Re-etching timing marks - Page 2 - PeachParts Mercedes-Benz Forum

spock505 · #16 05-17-2017, 05:39 PM

The other slight concern with this head relates to the pre-chamber which needed machine for glow plug removal.

As you can see pre-installation, it looks a bit oval along with the head recess itself, I did query this at time but was necessary in order to get the plug out, it also pressure tested okay so shouldn't be an issue.

This was another consideration for swapping out the head.

Clemson88 · #17 05-17-2017, 06:47 PM

Quote:

Originally Posted by Dan Stokes

I have 2 dial indicators, a Mitsutoyo (labeled "NGK", a good Japanese brand) and a Harbor Freight which I bought because my old mag base had lost it's gause (or whatever you call magnetic stickyness) and it came with a dial indicator for pretty cheap. Just for fun I set them up and made the same measurement and they were identical so I'm thinking the HF one is OK, at least THIS HF one.

The reason to check TDC is that either the dampner can slip on the rubber (I forget if the MB one can do that but many can) or, believe it or not, the crank can take a bit of a twist over the years. Also, the key and/or keyway can get worn. These engines use a weird key/keyway setup and they're a stinker to reinstall after the dampner is removed (which you have to do to replace the front seal) so it's good to check. Mine was off only slightly so it turned out to be a lot of work for not much gain but I wouldn't have known that if I didn't check. Being a performance engine I felt like I needed to know for sure although the engine has proven to be relatively insensitive to minor timing changes using top speed as my yardstick.

Dan

The vibration original vibration damper slipped on my 84 300SD within a year of me getting it. It was clearly due to fuel and oil spilling down the front of the engine. Mostly oil, I reckon.

I ordered a new one from World Pac. Of course I checked the keyway while it was off. I'm good there but I'm going to buy a HF dial indicator for I will be attempting to check IP timing before I start the car again.

spock505 · #18 05-17-2017, 07:08 PM

Can't quite figure out this diagram for my engine model, perhaps are there two types of vibration dampers shown.

Mine looks like part number 74, it has that recess half way around the edge, does the outer then move?

spock505 · #19 05-18-2017, 10:19 AM

Okay folks, ordered a 22mm x 1.5mm bolt to take out the No 1 pre-chamber, should take a day or two to arrive (I completely forgot about the removal tool before posting).

Question About Precombustion Chamber Pulling Tool

I gave this a lot of thought before going ahead but decided on a process of elimination settings wise before proceeding ahead..

Please correct if wrong, but there are possibly only three options:

1. Existing timing set at appx 4/5 degrees ATDC which gave two fails during comp test, plus lots of oil burn.

2. Moving another tooth in this direction would give appx 20 degrees ATDC which would almost certainly make valve contact.

This leaves the last option (3) which is appx 14 degrees BTDC as below giving the best comp readings by far, but is way off the manufacturing spec.

Given that I have a spare head and a day or two wait for bolt, I decided to try option 3 by first measuring comp turning engine over by hand with torque wrench attached. What a difference, each of the comp strokes can be clearly felt hitting around 50-60nm before the clicking out on the wrench, did this several times to ensure nothing (valves) touching, then bolted together essential bits for starting.

Well, what do you think happened?

Diesel911 · #20 05-18-2017, 10:37 AM

Wow I forgot to mention as the other guy said you need to remove the glow plug before the Perchamber is puled out.

spock505 · #21 05-19-2017, 06:28 PM

Engine is running a lot better with the appx 14 degree advanced settings, more responsive with more power, its also lost the 'wobble' on tick over with a much smoother idle. Starting is also more or less on first click of key, this I compare to my 210 with 962.

Its slightly noisier than before with one injector nailing although this has improved with each short journey, it could be there is a large carbon build up from before which might need shifting for complete smoothness. I also need to refit the plastic cover which may make a difference to the engine tone.

Apart from the nailing above, it now sounds like a 606 which is a refreshing having driven it on the other setting for so long.

The oil is probably pretty contaminated, so will change this out tomorrow, refit rocker cover. top up with new coolant and go from there.

I need to explore the crank vibration damper and exactly how that may have moved, as a general observation it looks like one solid lump of iron so not immediately obvious.