gergstuff

I just finished buttoning up my leaky fuel tank vent hose problem on my '78 and all of a sudden I am hearing a loud ticking noise that varies with engine RPM. Car has been down 2 weeks and did not do this before.

Did some searching and seems like the the popular causes are noisy injectors and /or noisy lifters.

I will have to probe around with my stethoscope to see if I can isolate it to something.

The car only has 53,000 miles on it but it sat for along time for reasons not known.

I was afraid to drive it today although I was excited to do so last night before hearing this noise.

If it is some sort of lifter issue is there any harm in driving it? Would not imagine a noisy injector would cause any harm.

Craig

mdkelly1

Given your description, it's probably lifter noise. These cars tend to do that if they haven't been driven for some time (not always, of course).

Usually, once the oil warms up the lifter will pump up and the noise will be gone. If it is a lifter it should be safe to drive normally to see if the lifter noise does go away. Best not to do any hard acceleration until you know for sure that's the problem.

granprixweiss928

Prob lifter noise, go drive it about 10 to 15 min, keep rpm low. Mine does this too, if i let it sit too long

Or,

One thing i noticed, is if it does it, let it run for about 2 to 3 min, at idle, then shut off for about 5. Then restart. 9 out of 10 times this solves it on my car...

MainePorsche

Agree.
I used to get this too. Though not applicable to your MY, I did check my cam oil journal plugs and found that one of the old plugs was sitting in a corner and not in the covering the journals. Replaced with the superceded pins and the constant ticking was gone. I would still get the ticking if the car sat for at least a week. Driving around the block would then get rid of it. Some advocate adding the product Swepco to the oil. Even though I use Mobil 15-50 with 1100-1400 ppm zinc, I had a half a small bottle of Rislone zinc concentrate to every oil change. Gives a noticeable difference to engine 'humm' and now I never get a tick.

928#00076

Could be an exhaust manifold leak. Does it go away once the car warms up?

928gt

For what it's worth, the M1 15W-50 is too thick when cold for the 928 motor and tends to cause premature valvetrain wear as it is pretty thick and doesn't flow easily when cold (I was running it in my 89 GT for 12 years myself). There was noticeable cam lobe wear over ~35K km since I had the heads apart last, and the chain tensioners weren't happy with it either.

IMHO a better alternative would be a Shell Rotella T6 HDEO oil. The rated viscosity is 5W-40, but VOAs show it has 1300 to 1400 ppm Zn, HTHS of about 4.5 - and critially the cold (40C) viscosity is around 80 cSt instead of the 125 of the M1 15W-50 (IIRC the hot (100C) is about 15). In other words, it provides the same engine protection but flows - and thus lubricates and cools engine internals - much better than the M1 15W-50. Am switching to it as soon as the new camshafts and lifters are in the car.

mike77

Talk like that will get you barred

928gt

If it does, it simply means that someone desn't want to accept the cold hard facts. It's a very decent oil for a race car, but not the best choice for a stock and healthy 928 motor that gets driven on the street.

gergstuff

Curiously, I went home last night with my freshly purchased Harbor Freight mechanics stethoscope intent on tracking down the source of said ticking but when I started the car the noise was no longer there. Under the circumstances would assume it was a lift noise as previously outlined. Drove it to work this morning and no issues. Yeah!

MainePorsche

Agreed.
As you know from living in North Country the car never gets driven while salt/brine on the roads which means no cold weather operation. Where I am, she goes to sleep from late October till the thaw.