Two things- I have to keep my car on the road through winter, although I don't have to drive it every day, car still has to be available to me, due to my wife getting a job and needing the Cavalier every day. Second, I finally found a good Indie Mechanic close to home, and took car to him this morning to check out my cold start blues.

So, his diagnosis is to get rid of series glow plugs and go 12V parallel (duh!). He claims it will work WITHOUT changing the relay. I'm skeptical about this- we'll see what happens. Also, he's going to adjust my valves, replace thermostat and install a block heater. All the right stuff. He also thinks my starter is cranking fast enough, so that's good, but thinks I have way too much blow-by- not good, but car has plenty of power so I'm not opting for a new engine at this point.

Here's my question- he also recommended I put a "gasoline primer" on the intake for cold starts. It has a little tank to hold gasoline mized with some 2-stroke oil, and you pull a knob on the dash while cranking to spray a bit of the gas in- guaranteed to make it start, so he sez. I have never heard of such a thing and have never seen it come up on this Forum. He sez "no ether"- it will crack pistons, but it sounds just like an ether kit that uses 2-stroke gas mix instead.

Anybody know anything about this arrangement, or have I been BS'd?

Dave

1976 White 300D W115 "Pearl"

What follows is my opinion about what has been proposed to help your cold start blues:

Series or Parallel glow plugs are less important than having ALL glow plugs function. If they all work, that's good. If one fails in a series system, they all fail, and if one fails in a parallel system, you have 4 left. Slight advantage to parallel. I'll bet parallel requires a change of relay.

Valve adjustment must be correct to get maximum compression. Diesel engines are compression-ignition, you need it all.

You didn't mention any temperature problem, why is he replacing the thermostat? It won't affect starting one way or the other.

A block heater can improve your cold starts.

Blowby is a sign of leaking compression. It may affect cold starting, but not much you can do about it.

M-B never made a gasoline primer for automobile use, and I'd never consider installing one. I would be very leery of gasoline under the hood in who-know-what kind of container, sitting on a hot diesel engine.

If it doesn't start with good glow plugs, a block heater, a good battery and starter motor, it's time to rebuild or replace it.

Best Regards,
Jim

I have a post near the end of this thread in which I mention the way I was taught to use gasoline and starting fluid to start a diesel.

Be sure you have good compression, good glow plugs, clean injectors and proper timing, let the glow plugs run extra time. Use synthetic oil and a block heater.

Or move to the gulf coast, there is a population boom going on here for the last 30 years.

"Ether", use and abuse. *Flame suit on*

I never got to test parallel glow plugs using the original relay, but I can't think of a reason that it wouldn't work. The pencil plugs that fit into the larger series plug head were not that expensive when I priced them, about $12 each locally. And they may make a big difference in cold starting, as the pencil plugs seem to get hotter, and you are not dropping all that heat outside the pre-chamber, like the resistors in the series plug chain.

__________________
'83 240D with 617.952 and 2.88
'01 VW Beetle TDI
'05 Jeep Liberty CRD
'89 Toyota 4x4, needs 2L-T
'78 280Z with L28ET - 12.86@110
Oil Burner Kartel #35

http://i16.photobucket.com/albums/b1...oD/bioclip.jpg

Didn't mention it but there is a temperature problem- on a cool day (meaning warmer than 20 but colder than 32), provided I get it started, the temp gauge barely gets off the pin, even on a 2 hour highway run. In summer temperatures, it registers a healthy 150 to 175 (my gauge is Fahrenheit BTW).

I did install a rubber radiator blind behind the grille, it helps a little, but still doesn't get over 100 on the gauge.

As for the GP relay, I am skeptical because 12V plugs in parallel will draw far more current through the contacts than the original series circuit. My guess is that the fuses located on the relay mount will blow immediately. We shall see.

Dave

Dave,

Thanks for additional info on thermostat, makes more sense now.

The parallel GP relay has a current balance sensing circuit. If there is enough current unbalance (such as one or two GPs open) the GP lamp will not glow. My SDL tried to warn me of one GP out but 'fixed' itself, then finally warned me when the 2nd went.

If your series relay has 80A momentary capacity (there is an 80A strip fuse in parallel GP relays) it may work, but will not detect open GPs, as it was not meant to do so.

Best Regards,
Jim

Coldwar,

What makes you think it will be easier to start your engine with gasoline. Gasoline has a much higher ignition point (the higher the octane rating, the higher the ignition point) than Diesel fuel. The higher cetane rating of Diesel fuel the lower the ignition point. Cetane and octane are the opposite of each other. So Diesel fuel will ignite at a lower temperature than gasoline.

In other words gasoline will cause harder starting, not easier starting !

As far as the current thru the GP relay, it is probably about the same. If anything it the current would be higher with the series GP because of the wasted energy in the resistance wires to get the same heating effect from the GP. I converted to Parallel GP and it really worked good and made starting easier and much quicker.

P E H

couldn't have said it better myself.

__________________
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

try adding about 10% gas when you fill up with diesel.

Put a gal of RUG int he tank and then switch to the diesel hose for the rest.

RUG helps thin the diesel in cold weather to flow better.

I'm running 50% WVO, 40% diesel, 10% RUG. It started fine this morning at around 35-40 degrees. Unheated system in S Texas though...

__________________
1987 300TDT
1981 VW MKI Caddy 1.6 diesel, waiting on engine swap
1983 D-50 Power Ram 4x4 "Mitsubishi" 2.3 turbo diesel
assorted gas powered crap and motorcycles

RIP: 1984 300TDT, 1982 300TDT, 1984 190D 2.2, 1992 300D 2.5, 1987 300TDT, 1982 Maxima LD28, 1983 Maxima LD28, Isuzu C223 P'ups X3, 1983 Holiday Rambler 6.2 Banks turbo diesel, 1984 Winnebago LeSharo 2.1 TD, 1985 Allegro 6.5

It sounds as if you're dealing with a tired diesel engine. When the compression gets low, the block heater will help a LOT.

I wouldn't put the gasoline apparatus on it, even on a bet. That's just my opinion. If the engine is so tired that it needs some contraption like that to keep it going, it's overhaul time.

Best of luck with it and Merry Christmas,

That's a good point. Both glow plug relays have an 80A fuse, so you will not have a problem with fuse blowing, but you will not have an indication of plug failure. However, my car was starting a little rougher in the cold, and I found 1 bad plug. Replacing it fixed the problem.

__________________
'83 240D with 617.952 and 2.88
'01 VW Beetle TDI
'05 Jeep Liberty CRD
'89 Toyota 4x4, needs 2L-T
'78 280Z with L28ET - 12.86@110
Oil Burner Kartel #35

http://i16.photobucket.com/albums/b1...oD/bioclip.jpg

I've never seen one in fahrenheit before.

Sounds like the thermostat is open (or missing).

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

P.E. Haiges wrote...

"...Gasoline has a much higher ignition point (the higher the octane rating, the higher the ignition point) than Diesel fuel. The higher cetane rating of Diesel fuel the lower the ignition point. Cetane and octane are the opposite of each other. So Diesel fuel will ignite at a lower temperature than gasoline..."

I must disagree in part.

Gasoline has a lower flash point (gasoline -50F, Diesel 140F) and lower ignition temperatures (500F gasoline, 750F Diesel) so it is easier to ignite at lower temperatures. Flash point is the lowest temperature at which the vapor above a liquid can be ignited in air. So, a match will ignite a gasoline fire well below freezing, but will do nothing to a pool of diesel fuel.

I didn't find that diesel will ever ignite at a lower temperature than gasoline.

I found this Chevron paper most interesting .

"Diesel Fuel and Driving Performance"

http://www.chevron.com/prodserv/fuels/bulletin/diesel/L2_2_1_rf.htm

"A fuel with a high cetane number starts to burn shortly after it is injected into the cylinder; it has a short ignition delay period. Conversely, a fuel with a low cetane number resists autoignition and has a longer ignition delay period."

Cetane and octane numbers are opposite, with higher cetane means faster ignition and less knock, while higher octane means slower ignition and less knock, for a different reason.

Best Regards,
Jim

The question is "what makes HIM think it will be easier to start with gasoline"- this is the mechanic's idea, not mine. However, he claims that heavy equipment used in the far north has gasoline primers equipped. From all of the replies on this thread, I am convinced I don't want one, and once I get glow plugs, block heater and valve adjustment done, won't need one.

As for part (B) of your reply- what if you had a pot of Diesel and a pot of gasoline on your kitchen stove and put the burner on high in an attempt to boil them- which would erupt into flames first? I'd put my money on the gasoline. Why? Because gasoline needs almost no heat to ignite it- rather, it needs a spark or source of open flame. As the gas heats up it will vapourize more rapidly than the Diesel, becoming volitile and explosive at a lower temperature, and more likely to be ignited by the stove burner. That is why fishermen feel a lot safer with Diesel engines in their boats- the likelihood of being caught at sea in a deadly fire is far less than it is with a gas engine on board.

Jim H,

You are comparing apples to oranges when comparing ignition points in the air and inside an engine. The flash point has to do with vaporization of the fuel in still air. Inside the engine, the Diesel fuel is vaporized by the injectors so the air flash point is not important. Diesel fuel actually explodes inside the cylinders more than Gasoline, thus the Diesel knock. Gasoline will also knock if it preignites before the spark if the octane rating in not high enough.

I read the Chevron article, and I can see nothing in it that contradicts any of my previous startements. As Chevron said, the higher the cetane number, the lower the ignition point of the fuel. Since gasoline has a much lower cetane number than Diesel fuel, a Diesel engine will be harded to start on gasoline. This is what the Chevron article related to.

The principel behind using high octane gasoline is to resist preignition in high compression spark ignition engines.

P E H