300 SE Cab

[SL]

All, a slightly 'off topic' . I have a 300 SE with the "Two String injection pump" and electronic Ignition. The challenges is that the spark plugs on the one group of cylinders (4,5 and 6)), are apparently getting to much fuel , as they are fouled. The other 3 controlled by the 'first' string is perfectly OK. I assume that the problem is either in the Ignition or the injection pump, any ideas ? TX

[al_lieffring]

I don't know if this is possible or not, but if you could remove the two lines that go from the injection pump to the splitter blocks then reinstall them crossed from the front cylinders to the back, then you could see if the problem moves to the other three cylinders.

If it changes, the problem is in the pump, if it stays the same the problem is with the splitters, nozzles or ignition.
 
Originally this car had a dual point distributor, an improperly set up distributor could cause the front three cylinders to fire differently than the rear three. What is the "electronic ignition" that you are speaking of? is it an aftermarket breakerless system that was installed in place of the dual points?

[ja17]

Hello,

Yes the two piston pumps squirt three cylinders at a time. You may have a pump issue.  There are always other less expensive possibilities. Look into these first. Check the injection pump air filter, make sure the WRD is shutting off all the way when the engine is warm. Check to  make sure the intake starting valve is not leaking. Also the splitter blocks have very fine fuel screens in them that can get clogged.  Use an ohm meter to make sure the ignition wires and their ends are good.
There is no adjustment for individual cylinders.

Keep us up to date.

[Benz Dr.]

For those of you who may have wondered where I've been the past couple of months I can tell you that I've been working on the car from hell. A ' 65 300SE RHD. I had the engine in and out of the car 4 - 5 times, every time with a different problem. This one has the 6 element pump but there isn't too much I've not familiar with after this trying deal.

Your problem could be pump related but all the injectors have to break at exactly the same pressure. New injectors a NLA anywhere but I have a box of NOS ones if you need any. If you have serious doubts about the pump get it rebuilt. There's a pretty good site called 300SE.org that has some good info that you should check out.
 
These are VERY exspensive engines to rebuild and most places won't even look at you. Very rare and very advanced for the time the car LSD, dual point ignition, 4 wheel disc brakes, 4 speed auto, leather interior ( not all cars ) air suspension, retractable seat belts, power steering and lots of wood veneer.

 The king of the fin cars. Only 5,000 cars made and maybe 200 RHD cars built. Not many of these things around and only a few RHD cars still running.

[ja17]

Hello Dan,
Yes very advanced, also an alloy aluminum block back in the early 60s! Expensive! the new water pumps are nearly $1000.00 these days. The cylinder heads do not have combustion chambers. They are flat. The aluminum block is cut at an angle forming a wedge shaped combustion chamber. With all this advanced technology of that era, they kept the ancient design of a generator (not an alternator) which drives the water pump !
I drove 300SE W108 (M189 engine short wheel base) for many years. These engines along with the 300SLs had a engine  sound like no others.

[hkollan]

As Dan said the opening pressure is important. Test all the injectors for opening pressure and spray pattern, if they are OK and not too far off from specs, then sort and install them so that within each group the 3 injectors are as close as possible regarding the pressure break. One bad injector in one bank could prevent all 3 injectors in that group from performing correctly.

[Benz Dr.]

Oh it gets better.
 The water pump has a small gromet between the block and the pump. The gromet is held in place by two C shaped clamps. On this car the clamps were touching each other and they weren't clamping the gromet enough to stop it from leaking coolant. That took a while to figure out.
Then you have to have all the lines and manifolds on in just the right order or they won't go on. The RHD stuff added a whole new element of difficulty. This is a VERY complicated engine. The IP runs off of a small chain that runs off of the distributor/oil pump drive gear. Fitting that chain in there and getting everything to work was more than a special challenge.

 I let my machine shop guy install the piston rings because I knew better than to even try it. He machined the top piston groove to square it up with the cylinder and then put a small spacer above the ring so that it would move down a small amount inside the cylinder. Removing the steel sleeves in the block is VERY difficult and exspensive so we cleaned them up instead. This always leaves a small ridge at the top of the cylinder from ring wear. By moving the top ring down slightly it prevents the ring from hitting that ridge and possibly cracking. Since this is a fairly long stroke engine that will pull high RPM it was a cause for concern.

But it gets better.
The coolant had oil in it ( two years ago ). I figured the oil cooler had a hole in it. It did. This cooler sits on the IP side of the block and a loop of brass pipe sits in the coolant so it's really a heat exchanger.
So I got it fixed. While we were taking it off 3 or 4 screws that held the cooler on broke off in the block. Pull the engine out and drill out the screws. Put it all back together and drive the car. It's still full of oil in the coolant!  Turns out the block had a hole that went all the way down to the main oil galley.
I got all of that fixed ( a year ago ) and put it all back together at the end of last year. No oil pressure! Pull the engine and take the oil pan off.  Remove the oil pump and fix the pump. Fix the water leak on the side of the block and put it all back together. Car runs eye watering rich. Turns out to be a bunch of spooge in the IP thermostat housing blocking coolant flow. Fix that but now I have no forward gears. Bad converter that ended up taking out the main pump in the trans.
You can't pull the trans off so out comes the engine again.

Want me to go on? There's lots more..........

[SL]

All, thanks a lot for your input - I will start with the injectors - will keep you posted re. progress