OM603.
The ill fated cylinder head removal continues. I busted lower timing chain guide pin. Let's just say, it not coming out with the head installed.

I set the crankshaft to TDC and the camshaft to its mark and tie wrapped the timing chain to the camshaft gear (3 places). I removed the camshaft gear from camshaft, it now rests in chain compartment.

Have I yet disturbed the IP timing?

I want to cut the timing chain to remove head. Can I do so and suspend the ends of the chain and keep the IP timing correct.

Are there IP timing marks on the gear under the vacuum pump that I can use to verify timing?

You have not disturbed the timing.........yet.

However, you should absolutely not cut the timing chain at any time.........even if it's properly installed on the engine. All timing will be immediately lost and you'll have to set both the cam and the IP to the crank............not a very simple procedure for those that haven't already done it.

For that matter, I wouldn't bother tying the chain to the sprocket. Scratch some marks you will find later and put the spocket on the shelf. The chain isn't going anywhere and it won't come off the crank or IP sprockets.

Sixto
87 300D

The best solution at this point would simply be to drill a small 2-4 mm hole from the back side of the cylinder head timing chain chase and then use a punch to remove the pin driving it forward. The lower pin has a recess into which the rearmost end fits, you could drill the hole 40 mm inward from the end of the casting and 8 mm above the bottom edge of the cylinder head's lower surface. The opening could be easily sealed after the fact, I would use the aluminum based Lab Metal to do it.







Good Luck!

If you remove the vacuum pump you will avoid the freak-out when the return spring in the vacuum pump acts against the timing device's ramp and gives that "tug" as the pump's cam follower wheel rolls into a valley on the timing device's cam profile!

Thanks sixto!!!!!

If you add [img] and [/img] tags around the image URLs the images are displayed in the post.

Sixto
87 300D

I see no problem with cutting the timing chain. I've done it without drama many times. Older engines had a master link in the chain that I always used instead of pulling those troublesome pins.
Tie about 6" of stiff wire to each end of the chain and lower carefully down in the the timing chest. Don't move the crankshaft.

But why cut the chain if you don't have to?

Sixto
87 300D

Exactly. But sometimes it's the most expedient route.

I thought of that early on, however it seems the IP fuel line nipples are in the way. Now, if the IP wasn't there...hmm, I suppose I could remove the headbolts, free the head and raise it slightly above the IP and drill as you specify. Sounds the best so far. I really don't want to cut and rivet the chain. The timing issue can be a bear. I'm replacing the vacuum pump. I did feel the pull on the timing chain, however I didn't asscociate it with the vacuum pump, until you mentioned it. Thanks. I was concerned.

Thanks for all the ideas.

That being the case you could try two different approaches, first I would mark the position of the IP and then loosen its bolts and rotate/clock it towards or away from the block, you may be able to get by it then. You might also try a Dremel type tool with a 1/8" ball carbide cutter so that you can get into it at less than a straight shot from the rear. There appears to be about 1/4" of material at the rear of the recess. Good Luck!

UPDATE. I have removed the damaged tesioner pin, removed head bolts and raised head to drill hole from behind tensioner pin. Eureka! It was easy to drive out.
The head has 7 cracks in the combustion chambers. Cylinder 1 has no cracks.
Good news is I bought a rebuilt #20 head for 850! It appears to have been rebuilt. Now if I can get a rebuilt turbo I'll be set.

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Thanks for the update!

__________________
84 300D, 82 Volvo 244Gl Diesel

You do know that your pre-chambers, injectors, and injector lines won't fit this head without modification? Also, you'll need the longer bolts in the timing chain cavity.

__________________

Gone to the dark side

- Jeff

Ah, no. I thought that was the #22 head.
The head has pre-chambers installed. I just ordered Bosch GPs, number
0 250 201 039, are these wrong? What GPs work with the 20 head?
What model and year is the 20 from?
What's the mod to the injector lines?
What injectors work? Damn, I just bought rebuilt injectors for the old head.

Thanks for your post!

There's some argument about newer heads though I might be the last holdout I believe #17 was standard issue on all US 603s through 95 based on seeing a 95 S350 with original #17 head. Others say they have newer castings on cars that have never been touched. Short answer, I don't know what year #20 was standard.

All the parts different between #14 and later heads are the same for all later heads. What works for a #17 works for a #22. When buying parts, you can say anything from a 90 350SDL to a 95 S350. I don't know glow plugs by number (too lazy to check the FSM). What car are they originally for?

You can try to force the injector lines to fit. Attach them to the injectors than gently bend them to attach to the IP. Hope the lines meet the clamps.

gsxr has guidelines to machine vertical prechambers to work with later head castings. You can keep the vertical injectors, glow plugs and injector lines. You still need a couple of 80mm long bolts to replace the 50mm long bolts.

Sixto
87 300D