OregonMike

Hi all,
Noticed a much louder than normal sewing machine click/clack the other day on my way home from work so parked it. Narrowed it down to the passenger side with a stethoscope. Here's a video I took after popping the valve cover:

https://www.youtube.com/watch?v=ami3...ature=youtu.be

I pulled cyl 2 rockers & pushrods thinking something was wrong with the pushrod. It looks exactly the same as the intake one. Maybe that much slack is normal but I didn't think so. I didn't mic them but they appear to be the exact same length and they both appear to be not bent rolling them on a flat surface. That was 1/8" of slop, not a few thousandths.

What should I do next? Pull those 2 valves to take a look? Pull that head to see if that lifter grenaded and took out the cam?

I was hoping the OP would come back to this thread and fill in some details but he/she hasn't: https://www.corvetteforum.com/forums...ce-please.html

Not sure mine was quite that loud, but close.

Car specs:
05 m6 200k on the clock.

Thanks in advance for advice (besides buying a crate engine replacement anyway )

CI GS

If you’re sure that the pushrod isn’t bent, check lifter preload as against another lifter to see if the lifter hasn’t collapsed/stuck in full preload.
If the lifter internals aren’t the problem, then it could be the cam lobe. You can check cam lift as against another lobe with a dial indicator to see if that’s the problem.
First thing I would do is drain the oil and run a magnet through it and then take the filter off and cut it open carefully and look for metal shavings in the pleats. If it’s the cam lobe, you’re going to see metal shavings in there.

Apocolipse

If its lifter head comes off...if its cam...heads come off...if its you making cookies.. heads come off.

Point being - take em off and see whats up, crack open a couple of beers too.

chevelles101

Heads have to come off or just intake manifold?

OregonMike

Heads. Lifters are inside plastic trays inside the heads on the LS2. I don't know about the rest of the LS models.

Going to pull the passenger side head next. Picked up a couple of new rocker arms just in case the slop I felt in the needle bearings was enough to cause the sloppiness but no chance. Got #1 on compression stroke TDC and the pushrod still doesn't make contact with the rocker arm.

Plugs were definitely toast and I ordered a set of replacement OEM plugs and wires for it. About $10 more from Amazon for both vs just the plugs in town :banghead

OregonMike

Well finally got a rountuit and spent some time working out in the cold this weekend. Definitely bad lifter. It's out of round with flat spots. The cam lobe looks OK from the outside but I haven't looked closely at it nor have I rotated the engine.

Looks like it's needle bearings like the rocker arms. Looks like the bad one has no more needle bearings :banghead.

Head wasn't too bad to get out. Hose on the *** end of the intake was a pita. Bolt at the back holding wiring loom was a pita. Getting the bottom head bolts out around the exhaust manifold was a bit of a pita.

My plan is to rotate the engine around and look closely at the cam to see if there's any wear/damage there.

If no damage there does this seem reasonable for replacement parts to freshen up the top end?

New lifters & trays.
New pushrods.
New style rocker arms.

Valves look OK to me but I'm just a shade tree mechanic.

Should I think about new valves/seats/springs while it's apart?

Am I being pound foolish not swapping out the cam for a beefier one while I've got it this far apart?

Thanks in advance for advice

Vid was too big to attach so uploaded to:

farmington

That camshaft is junk.

S.C. vette

How many miles on this engine, rebuilt, aftermarket cam, Stock valve train?

OregonMike

200k, and I think it's bone stock OEM through & through. PO put 190k on it in the past 2 years so almost all of the miles are recent and from long road trips.

Not 800k 1/4 mile runs

S.C. vette

If you really like this vette and plan to keep it for a number years (ROI) then re-build the heads, new cam, Fast manifold and headers

If getting it running is all you want, new cam, lifters, springs and move on.

mikeCsix

Obvious question, where did the needle bearings for the lifters go?

Apocolipse

They go into oil pan but are too big to get sucked up by the pickup tube.

OregonMike

Ok, have an email off to Texas speed about cams but you guys can probably answer faster. Does this look reasonable for specs on the cam and am I missing anything major or minor on that list of parts?

Thanks for the advice

farmington

Replace the oil pump when you do the job.
Use a ls2 timing chain set.
You will need to get the car tuned with this camshaft.

Apocolipse

I have pretty much everything you need except for cam and springs. We will talk

Agreed on the pump. Have that too lol

OregonMike

How close to me are you Apocolipse? Wanna bring the piecesparts over & help lol

Forgot to ask about the oil pump. I see TSP lists it as an option when I'm configuring the kit parts. I assume then that the oil pump can come out without pulling the engine? I have not read up on that yet but am off to search the forum for info on that.

And thanks Farmington. When you say 'get the car tuned' do you mean taking it in to have someone do that or do you mean tuning it with the tech2 scanner that's on my list of tools to buy?

Thanks guys, I really appreciate the info!

farmington

Oil pump needs to come off (behind timing chain) to pull camshaft.
You will need to get it professionally tuned. I have the same cam in a 99 z28. Nice street cam but still makes great power.

Dano523

With 200K on the motor, time to pull is down to at least freshen it up, if not rebuilt it instead.

Hell, until the cam bearing had been replaced in the block, no way in hell would I drop anything other than a stock cam back in the block to just try to get a few more mile out of the motor. Same goes for the crank bearings as well, since they have to be dam near work out too. Piston pins to top of rods are going to be sloppy, as pistons to cylinder walls.