Valvetrain noise has me baffled, am I just being too picky?

[Guest bastaad525]

Time for a hydraulic head

 

Seriously though... I posted a while ago, a thread about possibly setting my valve lash to tighter than spec, to get rid of some annoying valve train noise I was getting.

 

When I start the motor cold, the valve noise is like 2dB higher than dead silent nothin but injector noise, but as the motor warms up, the head starts making quite a racket. So I figured maybe the valve lash adjustments were a little loose.

 

So I finally got around to checking them the other day... and... oddly... they actually were ALL adjusted on the tight side! I ended up having to loosen some of them quite a bit, to even get them back to the stock setting. Afterwards I did set them on the tight side of stock, jusssst tight enough so that the stock setting feelers wouldn't fit, but the next size down would fit effortlessly. But... this was still considerably more loose then how they were when I started.

 

 

So... fire it up... and sure enough the valve tap has gotten a little louder. But, started cold, still silence.

 

I'm baffled. What are other possible explanations for this? Am I just being too picky about the noise? Whenever I stop at a light, if I have cars next to me, the racket of valve train noise echoes back at me, and is more noticeable than the exhaust note, injector ticking, or whatever. It's annoying. It seems to me like they are way too loud... I don't remember my N/A motor sounding this loud. Does it have something to do with the turbo head? Or does it indicate something being wrong?

[Tony D]

yer too picky!

"Tight valves burn"!

 

You learn that

"Quiet Valves Burn"

 

If you drive an old air cooled VW for any legnth of time...

 

The valve lash noise is part of the engine harmony. It's not natural for a solid lifter camshaft to be quiet.

[Bluto]

Have you verified solid oil pressure after warm up?

 

Your head may be starved for oil that has warmed up and thinned out and no longer makes it to the head past possibly worn main or conrod bearings... ( I dont recall if you had repalced all your bearings or just the thrusts)

 

This is one explanation for noisey valve train that was quiet befor warmup.

 

Sam

[Guest bastaad525]

The stock oil pressure gauge shows good, about 15psi at idle, 40 psi at 2500-3000rpm cruise. On cold start, pressure reads quite a bit higher, 40ish at idle, 60ish at cruise.

 

I have now replaced all the crankshaft and con rod bearings, EXCEPT for the rearmost crank/main bearing, which as I understood it, is almost impossible to replace with the motor still in-car and the trans still attached (which is how I did my ghetto-fied rebuild). For what it's worth, readings on the oil pressure gauge were NOT any different after replacing all the bearings. So unless that last bearing is extremely worn....

 

 

I need to get another Z guy to have a listen and tell me if these are too loud....

[COZY Z COLE]

This is my observation only but the 280ZX engines have a sound of their own (I've had a 80 280ZX since 1984) and every other one I've been around has that sound. Go listen to a few 280ZX'S and compare. On a side note I only worry when there is a new sound as most of us can tell there's a problem just by listening to it run. My better half says she knows when I'm near the house because my dogs start in when I'm 3 blocks away. Must be the sidepipes!!!!!

 

 

 

LARRY

[Guest bastaad525]

and that's where my ears are messing with me, because it SEEMS that the sound has gradually (over months) gotten louder... hence why I thought it was time for an adjustment.

 

by the way re: oil starvation, the cam lobes and lash pads don't show any signs to my rather untrained eye, of having any problems getting well oiled.

[COZY Z COLE]

Don't you think just maybe, with all the wrenching and engine changes, that over the months you are going to hear the basic engine noise change????

 

 

 

LARRY

[Z-Gad]

Replace the lash caps w/ new ones. I had a similar issue w/ an old n/a motor and that quieted it right down.

[Guest bastaad525]

Don't you think just maybe' date=' with all the wrenching and engine changes, that over the months you are going to hear the basic engine noise change????

 

 

 

LARRY[/quote']

 

 

not like this, no. At least, it's not what I would expect.

 

 

Z-gad - heheh I didn't even know lash pads could wear out!! I'm gonna chew it over in my head for a little bit but I'm having trouble understanding how new lash pads would affect this type of problem.... well... I'll put it on my to-do list a little ways down and hopefully figure something else out before I get to it.

[Guest Cronic]

Mine has a similar noise. Has had it for quite some time. As long as your oil pressure is good, and she still cranks up, I wouldn't worry about it.

 

To get rid of it, im told you will have to replace the part in the valve train that's tapping, I believe its the lifter. You could also just have a clogged oil hole. I hear Seafoam works well.

[Nismo280zEd]

upgrade your exhaust, and sound deaden your hood.

Problem solved

[Guest bastaad525]

I was checking for clogged holes on the cam as I was rotating it to adjust the valves... all seems well.

 

no way I'm sound deadening my hood... that's like 2-3 extra lbs. on my car right there!!

[Guest bastaad525]

Okay I have another question, if the valves are loose, or even if they're not, whatever's causing them to be so loud... does this mean there is some wear (more than usual) happening there or what?

 

I know you guys advised against setting them tight, that it could accelerate wear or cause the valves to overheat, do I need to worry about similiar things if they are too loose or tapping too loud?

[Nismo280zEd]

ok so take off the big chrome bumper up front, and the bumper mounts.. there's like 30lbs off...

 

Anyway... this may seem like a dumb? But when you adjusted the valves it sounds like you did it cold. Try doing then hot... and i mean hot, not warm. This is how i adjust mine and get very little valve chatter.

-Ed

Also.. do what kind of oil do you run? that will make a difference.

[Guest bastaad525]

I usually just do them hot to begin with, this time I wanted to take my time so did them cold and then rechecked them hot. Once hot I only had to readjust two of them the tiniest amount (they got a bit too loose).

 

I hate the way 240's look w/o the front bumper, already pulled the rear off though

 

 

I run Mobil 1 10w-30.

 

So does all that tapping mean it's getting damaged/worn?

[JMortensen]

I got an answer!!! Get that bigger cam you've been talking about. Get new rockers or have yours resurfaced. You'll need new lash pads anyhow to go with the cam. Problem should be solved, right???

[Guest bastaad525]

heheh no... that won't be happening any time soon. I wish.

 

 

And anyways, who's to say that would solve the problem? Might make it even louder

[Nismo280zEd]

OK.. pure nature of the engine is they are going to make noise. Plain and simple. Now there is a problem if one valve makes a distinctly louder noise than all the others, or if the engine feels as though it's lost power. If neither one of those are occuring then i would say turn your radio up louder and forget about it, or learn to like it as the rest of us have.

-Ed

btw... they make fiberglass and CF bumpers for the 240's

[spotfitz]

Not to steal the thread, but who makes CF bumpers? I've been wanting the FG bumpers, but I would rather have the CF.

[Guest bastaad525]

Tim240z had a whole fiberglass (I think it was fiberglass) front end he wanted to sell me like maybe a year ago. Hood, fenders, headlight buckets, lower air dam.... all one piece.... VERY tempting but I was tapped for cash.

 

 

 

Well... as far as the noise... I need to find another Z and listen to it, see how it compares, or get someone with a Z to listen to mine and see what they think. I think that's the only way I'll get an idea really. Til then, I'm not gonna stress it, as at least I know they are adjusted right, and no one here is saying that tapping like that is causing any harm so....