Such a beautiful thing! OM 617 eye candy! - PeachParts Mercedes-Benz Forum

ROLLGUY · #1 05-07-2016, 10:16 PM

Isn't this a beautiful thing! It looks so good (especially with two new valves from Pelican Parts), I don't want to install it!

ROLLGUY · #2 05-07-2016, 10:22 PM

Actually, I can't install it until I get some prechambers and screw plugs. I got the bare head cheap, and a donor head for the valves, but it did not have prechambers, nor could I get the screw plugs out. Anyone have a junk head with these parts I could buy?

mistersooty · #3 05-07-2016, 11:23 PM

Almost too pretty to hide. My new wallpaper.

vstech · #4 05-08-2016, 08:47 AM

I do.

vstech · #5 05-08-2016, 08:48 AM

No idea if the screw plugs will come out though.

ROLLGUY · #6 05-08-2016, 10:48 AM

Quote:

Originally Posted by vstech

No idea if the screw plugs will come out though.

Right now the prechambers are most important, but I can use the adapters (with plugs) that screw in for the heater hose outlet and temp switch (taken from wrecking yard car) until or if I don't find the proper plugs.

ROLLGUY · #7 05-08-2016, 10:49 AM

Quote:

Originally Posted by mistersooty

Almost too pretty to hide. My new wallpaper.

If that is the case, I will try to get a photo with a better background!

BillGrissom · #8 05-09-2016, 02:48 PM

Is there any way to leak check one before you install it? When I had gas engine heads rebuilt, the guy clamps them to a flat plate w/ rubber liner to leak check w/ compressed air, but I doubt he would have a plug for the pre-chamber holes, and installed pre-chambers would stick down so not a flat surface for the plate.

A less-assured shade-tree method is to pour gasoline (or diesel?) into the inverted head bowls and see if it leaks past the closed valves. One would could install the pre-chambers and injectors to block off that hole. There sure isn't much of a bowl in these 20:1 compression ratio heads vs a gas engine head.

ROLLGUY · #9 05-09-2016, 04:09 PM

Quote:

Originally Posted by BillGrissom

Is there any way to leak check one before you install it? When I had gas engine heads rebuilt, the guy clamps them to a flat plate w/ rubber liner to leak check w/ compressed air, but I doubt he would have a plug for the pre-chamber holes, and installed pre-chambers would stick down so not a flat surface for the plate.

A less-assured shade-tree method is to pour gasoline (or diesel?) into the inverted head bowls and see if it leaks past the closed valves. One would could install the pre-chambers and injectors to block off that hole. There sure isn't much of a bowl in these 20:1 compression ratio heads vs a gas engine head.

The machinist magnafluxed the head before machining it. Pressure checking can be done on this type of head, but that process is mostly for aluminum heads (magnaflux does not work on aluminum).

acb70 · #10 05-09-2016, 05:58 PM

Quote:

Originally Posted by ROLLGUY

Actually, I can't install it until I get some prechambers and screw plugs. I got the bare head cheap, and a donor head for the valves, but it did not have prechambers, nor could I get the screw plugs out. Anyone have a junk head with these parts I could buy?

I have a junk head with prechambers and valves intact! PM me

Mike D · #11 05-09-2016, 06:18 PM

I have never had much success with removing the plugs. The only times I did involved a torch and an impact gun. Usually the hex sockets would strip out.

Those are the ones leading into the coolant passages, yes? I'm trying to stir my memory and it seems one is for a GP temperature shut-off, one is for the heated water and depending on the model year, the other two were just plugs.

Don't forget to check for pre-chamber protrusion when you re-assemble the head. Since it appears you have had the head milled it might be a factor. The shims are available through PP.

ROLLGUY · #12 05-09-2016, 10:01 PM

Quote:

Originally Posted by Mike D

I have never had much success with removing the plugs. The only times I did involved a torch and an impact gun. Usually the hex sockets would strip out.

Those are the ones leading into the coolant passages, yes? I'm trying to stir my memory and it seems one is for a GP temperature shut-off, one is for the heated water and depending on the model year, the other two were just plugs.

Don't forget to check for pre-chamber protrusion when you re-assemble the head. Since it appears you have had the head milled it might be a factor. The shims are available through PP.

You are correct, three are plugs (two on the side, one in the rear) and one each for heater hose outlet and temp sensor. I will check PC protrusion, and get the proper seal rings. I hope the stock thickness will still work, as I have five of them on hand. As far as removing the plugs, I may have to just use blank plugs in adapters (harvested from wrecking yard cars).

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