M12 compression tester adapter

[signcrafter]

I have a nice snap on compression tester set. I got it used and replaced the gauge and it has a couple adapter hoses in the set. Think they all m14 though. I need to test an engine that has M12 threads. Snap on has an adapter but it's 70 bucks. I guess if that's my only option then so be it. But wondering if there any other options that may work with my snap on gauge? Something I rarely need to use so wasn't looking to spend 70 bucks for one adapter. Other option is to just buy a whole new kit. Haven't looked into it yet as far as what they cost but might be a better option if I have to spend 70 for one adapter.

 

[charbar]

A lot of my adapters are OTC or Lisle brand. Give them a look, I have no idea on cost.

 

[charbar]

Maybe some of the bigger parts stores that have loaner tools would have an adapter or complete kit that you could borrow too.

 

[bwringer]

1) Buy "Pittsburgh" compression tester set from your nearest Harbor Freight for about $30.

2) Harvest adapters.

3) Discard crappy-*** gauge and case.


This is what I did in order to make an "air hold" for replacing some valve stem seals a while back. Worked like a charm. The couplers are standard air fittings, "industrial" I believe.

 

[signcrafter]

1) Buy "Pittsburgh" compression tester set from your nearest Harbor Freight for about $30.

2) Harvest adapters.

3) Discard crappy-*** gauge and case.


This is what I did in order to make an "air hold" for replacing some valve stem seals a while back. Worked like a charm. The couplers are standard air fittings, "industrial" I believe.

I thought about this but some of the reviews for the HF kit aren't so good. When it comes to diagnostic tools I try to buy quality tools to hopefully they dont lead me in the wrong direction. I know it's just a threaded hose but some reviews said the adapter didn't seal to the plug hole. I would have no issue spending the 70 bucks for the snap on one if I saw myself using it more. This is the first time I ran into a M12. The M14 has been all I needed. I just looked at the OTC kit and it only has m14 and m16 so my thought of buying a whole new kit won't work. Didn't look at other kits yet.

 

[cgrutt]

I have the Harbor Freight Maddox kit I just checked online and it says it includes the M12 adapter. I'd mail it to you if you promised to mail it back but I have no clue if the adapter will work with your snapon gauge. I seem to recall all of the adapters are threaded in M14 on the gauge side but id have to pull the gauge out to confirm that. I haven't used this that much but don't recall having any problems with it. Anyway let me know if you want me to send you the M12 adapter. Between mailing, time and compatibility concerns you'd probably be better off just buying the adapter that you need or a new kit that includes one.

 

[bwringer]

The HF Maddox kit is actually pretty skookum, and contains 10, 12, 14, 16 and 18mm adapters. The OP could grab it for under $50 with this weekend's $10 off coupon.

 

[kbeefy]

Can you just cobble one together with some fittings and hose from the parker store?

 

[Ruination Fan]

I use Lisle 20540 adapter along with my Snap-On compression tester and leak down. It works fine and is easy to thread on and off. Price is hard to beat:
Lisle Spark Plug Adapter https://a.co/d/cTYdta2

 

[LXCam]

I'd do what @bwringer suggested Scott. Even if the threads aren't dead nuts on in order to seal against themselves there should be an o-ring between the connection and to the head.

@Ruination Fan nailed it

 

[cgrutt]

I use Lisle 20540 adapter along with my Snap-On compression tester and leak down. It works fine and is easy to thread on and off. Price is hard to beat:
Lisle Spark Plug Adapter https://a.co/d/cTYdta2

Yeah, cheaper than mailing the adapter one way. That is threaded M14 on gauge side as well I'm pretty sure that's how the Maddox adapter works

 

[cgrutt]

Note of caution with the adapters make sure they are on tightly or taped. I had one stay deep inside head one time and come off the hose. That was a major headache.

 

[signcrafter]

I have the Harbor Freight Maddox kit I just checked online and it says it includes the M12 adapter. I'd mail it to you if you promised to mail it back but I have no clue if the adapter will work with your snapon gauge. I seem to recall all of the adapters are threaded in M14 on the gauge side but id have to pull the gauge out to confirm that. I haven't used this that much but don't recall having any problems with it. Anyway let me know if you want me to send you the M12 adapter. Between mailing, time and compatibility concerns you'd probably be better off just buying the adapter that you need or a new kit that includes one.

I really appreciate the offer. Even though I'm crying about the price for something I won't use often I still want to get something to have if I do need it again. Just trying to figure out my best option.

The HF Maddox kit is actually pretty skookum, and contains 10, 12, 14, 16 and 18mm adapters. The OP could grab it for under $50 with this weekend's $10 off coupon.

Thanks for the info.

I use Lisle 20540 adapter along with my Snap-On compression tester and leak down. It works fine and is easy to thread on and off. Price is hard to beat:
Lisle Spark Plug Adapter https://a.co/d/cTYdta2

I saw that adapter but was Leary about it getting stuck deep down in the hole like cgrutt mentions below.

Note of caution with the adapters make sure they are on tightly or taped. I had one stay deep inside head one time and come off the hose. That was a major headache.

 

[cgrutt]

I really appreciate the offer. Even though I'm crying about the price for something I won't use often I still want to get something to have if I do need it again. Just trying to figure out my best option.

Thanks for the info.

I saw that adapter but was Leary about it getting stuck deep down in the hole like cgrutt mentions below.

It happened to me once but just knowing about the possibility is most of the battle. Just make sure adapter is tightly connected is all that's really needed. You could wrap some electric tape around it or use some blue loctite and you shouldn't have a problem. Anyway good luck.

 

[Wrench97]

M12 to M14 adapter.

 

[OccupantRJ]

I made my own when I first started working on Honda motorcycles by removing the guts and spark tang from a spark plug, then welding or soldering on whatever attachment I need to the shell.
I made my own compression gauge setup and leak down tester to use with it. It has a male quick disconnect to attach an air hose also.