Audi a8 d2 2.5 tdi 132kw knocking nose AFTER CAM REPLACEMENT

milenajdoski · #1 24th September 2016, 08:05 PM

Hello ther
1 month ago i replaced the whole head issues new camshafts new valvle lifters timing belt .... the whole thing.
The car starts on 1st pulls nice no smoke all seems ok.
When cold and untill it reaches temp.no noise but after it passes 60 degrees i can hear knocking sound.
Suspected on not good guality valve lifters oppened the whole thing again ang changed all 24 to new INA lifters.
Same thing again when cold no noise at all.when warms up the noise is when reving between 1200-1800 rpm.on over 2000 rpm it is eather lost or i cannot hear it.
If keept at 2500 rpm for 2 minutes it is silencing but after a while the noise comes back again
Logicaly the oil retain valves dont hold enough oil up there.but if so why on start and while cold it is so da.n quite?

Any idea guys

Btw it pulls realy good, no smoke not at all even at full trottle.

Please????

homer simpson · #2 24th September 2016, 08:24 PM

How many miles between replacing the camshaft and lifters until the new INA lifters? Were they worn at all?

If the quality was poor, I'm wondering if they wore the camshaft

MikkiJayne · #3 24th September 2016, 08:26 PM

Have you tried a thicker oil?

When these engines eat their camshafts a lot of metal debris goes through the oil pump and grinds it up so it may well be low on pressure, and just doesn't have enough when the oil gets hot.

ainarssems · #4 25th September 2016, 11:25 AM

I don't think it's oil retaining valves as they would only cause knocking on cold starts when oil has drained to sump and would not affect warm running when the oil pressure builds up.

It does sound like like possibly low oil pressure when the oil heats up and becomes thinner. Is it mechanical knocking or just different combustion noise more like old diesel. Our A6 would sometimes got funny combustion noise when EGR valve was dodgy it sounded more like older diesels.

I guess there was no knocking before change of parts.

Sorry I cannot help much but I will definitely follow this thread as I guess our A6 will need the same job doing sooner or later as it's almost 200k miles now. I guess you have older style engine without rollers on rocker arms same as our A6. If you have any tips and if you could let us know what parts you used and where did you get them from that would be great.

milenajdoski · #5 25th September 2016, 06:51 PM

Between changing lifters to ina type and camshaft job only 5 days and 300km.
The irony in these is that before any job on the car there was no knocking nise at all.
I discovered that i need to replace camshafts when i oppend the oil sump in sake of gasket leak.so in the sump i fond parts from cam rockers etc...
So after everything new and once more changed lifters(ones putet from the camshaft set had no name on them) to ina again samo like old mercedes knlcking sound.like some old car with mechanicly adjustable valves and to far retarded.....
And today i did some more test.the noise is limited from 1000-2000 rpm below and over the noise is gone.
And one more question?
Can a fuel injector do that noise??
I also own audi a6 c4 2.5 tdi 5 cilynder and it produces similar sound but i know the source there,ael engines have mechanical vacume pump directly on the camshaft so in my a8 i cannot find the noise maker.
Even thou i think it comes from the right head and the cylinder closer to the windshield.
I suspect on 2 possible things
Eather bad oil (inside is aral 5w40 500km old and ufi oil filter)
Or noise injector(debrie or sticed somehow closed)

Any ideas or similar expirience wont harm

milenajdoski · #6 25th September 2016, 06:56 PM

Quote:

Originally Posted by ainarssems

I don't think it's oil retaining valves as they would only cause knocking on cold starts when oil has drained to sump and would not affect warm running when the oil pressure builds up.

It does sound like like possibly low oil pressure when the oil heats up and becomes thinner. Is it mechanical knocking or just different combustion noise more like old diesel. Our A6 would sometimes got funny combustion noise when EGR valve was dodgy it sounded more like older diesels.

I guess there was no knocking before change of parts.

Sorry I cannot help much but I will definitely follow this thread as I guess our A6 will need the same job doing sooner or later as it's almost 200k miles now. I guess you have older style engine without rollers on rocker arms same as our A6. If you have any tips and if you could let us know what parts you used and where did you get them from that would be great.

I both autokraft kit (big one with timing belt etc.) From ebay.de
Cams are cold cast belt and rolers dayco so all good.besides the lifters.after 300km they were very soft.not broken but soft.

All good gaskets and everything for 720 euros.

Btw old type new type doesnt matter if not serviced regulary cams will be worn.

MikkiJayne · #7 25th September 2016, 07:03 PM

If you think it is just a single cylinder, have you tried moving the injector to another cylinder?

Also, have you tried a 'listening stick'? A long screwdriver or extension bar works well, and may help you isolate the noise to an injector or particular area of the engine.

milenajdoski · #8 25th September 2016, 07:34 PM

Listen it with mechanic stetoscope (same like doctors but with iron pipe at the end) and it is more noisy right side and as back to the windshield.
And if i decide to mess with the injectors i will take all out and on a check at bosch service but i am trying to acoid the work of taking out cleaning etc....
I will try some wurth diesel fuel system cleaner.
Maybee something will change