1st of all where is it easier to check the compression the injector hole or the glow plug hole? If I pull the injectors out are there any washers that should be replaced? Is there any one on the site that could test them and rebuild them or is it best to just buy rebuilt? I think I heard monark was a brand. If there is any one close to me in N. W. IN. I would really like to get together to check them and also do a compression check on the motor so I get a better idea of condition of motor. It is the 617 in an 85 300 SD.

Greazzer is Da Man on rebuilding these - he's here on the Forum so just search for his name and PM him. He uses Monarch nozzles. I have a set of his in my 617 and though I haven't fired the engine yet they looked great. Yes, you'll need a new set of seals - they're sort of a thick, hard washer. Pretty cheap from Pelican. I bought 2 sets just in case I need them and the shipping was about the same - not a major investment.

My Harbor Freight compression tester accesses thru the glow plug holes. I'd think that the hole you would use would be determined by the compression tester you have access to but the ones I've heard about all use the glow plug hole.

Dan

I would recommend using the injector adapter for your compressing tester. Yes, Greazzer is the one that well known around here for injector service. Top Class!

The washers can be purchased over the counter at carquest auto part stores with maybe a couple days ordering time at most. Maybe in stock if it is a good one. If you want to just remove the injectors to test the compression.

I't would be one of those jobs where there would be a few "while you're in theres" to add onto.

Are you planning on keeping and driving this car for sometime?
Do you have the ability to be without the use of this car for sometime?

Read up on and perform the compression test, leakdown test, and chain stretch test.

You would actually need to make sure the valve lash is set properly before you do a compression test. If you can get a good idea of the general health of the engine you could just go ahead and knock out a good bit of service all in one swoop.

Injectors serviced
Check/Renew Glow Plugs
Ream out GP carbon
Valve last adjustment is super easy to do with the injectors out. Wont even need the special wrenches.
Drip time the Injection pump
New valve cover gasket

Button it all back up and ride on!

__________________
Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

Why do you feel the need to rebuild the injectors? What are the problem symptoms you are having?

Checking compression is not a bad idea since it is not destructive, takes only an hour or two and can give you a glimpse into the health of the engine. You will want to do it through the injector holes, though. I can't fathom how people get a compression tester in the #5 GP hole...baffles my mind. You can use the old heat shields for the compression test. Be sure to replace the heat shields and clean the prechamber seats before re-installing the injectors. While they are out, you might as well have them pop tested.

__________________
1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge

The "heat shield" and the washer sort of things that I mentioned. When I hear "heat shield" I think of a sheet metal sort of thing but that's not the case here. By all accounts you MUST replace them before you head down the road. I agree that the old ones should be OK for the compression test.

As far as access - mine is in an S-10 pickup and I have TONS of room so I can't relate to what it's like in a M-B chassis. I'm sure the guys are right, though.

Dan

If you have the stock oil filter housing on your engine, it is a PITA to get #5 glow plug out never mind a compression tester fitting in there.

__________________
1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge

Greazzer is the mann! He did a set for me and
I put before Christmas and what a difference more power,smother idle and did I mention more power?

greazer2b