V8 Tuning Books

[hirot]

Wow many thanks for the replies and Sidecar I will read and hopefully inwardly digest your information.

I have a standard rover spec. 82 thermostat and the fans come on around 90 and Normal on the gauge is 85. I checked these temperature settings using a cooking thermometer which seemed to be accurate at 100 ie boiling water so I assumed the 90 and 85 to be accurate.

When I run anything above about 20 mph the gauge is on Cool which I guess at 82 ish and only goes to normal when driving slowly or stationary.

I can easily let the fans come on sooner and they are quiet, however, they do tend to cause the inside of the car to warm up as the air gets sucked in through the windscreen vent. I suspect I won't have ice on the windows this winter.

I understand what you are saying about boiling fuel, as I too have seen it boil on the manifolds when I was trying to get the fuel pump working, but I would have thought the pump would have refilled the carb very quickly as I let it run before starting.

Is there likely to a fuel vapour lock somewhere in the jet passages ?

Not easy is it.

[sidecar]

Wow many thanks for the replies and Sidecar I will read and hopefully inwardly digest your information.

I have a standard rover spec. 82 thermostat and the fans come on around 90 and Normal on the gauge is 85. I checked these temperature settings using a cooking thermometer which seemed to be accurate at 100 ie boiling water so I assumed the 90 and 85 to be accurate.

When I run anything above about 20 mph the gauge is on Cool which I guess at 82 ish and only goes to normal when driving slowly or stationary.

I can easily let the fans come on sooner and they are quiet, however, they do tend to cause the inside of the car to warm up as the air gets sucked in through the windscreen vent. I suspect I won't have ice on the windows this winter.

I understand what you are saying about boiling fuel, as I too have seen it boil on the manifolds when I was trying to get the fuel pump working, but I would have thought the pump would have refilled the carb very quickly as I let it run before starting.

Is there likely to a fuel vapour lock somewhere in the jet passages ?

Not easy is it.

I think that you are right in that the pump will refill the carb very quickly and even the fuel passages and jets won't take long to fill but you have to think about what has happened to all that fuel vapour produced by the boiling fuel. I reckon that a lot of it ends up down the manifold or hanging around in the air filter space. Then when you crank the engine over all it can breath in is fuel vapour and no air at all for many revolutions, fuel with no air won't burn! I bet when the engine does finally fire it's all farty and splutters for a couple of seconds, its because the mixture is rich. (Like you said pumping the throttle makes it worse, again this points to a rich mixture). Each revolution won't remove much of this vapour out of the system because the throttle will be more or less closed. A 3.9 litre lump won't move 3.9 litres of air quickly when being cranked with the throttle just cracked open.

If you let the engine completely cool down I bet it would start quite quickly even though the float bowls are empty, this would be for a couple of reasons, the pump will refill the bowl quickly but more importantly some of the fuel vapour would have escaped out of the filter, some of it would have condensed back into a liquid which takes up about 100 times less volume than the vapour, this will allow air back into the air filter space above the carb and what's more the liquid fuel will actually help you get a stone cold engine started!

With regards to the engine temperature I reckon that Rover ran the later blocks hot purely because they were trying to get an old engine which they did not even design through emissions tests which it was not designed to pass. That and the fact that they ran them lean and that they had bored and stroked the original engine along with the fact that the molds were wearing out led to a load of block issues. (Oh and the fact that they did not bottom the liners out on some engines!)

[DaveEFI]

My Vitesse unit has the same bore and stroke as the first RV8. Although the higher coolant temp was undoubtedly to do with emissions. As was the injection.

[hirot]

Sidecar you have just answered my next thoughts as whilst I had noticed black smoke, to be honest I never looked as I was so happy baby was running. Rich sounds right though as last week after being around town and stopping 3-4 times for stuff, the last time I came to start her she was very rough and wouldn't run well until I got on a straight bit of road and then no problems.

As you say it can only be a small amount of fuel that evaporates or my fuel consumption would be lousy. There must be 1/4 to 1/2 pint of fuel in the bowls and yes the car always starts first time when cold and the heat cycle would have gone through the fuel when I stopped previously.

I will get her warm and then take off the carb top blow in some fresh air and see if that works, however, its not a pretty solution.

I put in my mgb thermostat gauge sensor as the official V8 one showed nearer 90 for normal which I thought was a little warm. The problem I have with my set up is that 4 cars in one and no manual and if I go for parts all they want is my registration or VIN which doesn't help at all.

From what everyone has suggested there is a lot of trial and error and fixing of things that wern't broke. At least I might not chase too many rabbits and even learn to live with hot starts.

Any advice on plug gaps as the efi discovery defaults to 35 thou but I have an SD1 distributor. I only ask as if running on is usually caused by too hot a plug then I can either widen my plugs from 32 thou to 35 or go to the next cooler plug. Thats assuming
the timing (set at 12 degrees at 800rpm) is not too retarded and my mixture is not too lean.

[sidecar]

Personally I think that whilst the Lucas systems are OK they are not all that great, I spent ages adjusting the curve on mine and I got the whole system performing as good as it could. I then ditched the system and went to an MSD system. The improvement in starting, idle and WOT at high revs was very noticeable indeed! I've fitted MSD systems to three other Rover lumps and they all responded well.

I would not 'load up' the standard system too much so I'd say that 30-32 thou plug gap would be fine. It is better to run too small a gap rather then opening it up and causing the system to not fire a plug at high RPM.

12 degrees at idle is OK but you should check the all in figure, 32-34 would be a good figure in at 2700-3000 RPM. I'd ditch the vac advance system, it does not suit the Eddy carb and the only way to use it with this carb is to run a lot less mechanical advance across the rev range, this will result in a loss of performance at any given RPM.

With regards to the float bowls you'd be surprised, there is only a couple of egg cups worth of fuel in each bowl. (The floats take up a lot of space)

[hirot]

I am to Goodwood this weekend, all being well, so will not be able to play until next week.

I guess if the theory on rich fuel is correct, which seems sense to me, I end up with a different air filter or maybe a small fan to blow air in the carb before I start.

I have not looked into MSD as yet and have no idea of costs or what it consists of.

Have a great weekend.

[hirot]

The story continues.

I have just done a round trip of 500 miles watching the temperature gauge like a hawk and above 30mph the car runs cool, much below that and she heats up and fans whirrr and she remains around 82.

We were stuck in crawling traffic on the M25 for 2 hours and whilst the temp stayed around 90 she never lost any water, however, my feet got a tad hot from the exhaust.

So following Sidecars suggestion I will swap the 82 thermostat for a 74 as I suspect the engine has its own micro climate which is Tropical below 30mph and Temperate once air is blown passed the engine. Also the P5 I used to have ran a cooler thermostat which also helps confirm his theory on Rover running hotter for emission reasons.

Also on the return trip I turned the fans to come on earlier which did keep her cooler longer.

And of course I got the tell tale smoke from the rear when she starts when hot.

So next to blow in the carb to see if that clears out the fuel vapour and then I will try and find a thin phenolic gasket as my minimum bonnet clearance is 3/8". From what I have read you can buy a 1/4" laminated phenol/alderhyde resin gasket which might do the trick
of insulation. I assume this is the better type.

Regards Ian

[hirot]

Sidecar, fitted a standard edelbrock phenolic spacer and it appears to work a treat.

Thanks.

Ian

[sidecar]

Sidecar, fitted a standard edelbrock phenolic spacer and it appears to work a treat.

Thanks.

Ian

Nice one, I'm glad the spacer worked for you.

[hirot]

It is difficult to believe that something 5/16th thick can reflect so much heat. I guess its the same as the exhaust wrap which is only tape and you can touch it whilst the engine is running.

Again Thanks.

Ian