I'm hoping to get some help with what I found to be my 300SD injection pump is significantly off timing.

Some background; When I got the car, the timing chain was new, however the previous owner never removed the metal from the failed Vac pump, and this subsequently damaged the new chain. I discovered that when the previous owner was installing a new chain, the jumped a tooth on the valve sprocket. When I installed a new chain I realigned the marks on the sprocket/tower with TDC. It was previously ~18 degrees before TDC. I immediately had concern about the IP timing.

Brushing up on some scattered info online, I got the idea that the first port should flow around 60 Degrees and shut of around 24? I removed the fuel lines from the IP, but did not remove anything else on the pump. Do parts need to be removed from the #1 valve on the pump for a drip test? I soaked up the fuel from the top of the #1 IP stem. I noticed fuel began to well up in the stem around 30-40 before TDC. I soaked up the fuel at 30 Before-TDC, and continued to crank. The fuel welled up again in the #1 stem, until the fuel kinda popped and stopped around 0-5 before TDC.

It seems to me like the IP sprocket has skipped a tooth on the chain, and is no longer timed correctly. How can I get my timing back to where it it should be?


Side Note: When I pump my hand primer, it dumps fuel out of the braided fuel return line for the injectors. Do I just plug this line? I still can not get the fuel stems to drip when I pump and any point on the crank.

Thanks for any help!

when doing the drip test it should start to drip at a rate of 1 drip per second at 24 deg btdc ON COMPRESSION STROKE



yes you have to remove the delivery valve and the compression spring (#3 and #4)






in your case to be safe I would just remove the ip and re-install it.


line up the front notches on the ip and install it at 24 btdc ON COMPRESSION STROKE




replace them asap you can't plug them

Thank you very much for the diagram! That was just the piece of info I was missing.

Is it really just that simple as to line the shaft marks up on the removed IP, set the crank to 24 BTDC (on compression stroke), and reinstall?!? Seems very straight forward. Is there anything else I should watch out for when pulling and reinstalling the IP?

Yes

you can remove the valve cover and make sure both valves on #1 cyl. are closed

remove all injection lines completly don't bend them out of the way.

I had a 616 that the injection timing kept drifting. We had that pump in and out a half dozen times. Finally discovered the splined coupler that the drive spline that takes the power from the cam chain was so worn it would slip. Replaced the spline from something like a 1962 300 gas motor that the repair shop had sitting in the back room. Fixed.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

On the diesel discussion part of the forum. We reciently dealt with a member with essentially the same issue. Might want to go over and check. Second case in probably two months now. Rather than pull the injection pump he restored the chain sprocket relationships. Posting over there as well might be a good ideal. Also mention the year of the car..

You were extremely lucky the chain did not break. Then it becomes a real mess usually.