Date registered: Nov 2008
Vehicle: 1981 300TD 310k--1966 230 165k--1970 280se 172k
Location: Ohio City, Ohio
Mentioned: 1 Post(s)
Quoted: 33 Post(s)
Well, I'll tell you what I know.
Compression should be around 145 psi with a max variation between cylinders of 23psi. Be sure that you cycle the engine at least 8 times to get an accurate reading. If your compression is low, squirt some oil into the affected cylinders and see if the reading comes up. That will tell you if the rings are worn. If not, it's probably the valves, valve clearance or cam timing.
How do know that the head gasket has been worked on? Do you have the head off? The look of the top of the pistons will really not tell you anything. The bottom end of this engine is pretty robust. The valve guides, seals, and adjustment posts usually wear out long before the bottom end does.
Maintenance parts are pretty available. Google the part and you'll get many options. Some parts that aren't easily found can be obtained from the Mercedes-Benz Classic Center. You are out of luck with any body or trim parts. You will have to find somebody selling them or if you are really lucky from a scrapyard. Ebay has some used parts.
The 13 inch tires are hard to find but are available and relatively expensive.
When I wanted to replace my mechanical fuel pump, I could not find a new unit that was satisfactory or even a rebuild kit. So I installed an electrical pump instead. It works fine, but is a little noisy. Also consider installing a Pertronix electronic ignition. Easy to install and cheap ($90). An excellent upgrade.
If you have the Zenith carburetors, be prepared for an expensive rebuild or if you do it yourself, a fairly complex job. Information is available for this procedure. Often the frozen heat risers or over-aggressive tightening cause the carb body to warp. You can tell the Zeniths if you have two nuts holding the plenum at the top of the carbs. If the carbs are badly warped, you can install a Weber conversion but will cost you around $700.
Rust is the most important problem. Service records are important. Tight front end, brakes, transmission shifting and overall condition of the interior play a part in value. Rubber parts (engine mounts, subframe mounts, trans mount, center driveshaft bearing, and swing axle bushings) are likely to need renewed if not recently done. Rear brake shoes are no longer available and will have to be relined if needed.
It's hard to determine value without detailed photos and mechanical information. Good examples (8 or 9 out of 10) are currently selling between $4000 and $5000 on ebay. The prices seem to be rising over the years.
The fact that the car is not running should be damning enough to get a substantial discount. No more than $1500 to $2000, I would say, if the rest of the car is decent.
These cars are very easy to work on, and if your husband is a good mechanic he should be able to solve any problems. I love this model and it's a great, stately ride.
The finnys are just too cool.
1981 300TD--310k miles
1970 280sel--172k miles
1966 230--162k miles