vacuum advance missing
Discussion
Whilst checking my cold idle problem i checked the vacuum pipe on the top of the plenum - this was crakced - followed the think pipe and it was not connected to anything - indeed it looked like it never has been.
Looked on the distributor and can see the screw and a hole where the vacuum advance should be - but there isn't one there.
I have owned the car from new in 1995 (serp engine) - i never removed it.
Any ideas? - should i get one and fit it? If not should i cover the hole in the distributor>
Looked on the distributor and can see the screw and a hole where the vacuum advance should be - but there isn't one there.
I have owned the car from new in 1995 (serp engine) - i never removed it.
Any ideas? - should i get one and fit it? If not should i cover the hole in the distributor>
hope the pipe fix is an easy one.(ACT manifolds aside) why anyone would delete the vac advance intentionally is beyond me.
It's there to improve economy at high levels of manifold depression, IE small throttle openings & highish engine speeds.
It only operates under such conditions, as such it has no negative benefits, it can only do one thing & that's improve fuel economy.
The only possible reason for deleting it would be on an engine that operates exclusively at wide open throttle, say a race engine.
And only because in such an environment you will never come into operation, not because it damages the performance of said race engine.
The vacuum advance module is there for a reason, if it wasn't of benefit Lucas wouldn't have wasted money fitting it.
The vac advance is actually in effect the nearest thing you have to three dimensional ignition timing control on these cars.
So, like I say, & with all this in mind, it completely baffles me why anyone would choose to delete it on a road car.
I can only assume they don't understand how the system works.
Put simply, if your vac advance module is inoperative, it needs replacing.
And if the OP talks to someone like "The Distributor Doctor" he should find a replacement needn't be costly at all.
It's there to improve economy at high levels of manifold depression, IE small throttle openings & highish engine speeds.
It only operates under such conditions, as such it has no negative benefits, it can only do one thing & that's improve fuel economy.
The only possible reason for deleting it would be on an engine that operates exclusively at wide open throttle, say a race engine.
And only because in such an environment you will never come into operation, not because it damages the performance of said race engine.
The vacuum advance module is there for a reason, if it wasn't of benefit Lucas wouldn't have wasted money fitting it.
The vac advance is actually in effect the nearest thing you have to three dimensional ignition timing control on these cars.
So, like I say, & with all this in mind, it completely baffles me why anyone would choose to delete it on a road car.
I can only assume they don't understand how the system works.
Put simply, if your vac advance module is inoperative, it needs replacing.
And if the OP talks to someone like "The Distributor Doctor" he should find a replacement needn't be costly at all.
ChimpOnGas said:
(ACT manifolds aside) why anyone would delete the vac advance intentionally is beyond me.
It's there to improve economy at high levels of manifold depression, IE small throttle openings & highish engine speeds.
It only operates under such conditions, as such it has no negative benefits, it can only do one thing & that's improve fuel economy.
The only possible reason for deleting it would be on an engine that operates exclusively at wide open throttle, say a race engine.
And only because in such an environment you will never come into operation, not because it damages the performance of said race engine.
The vacuum advance module is there for a reason, if it wasn't of benefit Lucas wouldn't have wasted money fitting it.
The vac advance is actually in effect the nearest thing you have to three dimensional ignition timing control on these cars.
So, like I say, & with all this in mind, it completely baffles me why anyone would choose to delete it on a road car.
I can only assume they don't understand how the system works.
Put simply, if your vac advance module is inoperative, it needs replacing.
And if the OP talks to someone like "The Distributor Doctor" he should find a replacement needn't be costly at all.
I guess act, mark Adams must be mis informed. I guess a 2.5 ton range rover might benefit from a few mpg gain. Having had a rangie and TVR for many years, the mpg in the griff is hardly important. Also I would say running without vac advance for the TVR improves "shunting" at low revs. It's there to improve economy at high levels of manifold depression, IE small throttle openings & highish engine speeds.
It only operates under such conditions, as such it has no negative benefits, it can only do one thing & that's improve fuel economy.
The only possible reason for deleting it would be on an engine that operates exclusively at wide open throttle, say a race engine.
And only because in such an environment you will never come into operation, not because it damages the performance of said race engine.
The vacuum advance module is there for a reason, if it wasn't of benefit Lucas wouldn't have wasted money fitting it.
The vac advance is actually in effect the nearest thing you have to three dimensional ignition timing control on these cars.
So, like I say, & with all this in mind, it completely baffles me why anyone would choose to delete it on a road car.
I can only assume they don't understand how the system works.
Put simply, if your vac advance module is inoperative, it needs replacing.
And if the OP talks to someone like "The Distributor Doctor" he should find a replacement needn't be costly at all.
David Beer said:
I guess act, mark Adams must be mis informed. I guess a 2.5 ton range rover might benefit from a few mpg gain. Having had a rangie and TVR for many years, the mpg in the griff is hardly important. Also I would say running without vac advance for the TVR improves "shunting" at low revs.
Well I can tell you a few stories about Mr Adams 
And maybe ACT assume if you invested in one of their systems you would have already had the good sense to delete the distributor for something more modern.
Like I say, the vac advance can do do harm, only give you a few extra mpg, that's why TVR never deleted it.
ChimpOnGas said:
David Beer said:
I guess act, mark Adams must be mis informed. I guess a 2.5 ton range rover might benefit from a few mpg gain. Having had a rangie and TVR for many years, the mpg in the griff is hardly important. Also I would say running without vac advance for the TVR improves "shunting" at low revs.
Well I can tell you a few stories about Mr Adams And maybe ACT assume if you invested in one of their systems you would have already had the good sense to delete the distributor for something more modern.
Like I say, the vac advance can do do harm, only give you a few extra mpg, that's why TVR never deleted it.
The one thing I did notice is a slight hesitation on full throttle.
ChimpOnGas said:
David Beer said:
I guess act, mark Adams must be mis informed. I guess a 2.5 ton range rover might benefit from a few mpg gain. Having had a rangie and TVR for many years, the mpg in the griff is hardly important. Also I would say running without vac advance for the TVR improves "shunting" at low revs.
Well I can tell you a few stories about Mr Adams And maybe ACT assume if you invested in one of their systems you would have already had the good sense to delete the distributor for something more modern.
Like I say, the vac advance can do do harm, only give you a few extra mpg, that's why TVR never deleted it.
especially in your car on the rollers .
£100 asleep sounds like a good job ..Edited by SILICONEKID350HP on Saturday 23 March 21:35
I thought that the vac advance allows for dynamic timing adjustment.
Without it TVR tended to set the timing so that they were a bit lumpy at low revs, and they were set for "high" rev power where they smoothed out.
The vac advance gives a smoother idle, possibly at the expense of top end power.
Without it TVR tended to set the timing so that they were a bit lumpy at low revs, and they were set for "high" rev power where they smoothed out.
The vac advance gives a smoother idle, possibly at the expense of top end power.
JPW231 said:
I thought that the vac advance allows for dynamic timing adjustment.
Without it TVR tended to set the timing so that they were a bit lumpy at low revs, and they were set for "high" rev power where they smoothed out.
The vac advance gives a smoother idle, possibly at the expense of top end power.
No. At idle the vac advance wont be coming into play at all. Its the wrong side of the throttle plate. As Chimpongas says it activates at small throttle openings, ie light load cruising. That one way valve thingy in the line is there to stop any advancing spikes when you suddenly open the throttle.Without it TVR tended to set the timing so that they were a bit lumpy at low revs, and they were set for "high" rev power where they smoothed out.
The vac advance gives a smoother idle, possibly at the expense of top end power.
Hi. Yes i have owned the car for coming on 18 years. Never had much trouble with it. It now has 110,000 miles and i am giving it a good refresh.
I certainly never removed the vacuum advance unit - in fact the last time it was ever touched by a TVR garage (or anyone other than me) would have been in 1998 (i then forgot about it under a cover in the garage for 5 years).
So i guess what i am hearing is that i should buy a unit and fit it and see what happens?
I certainly never removed the vacuum advance unit - in fact the last time it was ever touched by a TVR garage (or anyone other than me) would have been in 1998 (i then forgot about it under a cover in the garage for 5 years).
So i guess what i am hearing is that i should buy a unit and fit it and see what happens?
carsy said:
No. At idle the vac advance wont be coming into play at all. Its the wrong side of the throttle plate. As Chimpongas says it activates at small throttle openings, ie light load cruising. That one way valve thingy in the line is there to stop any advancing spikes when you suddenly open the throttle.
I agree - as I say when RV8s do not have vac advance TVR tended to set the timing for higher revs (when the vac advance comes in - under load and dynamic timing). As there is more vacuum created in the inlet manifold, the valve in the vac advance unit advances the ignitIon timing.Gassing Station | Chimaera | Top of Page | What's New | My Stuff