According to the M-B CD engine manual the 1985 300D turbo engine has a detent-type chain tensioner (OK, I called it a ratcheting-type but it means the same thing - the plunger increases chain tension as parts wear and is prevented from loosening with a detent mechanism). Perhaps Larry knows something about the type of chain tensioner in Mark's engine that others do not know and the M-B manual is wrong (not unusual, I've found mistakes in the M-B manuals and most other service manuals from all manuf.). If it is the older style chain tensioner, then Mark will have an easier time removing the head since the older type chain tensioner does not need to be removed to R&R the head since the plunger can be compressed to free the tensoiner rail a bit and allow the timing chain more slack. If it is the detent-type chain tensioner, then R&R'ing the head is easier if the tensioner is removed so the tensioner rail is not tensioned and the chain will have more slack.

Paint remover can also be used to remove old gasket material if there is a lot stuck to the mating surfaces - I've used Stripeze for years (spelling may be wrong) on aluminum and cast iron. Paint remover has a plus since it can be brushed onto the old gasket and not sprayed on which can get into places where it is not wanted. I've had 4 300D heads off of different engines and only minimal amounts of head gasket material was stuck to the mating surfaces and what was stuck scraped off easily (I've had some types of head gaskets split almost evenly with gasket material nearly welded to both the head and block because the manuf. used a really good adhesive - meaning the use of paint stripper made it a lot easier to remove the old gasket, in fact a necessity).

My, very cheap, $0.02 worth!
Tom

__________________
America: Land of the Free!

1977 300D: 300,000+ miles

American Honda: Factory Trained Technician & Honor Grad.
Formerly:
Shop Foreman;
Technical Advisor to Am. Honda;
Supervisor of Maintenance largest tree care co. in US for offices in Tex.