I've never done a compression test just because I don't want to know. It shakes a bit at idle but has good power and I found my starting problem. All my glowplugs and completely stuck with carbon and reading 1.1-1.2 ohms so a new set of plugs and reaming out the holes should have her starting nicely this winter just like last year.

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Adam Lumsden
(83) 300D
Vice-President of the MBCA International Stars Section

The plugs are the old series type. They work to the point that the resistance wire glows and the mechanic I had do the test said they all glowed with the injectors out. I usually glow for 1min 20sec when it's cold. The engine always seems like it's just under starting conditions, maybe kicking a bit but just not enough. I am thinking about switching to parallel plugs. (and installing them on a seperate relay)

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'84 190d 2.2 - Silver
Converted to 5-Speed
'84 190d 2.2 - Blue
Factory 5-Speed

'76 300D (W115)
Sold, found again in less auspicious circumstances

I have only heard of improvements with the newer style of plugs. Their is a guy here in FW who is also on the forum who did the switch on his '78 300D and he said there was a significant change.

Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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At just 161,000 miles on your car, I am surprised to read about the two cylinders that aren't doing so well compression wise. Unless the engine has more miles on it (like it was taken from one car with higher miles and put in your car ), it should be in better shape than the results revealed.

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1999 Mercedes-Benz S600, 103K miles - garage queen
1988 Mercedes-Benz 560SEL, 89K miles - daily driver
2007 Hyundai Sonata Limited, 31K - daily driver

"(and installing them on a seperate relay)"


You could do that or just use the old one and cut the glow time down to 5 to 10 secs, the new style GPs will help ALOT

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

where does one buy the pencil type plugs with the wide body? the loop type plugs are wider compared to the pencil type. And without a pencil type with the wide body, nothing short of replacing the lower block would accept the new pencil type plugs....

i've been musing over this upgrade for sometime.. i've read dieselgiant's webpage.. but i cant find the pencil type plugs that has the same wide body as my loop types... if one can post the part number used (maybe bosch?) to fit the pencil type.. i'd really be happy... tnx..

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Mike

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1975 200 - Sold (no pix);
1978 200 - Sold - http://www.pbase.com/hboy/redbaron
1979 300TD - Sold
http://www.pbase.com/hboy/greenwagon
http://www.geocities.com/hboy726/300TD.html
1985 230E - now my daily driver...

The pencil glow plugs are a good irea, but I think Barry from Canada has hit on the source of your low compression. Rings are rarely the cause of low compression on these diesels. The culprit is usually the head.

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Auto Zentral Ltd.

I'd wonder if the ring gaps lined up, but it would be quite a coincidence to happen to two cylinders at once. Still, if a two cylinder compression test isn't expensive, it might be worth repeating.

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'79 300SD W116
'86 190E 2.3-16V W201
'92 300D 2.5 W124
'99 E320 4MATIC S210

I would just drive it and don't worry about it; I'm sure there are other more important things not car related that need your attention... Nothing in life is perfect.
Heaven help me if I started doing compression tests on all my cars and motorcycles; I would go crazy.

The kit and individiual plugs here:

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1JR08J2SB1O80PZXOD&year=1974&make=MB&model=240-D-001&category=F&part=Glow+Plug+Kit

You can find them cheaper elsewhere...PM if you want a address.

This is just to support the site

engine shake at idle once it warms up is usually a fatigued Rack damper bolt....however there are other things that can casue it also...

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

OK..missed that part of the equasion....I spend too much time with the OM617 Turbo......

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

And mac isn't actually complaining of an uneven idle...his question was just related to lower compression.

I think others chimed in with rough idle problems...with turbo models...and in such a case a rack dampner change/adjustment might fix the problem.

I just picked up a set of fast glow plugs today ($99 for 5 & timer) and will (hopefully) get them installed before the week is out. Crossing my fingers that this gives just enough heat to get it to start.

__________________
'84 190d 2.2 - Silver
Converted to 5-Speed
'84 190d 2.2 - Blue
Factory 5-Speed

'76 300D (W115)
Sold, found again in less auspicious circumstances

Piston ring gaps DO NOT LINE UP !

Having said that...let me explain, 'cose there will be a certain amount of ridicule and desent otherwise.........and will be anyway no doubt, and ugly too.....

I worked, a long while ago, with a piston ring manufacturing company.
Tests where done to determine the operations of rings under load, ie: on a running single cylinder test mule......with a gieger counter and rings that had been loaded with radio active end(s)..... it was found that the ring would rotate about the piston at 5 to 6 rpm at most rpm speeds.....it was also futhur noted that, at no time did the rings line up their gaps.... this was due to gas pressure working on the rings which act like little jets to keep the ends apart by a minimum of 5 degrees....at which time they would slowly move apart....each rotating at slightly different speeds about the piston.

SO......unless the rings have siezed, and at that very moment, the gaps of two came close together ( it would only ever be two of the three...) THIS IS NOT YOUR PROBLEM !



.

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[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."