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Can engines ping on LPG like it does on low grade unleaded?
http://lpgforum.co.uk/viewtopic.php?f=37&t=4522
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Author:  tempestv8 [ Mon Feb 12, 2007 12:19 pm ]
Post subject:  Can engines ping on LPG like it does on low grade unleaded?

Howdy folks, <BR> <BR>Just wondering whether an engine can ping (premature detonation) on LPG like it can on low octane petrol. <BR> <BR>Anyone got some info for me? <BR> <BR>I have a Land Rover Discovery V8 with vapour sequential injection recently installed.

Author:  MarkJones [ Wed Dec 12, 2007 11:39 pm ]
Post subject: 

very hard to

its a lot higher octane than petrol

you can move the ignition timing more than 8 degrees without trouble

eg from 8 degrees before tdc to 16 degrees.


thats on a conventional distributor equiped car.
all the best.markj

Author:  p38arover [ Sun Apr 27, 2008 8:12 am ]
Post subject:  Re: Can engines ping on LPG like it does on low grade unlead

Lawrance Lee (Tempes wrote:
Howdy folks, <BR> <BR>Just wondering whether an engine can ping (premature detonation) on LPG like it can on low octane petrol. <BR> <BR>Anyone got some info for me? <BR> <BR>I have a Land Rover Discovery V8 with vapour sequential injection recently installed.


Mine does occasionally, Lawrance, and I've got sequential on my P38A.

Ron

Author:  p38arover [ Sun Apr 27, 2008 11:37 pm ]
Post subject: 

Re damaged knock sensors, yes, one of mine disintegrated when I unplugged it. The plastic was so brittle.

However it was replaced before the pinking was noticed.

Mine is Lucas GEMS.

Author:  p38arover [ Mon Apr 28, 2008 1:32 pm ]
Post subject: 

Thanks for the reply Ross.

I'll give it another test tomorrow on both petrol and LPG.

Unleaded Petrol here is about 92 RON which isn't too good with the HC pistons (they came with LC in Australia) so I need to run premium. I'm not sure what it has in it at the moment (I have a 155 litre long range petrol tank so I haven't fuelled up with petrol for months).

I doubt it's a tappet. The engine has less than 8,000km (5,000 miles) on it since a total rebuild - new pistons (HC for LPG), stage 2 cam, bearings, tophat liners, ported and polished heads, de-shrouded valve guides. etc.

It's definitely pinking. I plan to get it "chipped" (actually have a Haltech Interceptor fitted) with dual ignition mapping for petrol/LPG.

Author:  p38arover [ Thu May 01, 2008 7:16 pm ]
Post subject: 

Actually, there is a scarcity of Aussie LPG forums! That's why I'm here. Lots more LR experience here, too. LR sell about as many vehicles (total)in a year as Toyota sell 4WDs in a month here. (Where my daughter lived, the nearest LR dealer was interstate and 1600 km away. The one in the capital in her state was 2500km away.)

The people who built my engine are both LPG installers and LR engine specialists. They knew I was having LPG fitted - in fact they drilled and tapped the inlet manifold ready for the nozzles whilst they wre doing the build.

Anyway, try as I might, I couldn't get the flaming thing to pink on either petrol or LPG. :D

The next time I'm down at their place, I'll ask.

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