Outer Limits 4x4 Board

I have a couple of questions for the LPG experts out there but first I will give a brief example why I am asking.

About five months ago I blew a head gasket on my 93 4.5L 80 series but the obvious reasons for the blown gasket did not happen first because it was running like a dream in the 12 months I owned it the temp always ran a good level and it never went through a drop of water the only things I found when I took the head off was it had work done on it before I had got it and the exhaust camshaft sub-gear was assembled wrong causing the hole for the service bolt not to line up and the valves were deeply seated into the head causing my valve clearances to be way over spec the only other thing I thought could cause the gasket to blow is a breach in the gas converter and I am about to put things back together and with the head getting a full rebuild leaves only the gas converter to test.

I have called a couple of different mobs to do the test for me some say its an easy process while other have stated they charge by the hour and it could take a few hours to do so I was wondering how difficult it would be to do the test myself.

Q1 how do I find out what kind of converter it is?

Q2 how do I go about doing the test? Do I leave the gas turned off at the tank put everything back together leaving off the gas delivery hose to the manifold block the hole in the manifold and kick the engine over and if there is a breach there would be water getting pushed out the gas delivery hose or is there another way?

Any help on this would be great thanks in advance.

Cheers Mark.

I'm no expert here, but....
I had a 351 on lpg and the converter crapped out so I pulled it apart....inside was like cancer had attacked the alloy, it was a real mess. They generally consist of a series of tunnels between water jackets to warm the gas, and a needle and seat arrangement.

The lpg is quite acidic and attacks the converter surface....Additionally if the previous owners were slack on keeping decent coolant in the system with anti corrosion properties (ie they just ran water in the cooling system) then the water passages may also be corroded to the point whereby they have become porous. As far as I know they are an expendable item with a finite life, a bit like an alloy water pump. Whilst they are generally able to be split with a gasket between mounting surfaces, if the gasket is breached it may be because the gasket surface is also shot.

The testing method you describe may work, you may get water etc coming from the hose that delivers gas to the mixer, but only after the coolant warms.

The converter make and model should be stamped or cast on it, common brands are OHG and Impco, there is a well known Italian make too but can't think of the name.

convertors are pretty cheap, if you suspect it get a new one.