LPG in an engine without hardened valveseats?

[OneCarefulOwner]

I'm often tempted by the idea of converting one of my old Allegros to run on LPG, partly for the saving over the remaining life of the car, partly for the difference of it, but mostly because I don't know better. Anyway, I've talked about it elsewhere before & the main thing to look out for that was mentioned at the time was that, as a carb'ed engine, it would need careful regulation so as to avoid a manifold explosion.

I've more recently been exploring LPG as an option on other vehicles, and the manifold thing hasn't been mentioned anywhere in relation to these applications despite some of them also using carbs - but what has been mentioned is increased wear on the valve guides & the unsuitability in some engines not designed/modified to run on unleaded petrol.

Saying I was brave/foolish enough to go down this route, would I need to install a lead-free head to my Allegro, or would using lead replacement additive in the startup fuel be enough to keep things running smoothly?

[TerryG]

I would suggest asking on http://www.lpgforum.co.uk/ to be certain as there is a bloke on there that knows everything there is to know about gas conversions. From memory though you would need to have the head converted.

If you have the mixture and timing right the risk of combustion in the manifold is minimal (i have cured mine completley by advancing my ignition a few degrees further)

[bnicho]

There are a lot of older cars in Aus on LPG which don't have hardened valve seats.

Many of them use a little tank under the bonnet to dispense flashlube or valvemater into the intake manifold via a vacuum takeoff.

We used to be able to buy kits for this in good auto parts stores. Just found one on eBay:

http://www.ebay.com.au/itm/Flashlube-Va ... 1e63aa1f42

Cheers,

[OneCarefulOwner]

Ah, I'd seen something about those kits but only in relation to high-BHP turbocharged engines! Fancy an old A series needing the same tweaks as a turbonutter