L2850 Glow plug adapter

[Selkirk_D]

So my new to me L2850 starts easy, runs good, but it smokes some, whiteish smoke. It has 2500 hours , and the maintenance records show that valve seals and #1 injector were replaced in an attempt to address the issue. No oil loss, no milky oil, and no coolant loss or abnormal system pressurization. I want to run a compression test and I have the kit from Amazon. My question is , what adapter do I need for the V1702 DI engine? Is it 8mmx 1.0 or 10mmx1.25 “short”?

 

[Selkirk_D]

So what worked for me was to take the longest 10mmx1.25 adapter in the kit and chop off about 1/2” so that the reach matches the reach of the glow plugs. I then chucked it up in my drill press and finished the tip with a file and put a small taper on it. Final polish with some 400 grit sandpaper and it works great!

 

[North Idaho Wolfman]

So what worked for me was to take the longest 10mmx1.25 adapter in the kit and chop off about 1/2” so that the reach matches the reach of the glow plugs. I then chucked it up in my drill press and finished the tip with a file and put a small taper on it. Final polish with some 400 grit sandpaper and it works great!

That engine and other in its class are the hardest to do compression tests on because of the odd Glow plugs and the Odd pencil Injectors.

You sound like you got pretty good results.
The problem with that glow plug adapter is it doesn't have a sealing surface on the top of the threads like the glow plugs, so your results can be off if the threads don't seal.

 

[Selkirk_D]

The glow plugs have a slight taper near the end to aid sealing. I attempted to duplicate that taper with the file and drill press ( my hillbilly lathe LoL). Really love the fact that you have to pull the lines and intake just to do a compression test. Reminds me of working on my sister’s ‘75 Honda Civic. Everything was a PITA!

 

[North Idaho Wolfman]

They seal at the green arrow not the red arrow.

 

[Selkirk_D]

They seal at the green arrow not the red arrow.
View attachment 151328

Yes but the end of the adapter does bottom in the glow plug hole. Not sure how well it seals, but the taper should help

 

[Russell King]

They seal at the green arrow not the red arrow.
View attachment 151328

@North Idaho Wolfman
Could he use a nut and a flat crush washer to seal it on the adapter?

I guess there might be a tapered washer (ferrule from compression fitting?) that could work but I would be afraid of getting it stuck in the hole.

 

[North Idaho Wolfman]

@Russell King yes that would work!

 

[North Idaho Wolfman]

Yes but the end of the adapter does bottom in the glow plug hole. Not sure how well it seals, but the taper should help

Pipe dope on the threads would help too.
Or better yet as Russell pointed to, a nut with a taper on the face would be great.

 

[Selkirk_D]

@North Idaho Wolfman
Could he use a nut and a flat crush washer to seal it on the adapter?

I guess there might be a tapered washer (ferrule from compression fitting?) that could work but I would be afraid of getting it stuck in the hole.

Good idea! Or even a nut with an o-ring

 

[North Idaho Wolfman]

Good idea! Or even a nut with an o-ring

O-rings like that will get swished out, use a copper washer.