Fuel vapourisation... A problem when new?!

Seeing as this is quite a 'hot topic' right now I'd be interested to know if the dreaded V8 vapourlock was occuring in our beloved beasts when they were new...? I only ask as it seems strange that for some of us this is happening now and if it was not an issue when the car was new what has occured over the last 30-40 years to make it occur now...?! If anybody knows the answer to this question please let us all know as I for one would be fascinated to know if this was something that affected our cars when they were brand-spankers...!!! I cannot imagine this was the case but, of course, I could be very wrong indeed...!
 
When they were "Brand New" I don't ever remember curing the problems under warranty, but when they were new they hadn't had the chance to develop the problems that cause it. I certainly remember curing them in the late '70's and right through the '80's, but as I've said many times before I never had to resort to fitting an electric pump to do it. The only difference between then and now is the quality of petrol.
 
As Harvey says, and has been said before, it's usually down to things being worn, blocked or not properly maintained. I'm only speaking for the UK to be fair, and we used to service and maintain plenty of P5Bs and P6Bs when they were dailys for everyone, rather than freaks like me who choose to still drive 'em every day :LOL: :)
We used to talk most of them round to fixing the culprit and only having the leccy fan to save fuel, give quicker warm up and reduce noise :wink:
 
harveyp6 said:
The only difference between then and now is the quality of petrol.

Yes, you are right when unleaded first came out I noticed that when I got it on my hands it was noticeably colder
than 4 star and so must be evaporating quicker. Hence easier vapour lock.
 
Talked to a previous owner of my car and he reported fuel vapour problems climbing steep hills, this would have been in the early 80's well prior to fuel changes, I did not experience these problems till the mid 90's when fuel did change.

Graeme
 
As I mentioned before, the only time mine suffered varourisation problems was on one brief occassion in Summer of 1986 and then again during 1990 and 1991 through all months and all conditions, totally independent of both ambient and engine temperature. On each of these occassions the fuel was full leaded. Since that time the problem has never returned, and with unleaded fuel as I use now,..not a problem no matter how hot it has been.

Ron.
 
ghce said:
Talked to a previous owner of my car and he reported fuel vapour problems climbing steep hills, this would have been in the early 80's well prior to fuel changes, I did not experience these problems till the mid 90's when fuel did change.

Graeme

Problems with fuel delivery on steep hills is more down to mechanical fuel pump problems than vapourisation.

The petrol tank sits very high in the car and not far off level with the Carbs - so pumping requirements are minimal on the flat, a weak diaphram, sticking/worn none return valve and yes on steep hills you may well get fuel starvation problems. Rebuilding the mechanical pump isn't hard and doesn't cost much.
 
The first time I saw Thunderdog was in the early eighties when a friend of mine broke down in it at Thruxton. There was a queue which he got caught in and the car just stopped, refusing to start.

I towed it back to my place and left it there overnight. The following day it started and only ever let him down when parked in queues with the engine running.

This was on 4 star petrol.

When I bought it from him, I went to a local scrap yard and bought an electric fan which cured the problem - well nearly.

After back flushing the rad and the engine, it rarely gave me problems.

I must have given me some problems though, as I still get a mild panic feeling when I get into a queue with Sparky.

Richard

One of the main problems with the V8 these days, apart from fuel quality, is the fact that there is a lot more queuing to be done
 
quattro said:
One of the main problems with the V8 these days, apart from fuel quality, is the fact that there is a lot more queuing to be done

That all depends where you live. I very seldom get stuck in queuing traffic unless I have to travel to Glasgow or further south :D The car has got very warm whilst queuing on the M8 into Glasgow several times with the needle flirting with the red zone, but thankfully I've not suffered from any problems with fuel vap. I've recently overhauled the mechanical fuel pump (but only because it started leaking) and retain the engine driven fan (not sure how much longer I'll keep that for if I can find a decent 2nd hand electric fan locally). My next job this weekend is to fit an expansion tank that I've been cleaning and painting this week. I'll post some pics in the projects area when it's done as I know there have been a few queries on that one too. I've got an old brass Land Rover tank.

Dave
 
Vapour lock can't be a new phenomenon - I remember getting it in a 1967 Corsair 2000E in 1973 -1976
Quite a similar set up - a V engine with a mechanical fuel pump on the timing cover
 
Don't you people keep up with events in this important area that is threatening our very existance..........It's not called Global Warming anymore, it was altered to "Climate Change" when too many people started asking too many awkward questions, and before the same thing could happen again, it became "Climate Science" now, or it is this week at least.
 
I remember the 1970's and 80's when it was global cooling and we were about to enter an unscheduled and unexpected ice age :?

Oh well I suppose it keeps a lot of scientists (and politicians) employed on useless scarey monster in the closet (work?) projects.

Graeme
 
‘The whole aim of practical politics, is to keep the populace alarmed (and hence clamorous to be led to safety) by menacing it with an endless series of hobgoblins, all of them imaginary.”

H.L. Mencken
 
With apologies for bringing this topic back "on-message"...

I'm now on my fourth series 1 V8, have driven many others, and have found that vapour-lock seems to be quite car specific. I live in London and, until this one, had used the Rovers as everyday drivers in all weathers.
Some cars just don't seem to suffer from it. One was 'cured' by an electric fuel pump. My current one really seems to be bad at present. It doesn't run too hot - 2/3rds up the green section when stuck in summer traffic. But will then give a couple of light coughs at idle (always a polite car) and stall if you do nothing.

Given the conditions which cause this - You find yourself blocking an already jammed road or junction at peak hours when everyone's really hot and bothered. Even more likely if you're pointing uphill (see earlier post) which makes it very hard to push to the side of the road. Cue lots of horns and impolite descriptions of the car.

When I used them everyday I perfected the "quick-start" technique. Don't try this at home...

Push car nearer side of road. Try not to get run over by first van/4x4 to scream past hand on horn. Open boot. Fill a syringe with cooler petrol from the can in the boot. Pop the bonnet. Unscrew the 3x2 screws holding the lids on the float chambers. Syringe the petrol into the float chambers until it stops boiling. Put the lids back on and screw down really quickly. Close bonnet, leap back in and start the car. Use the short amount of guaranteed running time to move the car somewhere sensible. Put into neutral and rev to 2500rpm until cooler (with the heater on inside). Sweat like a pig in a sauna. Take the longer way home with less traffic (where possible). Contemplate modern car again.

So forum friends - I ask for help. Having recommissioned my V8 from 5 years of dry storage I decided to go to a friends party in it last weekend. It managed 5 miles in London before vapour-locking. My wife and I went took the modern for the rest of the way (using our glad rags as the excuse for not getting oily).

This is not good enough. I don't want a car I'm afraid to use. So which of the following are sensible and which are daft:
1. Recondition the mechanical fuel pump.
2. Reroute the fuel line (currenly between block and exhaust as per original).
3. Better lagging for the fuel line.
4. Electric fuel pump in engine bay.
5. Electric fuel pump in/near the tank.
6. Flog the car
7. Something else

Answers please!
Thanks
Simon
 
I am having exactly the same issues ( I was kind of expecting them when I bough the car) used this weekend's hot weather to test the car I just bought last week. I am going down the electric fuel pump under the boot option and am having fitted by an expert next Monday/Tuesday. In the meantime in this hot weather, the car is not being used as much as I would have liked to have done since getting it last week:(
 
Simon - your comments on the problem being car specific chime with comment from a lot of other people. Harvey is convinced that the answer is to make all the car systems, but particularely cooling, work as Rover intended. I think I agree but remain on the lookout for something bizarre.

So first up, "everything working as Rover intended". We've had one very good clue from a member down under - I think from memory in NZ - who did a top end overhaul and identified serious issues in his inlet manifold. It would appear that it is very possible to get the coolant passages in the inlet manifold very blocked indeed with gunk without necessarily ruining the ability of the engine to maintain temperature on the car gauge. That definitely sounds like something that would feed through into vapourisation. Also something that might actually vary according to how well Rover cast the manifold. So assuming you're confident in the cooling capacity of the rad (Fitted a three row core yet? That often seems to help in this respect as well as in guaranteeing adequate cooling under all circumstances) and performance of the rest of the system, use advanced search in the top panel and see if you can find the thread on inlet manifolds. If not come back and I'll identify.

Then, from your list of options, I'd go for No 2 first. GarethP6 has put up a thread on a mod he has done to his car which is extremely sensible indeed. He has taken a new petrol line from the bottom of the reserve tap, across the back of the engine bay and then up and out behind the steering idler into the inner wing area. He then runs the pipe down the inner wing on the road side and brings it back into the engine bay in the pocket behind the near side headlamps. From there it is an easy leap to the fuel pump and back into the normal pipework.

Next up I'd do No 1 and fit a recon kit to the mechanical pump, simply on principle. After that my personal choice would be to fit an electric pump in series with the mechanical pump with the electric pump located in the engine bay down behind the near side headlamp where it is nice and cool and where the afore mentioned rerouted fuel pipe enters (location again borrowed from GarethP6). I'd want to use one of these Huco pumps: http://www.gowerlee.dircon.co.uk/HUCO.html from Gower & Lee in preference to a Facet. Not least because it looks period (although it's actually plastic) and because they give you a choice of specs which allow you to simply choose the correct one for the location - in this case I'd go for a 133010. Most people seem to go for a pump adjacent to the tank. I think this solution is superior as it doesn't leave your pump unseen in a particularely vulnerable location and allows you to use the original tank pipework and reserve tap. Changing the latter to suit a single pump at the rear is a pain and detracts from the car - you inevitably finish up ditching the reserve facility. I see no point removing the existing mechanical pump. It's extra work and the resulting pipework won't look right in a very visible area.

All that said, I haven't had to do any of this, as mine is in the select group that seems untroubled by the phenomonen. But I had expected to have to do it, so had worked out my solution in advance!

Chris
 
Having just reread the whole topic, there's perhaps a couple more things to add.

The P6 suffers from very high underbonnet temperatures. These evidence poor airflow around and particularely out of the engine bay. Rover addressed this themselves on the NADA 3500S by fitting two scoops either side of the air intake scoop. The purpose of these was not to take air into the engine bay, but to let air out when the car was standing in traffic. So with this clue, we can suggest a modern day alternative - make sure your bonnet doesn't fit too well! A decent air path out the sides between the edge of the bonnet and the wings (make sure the sound insulation blanket isn't sagging down onto the wing humps and blocking this route) is a good plan. So also is making sure the seal at the rear of the bonnet isn't too effective. A standard trick for racers is to jack the rear of the bonnet around 1/2" on the hinges! I've done my own trick for the next iteration of Lucky which is to have rear pointing louvres pressed into the bonnet - an idea taken from the P7 prototypes. Looks very serious and vintage.

There seems to be general consensus that the P6B cooling system is marginal - able to be caught out even when in excellent condition by adverse combinations of circumstances. (eg: very hot day, a good thrash followed by standing at an obstruction / trafic queue) There is no doubt that the key mod to resolve this is to have the radiator recorred with a three row core instead of the factory two row. Not hugely expensive and completely invisible to the uninitiated. Electric fans are NOT a solution to overheating. They are a solution to a completely different question - how do I get more out of the existing set up? They eliminate engine noise and wastage of horse power - its the rad that determines how much cooling is available.

Both of the above are capable of tipping underbonnet temperatures just that tad too high for the fuel to cope so I guess they are on the list after the obvious ones from my post above.

Chris
 
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