What mods needed to run 3.5 on lpg

[pete]

What engine mods will I need to do to my 3.5 to run on lpg? The motor is bog stock with a holley on it but I want to put fuel injection on it so I can run a altronics computer with duel maps on it. My questions are will I need to mod the heads or cam or any other engine mods also what rover injection system would be best suited as there are a few different systems.The car is a stage1 ute and I definitley want to be a to run on duel fuel.
Thanks Pete

[JDNSW]

As I understand it all Rover V8s can run on LPG with no internal modifications. But I can't comment on merits of different fuel injection systems etc.

John

[Lotz-A-Landies]

What engine mods will I need to do to my 3.5 to run on lpg? The motor is bog stock with a holley on it but I want to put fuel injection on it so I can run a altronics computer with duel maps on it. ... ... The car is a stage1 ute and I definitley want to be a to run on duel fuel.
Thanks Pete
Pete
These are questions you should ask the LPG fitter, go an see Carl Hendrickson at Greenlight Car Care in Thornleigh, he is a Range Rover enthusiast and also fitted the LPG to my RR classic. Carl suggests that there should be dual mapping on the engine management with a different setting for the LPG over petrol, talk to him about your options.

My car originally was a carby 3.5 but subsequently changed to fuel injection 4.6. Don't get the early Lucas fuel injection get the later type.

The conversion to fuel injection was done by Graeme Cooper Automotive and uses a Motec engine management.

Diana

[loanrangie]

Rover V8 will happily run lpg with no mods just make sure you ignition system is up to scratch. The holley is the easiest to run with lpg as you can just use any impco system off a holden/ford/val, efi is only a plus if you intend runing on petrol a lot. I have converted 2 rangies using the same impco system and found i rarely used petrol unless touring. If your ecu does dual iginiton maps then that would be of most benefit but generally only the more upmarket ecu's do this.

[dungarover]

Rangies run well on LPG but I'm personally not an LPG fan. Just need to find someomne who know's what there doing because there's a lot of cowboys out there :eek::eek:

This is why I believe that gas is for BBQ's :D:D:D:D

Trav

[Tank]

What engine mods will I need to do to my 3.5 to run on lpg? The motor is bog stock with a holley on it but I want to put fuel injection on it so I can run a altronics computer with duel maps on it. My questions are will I need to mod the heads or cam or any other engine mods also what rover injection system would be best suited as there are a few different systems.The car is a stage1 ute and I definitley want to be a to run on duel fuel.
Thanks Pete
If the engine was designed to run on ULP it should have the appropriate Valves and Valve seats, if not it is advisable to have hardened Valves and seats fitted, if you are fitting an aftermarket ECU/Chip get the installer to set up 2 ignition maps, one for petrol, one for LPG, and Higher compression would'nt hurt. Ignition timing for both fuels should eliminate most of the downside of LPG, because if you're running LPG on Petrol Timing/Advance then you are compromising LPG performance, Regards Frank.

[djam1]

To answer your question if you tune it accordingly it will be fine
What engine has it got in it? while Rover V8s will run on LPG very well if it is the 8.13:1 and someone has replaced the tin head gastkets with composite ones neither the performance nor economy will be startling.
I went from a 8.13:1 to a 9.35:1 and on LPG the difference was really noticeable.

[loanrangie]

Rover V8's have hardened valve seat inserts already so no mods are needed, if you have lots of cash you can fit SS valves but not really economical.

[pete]

Is there any way I can tell what engine I have, ie compression ratio ect and so forth and what are the best ones? As far as I know my 3.5 is the standard stage1 engine with a holley on it.
Thanks Pete

[Disco300Tdi]

Is there any way I can tell what engine I have, ie compression ratio ect and so forth and what are the best ones? As far as I know my 3.5 is the standard stage1 engine with a holley on it.
Thanks Pete

I know it is the prefix or suffix of your engine number that tells you which one it is

Sorry I cant remember....:o

[Utemad]

If it is the same as the 3.9 then on the passenger side of the block below the exhaust manifold towards the front/middle the compression ratio and engine number is stamped on a machined flat bit.

However on mine it is obstructed by the exhaust manifold however you should be able to see enough to figure it out.

[Bulldog]

If it is the same as the 3.9 then on the passenger side of the block below the exhaust manifold towards the front/middle the compression ratio and engine number is stamped on a machined flat bit.

However on mine it is obstructed by the exhaust manifold however you should be able to see enough to figure it out.

Yep. On the 3.5L it's there too. Right above or below the engine number if i remember correctly.

Does anyone know the proper ignition advance for gas on a 3.5L, without compromising for petrol?

[Utemad]

Does anyone know the proper ignition advance for gas on a 3.5L, without compromising for petrol?

I just had LPG fitted to my 3.9 and the guy said he times for 10 deg BTDC. It runs fine on ULP and LPG. I'll fiddle with it and maybe time it for PULP and LPG after the first check up.

[PLR]

Is there any way I can tell what engine I have, ie compression ratio ect and so forth and what are the best ones? As far as I know my 3.5 is the standard stage1 engine with a holley on it.
Thanks Pete

G`day Pete

Where the dip stick is on the flat surface

The #s closest the cylinders or top #s is the compression ratio .

The first 3 in the engine # or prefix will tell what the engine is where it`s from ( vehicle ) and the ratio ?

If you can`t see the stamped ratio post the prefix and i`ll tell you if i have them .

Earlier 3.5s will run lpg ok but not as long as later 3.5s and early or late the prefix will tell .

The early had smaller valves and different materials than later .

Cheers

[Tank]

Yep. On the 3.5L it's there too. Right above or below the engine number if i remember correctly.

Does anyone know the proper ignition advance for gas on a 3.5L, without compromising for petrol?
Bulldog, did you time your engine correctly (as per other post), I hope you did'nt put the dissy in with the crank at 6 degrees, Regards Frank.

[loanrangie]

I just had LPG fitted to my 3.9 and the guy said he times for 10 deg BTDC. It runs fine on ULP and LPG. I'll fiddle with it and maybe time it for PULP and LPG after the first check up.

10 degree's is a good compromise, i was running 12 on my rangie but backed it off if i was using petrol alot.

[Utemad]

10 degree's is a good compromise, i was running 12 on my rangie but backed it off if i was using petrol alot.

When I first got my Disco it was running 12 deg BTDC (according to the timing mark) and it ran ok on ULP. Maybe I should just bump it up to 12 and see how it goes.

What is the ideal timing for LPG?
I have read that LPG requires more initial but less overall advance. I guess you can't achieve that without a twin map module.

[loanrangie]

When I first got my Disco it was running 12 deg BTDC (according to the timing mark) and it ran ok on ULP. Maybe I should just bump it up to 12 and see how it goes.

What is the ideal timing for LPG?
I have read that LPG requires more initial but less overall advance. I guess you can't achieve that without a twin map module.

About 12- 14 for lpg, advance it 1 deg at a time and then rev it till it pops and then back it off, a test run under load will let you know if its happy or not.

[djam1]

With a Rover V8 you may be wise not to take too much notice of the actual timing mark and tune it by ear.
The reason I say this is because Rover timing marks are often completely innacurate and this situation gets even worse with an old engine that has a stuffed timing chain.
I run mine at about 12 degrees and it seems fine on both LPG and Petrol this may not be the same for all engines though.
With LPG you are much better off with Electronic ignition (don't skimp on the leads either) as it will be less labour intensive than the standard points system I used the Electronic system from a 1994-1999 Discovery that I bought from Triumph Rover Spares in Adelaide and its the best thing I did.