Installing prechamber D318

[oldbeek]

Been messing with this engine for a week. Didn't know I had a later model head on it. Ordering parts and nothing fits. Finally find I have a head that has a larger size prechamber. That story is in the ( for sale/ wanted) topics.Thanks Old Magnet for getting me to the right parts. I install the prechambers without the adapters. Then go to install the Adapter and the valve cover base is in the way. CRAP. Didn't even need the retainer installation tool. Pull the chambers back out. Good thing I did. The proper cat crush washer(5B3265) was to big and even though I tried to center the washer on the head, one only had 1/16 inch of crushed area on 2 of them. The washer is 1.130 id X 1.5 od. The prechamber has a relieved area at the contact area that is .98 dia. The ring can get off to one side as much as .150 and nearly miss the sealing surface. The ring widths only .185. Someone said they liked the Mc Master Carr crush rings better (94397-A001) 1 in x 1.5 X .064. I am going to relieve the ID just enough to get the ring over the threads (1.100). That will get me .030 more contact. Them I am going to center the crush ring on the chamber and use 3 little spots of 2 part epoxy to center up the sloppy fit during installation. All this sloppy fit may be why prechambers leak, and maybe all this works if everything is brand new but we are not working with new.

[Old Magnet]

Sealing washers for the 1S1970 are different than the ones used for the non glow plug chambers. I've lost track of what chamber or chambers your working with.
2S1273 (early) uses the 5B3265 seal
1S1967 (late) uses the 9H4885 seal
1S1970 (glow plug) uses a combination of 9H4885, 9H4883, 9H4882 to index the glow plugs.

[oldbeek]

Getting one new 1s1970 coming. Scratching my head as what the difference the seal ring will be as they are all 1 1/8-12 thread. Thickness? EDIT: 9h4885 and 5b3265 have the identical measurements with 1.64 mm thick. 9h4883 is same with 2.04 mm thick

[oldbeek]

1s1970 came today. I did not get the splined retainer (6f8061) to clear the glow plug because I am not using glow plugs and didn't have the splined tool (8s2243) to install it. Bought a (5h7225) nut 1 1/4 hex. 2ea 5/16-24 set screws in glow plug hole
The 1s1970 does not have a relief below the threads so the standard copper would work great without all the monkey motion to keep it centered. If I valued my time at $.50 an hour, it would have been cheaper to buy all new chambers and retainers for $29.00 ea.
Pressure testing the water system now. Time for a nap. 106 degree outside.

[oldbeek]

More drama on this job. I want everyone to know my mistakes. When pulling the prechambers, they did not clear the valve cover base. It pulled just a little hard. WELL, I broke the aluminum ears off the rear base, on the chamber side. There are eyebrows at the chambers and the chamber is supposed to clear the base. ANYWAY, those eyebrows are going to be ground a little deeper when it goes back together.
Pulling the valve rocker arms and both bases in one piece is a PIA. Even had to pull the pony fuel tank and air intake.

[MetalmanD69U]

Thanks for the info oldbeek.
I am in the process of cleaning and reassembly of the top end on a D318 after an over heat.

[Old Magnet]

Can't explain that one, same rocker boxes on early and late D318's. Plenty of room on my D4's and D6's to clear chambers.

[greghill25]

More drama on this job. I want everyone to know my mistakes. When pulling the prechambers, they did not clear the valve cover base. It pulled just a little hard. WELL, I broke the aluminum ears off the rear base, on the chamber side. There are eyebrows at the chambers and the chamber is supposed to clear the base. ANYWAY, those eyebrows are going to be ground a little deeper when it goes back together.
Pulling the valve rocker arms and both bases in one piece is a PIA. Even had to pull the pony fuel tank and air intake.

Ouch! Hope the broken part is not that bad.

[oldbeek]

Can't explain that one, same rocker boxes on early and late D318's. Plenty of room on my D4's and D6's to clear chambers.

Were the chambers on your D-4 and D-6, 2 1/8 or 2 3/8 dia. like these? When I place a new gasket on these boxes, the box is 3/16 wider than the gasket at the eyebrow area. Maybe these were older boxes on a newer 2 3/8 dia. prechamber heads.

[Old Magnet]

I'm referencing one piece glow plug chambers (2-3/8"). Same rocker box part numbers for 2-1/8 and 2-3/8 chambers??? Change could be the reason, something to watch out for.