CSD:Plunger Travel

[Dr. Jones]

The plunger lift is affected by the CSD, but, there is a lot of play in it's total travel (.10 mm) and thats on the top of it's perch. After about a thrid of way down the 'do not remove cable' there is no affect on the plunger. At the bottom of the stroke their is a catch attached to the Injection Pump that holds the CSD arm.

I'm not sure when I'm going to strobe my other car but, hopefully soon I got the parts for it today couldn't get the oil pressure 'sending unit' they had one with a two prong plug in type connecter.

Mine 5-Spd is having trouble starting in the cold (36 degrees F) could this be my CSD?

[asavage]

In reference to an email I sent earlier, where I stated:

I've been slowly chewing away at the Bosch VE IP manual, and I can not state for certain . . .

I just realized the typo I made, a common one for me. That should have read, ". . . I can NOW state for certain . . . ".

. . . that the CSD operates a manual advance eccentric in the pump, moving the timing ring. Unless you know for *certain* how much advance (plunger travel) the CSD provides, the plunger lift you measure isn't going to have a lot of meaning.

More later -- I'll post this info over at my site sometime, with pics and maybe a scan from the book. I took pics of my "spare" IP tonight while down in storage.

The plunger lift is affected by the CSD, but, there is a lot of play in it's total travel (.10 mm) and thats on the top of it's perch. After about a thrid of way down the 'do not remove cable' there is no affect on the plunger. At the bottom of the stroke their is a catch attached to the Injection Pump that holds the CSD arm.

.10mm is about .004", which I don't think of as a lot of play.

The CSD advances the injection timing, but only advances a couple of degrees (from the Bosch VE book, it looks to be in the range of about 5° crank). It props up the advance to a fixed point -- say, for example 10° BTDC -- and the timing stays there, and the normal advance takes over above the point that the hydraulic advance exceeds the CSD advance -- I'm guessing at about 12-1500 RPM. Above that RPM, the CSD has no effect on the timing.

The other thing the CSD does is prop up the idle a bit. Mine's never worked, so I can't comment on it.

Mine 5-Spd is having trouble starting in the cold (36 degrees F) could this be my CSD?

I don't think so, but it's possible. Without being timed to the correct range and having the CSD further advance the cranking injection timing, in theory this could make cold starting more difficult. Just don't resort to starting fluid! No starting fluid if the glow plugs are active!

I always run through the glow plug cycle twice when it's below 40°F outside. It just seems to run nicer that way.

(Snowing but not sticking now)

Joe, what I was getting at in my email is that if the CSD isn't deactivated/rendered inoperative when using the plunger lift method of timing, then what you're measuring could be as much as 5° off, which in the world of diesel is apparently a lot bigger deal than a gasser being off by the same amount -- this last is conjecture on my part from some reading I've been doing recently.

[Dr. Jones]

I set all my IP's with the CSD in the disconnected manner and feel that they are very accurate. By a lot of play I meant that (I'm not sure if it's a one to one ratio) there is not a large range of cable that affects the CSD just when CSD fork is in the engauged position and roughly quarter to a thrid of the way down the cable, you lose any affect the CSD has on the IP. No I agree .10mm is not a lot of play. And when writing that last message I implied that for an automatic is .10mm on CSD, but I not for sure it is. I know thats how much is in the manual trans.

[asavage]

Oh. I had thought that you were not disconnecting the CSD cable when measuring the plunger lift, because your CSD cable was in poor shape. I didn't know that you ended up taking the cable off.

It makes sense, that 2/3 of the total CSD travel does nothing to affect the advance. When cold, the idle is propped and the low-speed timing advanced (in the 0-1500 RPM range). As the engine warms, the idle is gradually dropped, but the timing remains advanced, right up until the engine is well above 120°F or so.

Thanks for clarifying.

(none of the snow here "stuck")