'84 300D with 375M. The engine just started pinging (pre-ignition) a week or 2 ago. I haven't changed fuel sources. Doesn't use oil or have a water leak. Pings mostly off idle when engine is cold for first 5 minutes (cold in So. Cal is 55 degrees). I use a diesel Bio-cide from Racor to prevent algae (had a clogged tank screen 6 months ago). Absolutley no change in power at freeway speeds when warm. That's OK. To me Off idle is 800 to 1500 RPM. Injection Pump timing has never been touched since I have owned the car (bought w/81M). Any Ideas/

Just drove home last night and the pinging is worse. Had a hard time going up the hill after car was running for 30 minutes. Pinging starts at around 1800 RPM up through 2600 RPM. Losing power. Idles perfect though. Runs fine at freeway speeds on flat running at 3100 to 3300 RPM. Any ideas?

When was the last time the valves were adjusted?

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2001 Dodge Ram 2500 Cummins Turbo Diesel - 4x4, auto, 3.54 gears, long bed
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'92 300D 2.5 Turbodiesel - sold
'83 300D Turbodiesel - 4 speed manual/2.88 diff - sold
'87 300D Turbodiesel - sold
'82 300D Turbodiesel - sold

Eric,
Adjust the valves and while you have the valve cover off check the camshaft/valve timing to see if you need to install a $4 offset Wodruff key, or get a new chain installed for about $400-$600.If timing is off more than 10 degress, have a new chain put on.
Bill Lewallen;Lexington,Ky. The Bluegrass State where the grass is really green, and so is our antifreeze.

The timing chain has never been changed. Was inspected at around 355M. My mechanic said on a scale of 1 to 10 (10 being best) it was a 5 based on wear and a 1 based on age. What is the recommended interval for timing chain replacement? I know the MB V-8's are a lot more sensitive in this area. Valves have been serviced per maintenance schedule. Is $700 the going rate for a timing chain replacement on a 617? While the timing chain is being changed what other items would be a good idea to service at that time? I don't have the time to do the timing chain. Are the aftermarket brands of timing chains as good or better than the factory chains?

it is not that hard and you can get a new chain for under $100 on Fastlane.com. You will need to rent the crimping tool unless you want to just purchase one. Shouldn't take more than about 3 hours (for a diyer) start to finish.
Jim

'85 300D
'95 E320
'97 CRV

Timing chain replacemrnt is not too hard of a job, if that is what you need. You can get a chain for about $70 and rent the crimping tool for $20. If you need instructions/help to do this job, I'm sure there are many people on this forum that can give you plenty of help.
Bill Lewallen;Lexington,Ky.Where diesels purr and torbos whirr

This is probably going to surprise you... the chain should be inspected/replaced (if necessary) at about 1/2 of your car's current mileage.

I'm guessing that your timing chain is about to snap on you... a very rare event indeed.

My recommendation: DO NOT START THE CAR!

I could be wrong, but you're saying that it's getting progressively worse (very quickly). If your timing chain snaps, bye bye head, bye bye valves. It could also be that the chain has stretched so far that the pistons are dangerously close to smacking the valves.

Good luck.

-Lawson

With a Full Bottle of Red Line Diesel Cat., the Pinging/Knocking is much reduced and I'm comfortable driving it. I'm thinking from all I have read here on the threads that the injectors were most at fault. When I had the timing chain inspected 20M miles ago it looked real good (a 5 on a 1-10 scale). Timing chain, tensioner, 2 upper gears and 2 rails getting replaced next week. New injectors going in this weekend. Injectors have never been replaced. Oil in this car has been changed on a regular basis, so chain has been well taken care of.

Sounds like a good plan to me... I just didn't want anything catastrophic happening to your car.