TB42 Head Problems on Gas

[MARKx4]

I am considering on putting my GQ onto a dual fuel set up, i am concerined with all the stories you hear about them doing there heads in after a while and the cost to repair it.

What i want to know is, is this problem caused by the extra engine temps involved with gas or changing between the 2 fuels?

If it is a heat problem could you use replace the radiator with a deisel on or a PWR radiator to cool down the extra engine temps and maybe also look at putting a higher flowing water pump be it a mechanical pump or a electrical pump.

Or would it be best to put it on straight gas? My only concern with this is the avalabilty of gas when traveling between states and on trips.

Your thoughts and experence on this would be greatly appricated.

[danman-gq]

Go gas and never look back - heaps cheaper running. i have had my GQ on gas / dual fuel for 2 years now with no probs. It is my understanding that most head problems occur from lack of coolant / servicing. my temp gauge always sits just below the half way mark, even when off roading with the a/c on (yes im soft). i also now have extractors and 2.5 inch stainless exhaust. i found this helped with economy. i can get 450 k's to tank 85l with mix of city / highway driving (possibly more if took real notice) and care driving.

Personally i would not go straight gas even though it would possibly run better. Keep the petrol for those times you are away. i drive out to landcruiser park on gas and have fun till its runs out then i still have the petrol and jerry can so it give me plenty of k's driving to the nearest fuel stop.

I did think the gas guys replaced the sparks with a different heat range to compinsate for the temps. Hope you find this helpful.

[PGS 4WD]

In breif as this has been covered before, LPG burns slightly hotter (and slower at low RPM). This causes the exhaust valve temperatures to be higher which can result in exhaust valve and seat burning. The ways to remedy this are.

Adjust your valves regularly (the extra heat means the exhaust valve grows longer and the heat cannot dissapate to the seat as efficiently, tight tappets reduce the time on the seat and leads to rapid wear.)

Run the correct mixtures, lean mixtures burn hot, rapid wear a result.

Use premium when on petrol and optimize the timing to suit(on a dyno) as advanced timing reduces exhaust temperature as combustion starts earlier and is more comletely burnt when exiting the exhaust port. Do this with care as detonation causes rapid damage.

Joel

[BoostinMav]

Gas is a bit similar to diesel, rich mixtures burn hotter.... not lean.