MEP-003 Glow Plug Question

[Nitrodiver]

Has anyone ever accurately measured the angle (+/- 1 degree). Of the sealing surface on glow plugs? The angled part of the glow plug body that seals on the copper washer. Or does anyone have the ability to accurately measure it in degrees? My attempt to measure 4 different glow plugs returned 4 different numbers. I’d like to be more precise than an average. I need to ck compression and removing a glow plug to do so is much easier than breaking down the fuel system to remove the injectors. That adapter is also easier to make. Knowing the correct degree will allow me to machine an adapter that will properly seal. Yet also allow the glow plugs to reseal properly after testing. Proper sealing would be helpful for leak down testing as well.
Thanks in advance

 

[Chainbreaker]

There is a dimensioned drawing somewhere that I have seen before. I did a quick search on my computer for it and came up empty. If you have the P/N handy, do a Google search for something like... Glow Plug Dimensions P/N XXXXXXXX and see what comes up.

 

[Nitrodiver]

I actually spent a couple of hours looking for a dimensional drawing both here and on the net. Best I could come up with were Champion glow plug specs from their site. Like you I want to say I’ve seen a dimensional drawing. But I don’t recall where and if the sealing angle degrees were listed as part of it. I figured if that info is out there someone here is bound to have that drawing/information.

I appreciate you taking time to reply. Search continues….

 

[Light in the Dark]

You probably got 4 different measurements, because this plugs tolerance was not that great. Thats probably why they have the copper sealing washer... takes up the difference in manufacturing tolerances (and probably thermal cycling changes too). How varied were your 4 measurements?

 

[Nitrodiver]

You probably got 4 different measurements, because this plugs tolerance was not that great. Thats probably why they have the copper sealing washer... takes up the difference in manufacturing tolerances (and probably thermal cycling changes too). How varied were your 4 measurements?

I have no doubt you are spot on.
10 degree variation. Which seem like a lot to me for a manufacturer’s tolerance.
I may have figured out a work around, testing it will prove/disprove my theory. After the fact perhaps I’ll have some info I can contribute.
I appreciate the input gents.

 

[glcaines]

I think you are over-thinking this. I agree that removing the glow plugs is the way to go, but why worry about the angle of your adapter for sealing? Why not simply wrap the threads with teflon tape to do your compression test. You aren't running the engine, only spinning it with the starter. The teflon tape should be sufficient to seal good enough for the compression test and a leak-down test. I've done this many times in the past. Make sure all glow plugs are removed when you spin the engine.

 

[Guyfang]

My thoughts also. But what ever spins your wheels!

 

[Chainbreaker]

Also, something to be aware of... sometimes the copper washers do not come out with the glow plug. I had to take one of those metal paint can openers (church key type on opposite end) & file down the hook end to fit & used it to hook & remove old washer. IIRC, some people have encountered situations with 2 copper washers coming out with glow plug.

If GP tips are swollen very much, its best to replace glow plug & washer when you have it out. Swollen GP tips can pose a real problem down the road with getting them out or breaking off tips when trying to remove, potentially doing damage to head/cylinder if broken tips not retrieved/removed before restarting.

 

[Nitrodiver]

I think you are over-thinking this. I agree that removing the glow plugs is the way to go, but why worry about the angle of your adapter for sealing? Why not simply wrap the threads with teflon tape to do your compression test. You aren't running the engine, only spinning it with the starter. The teflon tape should be sufficient to seal good enough for the compression test and a leak-down test. I've done this many times in the past. Make sure all glow plugs are removed when you spin the engine.

You know that’s not the first time I’ve heard that.
If you think Teflon tape is sufficient enough for a leak down test I’m certainly willing to give it a try.
I do try to open all the cylinders except the one I am testing if I can. How long do you hold a leak down test?

If it’s not the IP, I’ve likely got piston/ring issues. Since it’s mostly free testing the cylinders, hopefully that will tell me what to remove from the equation. Before I get into $ of inj pump work. With over 5K hrs on this set. Testing cylinders wouldn’t hurt.