Any recommendations for tuning around Reading/Wokingham ?

[chedz]

70 litres according to the spec = 15.35 gallons.

Could lead your calcs to be more like 15.6 mpg, which isn't the best unless you were booting it a bit :O

[Sidecarbod]

Originally Posted by dbsmith

Hi Pete, Chris et al

Hope you don't mind me bending your ears a bit further on this one, slowly making progress but would appreciate your further advice !

Where I am so far, slowly but surely.....:

1. Alternator fixed & replaced.
2. Fuel system sort-of sorted. Chris, you were right about the Facets, they were feeding two separate lines. The one line with the dodgy pump is now terminated. The second line is still running a Facet, but I can't identify the type of pump since the serial no. is rusted over, and the 574A only denotes a series. However, it does seem to be pumping enough fuel into the system when we tested it at Pilgrim yesterday. Despite this, i'm going to order up a new fuel pump as per recommendations to be sure.
3. Pertronix electronic kit & new coil ordered, should be here next week. (Good value with Retro Rockets and the USD rate currently...).
4. Needles in the Edelbrock 500 are definitely 65-52, not 62-52 as on the receipt. I can't figure out what the jet sizes are though. Springs in the needles don't seem to have a colour either.
5. Ignition leads look fine & are good quality from what I can see.
6. Not burning oil or losing water after a 200 mile return run.
7. I'll also change the spark plugs this weekend for good measure & check compression.


So, I had the motor down to Pilgrim yesterday, at speed/cruise it's running fine and at a decent MPG I think (~20 mpg assuming the Sumo tank holds about 12 gals). They put it on their CO2/emissions tester and played around with the idle valves, etc. to get it to the best they could without a full tune up.

However, on the run back, it still had a few of the same problems to sort out. Hopefully some of these will be ironed out once I upgrade to Pertronix plus the ignitor coil, but would welcome your thoughts on them in the meantime.

1. Car starts fine cold, first time every time. But it still won't start very well at all when hot or even lukewarm. When it finally does, black fuel smoke everywhere (Chris experienced this on Sunday!). Idles OK once started. Too much fuel going into the engine ?

2. Hesitation when accelerating especially when changing gear. Hopefully this will be timing/disti/points, am I right in assuming this could also be a fuel pump problem which may be due to running a single facet ? I've also tried changing the setting on the throttle cable (the 3-pin hole arm that controls the valve) but no effect.

3. Pete- is it worth replacing the jets/needles anyway ? In which case where would the best place be to get these from ? And what should I be getting - 86 jets and the 65-52 needles ? The engine is a RV8 rebored to 3.9 with a 3.9 camshaft & uprated heads, although I don't know much more than that unfortunately without taking it to bits !

Thanks Guys

Dave

Originally Posted by dbsmith

Hi Pete, Chris et al

Hope you don't mind me bending your ears a bit further on this one, slowly making progress but would appreciate your further advice !

Where I am so far, slowly but surely.....:

1. Alternator fixed & replaced.
2. Fuel system sort-of sorted. Chris, you were right about the Facets, they were feeding two separate lines. The one line with the dodgy pump is now terminated. The second line is still running a Facet, but I can't identify the type of pump since the serial no. is rusted over, and the 574A only denotes a series. However, it does seem to be pumping enough fuel into the system when we tested it at Pilgrim yesterday. Despite this, i'm going to order up a new fuel pump as per recommendations to be sure.
3. Pertronix electronic kit & new coil ordered, should be here next week. (Good value with Retro Rockets and the USD rate currently...).
4. Needles in the Edelbrock 500 are definitely 65-52, not 62-52 as on the receipt. I can't figure out what the jet sizes are though. Springs in the needles don't seem to have a colour either.
5. Ignition leads look fine & are good quality from what I can see.
6. Not burning oil or losing water after a 200 mile return run.
7. I'll also change the spark plugs this weekend for good measure & check compression.


So, I had the motor down to Pilgrim yesterday, at speed/cruise it's running fine and at a decent MPG I think (~20 mpg assuming the Sumo tank holds about 12 gals). They put it on their CO2/emissions tester and played around with the idle valves, etc. to get it to the best they could without a full tune up.

However, on the run back, it still had a few of the same problems to sort out. Hopefully some of these will be ironed out once I upgrade to Pertronix plus the ignitor coil, but would welcome your thoughts on them in the meantime.

1. Car starts fine cold, first time every time. But it still won't start very well at all when hot or even lukewarm. When it finally does, black fuel smoke everywhere (Chris experienced this on Sunday!). Idles OK once started. Too much fuel going into the engine ?

2. Hesitation when accelerating especially when changing gear. Hopefully this will be timing/disti/points, am I right in assuming this could also be a fuel pump problem which may be due to running a single facet ? I've also tried changing the setting on the throttle cable (the 3-pin hole arm that controls the valve) but no effect.

3. Pete- is it worth replacing the jets/needles anyway ? In which case where would the best place be to get these from ? And what should I be getting - 86 jets and the 65-52 needles ? The engine is a RV8 rebored to 3.9 with a 3.9 camshaft & uprated heads, although I don't know much more than that unfortunately without taking it to bits !

Thanks Guys

Dave

Hi Dave,

That post is a long as one of mine!

Anyway the needles that you should go for are 67x55, that will lean off the cruise and the power step. That should get rid of the black smoke!

The dodgy starting when warm could be a couple of things:-

1.The mixture is a bit rich hence a warm engine does not want to burn it, this rich mixture is why it starts well when stone cold. (Once the mixture has been leaned off you will have to jab the throttle a couple of times to fire it up but that not a problem).

2. The fuel is boiling in the float bowls. This is a real issue with these carbs if the manifold is heated. Not sure what your manifold but my guess is that its heated. The cure is an insulation plate and longer studs. This totally gets rid of the issue. (I have the part number at home for one if you need it).

You could persist with your pumps but junking them sound like a better idea. Just make your that you go for a low pressure one that delivers enough fuel. (Fuel in CC per minute/4.6 = total BHP that can be made with that fuel). (I guess your 3.9 might make 250 BHP but it depends on loads of stuff!)

The three hole arm that you are messing with is the accelerator pump. Its not really worth messing with it until you get the needles right. As your needles are standard I would guess that the jets probably are. (This is a guess mind you!)

The standard springs for the needles have an orange tinge to them, if yours are bright silver then they have been changed. (I think but would have to look it up but the silver ones are stronger, this means that the carb goes onto the power step sooner, probably too soon for your carb).

To be honest mate, you may as well come round to my gaff, all this stuff can be sorted out easy enough. I may even have the needles, I'd have to check, I may have used them to make my home-brewed set that my car is running at the mo.

Have a look at the webber post that's running at the mo, I can't remember who I've told what to! There is a load of gumph in that post about these carbs.

oh by the way, I wouldn't bother going to Pilgrim, its a waste of fuel!

If you want to come round PM me your number so that we can sort something out.

Pete

[dbsmith]

Originally Posted by tonym

I believe the pilgrim tank holds 16 gallons

You could be right !
But i've just filled it up & it's coming in at 19 MPG so not as bad as I thought

[dbsmith]

To be honest mate, you may as well come round to my gaff, all this stuff can be sorted out easy enough. I may even have the needles, I'd have to check, I may have used them to make my home-brewed set that my car is running at the mo.

Have a look at the webber post that's running at the mo, I can't remember who I've told what to! There is a load of gumph in that post about these carbs.

oh by the way, I wouldn't bother going to Pilgrim, its a waste of fuel!

If you want to come round PM me your number so that we can sort something out.

Pete - thanks for that, will take you up on the offer. To be honest, Pilgrim have been pretty good sorting out the mechanical/bodywork stuff for me for free (bought the car off them) but they're not set up for the tuning part. also saw the Weber post too, very useful.

PM on its way to you.

cheers

Dave

[Sidecarbod]

Just a quick update for anyone that is interested!

Dave came round yesterday so we had a look at his setup.

The carb was setup as "out of the box" so we stuck in the 67x55 needles and set the float heights up.

The mixture screws were setup by listening to how the engine responded, they ended up being slightly odd, one side was 1.5 turns, the other being 2.25. I think that the "offy" dual port manifold is made so that both primary chokes feed all 8 cylinders so each mixture screw effects all of the engine, not half of it. (Can anyone confirm this?) If this is the case then the the difference must be down to tolerances in the carb.

The timing was quite stable at 10 degees static 30 total all in at 2800RPM. (I was very supprised as its running points )

The vac was kicking in hard just off tickover and putting the timing up to around 45 degrees. This I think was the main problem with the jerkyness.

Anyway, its now running 14 static, 34 total and NO VAC. (port in the carb bunged up)

The results.....well Dave is quite happy!

Other things that need doing are sorting out the crankcase breather system, at the mo the carb is not connected , the big hole in the carb is bunged up. I was told by Real Steel that the carb is calibrated to be "expecting" air from this port so I guess the current setup is going to be a bit rich. An insulation plate is also required along with a bit of work on the throttle spring.

Oh, the fuel pump delivers 2 pints per minute which I think is enough, Dave will have to work it out! (We don't know what the PSI was, but my finger over the end of the pipe test would indicate that its not mega high!)

The fans are more or less on all the time which is giving the alternator a hard time!

Dave I'll get the part numbers over to you of the bits and bobs that you need.


Pete

[craggle]

Think your right Pete

Both the primaries feed all 8 cylinders and when the secondaries open all 8 are fed again.

Rover V8 - JWR / Offenhauser Intake Manifold 4BBL - New on eBay, also Engine Tuning Parts, Performance Tuning Parts, Car Tuning Styling, Cars, Parts Vehicles (end time 24-Oct-08 21:53:24 BST)

Craig.

[dbsmith]

Yep, big thanks to Pete, all the jerkiness & hesitation has now disappeared and the car is running much, much smoother across all the rev bands and particularly when giving it some power. The thing still has difficulty starting hot, but Pete's given me a couple of pointers on this, not least the spacer between the manifold (Offenhauser) & carbs plus I also found an interesting article last night about problems with hot starting on Mallory distributors which could also be a contributory factor....

MGB - Rover V8 Engine Problem

& so once the electronic parts for the ignition arrive this week I'll upgrade those & see if it makes a difference to the hot starting.

Again, big thanks to Pete for not only sorting it out but teaching me how it all fits together as well.

Cheers

Dave