cold start question - PeachParts Mercedes-Benz Forum

larry perkins · #1 02-16-2007, 06:43 PM

ok guys put on the thinking cap.
question is why does the 602 and 603 engines start from a cold start better than a 615-616-617 engine?
i conclude that the starter is the most difference.
this winter in louisville has offered many days for testing and i have seen the 617 fail without a block heater from5-10 deg f,and the 602-603 will light every time.
now dont get into low compression because i have a few that i tested(617) that was rebuilt and have new everything and has compression 390-400 and they fail to start without heating.
if the starter is the weak link,has anyone found a gear reduction starter that would bolt up to the 617 without too much pain?
appreciate any input
larry perkins 95 old cars
louisville ky

pawoSD · #2 02-16-2007, 06:56 PM

Yes, mean green Inc. makes gear reduction starters for the 617 diesels....

www.mean-green.com

larry perkins · #3 02-16-2007, 07:11 PM

thanks, i sent them a email as they dont address the mercedes 617 on their site.
larry perkins

kerry · #4 02-16-2007, 07:13 PM

The standard starter for the 617 turbo spins the motor faster than the NA starter and will fit botht he 616 and 617 I think. I replaced the original starter in my 617 NA with a turbo starter and it spins faster at cold temperatures.

Brian Carlton · #5 02-16-2007, 08:31 PM

If you believe that a completely rebuilt 617 needs external heat to start at 0°F., you'll have to come up with a plausible explanation why the SD (195K on the clock with a rebuilt head) will start in 1 second at 0°F.

Others have started the 617 at -15F. I believe Kerry started his at temperatures lower than -15F.

It's compression that dictates the capability to start. The compression that we are interested in is governed by starter speed. If the starter is not turning at full speed, the engine compression will likely be somewhat less than if it were turning at full speed.

Note that I installed a Bosch reman starter when the head was rebuilt.

kerry · #6 02-16-2007, 10:06 PM

Quote:

Originally Posted by Brian Carlton

. I believe Kerry started his at temperatures lower than -15F.

Yep. I've started the 85TD with 150k at 30 below F without a blockheater. Started briefly at 35 below but the fuel had gelled so it quit running.

babymog · #7 02-17-2007, 12:25 PM

Kerry:

Although I respect the information that this cold start gives to the forum, what in the hell are you doing outside starting your car at -35? There's got to be a good excuse for staying home on days like that!
;~)

kerry · #8 02-17-2007, 02:08 PM

I wish I could have had an excuse. I'd gone skiing at a cabin last year in Fraser (Icebox of the nation). It was about 50 degrees in Denver when I left and I didn't bother checking the forecast. When I woke up Saturday morning it was 30 below but the TD started. I started it on and off during the day and considered leaving it running Saturday night but didn't. The next morning,at 35 below, when I had to drive home, it started and ran on a few cylinders for a minute or so, then the fuel gelled. (This was the occasion that I learned they don't sell winterized fuel in Denver). Lucky for me, the local towing company's big tow truck was broken down. I say lucky because just about every diesel within 20 miles wasn't starting and the tow company was overwhelmed with calls. But, since their big truck was broken, they could only tow cars and most of the others were trucks. So, I got towed to the shop, they fired up the salamander, opened the hood, and I was off in about an hour.
I installed a block heater on the TD yesterday and I now know not to expect winterized fuel from the pumps in Denver, so a reocurrence is unlikely.

babymog · #9 02-17-2007, 10:21 PM

I started my '87 300D today, a heat wave and it was in the mid-20s so it seemed a good time to fire up the beast with its tank still full of #2 diesel from last summer.

No block heater, hasn't run since early September, fired in less than 1rev, almost no smoke, sure love that 603 engine.

bustedbenz · #10 02-17-2007, 10:42 PM

I'd be interested in a poll of people with 617's AND 603's who have compared them.... I've only witnessed one of each and my 603 gives me the impression that it would stay in bed at ANYTHING much below zero, if it'd make it to zero - the only SD i've ever seen acted like you could just about take the glowplugs out if you wanted to.

Brian Carlton · #11 02-17-2007, 11:46 PM

Quote:

Originally Posted by bustedbenz

I'd be interested in a poll of people with 617's AND 603's who have compared them.... I've only witnessed one of each and my 603 gives me the impression that it would stay in bed at ANYTHING much below zero, if it'd make it to zero - the only SD i've ever seen acted like you could just about take the glowplugs out if you wanted to.

Both my '84 and my '86 will start about the same. After a 30 second glow, both will start within 1 second. The coldest that the '84 has seen was 0°F. The coldest for the '86 has been 8°F.

volare · #12 02-18-2007, 12:36 AM

My 190d will start at -20F.

larry perkins · #13 02-18-2007, 09:50 AM

ok ,then how is the best way to solve the problem on the 615-616-617,i will try a gear type starter if i can find one.
could install another battery(but where),i did a 1973 220d when i first started that had 3 12v batteries in the trunk that fed a dc to ac converter to heat the water,would start at any temp we have in louisville but thats extreme.
i think i will tinker with a small 12 volt battery and try heating the glow plugs for 15 minutes to see if i can get a warm spot for it to light up .
its for sure a lame car if one is to let set at work in zero weather.
larry perkins

TheDon · #14 02-18-2007, 09:54 AM

My 617 will start in 30F with no glow plugs and no block heater.

cgunderm · #15 02-18-2007, 12:07 PM

Quote:

Originally Posted by larry perkins

ok ,then how is the best way to solve the problem on the 615-616-617,i will try a gear type starter if i can find one.
could install another battery(but where),i did a 1973 220d when i first started that had 3 12v batteries in the trunk that fed a dc to ac converter to heat the water,would start at any temp we have in louisville but thats extreme.
i think i will tinker with a small 12 volt battery and try heating the glow plugs for 15 minutes to see if i can get a warm spot for it to light up .
its for sure a lame car if one is to let set at work in zero weather.
larry perkins

why go to such lengths if you could just install a block heater and that way also avoid engine wear. cold starts without block heaters are bad for the 617 engines, even if they do start up. if you can't plug it in, you might invest in a battery that powers a block heater. even 30 minutes will make a difference.