I think i bent something...

[sclay115]

i was doing a headgasket on my car and when i reassembled it, i had it timed way wrong, like 30-40 degrees retarded, problem is, i didn't catch it, and i went to try and start it, obviously didnt' start. so i retimed it and now it runs, but with a terrible top end noise, i'm thinking i just pulled a stupid mistake and just bent all the valves or at least some. i suppose everyone makes these type of idiot mistakes at least once. but info on the car, it's an L28 block with an E88 head with flat top P79 pistons and an unknown CWC cam...so either way, the head is coming back off to check for bent valves, but in the meantime...as i've never bent a valve before, what sort of noise would it produce? my motor, just sounds like a decently loud thunking in the head that varies with engine RPM, and a refusal to idle...but any insight anyone can offer would help. thanks

oh and try not to make fun of me for my lack of "L" series knowledge...

steve

[andrewg3300]

i bent valve in achevy 350 one time. I t made a loud hissing niose, and had no compression on that cylinder. It also produced alot of gasses coming from the valve cover( leaking around my valve) Your problem reminds me of the time a i dropped a washer in my intake and somehow managed to work its way in my clyinder. It sounded like it had a knock. But i got lucky and found which cylinder it was, took the sparkplug out and watever was left of that washer blew out when i started it up.(chevy 305)

Chevy sucks thats why i drive a Z. HAd good luck with my 2.4 so far.

You could have broken a valve and it is flying arond on top of your piston. kinda unlikely, though something is floating around in there. Compression test are always a good idea.

[beandip]

Dont Run The Engine !!! If You Run The Engine You May Punch A Hole In A Piston And Or Really Screw Up The Head And The Valve Seals And The Valve Train .

[sclay115]

Dont Run The Engine !!! If You Run The Engine You May Punch A Hole In A Piston And Or Really Screw Up The Head And The Valve Seals And The Valve Train .

yah i'm not going to, and when i did run it i only ran it for like 30-40 seconds, i'm just waiting for some time so i can yank the head off again and see whats up...

[sclay115]

hey update, i pulled the head off, and naturally, not a single score mark on the pistons....any of them...so now i dont know what the problem is...any other things i should check? my oiler tube in the head is pretty messed up, could that be causing this? i'm at a loss now...

steve

[beandip]

Where are you ? You diden't include that in your profile. Phred does heads and is top notch if you are close I would take it to him and have it checked out . Gary by the way he is in Gresham Oregon.

[sclay115]

orlando florida, but do you think it could be a problem with the cam/valvetrain setup thats in there?

[240ZMan]

Were your valves adjusted properly before this all happened? If so, then check your clearances now. If you bent a valve you'll have more clearance than before.

If the pistons just tapped a valve you may not see the mark on the piston and you won't be able to see any obvious signs that the valve is bent.

A friend of mine with a datsun roadster recently missed a shift at the track and over revved his engine. It had a mild knocking sound at idle afterwards and didn't idle well either. When he pulled the head at first he couldn't see any signs of damage either. But when he looked closely with a lot of light he could just barely see the nick where the piston just touched the valve when the valves floated. His clearances are now a few thousandths greater than before. His valves are bent.

Putting new valves in your head isn't too big of a deal. But depending on your head's condition you might want to look for a used one and replace it. All depends on $$$ and what's available in your area.

I know a guy I used to work with who is in Melbourne FL and does work on Zs. He used to have a decent stock of used parts. PM me if you're interested and I'll see if I can find his email address. Good luck.

[kinfish]

"my oiler tube in the head is pretty messed up, could that be causing this? i'm at a loss now..."

You imply that cam has the external oil distribution manifold ....... if messed up means broken or leaking braze joints ........ you may have insufficient cam lobe lubrication! If so, you should inspect each of the 12 cam lobes and look for signs of scoring and/or wear which can cause annoying valve train noise that increases with rpm.

[sclay115]

yah the clearances were perfect before, see i did the valve seals before i did the HG, and while doing so, did the clearances...but i'll check them to make sure, good way to tell, didn't think of it. but as far as the oiler tube, yah the brazing is all broken up, but i'm thinking, wouldn't that be a progressive problem? and not something that just happens all of a sudden?

steve

[LanceM]

If the oiler isn't working right cam damage would happen fast, there is a lot of pressure there. Once the metal gauls things happen fast.

[sclay115]

If the oiler isn't working right cam damage would happen fast, there is a lot of pressure there. Once the metal gauls things happen fast.

but it wasn't making noise at all before i did the HG...maybe the new headgasket brought the oil pressure up to spec and blew out the brazing even more, so on a side note...anyone have one for sale? and are they only on the 240's? because i know of several 280's in the junkyard....

steve