V8 Tuning Books

[hirot]

Anyone point me in the direction of some good books on how to tune my V8....other than the one you cant get (how to power tune a rover V8....).

I am OK with 4 cylinders, twin SUs and points but Rover Electronic distributor, edelbrock carb and 8 cylinders is a little more complicated.

Any help will be appreciated.

Regards Ian

[kiwicar]

Hi
can you give me some idea of what sort of tuning advice you are looking for?
I know this thing can get boaring when all you want is a quick referance guide that will give you a shopping list for parts.
The trouble is no one makes one and if they did it would be out of date by it came out!
If you want to do high performange race engine tuning then you really need to get specialist tuning guides for each area of the engine and then work from the general subject to apply the knowledge to a specific engine. For example there are several guides to cylinder head porting, however they are general porting advice across many engines and not specific to the rover, after all how many copies would you sell of a book dedicated to porting the rover V8 to race specification? Even guides for the Ford Mod and the Chevy small block would sell relativly small numbers.
If it is raod tuning advice you are after then I would recomend subscribing to one of the US performance magazines, Care Craft, Hot rod, chevy performance all regulaly do engine build ups and tests, cylinder head comparison articles and intake manifold comparisons, I know none of these are for the rover, but it gives you a good idea of what generally works for various stages of tune as regards component combinations.
Your best bet is to post on here what you want to use the engine for, giving as much detail as you can about what it will end up in and ask people to recommend a combination of parts, compare the answers.
Best regards
Mike

[DaveEFI]

Anyone point me in the direction of some good books on how to tune my V8....other than the one you cant get (how to power tune a rover V8....).

I am OK with 4 cylinders, twin SUs and points but Rover Electronic distributor, edelbrock carb and 8 cylinders is a little more complicated.

Any help will be appreciated.

Regards Ian

Do you mean how to adjust a standard engine to get the best results - or how to modify one?

If the former, there is really no difference with a V-8 in principle.

The Lucas electronic distributor is the same as a points one - but with the points replaced by an electronic switch. You set the ignition timing in the same way - with a strobe light.

The Edelbrock carb comes more under modifications. Which I personally don't like. Rolls Royce had the choice of carbs from anywhere in the world - but chose SUs for their V8, before going injection.

[hirot]

Thanks for both your replies. I am only looking to use my car, an mgb with a 3.9 ex discovery engine, for everyday use. I just wanted it to run well.

The minor issues I have is that it sometimes runs on, which could just be plug gap or plugs and most irritatingly it doesn't like a hot start after about 5 minutes. A friend suggested going to a better coil eg Bosch red/blue but I was unsure as to how this may effect the 35dlm8 lucas distributor.

So basically I was looking to read up on the basics before making a mess of something that already seems to run OK.

I am sorry about the Edelbrock but it fitted under the bonnet and worked out cheaper than finding the right manifolds and SUs.

Regards Ian

[sidecar]

Thanks for both your replies. I am only looking to use my car, an mgb with a 3.9 ex discovery engine, for everyday use. I just wanted it to run well.

The minor issues I have is that it sometimes runs on, which could just be plug gap or plugs and most irritatingly it doesn't like a hot start after about 5 minutes. A friend suggested going to a better coil eg Bosch red/blue but I was unsure as to how this may effect the 35dlm8 lucas distributor.

So basically I was looking to read up on the basics before making a mess of something that already seems to run OK.

I am sorry about the Edelbrock but it fitted under the bonnet and worked out cheaper than finding the right manifolds and SUs.

Regards Ian

There is nothing wrong with the Eddy carb once it has been setup properly, many are not setup and this does create problems such as bore wash. If it has been setup by RPI it will be running too lean!

I'm 95% certain that your hot starting issues are due to the fuel boiling in the carb, I've seen loads of engines running Eddy carbs that have had this issue. The cure may well be a bit tricky for you as I suspect that you have hardly any bonnet clearance but what is needed is an insulation plate between the manifold and the carb. Ones that I've used in the past have been about 10mm thick and are made from a fibreous type of material. You could check out your filter to bonnet clearance and then either use a spacer or maybe 4 or 5 gaskets between the carb and the manifold. You will need longer carb studs!

Other MG-V8 issues that I've seen include very poor clearance between the air filter lid and the top of the carb, I would think that anything under 50mm is getting dodgy. The other thing that holds this setup back is the low rise manifold that is usually used. The dual port ones being very restrictive. (According to V8 Developments and my own opinion!)

Some issues are made by human error such as using a 2" drop base filter with a 2" high filter, it does not take a genius to work out the filter lid to carb clearance with this sort of setup!

[DaveEFI]

I'd agree 100% with the fuel evaporation bit. Was a problem on the P6 3500 - let alone a 'special'.

[hirot]

Yep I have the drop base filter, low rider manifold and a 2" K&N filter and very little clearance. I am led to believe that after about 1000 miles the engine should settle down a bit which will let me get an Xtreme K&N filter on top....which may help a little bit. The rear of the filter has space, but the front is kind of close.

I had good advice from Jim (JVR8) and have only jetted down to the next level from out of the box standard which got rid of hunting at low speeds, plugs 1,2,7,8 black - others brown and now have nice (I hope) biscuit coloured plugs with 21 mpg on short runs and a heavy foot which I thought was OK.

The fuel evaporation is a bit of a problem as I really don't have the room. I have Bonnet louvres and insulation around the fuel pipe and exhausts and the engine really runs cool unless I get in traffic. Then it goes upto normal (85) and the twin electric fans cool it at 90 very quickly.

I also have an edelbrock fuel pump so it is getting the right fuel pressure, hopefully, and I was hoping that would refill the carb. I had tried pumping the throttle, but so far only once, as it seemed to make it worse.

I have set the plug gaps to 32thou as I had no data on what the 35dlm8 expects. The discovery sets it at 35thou, but with EFI and when I had a p5 it they were 25thou ish.

I will try leaving my bonnet up next time I can and see if that improves it and if so I guess I have to live with it.

A friend had suggested putting a sports coil on as it had cured his TR6, however, without any information I wasn't sure whether to try it and if so should I use a ballast resistor and would my 35DLM8 appreciate the sports coil.

Again Many thanks for the information.

Ian

[sidecar]

I reckon that when the fuel is boiling you actually end up with a very rich mixture as you are cranking the engine over. Basically the fuel turns into petrol vapour and the engine ends up breathing that in and no air at all, without air the fuel can not burn.


If you watch your exhaust when the engine fires I bet you get a load of black (rich) smoke coming out!

Opening the bonnet may help to degree but really the heat is soaking up from the manifold itself.

If you are handy with a dremel and cutting disks you might be able to cut the lip away at the front of the base of the air filter, you can actually cut in such a way the the base sits on the carb at an angle dipping down at the front.

I don't have much faith in plug reading with unleaded fuel, it will tell you whether you are massively rich but that's about all. To quote Vizard , "Plug reading is less of an art, it's more of a fallacy".

[DaveEFI]

It depends where the fuel is evaporating. If in the pipework, a return system can help - circulating it helps to cool things. If it is in the carb itself, you need to cool it in some way. I had a Jag which had a fuel cooler fed from the air-con.

The Lucas DLM system gives a more than adequate spark under all conditions. Messing around with non standard bits will simply make it worse - assuming it is performing to spec.

[hirot]

I too was wondering if it was rich as opposed to lean as after I have had the carb off or when my earth failed to the pump and the car was hot the car always starts as soon as the pump runs ie refills the bowls. It may turn over a couple of times as it redraws fuel as opposed to 10-15 times when hot.

Shame about the colour of the plugs I kind of thought I was OK there. I must stop thinking. Is it worth running on 98 instead of 95 or can that make it worse as it may be even more volatile.

I didn't really like the idea of a sports coil as it seemed like I was using a sledgehammer to crack a nut.

I don't think it is boiling in the pipe as it is covered in thermal protection around the exhaust....but I could extend the cover.

I will check for black smoke.

Maybe the Xtreme top will allow the fuel soaked air to vent out of the louvres. I just need the engine mountings to relax a very small amount.

[sidecar]

I too was wondering if it was rich as opposed to lean as after I have had the carb off or when my earth failed to the pump and the car was hot the car always starts as soon as the pump runs ie refills the bowls. It may turn over a couple of times as it redraws fuel as opposed to 10-15 times when hot.

Shame about the colour of the plugs I kind of thought I was OK there. I must stop thinking. Is it worth running on 98 instead of 95 or can that make it worse as it may be even more volatile.

I didn't really like the idea of a sports coil as it seemed like I was using a sledgehammer to crack a nut.

I don't think it is boiling in the pipe as it is covered in thermal protection around the exhaust....but I could extend the cover.

I will check for black smoke.

Maybe the Xtreme top will allow the fuel soaked air to vent out of the louvres. I just need the engine mountings to relax a very small amount.

I run the same Eddy pump as you and I think that they are just about the best pump that you can get for these carbs, they will pump nearly 2 litres of fuel per minute at the right pressure for the carb.

Yep it’s a shame that plug reading does not really work too well anymore, it will just about get you in the same ‘ball park’ but not any nearer than that. Really the only way these days is by monitoring the exhaust gas with an LC1 or something similar. There are a couple of the carbs circuits that you can set up just by ear and by feel. Basically you can set the idle circuit and the cruise circuit. The ones that you cannot set this way are the acceleration circuit and the WOT.

I wrote this lot ages ago, I’ve now changed my mind over one or two points such as the fact that I thought that though that 95% of Rover engines could run the same carb settings, I no longer think that’s true...
http://how-to-build-a-pilgrim-sumo.wiki ... ing-system

Running on 98 won’t make your running-on situation worse, 98 is less likely to pre-ignite compared to 95. The thing is if your motor is in reasonable nick and running a standard-ish CR then 95 should be OK. If things are wrong then this could cause it to run on. People generally state that too much idle timing causes run-on. I personally think this is wrong, retarded timing causes more heat to be retained in the combustion chamber and this may well cause something to get hot enough to allow run on. Also if your carb and ignition setup is bad you can end up with the throttle plates being opened quite a long way in order to get the engine to tickover, this seems to cause run on. (It’s the same with Small Block Chevys when the tickover is set near 1000 RPM, they will run on for ages). If you can get the engine to tickover at say 800 RPM with a big vacuum reading in the manifold then it must mean that the throttle in nearly shut, it then won’t run on. The Eddy carb does not work too well with the Lucas vac advance system, have a read of this....

http://how-to-build-a-pilgrim-sumo.wiki ... by-members

Your Extreme filter top may help with getting enough air into your carb but I doubt that it will help much with the fuel boiling. Some people don’t rate this sort of filter top as it can upset the signaling in the carbs boosters but I would rather use one than not if it was the only way of getting air into the carb.

You could consider fitting a 74 degree stat in the manifold, this will help in two ways, your carb will be cooler and your block will be a bit less likely to crack!

With regards to the fuel boiling I know that it will be in the carb where the issue is, I once removed the top of my carb before I had any form of heat insulator when the engine was hot, I could see the fuel boiling way in the float chambers, it had all gone within 30 seconds!

[DaveEFI]

On my SD1 (with the large AC rad, but not AC at present) the idle temperature on a hot day in a traffic jam goes way above the 88c opening point of the thermostat. So fitting one with a lower opening point wouldn't make any difference.

It too can suffer from fuel evaporation even although it's injection, if you attempt a hot restart soon after it's got well and truly hot. I just run the fuel pump for 20 seconds or so before attempting a start under those conditions. You can actually hear it slow down as it eventually starts pumping 'solid' petrol.

[sidecar]

On my SD1 (with the large AC rad, but not AC at present) the idle temperature on a hot day in a traffic jam goes way above the 88c opening point of the thermostat. So fitting one with a lower opening point wouldn't make any difference.

I was assuming that everything else in the cooling system was up to the job!

I run a Sierra 2.3 rad, my 4.6 lump never goes over 84 degrees, the fan kicks in at 83. Whilst driving the temp is 77-80 degrees.

[DaveEFI]

Well, the mid point on my SD1 dash temperature gauge is 100C, so it's safe to assume Rover designed things for that as a norm. Also, the hotter you run an engine the more efficient it gets - the SD1 thermostat was upped from 82 to 88 during its life.

Of course I could alter the AC aux electric fans to switch on at a much lower temp - but why would I? The noise of them running in a traffic jam would annoy.

My BMW has an interesting gauge for coolant temp worriers. It goes to exactly half way and stays there between a wide range of actual coolant temperatures. Only when outside this normal range does it go up or down.
It's fed from the engine ECU.

[Quagmire]

I'd agree 100% with the fuel evaporation bit. Was a problem on the P6 3500 - let alone a 'special'.

Still is! I now drive a P6 3500s as my everyday motor (still have both landrovers though ) and on a hot day I have to plan my fuel stops so that the car is cool. If I switch off to fill on a day in the high 20's, early 30's vapourisation can be so bad that the front mounted fuel pump I have cannot suck anything through for a good quarter of an hour!

This will all be sorted when I rear mount the pump so it is pushing cool liquid fuel forwards, instead of trying to suck on fumes.