1974 240D IP Timing off after head swap?
 

Thanks in advance for the help...because I have searched for days and days with no answer

I will try to keep this short but with all of the adequate information helpful for diagnosis.

I blew head gasket and cracked the head on the freeway.

Replaced head with rebuilt 123 Head, I used the W115 pre-chambers and Injectors and cam from the old head and installed onto the new 123 head.

Motor ran great before. It's a highly maintained car. I bought it from original owners.

Just fired it up and it idles way high, about 2500...so I guess it isn't really an idle is it??

Thoroughly bled the fuel and cooling systems.

All vac lines perfect and no leaks detected.

All throttle linkage is free moving and where it was before.

Idle screw will not lower idle.

When we were pulling the timing chain under the head when we swapped the head, the chain dropped out of our hands and onto itself. Not too sure if slack was created below, but this happened twice.

When putting the cam gear back on, all marks I painted on the gear and chain went back together and lined up perfectly as well as lines on cam tower. So no tooth was skipped on the crank for sure.

Nothing will get this to idle except for this...when I unhook the rod going from injection pump to throttle pivot arm bolted to the valve cover, and pull it up about an inch or so, the idle gets pretty good. A little up and down either way will change it and there is a definite sweet spot with smooth idle about 800 and no nailing.

Question posed: Could I have lost IP timing when the chain fell? Is pulling this rod mimicking changing the IP timing?

What are my fuel timing numbers on this motor, (i,e. fuel seeping out of line 1 at 15 deg. BTDC).

Thanks, and please help where you can. I am not keen on paying the dealership to finish this thing. Thanks!!! (so much for keeping it short)

I am going to try to only answer what I am pretty sure of...
Yes, if you look at the place and the relative position of the timing sprocket and the chain then dropping the chain could and probably did alter that relationship. You need to start at the most basic stuff and get everthing to specs... You do not want to risk burning a hole in a piston while you entertain yourself watching that ' high idle' ... LOL
I do not know what that ' fuel seeping' deal is... if the FSM says to use the drip method then I suggest you do it that way to be sure.
Tell me more about using the 115 stuff on the 123 stuff... is that a head number... or do you mean the 115 body style on 123 body style stuff ?
Why did you not use 123 stuff on your 123 head ?
Diesel rpms are pretty dependant on fuel.... so mixing and matching components may be what is wrong.

did you use a new head gasket, was it a quality replacement?
is it smoking out the exhaust?

do you think it may be burning crankcase oil?

If you remove all the linkages that connect to the IP, what is the baseline?
This includes the linkage from the firewall.

... because the crank NEVER moved, correct?

you are describing the motion that the manual shut-off lever makes. If you have to apply force to obtain that engine speed, the idle stop screw is not properly set - establish baseline with all linkages removed from IP.

NO, it is restricting fuel flow.

IP 'timing' will not be lost by dropping the chain, it is not possible to skip a tooth on the IP timing gear that interfaces with the chain.

If your crank did not move (and is set @ TDC) and your cam markings still line up, you're doing pretty good. Have you tried to line up those marks since turning the engine over? That may be a good idea.

I would be more concerned about the thickness of the two heads. Unless you had a reputable source assure you this is a reasonable replacement, the difference in height of the two heads could effect timing. (a little)

factory spec using that method is 23* - 25* with a preference for 24*. But for better burn time and power, you can go to 26* / 27*

thats the worst thing you can possibly do

http://www.peachparts.com/Wikka/OM615OM616InjPumpTiming

make sure to read the whole thing, there are some additions

Are you sure about that ? We regularly have people who have not dropped their chain come up 18 degrees off on IP timing... due I think to not keeping CONSTANT tension on the chain as per the FSM... if your description of the crank position not changing and the cam being lined up would preclude the timing being off then why are they so explicit in the FSM about keeping tension on the chain ?

Sorry, I was writing the post while you put yours up. That is not a direct attack.


I know for certain that on the 617.95 and the 616 that there are pins and or limiting bolts that prevent the chain from losing its relation to the IP timing gear. If those are missing... I cant tell. If this particular engine has those, I am not certain. It only follows the design of the very similar models I am closely familiar with.

about the second question... your wording is becoming as cryptic as mine, Leathermang.

In which direction?


The OP says he is certain it did not skip on the crank and that the marks he put on the chain and sprocket match up.

the only way for him to be wrong is if the chain was NOT fully tensioned on the IP side as you suggest.

this is why he needs to check that the TDC marks still line up now that the tensioner has taken up all the slack.

I do not take questions or answers directed towards the physical mechanical questions we are trying to fix as attacks... all of it is ' brain storming' in my book.

I do not know which direction.. when it happens I am just thankful it was not me and my engine that found themselves 18 degrees off.

No offense to this particular OP... but OP's can think they are sure of lots of things...and if we do not address all possibilities they can be left without a good answer...

Thank you for all of the thoughtful responses.

To answer the questions.

I used the W123 head off of an 83 because I was told it would work and it was a good deal. The pre-chambers did hit the pistons when I did the clay check method prior to installation. The W115 pc and injectors were used from the original head and were a perfect fit. I had to use the small glow plugs and swap the water sender and heater ports, and along with different valve cover studs and fuel filter housing mounts, it was what seemed to be a direct swap.

As far as head thickness changing timing a little. I thought about this because the ip being driven from the tensioned side of the chain. The head was milled, but not too sure how much which may help as well.

I used a new Victor Reinz head gasket and torqued to the proper newton meter setting from the head gasket package insert.

I did re-check the cam-to-crank timing after all was back together except the valve cover. I have not rechecked, however, since it was fired up.

Thanks for the timing numbers. I will do the drip method and just see where I am. If I am off, we know that dropping the chain and/or the head may be the issue.

Thanks again, if you all need small block Ford help I am your man!!

Blackberry posting so disregard typos as I have fat thumbs.....

did you use a new head gasket, was it a quality replacement?

Victor Reinz

is it smoking out the exhaust?

do you think it may be burning crankcase oil?

Yes, smoke is coming out but not thick. Not too sure if it is burning oil. Are you thinking the high heat fried a cylinder?? I will do a compression test as well.

If you remove all the linkages that connect to the IP, what is the baseline?
This includes the linkage from the firewall.

I did all of this except for the firewall linkage. I will do that, thanks.


... because the crank NEVER moved, correct?

Correct. The bottom end remained un-moved during head work.


you are describing the motion that the manual shut-off lever makes. If you have to apply force to obtain that engine speed, the idle stop screw is not properly set - establish baseline with all linkages removed from IP.

I did this with that rod disconnected from the linkage on the valve cover. Not too sure what you mean, please elaborate.

THANKS!! Best directions I have found yet. Question is, if I am way off on the timing, let's say farther than the 6 degrees of adjustment, how can I get it back in time? I can easily pull it, but how can I get the IP back to tdc or where ever it should be prior to re-install?

Thanks again, Carl

Also, my injection pump doesn't look like the one in this write-up. The front looks the same, but I do not have the vacuum shut off valve, and the linkage looks different.

Pics. Is that inner throttle body butterfly suppose to be free moving like it is now?

Notice, no vac lines going to the rear of the IP pump...that I can notice.

I can't tell you why but I don't like the idea of swapping the injectors in from the 115.
I think when you milled the head that automatically meant that for the precombustion chambers to fit that you would need to shim them....and then use the reamer to make the glow plug hole line up afterwards... Those Germans did very few things without good reason. So with the mixing you do not have their R and D department final adjustments and such to go on. Did you check and clean the precombustion chamber holes yourself ? How many are there in your present ones.... they changed the configuration a couple of times... and the size also... you may have a combo that did not work at any time for the people who were making the engines.

I bought the head from a member here, Tom Walgamuth. We both did extensive looking at part numbers and such. Most, including the pistons were the same from each year, 82 and 74. He had a contact that said the head would work but we would need to put the injectors and pre-chambers in it from my 115 head. The design of the later pc's are identical from what I can tell except for the nozzle part. It has the same amount of holes, it simply isnt flat and not at the same angle as the early pc. The newer pc's did interfere a LITTLE, I mean about .030 tops with the piston. The new ones installed perfectly and with existing sealing rings and the glow plug hole was an exact match. I will look at doing the drip method to see where I am at.

Is the timing procedure the same with my early style pump?

Thanks again, Carl.