General w124 E300d 606 Cylinder head replacement questions

[stigsblade]

Have removed head from my w124 e300d (606 engine) according to very helpful info on here. having spent £600 on parts (Gaskets, head bolts plastic parts) and recon etc I just want to make damn sure I get the reassembly right! I have the following questions;
1. Is there a way to check if injectors are ok, and what torque setting is required when I refit them.
2. Is there a recommended procedure for tightening head bolts and what torque setting is required.
3. I am going to use original glow plugs + one new one, they came out ok and they glow red when tested. Is there some compound which will make them easier to remove in future and again, what torque setting is required.
4. The gasket set came with a bag of smaller seals and washers, it is not clear where they belong. i presume they were either missing from the old assembly or have been introduced as a mod. How necessary are they?

Finally, my computer will not allow access to the russian site, am I alone in experiencing this?

Your help as ever will be hugely appreciated.

 

[Number_Cruncher]

Regarding torque settings and procedures, see here;

Mercedes Benz Model 124 - OM606 Maintenance Manuals

Have you checked carefully for inlet valve seat recession? Did you find any?

The injectors can be tested by any diesel specialist. Ask them to check opening pressure, spray pattern and leakage. Be *very* careful not to touch / damage the tiny pin which protrudes from the nozzle / tip.

When doing the angle part of the cylinder head bolt tightening procedure, begin by marking the bolt heads with a dab of whie paint / liquid paper. Begin with all the dabs, say, to the front. Then, once you've done 1 90 degree stage, they'll all point to the driver's side, etc, etc.

The reason to mark them in this way is that if you get disturbed part way through, or you forget which you've done and which you haven't, there's no easy way to tell - where with a paint mark, it's obvious.

The main thing with glow plugs is to make absolutley sure that the taper seal is good and clean. It's combustion gases leaking past this which makes the glow plugs difficult to remove rather than usual seizing problems.

In your shoes, I would fit a new set of Beru plugs, so you don't have to touch them again for a good long while (mine have been in for 50K and are still OK)

 

[stigsblade]

Regarding torque settings and procedures, see here;

Mercedes Benz Model 124 - OM606 Maintenance Manuals

Have you checked carefully for inlet valve seat recession? Did you find any?

The injectors can be tested by any diesel specialist. Ask them to check opening pressure, spray pattern and leakage. Be *very* careful not to touch / damage the tiny pin which protrudes from the nozzle / tip.

When doing the angle part of the cylinder head bolt tightening procedure, begin by marking the bolt heads with a dab of whie paint / liquid paper. Begin with all the dabs, say, to the front. Then, once you've done 1 90 degree stage, they'll all point to the driver's side, etc, etc.

The reason to mark them in this way is that if you get disturbed part way through, or you forget which you've done and which you haven't, there's no easy way to tell - where with a paint mark, it's obvious.

The main thing with glow plugs is to make absolutley sure that the taper seal is good and clean. It's combustion gases leaking past this which makes the glow plugs difficult to remove rather than usual seizing problems.

In your shoes, I would fit a new set of Beru plugs, so you don't have to touch them again for a good long while (mine have been in for 50K and are still OK)

Thanks for your reply numbercruncher, Thanks for the link. I had the head tested so im assuming valves were all ok. as for glowplugs I'll take your advice! Do you know about these seals and washers? There are 2 sets of rings for (I think) around the injectors, one set green 40mm the other black 45mm. is it an either/or situation? also 6 washers about 22mm with a 7mm hole, with a chamfered edge and a recess, any ideas?

ps Nick Froome says the russian site is down

 

[Number_Cruncher]

Thanks for your reply numbercruncher, Thanks for the link. I had the head tested so im assuming valves were all ok. as for glowplugs I'll take your advice! Do you know about these seals and washers? There are 2 sets of rings for (I think) around the injectors, one set green 40mm the other black 45mm. is it an either/or situation? also 6 washers about 22mm with a 7mm hole, with a chamfered edge and a recess, any ideas?

ps Nick Froome says the russian site is down

**Don't** assume that you haven't got valve seat recession - these engines are prone to it. With the valves intalled, check the height of the inlet valves - by eye is good enough - as they're tilted, it's a bit difficult to measure properly without special tools. Look carefully at the inlet valves towards the back of the head, and check to see they're not sinking into the head.

While you've got the head off, fitting new valve seats and replacing the odd intake valve is cheap and easy.

The rings sound like the O rings which seal the trumpets around the injectors - those that fit between the head and the cam cover.

The metal washers are the injector heat shields - whenever the injectors are removed, you *must* fit new ones. If you don't, your injectors can quickly overheat, and the nozzles become damaged. Fitting injectors with old heat shields is almost the definition of false economy! (Something quite expensive being ruined for the sake of something very cheap!)

 

[stigsblade]

**Don't** assume that you haven't got valve seat recession - these engines are prone to it. With the valves intalled, check the height of the inlet valves - by eye is good enough - as they're tilted, it's a bit difficult to measure properly without special tools. Look carefully at the inlet valves towards the back of the head, and check to see they're not sinking into the head.

While you've got the head off, fitting new valve seats and replacing the odd intake valve is cheap and easy.

The rings sound like the O rings which seal the trumpets around the injectors - those that fit between the head and the cam cover.

The metal washers are the injector heat shields - whenever the injectors are removed, you *must* fit new ones. If you don't, your injectors can quickly overheat, and the nozzles become damaged. Fitting injectors with old heat shields is almost the definition of false economy! (Something quite expensive being ruined for the sake of something very cheap!)

Thanks NC
changed the heat shields, (must be some kind of alchemy!) but had already bolted on exhaust to head so did not feel like removing to doublecheck the valves. (surely this would have been picked up by specialist on vac test?) engine was reconed 50k ago so hoping for the best! What are symptoms of valve trouble? found homes for the big seals Had to remove the trumpets) now have to find them for 3 small rubber seals, one of which is surely for the cooling pipe near the oil filter housing and a couple of other washers. Just the final 90degree turn and the finish is in sight, Picking up breather nipples and seals for the trumpet tops today so hopefully will finish today with the possible exception of the dastardly vac pipes to get found my neck.
One oddity, someone in the past has removed the "vane" from the butterfly valve in the inlet manifold, the big one between the two connectors. why would anyone do this?

 

[Number_Cruncher]

Thanks NC
changed the heat shields, (must be some kind of alchemy!) but had already bolted on exhaust to head so did not feel like removing to doublecheck the valves. (surely this would have been picked up by specialist on vac test?) engine was reconed 50k ago so hoping for the best! What are symptoms of valve trouble? found homes for the big seals Had to remove the trumpets) now have to find them for 3 small rubber seals, one of which is surely for the cooling pipe near the oil filter housing and a couple of other washers. Just the final 90degree turn and the finish is in sight, Picking up breather nipples and seals for the trumpet tops today so hopefully will finish today with the possible exception of the dastardly vac pipes to get found my neck.
One oddity, someone in the past has removed the "vane" from the butterfly valve in the inlet manifold, the big one between the two connectors. why would anyone do this?

I've had heads back from very reputable places with serious faults. It's a shame it's too late to check.

Without the cam and followers in, the intake valves would close and the fault wouldn't necessarily be picked up.

With an engine apart, trust *nothing*, and check everything - or else you'll probably end up doing the work again.

If the valves are worn, you'll get poor starting and cold running, you'll get knocking from the rearmost cylinders, and poor glow plug life on the rear cylinders - your mpg will be down. As the forward cylinders aren't usually affected, the engine will still run - and with the long intake manifolds in place, you won't hear all the leaking that's going on. It'll run, but it will be a bit of a donkey!

One way to see if it's actually a problem is to plug the open vac pipes and run the engine without the inlet manifold in place - any leakage will be obvious.

Why did you take the head off?

>>why would anyone do this?

Clearly a misguided attempt to make better airflow. Misguided because the linkage open the valve at large throttle openings anyway!

 

[stigsblade]

feel a bit of a t**t for not checking now, but i think it was running ok before ie started ok ran well ok mpg. took head off as oil in water, i think it was you that advised. I checked oil cooler before and was left with little choice. i overheated last year and had to change radiator. not badly but i guess it was enough.

 

[Number_Cruncher]

It's good that it was running well before. Good luck! Did you find a clear leak path?, a clear and obvious failure of the gasket?

 

[stigsblade]

Hmm, not that obvious i'm afraid. There seemed to be some corrosion around pot nearest front but thats all.

 

[SilverSaloon]

Great link NumberCruncher

 

[stigsblade]

Hi NC
Just to say everything running like a dream, (Engine wise, anyway; I am experiencing a slight gearchange problem, particularly 2nd to 3rd. Will post again on this) excellent advice from start to finish. Will have no fear of this engine in the future!