PeachParts Mercedes-Benz Forum - View Single Post - Why do 617's require less glow time then 603's??

dieseldiehard · #9 01-23-2006, 04:41 PM

I've often thought about the differences too. My 603 (recently rebuilt) still takes more cranking to light er off, especialy cold!
My 617 turbo goes off with such a twitch of the key its unbelieveable to me at times I can count one thousand one, one thousand two and the engine is running already and time to get off the starter motor before I got to the second one in one thousand one! The engine has new pistons and was bored and hones 1st oversize so compression is super that helps I am sure. OTOH my '83 300D with almost 250K on it and the original head still on the engine needs a few more cranks, maybe three seconds when cold. I believe that compression has all to do with this. When I get my latest '87 300D turbo running after re-ringing it, I'll be able to comment on how a 603 is "supposed to start" but I still figure its going to be way different than a 617. The 603's always seem to rattle when cold too, it has to be air in the lines but there are no leaks around my fuel delivery nozzles or injectors so where would any air come from? I generally try to do the two-step glow plug warming procedure too, it makes a small difference in the crank time it takes to get the engine running but seems to me that makes no difference in the rattling noises when the engine is cold and starts running. And I don't mean really COLD, even an ambient of 45 degrees (F) is enough to make more rattling than say a relativel warm 60 degree day. Something is really sensitive in the 603 engine!