1985 300TD wagon broken camshaft - PeachParts Mercedes-Benz Forum

joeblack · #1 07-10-2014, 08:27 PM

Good evening folks.

Bought a 1985 300td from Nevada no rust with a broken camshaft.
$ 1050 no rust , looks good

The PO had brought the car to a garage for camshaft / timing work.
During pickup the car locked up. The garage removed the head and took their losses. I assume they settled with the PO?

I first thought that the vacuum pump caused the problem but.....

The chain was stuck at the IP sprocket and I found the camshaft washer had fallen in between the chain and the IP sprocket.

Camshaft and towers destroyed and IP sprocket damaged. I was able with a pry-bar to rotate the IP backward and found that the chain had snapped between the IP and the crankshaft.

The pistons look good, rods do not appear to be bend ( all piston come equal height)
Valves seem to be good but I did not do leak test yet.

The length of the broken timing chain is 130cm.
Only the top chain guide ( plastic part) seems to be broken

Here are my questions.
Is there a part of the timing chain missing?
The idler sprocket has a lot of axial play, is this normal?
What other parts are able to come loose and fall down?
Is the IP sprocket and mechanism the same as the one in a 240D?

I really do not want to pull the engine or drop the oil pan if I am not missing parts.

The timing chain was new, can I get another master link and reuse this chain?

Later J

vstech · #2 07-11-2014, 08:54 AM

you could come to my house, and get another engine... or just a long block... and head, and IP... or take another wagon as a parts car... euro...

barry12345 · #3 07-11-2014, 09:05 AM

I would not reuse the chain myself. The pressure required to break the chain may have elongated, stressed it or weakened it some where other than the break. Also by gathering all the parts to reuse the original head. You may be as well off in finding another complete head.

At least invert the original head and check for valve sealing with a thin liquid if reusing. One reason for another head may be perhaps there is a valve stem bent a little. So I would also check carefully for that.

The valve guides may be worn enough to semi tolerate it in a straight manual test of movement. Maybe the towers just let go before any stems bent though. Really careful examination of the individual pistons for contact evidence might indicate the most suspect valve or valves.

vstech · #4 07-11-2014, 09:11 AM

the turbo motors have hollow exhaust valves...
if one took a hit, it WILL break...

Maxbumpo · #5 07-11-2014, 09:44 AM

Quote:

Originally Posted by joeblack

Here are my questions.
Is there a part of the timing chain missing?
The idler sprocket has a lot of axial play, is this normal?
What other parts are able to come loose and fall down?
Is the IP sprocket and mechanism the same as the one in a 240D?

I really do not want to pull the engine or drop the oil pan if I am not missing parts.

The timing chain was new, can I get another master link and reuse this chain?

All this assumes the engine has reasonably low mileage and otherwise appears to be in good condition (i.e. it is worth saving).

First, I would highly recommend pulling the engine, then the oil pan and replacing all the bearings that you can reasonably reach. You may be able to do this without pulling the engine.

Get a new timing chain, and replace any other parts that are suspect (i.e. as already covered, some valves are now suspect (those that made contact), if you can determine which piston(s) made contact, I'd replace those pistons and their rods/bearings for sure.

Missing timing chain parts? Don't know, not relevant, pull the pan and clean it out, install new chain. You will need to inspect the crankshaft sprocket for bent/missing teeth and wear.

The EPC will tell you if the IP timer is common with the 240D.

The FSM should tell you if the axial play of the idler sprocket is normal.

junqueyardjim · #6 07-11-2014, 08:37 PM

What's the meaning of "during pickup the engine locked up". Tell us how fast they were running it when the engine locked up.

joeblack · #7 07-12-2014, 09:54 AM

Thank you for all the response.

First the last question. I do not know for sure how fast the engine was going when "locked up". The PO picked it up at the garage and it failed in the parking lot.

Maxbumpo,
I have no previous history the ODO meter has 180000 on it, but is not working according PO real is around 190 ???
The turbo has a lot of radial play, no axial. The air filter was replaced with a KN style.
The cross pattern in all cylinders is visible in each cylinder. No scores. Pistons tops look good. I was hoping to get it running check for noises and oil pressure/ blow by and so on before doing the for me extensive work of pulling it. I agree with all you recommend. It is the interest of willing to take a shorcut for time sake with kids, dog and summer and other work.
The IP timer itself seems to be loose and working. I rotate the IP by hand to feel if there was any unevenness and could not feel anything weird beyond the resistance at the injection intervals.
I have to read up on the removal procedure of the IP timer and if the sprocket itself is replaceable.

VSTECH.
can the valves be magna flux tested for cracks?

Barry.
Yes you are right, just thought to throw it out there and see how much flag I would catch for the chain suggestion. I like the idea of the thin oil to check for leaks. DW40 or diesel oil? Every thing is still attached to the head. The only thing gone is the plastic chain guide.

Three, may be 4 valves show a shine flat area C shape where the piston hit. It think it is where the soot got compressed, to bad it did not form diamonds with that pressure LOL .
I will pull the "marked valves out and examine them and the valve guides. Is there an amateur way of determining excessive play?

VSTECH, how far away for State College are you again?

I got a craigslist offer from a guy up north in PA ( 21/2H drive) to get a complete head with "new turbo" and manifolds for $ 200. He would throw the IP timer in as well. The head is of a sedan so the suspension high pressure pump is an issue.
Mine being a 85 California car has the exhaust filter between the exhaust manifold and the turbo. Something i do not know anything about but my gut feeling says to get rid of it.

I will attach a couple of pictures.

Thank all for help and advise.

Later J

Junkman · #8 07-12-2014, 11:06 AM

You have to decide plans for the car. I would pull engine and tranny. Swap another good running engine and make sure whatever could be easily done to the trans was taken care of while it was out.

Strip new engine down to long block and install new gaskets and seals. Reseal the turbo and reinstall as a unit. Deal with suspension front and rear with brakes as needed. You'd be good for years and finished by winter.

Diesel911 · #9 07-12-2014, 11:27 AM

I have not read anything on the Various Mercedes Forums about the Idler Gear. But, it can be replaced.

Do you have the Cylinder Head off.

I would Pull the little Oil Plan and see what is inside.

You did not say if the Camshaft Drive Gear was still on the Camshaft or not. If it was then where did the Washer came from that dropped inside?

If it was the Washer that caused the Failure then it is very likely that the Engine can be reused the way it is if you replace what ever it was the Washer damaged.

It would be worthwile to one at a time loosen a Valve and see if it is bent. Push it part way out and spin it with your fingers and see if the Valve Face wobbles.

New Chain and a Junkyard Camshaft and Bearing Tower and the same if the Timer was damaged or the Idler Gear.

scottmcphee · #10 07-12-2014, 11:28 AM

What why are you trying to rescue this engine?

Move on and find a better prospect.

Wanna stuff a om603.960 in there? Got a couple sitting around here.. Free.

dude99 · #11 07-12-2014, 05:10 PM

Seriously? Your giving away OM603 engines? Why am I in vancouver!!!!! I couldn't find one here if I wanted to let along for a price that's at all reasonable....

Diesel911 · #12 07-12-2014, 06:28 PM

Why does everyone think it is seriously damaged.

Others have reserected Engines that have had a similar problem but caused by the Vacuum Pump Pump Failure.

Apparently if the damage was done at a low speed often it can often be fixed. Some one just needs to inspect the Engine carefullly and then decide.

The Most expensive a new Timing Chain next is the used Camshaft and Bearing Towers.

But someone needs to be willing to do the deed. Perhaps there is a Member near State College PA that can take a look or even lend a Hand.

vstech · #13 07-12-2014, 07:08 PM

... I'm quite away, but my buddy that travels to me every year or so, lives in duncansville...

joeblack · #14 07-12-2014, 09:26 PM

This 300TD seems to be in a very nice rust free shape. This is my 5th W123. 2x 240D manual rusted out , 1x 300 turbo sedan rusted out, 1 300td wagon , rescued out of the wrecking yard in Florida, relative rust free, replaced the IP 3 years ago, 300+ k miles ???, the motor is on the way out. Before I start working on that i want this 85 300TD running.

It is not that easy to get a Good mercedes engine, one with a known history, measured compression. I am sure they are around but then it is not cost effective anymore, unless you are lucky.

Pulling an engine in a gravel parking lot is possible but if not required then I prefer leaving it in.

The PO drove this car from Las Vegas to Harrisburg,PA and he seemed to be very knowledgeable. So although I do not know this engine yet I am willing to give it a shot.

We have driven the last 7 years on WVO two tank systems HIH, injection line heaters without any problems. I feel that these OM617 are the best to to work with although a 603 might be good as well.
If I can get this engine running with $ 300 on parts and two days of work then I think that would be worth the try.

This car will stay on diesel as a backup ( if I get it running ) Our other wagon, the WVO one will get another engine and 5 speed manual that I bought and shipped from the Netherlands ( my country of birth).
But that is another project.

Diesel 911,
the sprocket was still on the camshaft. Nut was on. I need to look if the washer is there or the mechanic forgot to put it back on after offset keying the camshaft.

attached a picture of the washer and where it was when I found it.

t walgamuth · #15 07-13-2014, 08:30 AM

It is a tremendous amount of work to rebuild one of these diesel motors. Lots of parts and lots of bolts. I'd be afraid to do it with the engine in the car after a failure that is likely to have spread particles throughout the motor. I know its tough to find a good used motor but I advertised for one here and had several offers, but in the end did not buy any of them for my own reasons. The best source is to buy a good running car with cosmetic issues and pull what you need.

The last engine we went through because of a seized bearing did not need much and the cost of parts was minimal. My machinist took it all apart though and measured everything. Now that motor is the smoothest running 617 I have ever had.