Hello all there,
where do you set the timing point of your ignition? The manual says it has to be TDC. My engine is an original Stage One engine, with compression ratio 8,13:1. It was built to run fuel with 91 ROZ. If I run fuel with 95 ROZ or LPG, would it make sense to set ignition point on 7° before TDC?(some Range Rover engines have to be set so). Or could this cause damage to the engine? I think, acceleration and fuel consumption woud become better, but I don`t know wether it is realy so. Can anyone help?
best regards
Horst
Ignition
-
stirlsilver
- Posts: 339
- Joined: Tue Nov 21, 2006 9:45 am
- Location: Wheelers Hill, Victoria, Australia
- Contact:
Since your engine is a low compression engine, you should be able to run a fair amount of advance before it starts pinking.
Because petrol and LPG have different octane ratings you will find that they will need two different timing positions.
In your case, I would set the timing using the fuel that you use most. I think you probably run on lpg 90% of the time? If so, run the engine on LPG and set the timing around 15deg before TDC (with the vacuum advance disconnected). Connect the vacuum up again and take the car for a drive.
Try to feel how it responds, it should be more responsive. Also, listen for pinking. Put the car in 4th gear and from about 1000rpm open the throttle all the way (low rpm and high load on an engine is when it most likely pinks). Also check the top end, get the engine up around 4000-5000 rpm and then again open the throttle all the way and try to listen for pinking.
If the engine pinks you need to retard your timing a bit and take it for another drive. Don't be afraid to experiment with the timing, pinking isn't something that damages an engine quickly. You might find that you can go further than 15deg advance since your engine is low compression and on LPG.
Oh one other thing. After a certain point too much timing advance will cause your engine to loose low RPM torque, but gain power at high RPM, so you just need to find a timing which give you good low torque and high RPM power.
On my engine on LPG and the very high compression, I can get away with about 20 degrees advance.
Because petrol and LPG have different octane ratings you will find that they will need two different timing positions.
In your case, I would set the timing using the fuel that you use most. I think you probably run on lpg 90% of the time? If so, run the engine on LPG and set the timing around 15deg before TDC (with the vacuum advance disconnected). Connect the vacuum up again and take the car for a drive.
Try to feel how it responds, it should be more responsive. Also, listen for pinking. Put the car in 4th gear and from about 1000rpm open the throttle all the way (low rpm and high load on an engine is when it most likely pinks). Also check the top end, get the engine up around 4000-5000 rpm and then again open the throttle all the way and try to listen for pinking.
If the engine pinks you need to retard your timing a bit and take it for another drive. Don't be afraid to experiment with the timing, pinking isn't something that damages an engine quickly. You might find that you can go further than 15deg advance since your engine is low compression and on LPG.
Oh one other thing. After a certain point too much timing advance will cause your engine to loose low RPM torque, but gain power at high RPM, so you just need to find a timing which give you good low torque and high RPM power.
On my engine on LPG and the very high compression, I can get away with about 20 degrees advance.
Stirling
Videos:
http://www.youtube.com/watch?v=a8Xljp6DD9g 17 June
http://www.youtube.com/watch?v=_mlJblv9iUo 24 May
& Others!
Videos:
http://www.youtube.com/watch?v=a8Xljp6DD9g 17 June
http://www.youtube.com/watch?v=_mlJblv9iUo 24 May
& Others!
The low compression engine is intended to be capable of running on poor fuel. Simply changing the octane rating doesn't mean there is a need to change the timing.
If you car is German specification, you will probably find you have emission laws to consider.
If you are running duel fuel (LPG and petrol) and have a conventional distributor, timing will always be a compromise; not ideal for petrol, not ideal for gas. The only way around this is to have variable timing. Usually this is done by fitting an after market programmable ignition kit. The distributor stays in place but one of its functions (advance curve) is taken over by the new electronic box. As these have an alternate curve function, it is wired to the tachometric relay. When you change fuels, it changes timing.
If you car is German specification, you will probably find you have emission laws to consider.
If you are running duel fuel (LPG and petrol) and have a conventional distributor, timing will always be a compromise; not ideal for petrol, not ideal for gas. The only way around this is to have variable timing. Usually this is done by fitting an after market programmable ignition kit. The distributor stays in place but one of its functions (advance curve) is taken over by the new electronic box. As these have an alternate curve function, it is wired to the tachometric relay. When you change fuels, it changes timing.