Disco V8 Timing on LPG

[murph]

My Disco is playing up, it does not like reving past 2.5 to 3k rpm, it has been gettign hotter than usual as well, friend has said the timing is out, I have to agree it feels like it is, always runs on LPG.
Any ideas what the timing should be set at??

[petergalileo]

I read somewhere on the net that lpg burns slower than petrol and the ignition on a v8 needs to be advanced 8 degrees to compensate.  If you use petrol and lpg advancing it by 4 degrees would be a good compromise wouldn't it ?

Peter

[Range Rover Blues]

LPG does burn slower than petrol, it also has a lower calorific value but it does have an octane rating of 115 as oposed to 95 on unleaded so you can advance the timing on LPG or increase the CR to 11.5:1.

The problem with both scenarios is that the engine will cark on petrol, you have no choice but to run it as a standard petrol lump.  I set mine to 5 deg rather than 6 just to protect it from modern lead free fuels.

The answer is an ignition advance module, I bought mine from Chris Perfect (TBH it's a bit pricey and has given me problems) but others are around for less money.  It advances the timing when the LPG system is on, ours is set to +6 deg and it does give you back some performance.  It's not much more economical though as I've got big feet

[s.stirley]

Yep, found similar .. turned mine up around 4 degrees and it's a lot better mpg on gas now.

However on the original problem I'd not expect you to be seeing that sort of a problem unless your timing is hugely retarded. Mine was about 4 deg from where it should be when I got it and it still ran OK at revs, but hesitated on flooring it. Sounds to me more like you have a fuel delivery problem ? worth checking everything over though. BTW how does it run on petrol currently ?

[murph]

It does not run very well on Petrol in fact the carbs tend to leak a lot, suppose the joints have dried up from LPG usage, put your foot down and it does not go above 3k rpm.

I'm going to ditch the LPG after Xmas as I'm going to start the pick up project, just want to get it running properly for a few paly days between now and then, while check the timing later.

[s.stirley]

It does sound ignition related then .. worth checking the dizzy cap and rotor while you're getting cold outside anyway ! I had a bad cap not long ago, knocked one of the cylinders out totally - couldn't see any damage to it but that was definately the problem.

Also check the vacuum advance pipe to the distributor, had a blockage in mine and it would really bog down when trying to pull away and didn't want to rev very high either.

Cheers

[murph]

Finally got to the bottom of the overheating problem, put it into my local LR specialist.
Problem 1 restricted flow on the gas inlet, wrong size Y peice fitted.
Problem 2 vacuum advance knackered.

Oh not forgetting the MOT ran out and they failed it on body to chassis mount, I let them do it as could not be bothered to do it myself, not enought time.

£100 labour for the above just waiting for the parts bill.

Nice to have it running properly. :lol:  :lol: