Hi

Today I have been checking the IP timing in my 190D (OM601.911). For this I have used the small tool that bolts into the side of the pump. With the crankshaft in the OT mark I have bolted the tool. It has not engaged with the pump rotor groove, so I have turned the cranckshaft very slowly until the tool has popped in. This has hapenned at 15 degress after TDC. I was surprissed at such large value, so I have repeated the check and got the same result.
I will repeat the proceudre once again next week, but in the mean time do you believe this large deviation is really possible? The car smokes quite a lot and it is really slow off the line. Once in the motorway it goes pretty well though. It also cloggs the injector tips quite often. In the morning it starts straight away.

Next week I will post some photos.

Thanks
gonzalo

15* ATDC is about right for the lug in the IP to engage the locking tool. You might adjust to 14* ATDC for more performance but that is not likely the cause of poor performance, smoke and dirty injector tips. That might be a fuel quality issue. Did you check camshaft timing?

Sixto
87 300D

Hello Sixto,

Thanks for your reply. I thought the spec was OT, but if it is 15 ATDC then it is spot on.

Today I tried to check the camshaft timing with the 2mm valve lift method but had to cancel because the digital gauge would not reach the tappet. Next week.

By the way, when checking the tappet clearances I could not even fit a 0.1mm blade in any of the valves (spec is 0.4mm for this engine). I must be doing something wrong, but apart from making sure the lobes are pointing upwards I believe there is not much more into it.

Cheers
gonzalo

Check cam timing with eyeball method. Check crank position when the cam aligns with the indicator -



I find it easier to view from the front of the engine through a hole in the cam sprocket.

I'm not familiar with 601.911 but other 601/2/3 engines have hydraulic lash adjusters that are in constant contact with the cam lobe. There is no external adjustment.

Sixto
87 300D

Hello Sixto,

The 601.911 also has hydraulic lifters. The Haynes manual states that there must be a clearance of 0.4mm between the lifter (when pressed down lightly) and the camshaft.
However, now that you say that there should be no clearance, I have checked the FSM and you are right, it says nothing about those 0.4mm. This is confussing.
Anyway, I will check the camshaft timing (somebody recommended me using the 2mm method if I wanted good precission) and see how it goes.

Regards
gonzalo

I recently timed my 2.5 NA, experimenting with different settings.

My chain stretch measured only a little over 2 degrees, so I started at stock setting and advanced from there. To make advancing easier I moved the chain one tooth (the adjust range was at the bottom of the slot at 15 ATC). I had an idle knock at that setting, and power was a little down. I found my best setting by advancing until the knock just goes away. I estimate this to be about 11 ATC on my car.

It no longer starts on the button, but takes only about 5 seconds cranking. I expected the harder starting. But power is better than ever, it's quieter than ever, very little smoke, steady low idle, and more driveable than ever.

I would recommend that with any old engine, gas or diesel, to start with factory settings and then adjust to a worn engine's individual needs. Please understand that there are always tradeoffs to power such as hard starting, overheating or poor idle.

Good luck,
Craig

What's the mpg difference at the new setting?

Sixto
87 300D

I'll answer as though that mpg question is for me.

1986 2.5 NA automatic, about 300k miles. Before it would vary from 33 - 38 mpg. Since the last adjustment it's a consistent 36 - 38, but driving faster. With better throttle response I tend to push it a lot harder. It will still get to the good side of 40 mpg if I'm careful on the freeway.

That's good to know. I've always wondered about setting IP timing relative to the crank. Something tells me it should be set relative to the cam as the chain wears. There's also the matter of pop pressure. I don't know if pop pressure goes up or down with age. I imagine it goes down as the spring wears but there might be more influential factors. Reduced pop pressure would effectively advance IP timing. But then you're squirting less fuel. Too messy for me

Sixto
87 300D