420 sel working on timing chain and guides
 

hi , ian from australia and have just got my first mb
it is a 88 420 sel and has 395k on clock. Sounds a lot but car is very good condition and i am keen to maintain it. I am having trouble getting a cd on specs and need the tension settings for the bolts holding done the cam shafts as these are probably the most important ones I need at this stage, it also has the seemingly mandatory rough idle, but compression seems to even in each cylinder at about 190. does anyone have a cd avilable:confused:

I believe they are available from the sponsors of this board.

If you are in Australia you should try www.mbspares.com.au. I am in New Zealand and purchased mine through them.

Matt.

Thanks Matt, I will try them
We are trying to get it back together today but are having a few problems . We decided to replace the bottom chain rails as well as the 4 top ones, including tensioner. The top rails were very dark brown and showed a fair amount of wear , while on the main tensioner rail , the teflon? pad was worn HALF away and the chain had worn considerably into the alloy support it was attached to. This was enough to frighten me into delving into removing the front timing cover and all the extra work this involved. The biggest hurdle now is getting the timing cover to go back and the fiddling around to get the oil pump chain back into place. Does anyone know if it is easier to put back if the oil pump chain is broken and inserted this way and then using a joiner much like the main cam chain? We did not remove the whole sump, only removed the bottom of the front sump. I am taking photos of most of this with my digital camera and should be able to post these later if anyone is interested. As said before, dont have cd yet and have guesed the timing marks proceedure a bit. Put the crank at TDC for #1 and used what appears to be timing marks on the left and right cams , but would feel more confident if someone could confirm that I have used the right marks. The motor seemed to turn over normally when we used a spanner on the crank and turned it over about 4 revolutions. Dad and I have worked on lots of other cars/trucks/& buses before but this is the first MB , but I have a feeling this could be an addictive habit.
Regards Ian

Just remove the sproket on the oil pump or remove the the entire oil pump to replace the chain and rails. The oil pump chain should not be disconnected.

Hi
Haven't looked at thread for a few days, dad removed the front timing cover while I was away and found the oil pump had to come off to get it off. It also works easier if the oil seal on the crank is removed, this was infact hard to take out and seemed to have been put in with some sort of adhesive. When we reassembed the cover , we found that you leave out the seal until last and the oil pump chain will go in last and simply slips over the crank and drops easily into place. Did I understand you correctly that the timing cover could be left on, and the bottom rails will come out thru the the sump if the oil pump is removed? I don't think this will allow the removal of the pins in the botom rails? Thanks for your feedback , it really helps. I have found a guy here who is heading to the states this week to buy MB parts and he seems keen to buy low km 560's and bring back here . He seems keen to fit a 560 motor and contol box into my 420 and says it is a big improvement in power and economy(?) and a fairly cheap alternative to a major rebuild , about $4000 aus . Any comments from you guys who have sen this done ?

The 560 engine is a big brother to the 420 & should be a direct bolt-in.