3 valve adjustments in 30 days and still banging

scoll911 · 11-26-2002, 04:16 PM

I performed the first adjustment (my first and I had to try...), then my mechanic performed the second and after about 20 days the valves seemed worse. He just finished the third and it is still manking noise. He thinks some of the valve screws are bad. It has been about 1,200 miles since my complete rebuilld. Any and all thoughts welcome.

bell · bell's Garage

are they quiet once adjusted then they get louder?
or are they just loud immediately after the adjustment?
if they are getting louder the screws (and related components) may need replaced

tryan · 04:41 PM

are your rocker shaft bushings going? you might get an oil analysis to see whats up?

scoll911 · 11-26-2002, 04:57 PM

They were never really quiet but they seem to get louder the more I drive. I believe it is two intake and one exhaust making noise on the driver side. I believe my next step is to replace the screw and adjusting nut.

I'm assuming it is probably best to replace all as opposed to just those 3... and it seems fairly straight forward.

thoughts?

john walker's workshop · 11-26-2002, 05:00 PM

have the cams been reground? not everyone can do it right. i had some reground 66 solex cams in a 2.7 once, and never could get them to be quiet. changed to some new GE-60s and that fixed it.

scoll911 · 11-26-2002, 05:15 PM

I had the cams reground at Ollie's Automotive Machining in CA -- I was told they are very good. I also had the rockers rebushed and reground.

At some point during the rebulid my mechanic missplaced my rockers and replaced them with some of his (after holding the engine for two years, I couldn't get too upset).

Would this cause a problem, can I replace rocker parts without dropping the engine -- because, I do not plan on dropping the engine again for quite some time.

tryan · 11-26-2002, 05:26 PM

you could adjust them again and mark the threads to see if they are loosening up.

the rockers and the cam need to be the same hardness or the softer component will wear on an 'merican cam /lifter.

what does your oil look like?

i don't think it would be a easy job with the engine in.

addictionMS · addictionMS's Garage

did you check for an exhaust leak, I was fooled into adjusting my valves before I realized it was a leak.

Jim

john walker's workshop · 11-26-2002, 05:58 PM

reground cams have a smaller base circle, which means you have to turn in the adjustment screw more, until, in some cases you get the end of the screw flush with the locknut. reground rockers add to the problem. the operating goemetry of the rocker ends up on a different plane than it was designed to operate on. all this adds up to the "potential" to have ticky rockers. the sides of each lobe are designed as a "quieting" ramp. if care is not taken on the regrind, this effect is lost. i don't like reground cams with a smaller base circle. i'm sure that ollie did not grind the cams, but sent them out.

john70t · 11-27-2002, 06:09 AM

Bad plug wires could sound like that, but only on aceleration. Have you checked the side to side play for guide wear?

jhugh · 11-27-2002, 12:19 PM

Maybe at 1200 miles it's a little too early, but consider what happened to me..

Last year I had my 3.2L top end rebuilt. Cams reground to C2 spec, all valves & rockers replaced, heads re-machined, guides & seals replaced, etc. Then, 4K miles later, it started making ticking sounds. I had the mech readjust the valves. It still ticked. Then it began to smoke a bit.

Not trusting the mech or his machinist anymore, I tore the engine apart myself. I discovered that a couple of the valve guides (exhaust side 3 & 6) were worn into loose oval shapes! Already!!

Now I've had the heads redone, the cams checked out and I'm rebuilding the motor. I still don't know what did the valve guides in before, but am considering the possibility that the distracted machinist (his dad died while he was working on my heads) over-honed the valve guides. ??

Anyway, sounds to me like your deal is more serious than maladjusted valves. You may have to tear down to find out.

Good luck!

scoll911 · 11-27-2002, 04:26 PM

Before going the teardown route -- I think I'll change plug wires (they are probably as old as the car and I was looking for a reason to buy magnacore). If that doesn't work, I'll change the rocker components. Hopefully either or both will work.