Hello
Could anyone please tell me what I should set my ignition timing to on my bog standard Range Rover 3.5 v8 carbed engine please?
It has electronic ignition and the manual says 6 b.t.d.c. but I don't know if that has changed or not with the demise of leaded.
Many thanks and sorry for such a fundamental question.
Ignition timing setting?
Moderator: phpBB2 - Administrators
-
ramon alban
- Knows His Stuff
- Posts: 667
- Joined: Fri Nov 17, 2006 11:22 pm
- Location: Bedford UK
- Contact:
My understanding is that using bog std unleaded the Rover V8 requires ign retard of 4 to 6 degrees from the standard setting.
Thus on my Efi I have it reset from 8 degrees to 2 degrees
There is no pinking under full load and I use low grade unleaded (and it still goes like shove off a shittal).
However if one chooses to use high grade unleaded and/or an octane enhancement additive, the situation would become empirical.
Thus it would be necessary to leave the dizzy clamp slightly relaxed, go for a drive under load and see if there is any pre-ignition. Pull over, adjust by rotation of dizzy until it just disappears and you have the compromise situation of best possible performance without pre-ignition.
Tighten the clamp and the jobs a good'n.
Thus on my Efi I have it reset from 8 degrees to 2 degrees
There is no pinking under full load and I use low grade unleaded (and it still goes like shove off a shittal).
However if one chooses to use high grade unleaded and/or an octane enhancement additive, the situation would become empirical.
Thus it would be necessary to leave the dizzy clamp slightly relaxed, go for a drive under load and see if there is any pre-ignition. Pull over, adjust by rotation of dizzy until it just disappears and you have the compromise situation of best possible performance without pre-ignition.
Tighten the clamp and the jobs a good'n.
A bog stock 3.5 lump will take much more advance that what Rover recommend.
Ideally you need to know what the max advance is that you are dialing in and one way of finding this out is by taking the dizzy off the car and measuring how much the mechanical advance can be turned with a small 360 degree protractor stuck on the end of it. (This figure needs to be doubled to translate it into crank degrees. You should aim to run 36 total and hopefully that also gives you a reasonably high static figure).
I ran my tuned 3.5 with 8 degrees static, 36 total and it ran OK. I then pushed this up to 14 static but still 36 total. (I made some "stoppers" so that I could control the total advance).
There was a huge improvement in the mid range going from 8 to 14, it felt like a good 25 BHP more from 2k RPM up to where the mechanical advance was "all in" (3.5k RPM on my car).
All of the above was with normal unleaded.
I found that the tickover was very poor when the static goes below 8.
To do the whole thing properly whilst sticking with the standard rover dizzy you should first of all check that your timing marks on the damper are correct by using a positive stop on cylinder number one. I cut extra timing marks in my damper all the way up to 40 degrees using a fine junior hacksaw blade. I also run some white paint into each cut.
You should check the mechanical advance springs, all of the ones that I've seen have been pretty knackered! Real Steel do a kit for a tenner. One of the gun metal grey springs and one of the silver springs in the kit will give you max advance around 3-3.5k RPM. You need to be careful not to damage the springs when fitting them!
HTH,
Pete
Ideally you need to know what the max advance is that you are dialing in and one way of finding this out is by taking the dizzy off the car and measuring how much the mechanical advance can be turned with a small 360 degree protractor stuck on the end of it. (This figure needs to be doubled to translate it into crank degrees. You should aim to run 36 total and hopefully that also gives you a reasonably high static figure).
I ran my tuned 3.5 with 8 degrees static, 36 total and it ran OK. I then pushed this up to 14 static but still 36 total. (I made some "stoppers" so that I could control the total advance).
There was a huge improvement in the mid range going from 8 to 14, it felt like a good 25 BHP more from 2k RPM up to where the mechanical advance was "all in" (3.5k RPM on my car).
All of the above was with normal unleaded.
I found that the tickover was very poor when the static goes below 8.
To do the whole thing properly whilst sticking with the standard rover dizzy you should first of all check that your timing marks on the damper are correct by using a positive stop on cylinder number one. I cut extra timing marks in my damper all the way up to 40 degrees using a fine junior hacksaw blade. I also run some white paint into each cut.
You should check the mechanical advance springs, all of the ones that I've seen have been pretty knackered! Real Steel do a kit for a tenner. One of the gun metal grey springs and one of the silver springs in the kit will give you max advance around 3-3.5k RPM. You need to be careful not to damage the springs when fitting them!
HTH,
Pete
