Racer Al
Stainless
- Joined
- Feb 20, 2006
- Location
- Oakland, California, USA
Hello All --
I've shop-made a leakdown tester, and would like to use the hose and plug adaptor with my compression tester, which has the same quick-disconnect fitting.
The plug is a 10mm x 1 thread, which isn't commonly available at auto stores. It's for a motorcycle, which explains the uncommonly small size. Never mind that it's 4" deep in the valve cover/head.
I'll own up that I haven't tried too hard to locate a commercial solution because, after all, how hard can this be to make, right?
The good news is that my hose/plug adaptor work great with the leakdown tester.
The bad news is that a compression tester needs a one-way valve at the plug adaptor. Typically, it's a schrader valve. I figured I'd just braze a slug of brass into the plug adaptor and thread it for the schrader core.
No dice. I don't have any taps that match the core, or thread more than one or two threads into the valve stem before jamming.
There are only 2 solutions I can think of -- single-point the leeeeetle tiiiiiiny threads (an old PM post said they are 5mm x .7 pitch) which means I would have to buy a special threading tool, or come up with a ready-made thing to use.
Turns out that bicycle tires all have a small brass body inside the rubber stem. I used a knife to cut away the majority of the rubber and a scotchbrite wheel to shine it up. A little drilling, a little filing, little silver-brazing and voila, a schrader valve in the plug adaptor! I'm pretty pleased with myself & thought it was worth sharing. Oh, yeah, and modest, too.
So, does anyone actually know what thread the valve core actually is??
I've shop-made a leakdown tester, and would like to use the hose and plug adaptor with my compression tester, which has the same quick-disconnect fitting.
The plug is a 10mm x 1 thread, which isn't commonly available at auto stores. It's for a motorcycle, which explains the uncommonly small size. Never mind that it's 4" deep in the valve cover/head.
I'll own up that I haven't tried too hard to locate a commercial solution because, after all, how hard can this be to make, right?
The good news is that my hose/plug adaptor work great with the leakdown tester.
The bad news is that a compression tester needs a one-way valve at the plug adaptor. Typically, it's a schrader valve. I figured I'd just braze a slug of brass into the plug adaptor and thread it for the schrader core.
No dice. I don't have any taps that match the core, or thread more than one or two threads into the valve stem before jamming.
There are only 2 solutions I can think of -- single-point the leeeeetle tiiiiiiny threads (an old PM post said they are 5mm x .7 pitch) which means I would have to buy a special threading tool, or come up with a ready-made thing to use.
Turns out that bicycle tires all have a small brass body inside the rubber stem. I used a knife to cut away the majority of the rubber and a scotchbrite wheel to shine it up. A little drilling, a little filing, little silver-brazing and voila, a schrader valve in the plug adaptor! I'm pretty pleased with myself & thought it was worth sharing. Oh, yeah, and modest, too.
So, does anyone actually know what thread the valve core actually is??