Let’s Tune This Engine

Well, now you are alert.
You can take a screwdriver sharpened to a point, attach a wire to it connected to ground, and push the point through the plug wire boots at the distributor, grounding out 1 cylinder at a time.
 
Took it out for a drive. Smooth performance. Missing some top end. I’ll have to look into the timing at higher rpm.
 
Well, now you are alert.
You can take a screwdriver sharpened to a point, attach a wire to it connected to ground, and push the point through the plug wire boots at the distributor, grounding out 1 cylinder at a time.
Like poking a hole in the boot to ground it out ?
 
Took car for a drive today. At start up the valve train is a bit noisy. It sounds like one rocker is loose. Drive a couple of miles and it goes mostly away.

Hm. I do really wonder if these Comp Cams lifters are, as the brits put it: shite.

I don’t want to replace them unless, a.) I’m sure they’re the problem; and b.) new lifters will solve the problem.

I’m not even sure that this is a problem.
 
Maybe 1 lifter is taking a little longer to pump up or leaks down a little more as for what 302 said you can go to an auto parts store and buy a cheap pick set they all have sharp pointed ends and are small Harbor Freight sells them for 1 dollar over here look on their site to get an idea but I see them in most Auto Parts stores
 
Here I took the cut open valve cover off. Maybe that was enhancing the sound ?


And EDIT, I am not able to press down on the pushrods after I shut down.
I see your problem - or at least the indication to your problem.
Look at your video again. I don't know what side of your engine this is.
One rocker is not getting oil like the other seven are, and you can hear the tick as you pass the camera over that rocker.
Dorian NO OIL.PNG

And in the SLO Mo rocker video, from what I can see, your pushrods look like they are too long.
It could just be the camera angle, though.

Unfortunately, you are not going to like the solution. I have been through this before.
And it seems that I am the only one in the world that has figured this out - right here on Grumpy's. ;):D:rolleyes:
 
Last edited:
This could be your problem Dorian: http://garage.grumpysperformance.co...ulic-lifters-mystery-solved.12263/#post-60159
And yes, I know your lifters are hydraulic roller. The insides are still the same.
Because you have a roller camshaft, your lobes M-I-G-H-T be fine.

In my case, there was no oil to the rockers below 1700 rpm. Once you revved the engine above that, oil began to flow. But less than the proper amount.
The cheap offshore crap lifters I used were made wrong. No spoiler here, you will have to read about it. Mike.
 
Last edited:
Hmmm. Thanks Mike. I think it is becoming clear that there is a lifter problem. It ticks more at start up and then fades after about 2 miles of driving.

It’s quite a pleasant drive once it’s running.

More testing will be required. It seems like the lifter bleeds down within a few hours. At least that is the interval I checked.

Rats ! Replacing all the lifters will be expensive. I take it I should go with Howard’s lifters ?
 
ya know Dorian, I might pull that push rod and run a pipe cleaner through it, might have a clogged up pushrod!
 
Took car for a drive today. At start up the valve train is a bit noisy. It sounds like one rocker is loose. Drive a couple of miles and it goes mostly away.

Hm. I do really wonder if these Comp Cams lifters are, as the brits put it: shite.

I don’t want to replace them unless, a.) I’m sure they’re the problem; and b.) new lifters will solve the problem.

I’m not even sure that this is a problem.
Morley makes good lifters, I use Howards lifters myself!
 
Well, when I had my lifter problem, Brian recommended ISKY.
I took his advice and the ISKY parts do indeed function the way they are supposed to.
 
This is a bit OT, but since we are talking lifters, good hydraulic flat tappet sbc lifters, do they must have a hardened surface? How to recognize a good lifter?
 
Grumpy can field this question.
My 2 cents...….
Offshore crap has infiltrated everything.
I guess you will have to buy from a reputable brand name company and hope they stand behind the product.
That's really hard to do with engine parts, because by the time you figure out something is wrong, the entire engine might be trashed.
And they will only refund the cost of their part, not your entire (now ruined) engine.
 
I'm curious if the op figured out and resolved the issue or not...

The Comp XE SBC flat tappet lobes are infamous for their "Sewing machine sound" from the decel rate being too slow as they approach the valve close. -Over a year ago I found a thread with Harold Berkshire, the XE lobe designer specifically talking about the decel rate and how he learned that they were just too fast approaching the close and incorporated the learnings into his new Voodoo line under the Lunati brand. -I've tried to find that post several times again in the past year, failing every time...

If you look closely at the Comp XE FT lobes you'll also find that the exhaust lobes are just one size larger XE intake lobes... They didn't actually design a separate exhaust lobe for the Comp XEs; it's just a reused one size larger intake lobe. (You can go to the master lobe catalog and compare them and they're identical.)


On a mildly related note, with the highly aggressively ramped Flat Tappet cams, like the Comp XE, Lunati Voodoo, etc... Mike Jones the "cam king" has claimed a few times that he find DRAMATICALLY increased longevity by going with the "oiling lifters" with the EDM holes added. This was the quote I could find quickly, but he says it pretty regularly on ST: https://www.speed-talk.com/forum/viewtopic.php?p=156302#p156302


Adam
 
Hey All,

BLUF, I haven’t resolved it yet but I’m pretty sure I know what the issue is.

I do think that the babana-ed pushrod-gate damaged the lifter. I would agree with the feedback above and that oil doesn’t seem to be getting through the pushrod, at least initially.

After about a mile or two the problem goes away - the lifter seems to pump up.

As for the rest, I think it was a tempest in a teacup.

The valve train noise, I got used to. I think it’s completely normal for the hardware I’m using, the XE cam and the roller rockers. There’s no binding anywhere.

The rapid vibration of the cam seems also related to the nature of this cam.

And so, over the past months, I simply enjoyed the car. I took the car on a few “rallyes” and simply enjoyed it… as much as I could, knowing there was a lifter issue.

Also over the past months, I have been dealing with some professional issues - quite serious ones. I was too preoccupied to work on the corvette. The issue just got resolved the week before last but I was running on gasoline vapors and showing symptoms of a burnout.

Speaking of burnout, I’ll be taking the corvette out tomorrow and getting an eye on that lifter.

My plan is to cold start with a valve cover off and see if the ticking is coming from the rocker that bent a pushrod.

Stay tuned !!!
 
if you bent any push rod
you HAVE or HAD clearance/ valve train geometry issues
you'll need to locate the cause and correct it.


related useful linked info






 
Back
Top