PC-85-928S

i feel I have a slight tick from engine.
I wanted to try an oil additive.
Any suggestions?

ALKada

You sure it's not the tick from your injectors? Some here suggest Marvel Mystery Oil, which I have used myself with favorable results.

SMTCapeCod

Could also be that vacuum leak that is giving you other problems.

They can sound like a tick sometimes.

Can you isolate where its coming from?

Even if its a lifter or injector, you should be able to get a sense of where it is.

All that said, if you search, I think you'll find a number of folks that have some results from Swepco for lifter tick. There are others as well. If that's what it is, it may resolve after some driving once you get it squared away.

jpitman2

Thinner oil can work....
jp 83 Euro S AT 54k

Andre Hedrick

Injectors, try Lucas (30 gal treatment bottle)

Jim M.

First isolate the sound. Get a mechanics stethescope or the longest screwdriver you have and find the source. (put the screwdriver handle against your ear and move the tip of the screwdriver on the injectors then different spots on the cam covers.) If it's a lifter, Marvel Mystery oil has worked for lots of us. If it's the injectors try some Techron or a good fuel system cleaner. DON'T go to a thinner oil than what's recommended in the owners manual. Also check your HVAC diaphrams, when they leak they can make a ticking sound.

BC

Swepco 502 was suggested

danglerb

Tick can be exhaust leaks too.

Ed Scherer

Since it's been more than a year since I've heard anyone else's 928 and have forgotten "what's normal," I've been wondering the same thing as the O.P. regarding my car.

Is the ticking/tapping sound normal (injectors?) or something to investigate further?

I guess I should dig out my stethoscope and go hunting unless it's obvious to anyone that these are normal sounds.

Perhaps this can also serve as a useful reference to the O.P. Same sound? Something different?

(Turn the sound up pretty much or you can't hear the ticking/tapping.)

mx22

Ed - lifters? Last year I put my car away for the winter and when I first started it in the spring, I had that same ticking sound. Drove the car around and it went away.

dprantl

The frequency of that ticking sound matches the normal firing pattern of injectors. Are they new or newly cleaned? New/clean injectors are usually louder than old/dirty ones.

I have a similar tick but since I run 42lb injectors, mine are in enhanced mode at idle so only fire half the time.

Dan
'91 928GT S/C 475hp/460lb.ft

Ed Scherer

Yeah, fairly recently cleaned (September, 2010).

This morning, I probed around with a stethoscope, and sure enough, the noise was loudest at each injector body. That's pretty close to the valves, too, but probing around on the cam covers didn't reveal much noise. Furthermore, each injector sounded about the same; that would indicate normal operation rather than a sticky lifter or whatever, right?

Kind of interesting doing that. I might just have to shoot another video, this time showing what's being probed and what it sounds like. I'm rather ashamed to admit that I don't think I've ever actually used my mechanic's stethoscopes yet (have two, just took this one out of the shrink-wrap this morning. ) The one I just used ( ) has a metal probe that you touch to something and you can hear the sounds in all their glory.

Still waiting to hear from PC-85-928S: same sound, or not?

And thanks for your comments, Dan.

PC-85-928S

I recently had the injectors cleaned.
Does the marvel mystery oil go in the oil, or the gas?
Does it replace a quart?

LeRox

That’s definitely noisy injector sounds in the tube vid…

Jim M.

Again, isolate the sound source. If it's coming from the lifters then put one pint of MMO in the oil; if it's coming from the injectors then put one pint in the gas. Or you could just do both, but then you won't know which was the source of the noise.