Gentlemen, another valve-train mystery here!

Factory new Evo, less than 10K miles. Runs quiet with stock cam.
Changed the cam to VThunder 3010 - just a bit more aggressive than stock.
Kept stock lifters
The motor is perfectly quiet on idle.
After running it for a while on high speeds: 70-75mph, noticed clacking, very similar to what we'd call "a collapsed lifter" in cars. The noise then stays there on medium RPMs at any gear, even after shutdown and restart, coasting or accelerating does not matter, while STILL BEING PERFECTLY DAMN QUIET ON IDLE!
Only after complete cooling down it goes away.
Then it started appearing without highway run, just when oil temp starts pushing 200.

So, I changed the lifters to VThunder as well. Pushrods are adjusted 3 turns from the top (0 lash), oil screen is checked.
after the first highway run, the "collapsed lifter" noise is there again! After the second one, and subsequently on for two weeks - it's gone.

But today after maybe literally 3 min at 80 mph, it's back again! Still not that prominent as it was with the stock lifters, but annoying enough.

Thus:
Idle is always good - not the cam gear
Screen is clean - not the screen
Tappets/cam/pushrods are new - not them.
It is not as much the oil temp as the high RPM running that provokes it...

what else could it possibly be?
Pump check-valve spring is too weak?
Crappy oil (20-50 Valvoline)?

Appreciate the thoughts!

 

I would change the oil if it was me. Is that Valvoline just regular car oil? I also have Vthunder valve train, quiet as a mouse!
Just a thought, but do you have oil pressure??

 

could it just be a sticking valve?
I had the same problem with the Kwacker recently, similar mile age, stuck some 2 stroke oil in my fuel at 2% mix ratio and after half a tankful and a couple of cold starts the noise had gone and hasn't come back. I sometimes run a 1% mix now, when I remember, but not sure it will have a positive effect on the cat.

How is your gas mileage?

Do you get a smooth cruise on the freeway or is it a little stuttury?

How is the idle, smooth or a little lumpy?

Does it start okay, or sometimes need a little extra throttle?

 

20 50 dino Valvoline for bikes - have been using it for years, no issues...
The idle is smooth, the cruise is smooth, just the noise!
the gas mileage however is on the higher side, nothing extraordinary, but noticeably bigger then on my decker... Cold be due to Mik HSR42, I heard they drink gas...

 

one of the rollers on the lifters is loose and will keep getting worse as time goes on -

reason - at idle not as much movement or pressure on it to cause a shake in the pin to lifter attachment

 

not impossible, but unlikely on both fairly new stock lifters and brand new VThunders: would be to much of a coincidence

 

My opinion only ...
Have heard this before regarding a cam change resulting in noise that wasnt there before. Also use of adjustable push rods resulting in same .
Apperantly there is a quick and inexpensive aftermarket pressure spring available to boost the oil pres. that might help in this situation , google same for info.
Also , i believe that the adjustable push rod manufacturers specs. should be taken as
" initial " when being used with the many available cams out there.
Its a bit of a grey area in my opinion and some experimenting with the above might be needed to get to a reasonable valve train noise level.

 

OK two other things to check -1 - the cam gear was it swapped out or did you just install the new cam with its new gear ------- if so the gear lash is on the loose side BUT you might have checked the 2 gears to make sure they were the same size -- you did not say

2 i had a brand new set of jums hydrosolids and 2 of the pins on the 4 lifters walked out in less than 500 miles - calling jims we were asked for the date codes on the lifters i thought they had issues with production NOPE they want to tell me the shelf life had expired so to bad they were going to do nothing and THAN did not sell me the parts to fix them, the lifters -- F them from that point foward -- some day i will bump into him at a show i am sure i will get a different answer i cant wait

 

That's 3 turns, or 18 flats PAST zero lash, right?

 

Exactly, plus one more flat, just in case