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Started by TJ 450, 30 July 2009, 02:23 AM

TJ 450

#15
It was a granny drive the whole way. ;)

Yes, it may just be the modulator valve being out of adjustment under those conditions. Also, it may be that the larger 450 version K2 clutch piston means that the valve body needs to be modified accordingly. I don't know about that though, because all up-shifts and downshifts are otherwise perfectly smooth and positive.

The first step is to adjust the modulator valve to specification with the gauge... I have only done the ballpark method that is not recommended, probably for a good reason.

Regarding the diff, I think it is noisy because it only contains LS-90 without the additive, although there is some clunking as well.

It is a similar sound under the same conditions as in this well known video.

http://www.youtube.com/watch?v=K-AnPOXFjJs

It is most obvious when backing off the accelerator and and reverse loading the driveline in the same way.

I'd be interested to know of any other 6.9s that have this sound.

From memory, I think PB's is similar.

Tim

EDIT: Having just done some further research on the matter, I will use the additive first.
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Big_Richard

#16
my diff has also been slightly whiney since changing the oil, i also only have lsx-90, but you'd know that since it was you who put it in there  8)

I have never had the additive in there since the first year of ownership and it is even named a noise canceling additive specifically for 6.9 diffs so its pretty obvious what we need to do ... Its a bloody expensive 30ml additive though, i think ill live with the slight noise ;)

I don't have any kerclunking sounds from my rear end - only the noise of the floating rear calipers shifting from one extreme to another when loaded in either forward or reverse driving after immediately traveling in the opposite direction and that is to be expected with this design and my reckless application of the brake / accelerator pedal.





TJ 450

Yes, the clunking is the only thing that really concerns me... I'll have to find the source of it, for peace of mind.

The diff noise is something I'll have to get used to if the additive doesn't fix it.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Big_Richard

on the subject of success, i finaly got off my backside and arranged to have my 6.9's front end aligned

time taken: 45 minutes
cost: $45
results: awesome


as everything is new, its been recommended that i drive the car around for a while for everything to settle in, then take it back for a final fine tuning.

I enjoyed some wet road drifting for about half an hour then filled the tank up with ultimate, once thats empty its time to take it in again.

Ill then install the complete new fuel system assembly that hangs under the tank thats sitting here still in its packaging, hoses included. Also, I havent got and will have to order a new sender as my existing one is starting to play up - there seems to be no action between half a tank and reserve, the needle pegs at half then bangs down to reserve when it runs low. Its now up at full with a full tank though. Hopefully it is just the sender, cbf pulling the instrument cluster apart.

TJ 450

That alignment was very successful. It drives brilliantly, I must say. ;)

So, it appears that the noises I'm hearing from the diff are not an issue, but the whine may be less with the additive.

After an agressive application of the throttle this afternoon, the engine developed a missfire... I think I fouled a plug due to excess fuel in a very short period of time. I shut the engine off after driving for a bit to burn it off and now it is back to normal, it seems.

What the car needs is a good blast like PB's experienced today, I think. ;)

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Big_Richard

who was aggressive on the throttle? surely not you ;)

TJ 450

Yes, it was me. It's surprising though, because there were no problems after the PB tyre shredding... perhaps it was all that aluminium in the back. ;)

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Big_Richard

your lying - youve never accelerated any car with more than 1/100th throttle ;)


I find it ironic that after having both your car and my car sideways numerous times today, you end up making it misfire on your own, after all that nailbighting in the passenger seat of your own car ;)

TJ 450

It's very ironic. I had the same thing happen in the 450 and it was probably excess unburnt fuel after the abrupt backing off from full throttle, or more likely oil from the valve guides fouling the plugs under the huge vacuum created.

I think the engine enjoyed the PB tuneup and didn't like the return to granny mode. ;)

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Big_Richard

well, now that youve confiscated my number plate mounts, i can no longer excersize my car till i buy my own. Which in reality is probably a good thing, i cant be trusted in a 6.9, they are just too fun.


speaking of sudden backing off of throttle, my new "thrust augmentation valve" is now in transit. I noticed your 6.9 was burbling/backfiring out the exhaust just like mine does under extreme conditions. Supposidly this valve prevents this ??

TJ 450

I don't know that it's meant to stop it completely, but it's supposed to minimise it. When my hearing ability recovers, I'll listen out for it again. My EGR valve doesn't seem to do anything either. That's probably a good thing though.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

TJ 450

Well, I'm pleased to report that there is no missfire now.

I think the PB tuneup was beneficial for the engine at least... it is now very smooth.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Big_Richard

of course my driving it was beneficial - the worst thing for a 6.9 to do is be driven by a Nana ;)

Its a big engine and needs to stretch its legs.

oh, hope the syphilis clears up soon... there are treatments for that these days   ::)

TJ 450

#28
Quite possibly, however I would have preferred to have shown some mechanical sympathy to begin with. ;)

I think a happy medium is required and I'd rather not lose my license. However, I still agree that there is a huge improvement in how the car is now running to before. If I was left up to my own devices, it probably would have taken several weeks to have got to this stage.

Perhaps I am slightly over the top, but...
The basis of my opinion is that you do not get into a new car and test its limits straight way, do you? If you do, then the car will not last as long as if you gradually allow the parts to settle into their working routine.
You would ensure that the the car experienced a wide range of operating conditions progressively getting more intensive over time and eventually you could utilise full load operation.

In this case you are dealing with parts that haven't been used for a few years, but the principle is still the same, although probably not as critical as a new driveline.

Now what's this Syphilis you speak of? I think you may be mistaken. ;)

Tim

Edited for additional content.
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Big_Richard

#29
there is alot of debate on how to run in a new engine, some say the pussy footed method is the way to go, and others suggest driving a car like its stolen from day one for maximum overall performance of the engine.

Remember m100s used the second method, they were thrashed at the factory for 45 minutes at full throttle after being assembled. So clearly, there is some truth to method #2.

The only way you'd loose your licence is for driving so slow that you're causing a traffic obstruction ;)