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Old 01-25-2019, 12:24 PM
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gmog220d gmog220d is offline
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Quote:
Originally Posted by NZScott View Post
Running lean in a diesel means running cooler temps, its the opposite of a petrol engine (unless its running lean of peak)
With respect, the statement assumes the IP governor has not been putzed with. As I understand it, with pneumatically governed IPs, altering the position of the diaphragm/fuel rack by changing tension of the governor spring results in a change in fuel delivered in relation to the amount of air coming through the intake. In my case the bias was lean.


Quote:
Originally Posted by NZScott View Post
The prechambers changed during a few years for emissions reasons I believe, then changed back (I think, don't really know) so that will be why there is a difference. It's not a heat shield
I only know what I've seen with my own eyes.

My '74 240D came to me with with all four of the pre-chambers having that steel disc in them, and no removable heat shields like we are familiar with. I drove it for a while before getting into the injection system. When I did get around to removing the injectors I noticed the lack of removable heat shield and also noticed that the nozzles sealed up against those discs just fine, no signs of compression leakage. Still, I swapped in the set of "MADE IN GERMANY" chambers I had on the shelf so I could use the removable heat shields as usual.

I also pulled injectors and pre-chambers from a U-Pull engine that had these steel discs in them. The injectors were installed using the usual removable heat shields on top of the steel discs. After pulling the injectors I found excess carbon in the space between the nozzles and chambers. The removable heat shields had to be dug out of the carbon mess. Seemed to me they weren't sealing very well when used in conjunction with the riveted in steel discs.

I can't be the only fellow to have stumbled onto these oddball S&K pre-chambers . . .
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