Distributer vacuum tube missing...?
Discussion
Yep, That's the one, got one coming from them tomorrow (Lucas 35D LM8 V8 Distributor Vacuum Unit) but mine wasn't that much.
Checked with my spare dizzy and it should be easy to fit without removing or dismantling it from the car. Remove two screws and slip it off the pin underside the bed plate. Please tell me it's not held on the pin with a retainer, the one on my spare wasn't.
And for it to work correctly I will uncap the stub on the back.
Cheers
Checked with my spare dizzy and it should be easy to fit without removing or dismantling it from the car. Remove two screws and slip it off the pin underside the bed plate. Please tell me it's not held on the pin with a retainer, the one on my spare wasn't.
And for it to work correctly I will uncap the stub on the back.
Cheers
Following on from the original thread I worked on with CoG expert guidance https://www.pistonheads.com/gassing/topic.asp?h=0&... . I've added the results of my new to me TVR Chimaera 400. My previous one now waiting to be shipped to the USA by the new owner.
For the record of other members. TVR number 2. Chimaera 400 with 96k on the clock. New vacuum unit needed so purchased one from powerspark on ebay. They confirmed there version is the same Lucas unit in a plain box and is about £10 cheaper than the one in a Lucas branded box.
Timing at idle 12 degrees NO VAC
Full advance 30 degrees NO VAC.
VAC Connected and the idle timing changes by 14deg so idles in the mid 20's. Remembering that as soon as the throttle is opened the vacuum is lost and the mechanical advance comes into play which under load is limited to a nice safe 30 degrees.
The advance added on this car I find interesting. On my previous 400 HC the full vacuum added just 10 deg at idle, again on a new vac unit. This non-HC engine adds about 14deg. So would TVR had gone to the trouble of using a different distributer set up for the HC? I would have thought the high cam would require more advance than the standard engine? Or is it a case of pot luck regarding TVR in general and the new 'quality' of Lucas cav units? The latter is my suspicion..
Set up like this the car runs smoother, starts better, runs cooler, and on my commute this morning 25 miles on some 30 limits, 60 limits and a majority of Motorway at 75mph the fuel gauge barely moved.
Also to note this Chimaera has really bad diff mounts, and the knocking was considerably reduced during the drive because their was only a hint of shunting rather than the rodeo bull type of shunting it had when I first picked it up. So the timing and subsequent shunting is the death of the diff bushes in my opinion.
For the record of other members. TVR number 2. Chimaera 400 with 96k on the clock. New vacuum unit needed so purchased one from powerspark on ebay. They confirmed there version is the same Lucas unit in a plain box and is about £10 cheaper than the one in a Lucas branded box.
Timing at idle 12 degrees NO VAC
Full advance 30 degrees NO VAC.
VAC Connected and the idle timing changes by 14deg so idles in the mid 20's. Remembering that as soon as the throttle is opened the vacuum is lost and the mechanical advance comes into play which under load is limited to a nice safe 30 degrees.
The advance added on this car I find interesting. On my previous 400 HC the full vacuum added just 10 deg at idle, again on a new vac unit. This non-HC engine adds about 14deg. So would TVR had gone to the trouble of using a different distributer set up for the HC? I would have thought the high cam would require more advance than the standard engine? Or is it a case of pot luck regarding TVR in general and the new 'quality' of Lucas cav units? The latter is my suspicion..
Set up like this the car runs smoother, starts better, runs cooler, and on my commute this morning 25 miles on some 30 limits, 60 limits and a majority of Motorway at 75mph the fuel gauge barely moved.
Also to note this Chimaera has really bad diff mounts, and the knocking was considerably reduced during the drive because their was only a hint of shunting rather than the rodeo bull type of shunting it had when I first picked it up. So the timing and subsequent shunting is the death of the diff bushes in my opinion.
I have a 95 MGRV8, ex Japan that cam to NZ in 1996. It has the CATS removed and was originally still on a White tune resistor which I changed to Green, was a lot better after that, less shunting better idle.
I just tried moving the vac to the manifold (from the port) and followed the other suggestions to setup. When I removed the idle plug (looks like original plug, from new) to reset base idle, I found the base idle all the way in? so no adjustment to bring the base idle down? (base idle seems smoothest around 800)
Appears the ECU/Stepper eventually kick in to bring the idle down.. car takes off well, feels good until you start to slow down, kicks a little if you don't get into a lower gear or dip the clutch quick enough... once stopped, it takes a few seconds for the idle to drop to normal.. on the drive it seems to hover around 1300-1500 rpm when off the gas, once I slow down a little, the above kicks in. The car goes great when you push it, just not so smooth as you slow to a stop?
Conversely, when connected to the port, the issues above disappear? just wondering if Im missing something from what has been suggested, base timing is at 9-10deg, comes up to approx 24-25 when off the manifold
I just tried moving the vac to the manifold (from the port) and followed the other suggestions to setup. When I removed the idle plug (looks like original plug, from new) to reset base idle, I found the base idle all the way in? so no adjustment to bring the base idle down? (base idle seems smoothest around 800)
Appears the ECU/Stepper eventually kick in to bring the idle down.. car takes off well, feels good until you start to slow down, kicks a little if you don't get into a lower gear or dip the clutch quick enough... once stopped, it takes a few seconds for the idle to drop to normal.. on the drive it seems to hover around 1300-1500 rpm when off the gas, once I slow down a little, the above kicks in. The car goes great when you push it, just not so smooth as you slow to a stop?
Conversely, when connected to the port, the issues above disappear? just wondering if Im missing something from what has been suggested, base timing is at 9-10deg, comes up to approx 24-25 when off the manifold
Edited by KiwiRV8 on Saturday 10th February 05:51
24-25 is a little high, high teens is desirable.
If your sure you have no air leaks its got to be too much advance.
Looks like yours is adding a lot more than most, cant answer why.
Its a bit of a juggling act really, you could try tweaking the distributor to gain around 20 at idle but you need to check the all in mechanical timing too.
Having the base idle set correctly is quite important for correct operation too.
If your sure you have no air leaks its got to be too much advance.
Looks like yours is adding a lot more than most, cant answer why.
Its a bit of a juggling act really, you could try tweaking the distributor to gain around 20 at idle but you need to check the all in mechanical timing too.
Having the base idle set correctly is quite important for correct operation too.
Maybe something to do with the setup on the Japanese imports? when I first checked the timing it was around 2-3 deg.. (std 6 deg), in addition the base idle was all the way in..(maybe what they needed to dial in to the Japanese models to run off the manifold).
I guess its possible that on arrival to NZ, someone then changed the vacuum from manifold to port and didn't adjust the timing or the base idle (still had the original plug).. Basically let the ECU and stepper adjust what it could?
I guess its possible that on arrival to NZ, someone then changed the vacuum from manifold to port and didn't adjust the timing or the base idle (still had the original plug).. Basically let the ECU and stepper adjust what it could?
Appreciate your help..
So, I adjusted the timing back to about 2 deg (where it was originally) - adjusted the base Idle down to around 750 (where it was smoothest) connected the vac to manifold and plugged the port. Once connected the idle came up a little (I adjusted the base down slightly) rpm now around 850 and the timing at idle was just on 20 deg - total timing between 32-36 deg at around 3200 rpm.
A lot smoother at these numbers.. I'm assuming it would improve more as the ECU adapts? (remembering that originally the base timing was at 2 deg and the base idle all the way in?)
So, I adjusted the timing back to about 2 deg (where it was originally) - adjusted the base Idle down to around 750 (where it was smoothest) connected the vac to manifold and plugged the port. Once connected the idle came up a little (I adjusted the base down slightly) rpm now around 850 and the timing at idle was just on 20 deg - total timing between 32-36 deg at around 3200 rpm.
A lot smoother at these numbers.. I'm assuming it would improve more as the ECU adapts? (remembering that originally the base timing was at 2 deg and the base idle all the way in?)
I think over the years there have been various initial timing figures for the Range Rover engines but 8 to 12 btdc is about the norm.
I think the distributor adds roughly 18 degrees of mechanical advance so getting to the magic number of 30 degrees can be tricky.
Id prefer to see it closer to 30 to be honest, 36 is a little high.
I think the distributor adds roughly 18 degrees of mechanical advance so getting to the magic number of 30 degrees can be tricky.
Id prefer to see it closer to 30 to be honest, 36 is a little high.
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