Finally tested compression on my 300D - PeachParts Mercedes-Benz Forum

cmac2012 · #1 01-23-2020, 04:26 AM

Quote:

Originally Posted by christuna

looking at you compression numbers I would do this:

- rebuild the injectors
- change glow plugs and ream the carbon out
- valve adjustment

do that and it should improve your cold stating

check your overboost protection system.
check the boost pressure at the ALDA and intake (could be a plugged line)

I haven't yet read about rebuilding injectors. I'll look into it. I have experience with improved injectors (gasser) on my E30. I put in the next-gen injectors, rebuilt professionally, 4 ports instead of one, better atomization - wow, noticeable power increase and it was already fast.

Will have glow plugs in the mail soon. Need to read up on reaming the carbon.

Tonight I looked at the ALDA. I'm embarrassed I didn't notice it sooner. I don't think my mechanic buddy saw it either. The line not clogged but broke:

Don't think I did it while working on the engine. I was never in that vicinity. The banjo bolt is plenty clean. I'll need new line, not going to slide over this fitting.

I have a mighty vac vacuum pump. Is that useful for checking the ALDA? Or is the pressure the wrong way?

Usaguy · #2 01-23-2020, 04:34 AM

Quote:

Originally Posted by cmac2012

I haven't yet read about rebuilding injectors. I'll look into it.

I think greazzer rebuilds them for reasonable money.

Quote:

Originally Posted by cmac2012

Tonight I looked at the ALDA. I'm embarrassed I didn't notice it sooner. I don't think my mechanic buddy saw it either. The line not clogged but broke

that explains your low power problem.

Quote:

Originally Posted by cmac2012

Need to read up on reaming the carbon

you need a reamer that goes into the glow plug hole

cmac2012 · #3 01-24-2020, 04:21 AM

Quote:

Originally Posted by christuna

I think greazzer rebuilds them for reasonable money.

that explains your low power problem.

I likes me the sound of this.

Quote:

Originally Posted by christuna

you need a reamer that goes into the glow plug hole

Does it have the same thread as the glow plugs, sort of like a tap but not as agressive? I've seen the kits you can buy to extract broken glow plugs, it's not that kind of thing is it?

Usaguy · #4 01-24-2020, 08:50 AM

Quote:

Originally Posted by cmac2012

Does it have the same thread as the glow plugs, sort of like a tap but not as agressive? I've seen the kits you can buy to extract broken glow plugs, it's not that kind of thing is it?

link to a om617a reamer (connect mercedes and source together if I try to post it as one word the link gets blocked): https://mercedes source.com/store/heavy-duty-carbon-reamer-pencil-glow-plug-chambers

more on reamers:
https://www.youtube.com/watch?v=bdsojoTJ0p8

cmac2012 · #5 01-24-2020, 11:32 AM

Quote:

Originally Posted by christuna

link to a om617a reamer:

https://mercedes source.com/store/heavy-duty-carbon-reamer-pencil-glow-plug-chambers

more on reamers:
https://www.youtube.com/watch?v=bdsojoTJ0p8

Good stuff. I deleted the part about how to get to the site. Who knows, they don't like to be a platform for a competitor, not that I think they'd search every post.

I've heard of the trouble in getting reamers out. I don't have any Kroll, I have some PB Blaster. Probably wouldn't hurt to spray some on now. I'd hate to need to spring for one of the extractor kits now. IIRC I've read of home made reaming tools.

But yes, I think I'll be getting his reamer and the wrench that goes with it.