see if that helps, free it up?

liftc1f.jpg

worn5.jpg

then and only then if the problem persisted Id suggest you pull the valve cover on that side and push down on each suspect rocker at idle to locate the offending rocker and lifter, by the obvious change in the sound your hand pressure on the rocker will cause on a defective lifter, or rocker (and yes it may be the rocker BALL PIVOT not the lifter) Id verify that the rockers adjusted correctly of course and re-adjust it if required, before proceeding.verify the lifter is freely spinning in its bore if its a flat tappet design, or the lifters rolling on the lobe if its a roller lifter,look closely at the cam lobe, and in either case verify the cam lobes not damaged

if adjusting the valve has no effect pull the intake and inspect the lifter and replace it if thats required, be very sure to inspect the lifter, ROCKER, PUSH ROD GUIDE PLATES< PUSH RODS AND VALVE SPRINGS AND CAM LOBE FOR WEAR ISSUES, be aware a cam lobe or lifter base can be wearing excessively so inspect carefully, I,d also look for mis-alighnment or clearance issues in the valve train carefully and inspect the valve springs
 
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A few more things I should have mentioned.

I did the MMO trick when I got the car. The head gaskets need to be replaced when I purchased the car and the Vette mechanic I used said the car had been sitting for some time due to the amount of sludge built up in the engine. The car currently has 47K on it. I did a couple of MMO treatments with oil changes shortly after.

Cut open the last two old oil filters to look for shavings or junk. Nothing.

I adjusted the valves on drivers side and double checked #7. The adjustment made no difference in the tick.

I removed the #7 intake and exhaust rockers for inspection. The intake looked fine but the exhaust had a very faint irregular oblong wear pattern plus what liked like a nick in the same area. I'll get a picture up of it later. Installed a new rocker thinking I found it and nope still ticks.

I haven't tried putting pressure on the suspected lifter with the engine running so see if the tick goes away. I'll try that next.
 
What do the #7 Cylinder Intake and Exhaust Valvestem Tips look like Bytor ?
Are the tips beat up & rounded ?
Must be perfect flat square for quiet operation .
Only way to correct is grinding the valvestem tips in a Specialized Valve grinder machine.
Like my Sioux valvegrinder & seat machine I used on my wifes 1999 Honda CRV 2.0 DOHC Back in early to March 2014 on my thread here.
Worn valvestem tips common on high milage SBC.
Not usually at 47,000 miles.
Your 1987 Corvette has the Roller camshaft as my 1987 C4 vert.
1st year of the roller cam. The replacement lifter sets are not cheap. Expensive $$$.
Been lucky with my L98.
Casterole GTX Syntex 10w30 & Royale Purple has kept it healthy.
Adjusted the valves only once years back. Just to be sure.
 
If there is a small particle of dirt in the lifter, it may take hundreds of miles to work its way out.
Or it may never.
Replace. Might want to drive for 1week at see what happens.
Want to do the job yourself .
Shop bill be around $2k or more otherwise.
 
The original 1987-91 L98 Roller lifters are the same as 1992-96 C4 LT1 &LT4.
Also the same as 1st Gen LS1 C5 that came out in 1997.
Find the right GM Hyd Roller lifters in the GM Dealership High Performance Race Catalog .
 
Here's the pics of the old rocker off #7 Exhaust. Notice the wear. I can just barely feel it with my fingernail. Put a new rocker on yesterday and it still makes the same tick. I checked a few other rockers and they looked fine.




The heads were rebuilt including a valve job when I had the head gasket replaced. The valve tips look like they were refinished. I see no damage on the tip.
 

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Decision to make Bytor.
Old sludge likely the culprit .
 
87vette81big said:
Decision to make Bytor.
Old sludge likely the culprit .
Click to expand...


I know, I honestly can't remember if the car was making the noise when I got it. I wondered if my MMO treatements loosend some crud up and it ended up in the lifter. Is that type of rocker tip damage related to a lifter collapsing or sticking? Guess I'll have to dig into it to find out.
 
bytor said:
87vette81big said:
Decision to make Bytor.
Old sludge likely the culprit .
Click to expand...


I know, I honestly can't remember if the car was making the noise when I got it. I wondered if my MMO treatements loosend some crud up and it ended up in the lifter. Is that type of rocker tip damage related to a lifter collapsing or sticking? Guess I'll have to dig into it to find out.
Click to expand...
Lack of Oil lubrication at one time Bytor.
MMO is Good stuff.
I use it in my Daily Driver Suburban.
Sludge in Engine Block Rifle Drilled Main oil galleries .
Problem there.
Lazy prior owners Suck.
 
Yep, looks like a TPI manifold removal is on deck for this weekend to take a look at things. Thanks for the feedback.
 
When I tore down the 1971 GTO 455 Bytor, it was amazingly clean for its age inside.
I did find hidden sludge after removing the LH & RH Main oil gallerie plugs.
Not blocked up but still present .

Sometimes the only way to know is tear it down and inspect all.
Basic parts for SBC Are dirt cheap. Gaskets, Rings, & bearings can be had for $250-300.

Engine is real easy to remove from a C4 vette.
I can do.it 2 hours.
 
bytor said:
I wondered if my MMO treatements loosend some crud up and it ended up in the lifter.
Click to expand...


very possible, the lifter has very fine tolerances and can easily trap freed up sludge and debris causing it to fail.
 
Made a little progress last night. Removed the TPI runners and plenum, first time doing it.
 

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Ok, decision time. Got into the lifter valley today and pulled the suspected #7 exhaust lifter. Dissembled it and sure enough there were 4-5 small hard chunks of crud inside of the plunger. So the question is do I clean the stock lifters up or swing by Advanced and pick up some new SpeedPro lifters for $100?

Thoughts??
 
IF the the original lifter base is a solid or hydraulic flat tappet, it has lapped into & mated with into the cam lobe, if you can clean its internals and re-assemble it it will be less likely to cause a cam lobe wear issue than installing a new lifter that requires it to re-lap in.
 
grumpyvette said:
IF the the original lifter base is a solid or hydraulic flat tappet, it has lapped into & mated with into the cam lobe, if you can clean its internals and re-assemble it it will be less likely to cause a cam lobe wear issue than installing a new lifter that requires it to re-lap in.
Click to expand...


My 87 has roller lifters. Does cam wear issue still apply?

Also, comparing the check ball on #7 to a few others. It has a different finish on it. I would not say it's pitted but just not as smooth looking a the few others I have checked.
 
no! roller lifters are not the same and swapping out to new roller lifters on that cylinder, will be beneficial as it will have less wear and fatigue issues with a new lifter roller
 
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