Rover V8 with weber 500 problems

[CastleMGBV8]

Martin,

The Edelbrock carb pulls too much vacuum for the Lucas dizzy, if you have yours connected, disconnect and plug the port and see if this makes a difference, if so re-time the engine to 10-12 deg, BTDC and it should run a lot better. If it is connected it should be on the left hand port that is with the 3 ports facing towards the front of the car incase you have the carb on back to front which also may make a difference!

You didn't say whether the engine has standard heads and cam?

Kevin.

[shiner]

Hi sorry for delay but managed to finally get out and start solving this.

I checked the float levels and changed accordingly but they weren't too much out.

It starts but only if I keep revving otherwise it will die but probably need to sort out the mixture screws for that.

Before I could play with those I needed to put a new radiator in it as I am suffering with overheating aswel and hoping it was due to a blocked radiator - the water was brown!

Anyway that's now installed so can hopefully get the engine warmed up and sort the mixture out so it idles then I can spray the easy start around it.

Let you know tomorrow of any problems/cures I have found

[shiner]

Sorry Kevin I missed your post as I did not see 2 pages.

My RV8 has standard heads and cam and I do have the vacuum on the left port at the moment.

Are you saying change the timing to 10-12 deg BTDC and then reconnect the vacuum or have this disconnecting permanently?

Thanks for the posts.

I will also put the stock jets back in tomorrow

[sidecar]

Hopefully Kevin won't mind me butting in but yep, leave the vac system disconnected, it does not work well with this carb. (It does not work too well with SU's either!) Rover got round the problem the cheapest way possible, they wound the dizzy back to give only 6 degrees static.

If you are prepared to spend a fair while sorting out the ignition then you will be pleasantly surprised (Assuming that it is set to standard).

It does take ages though, and you must be sure that your timing pointer really is at zero at TDC.

If you want to mess about with the vac system then it might be possible to use the ported vac port but connect it to a Tee piece, one side of the Tee goes to the vac canister, the other connection on Tee goes up to a union in the air filter base. A restriction in the form of a jet needs to be in this second pipe. The greater the restriction the bigger the vac signal that gets to the canister. A pipe going straight from the carb to canister with a restriction won't really work. It will just cause a slight delay before the full vac signal gets passed the restriction. Also it might cause a delay in the vac canister shutting down, this would be bad!

I wrote a whole load of gumph on Rover dizzys, its under the bit on braided hose....

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

[shiner]

Thanks for the info - will come in very useful!

I'm a little confused with the vac tho, so if I just blank off the vac in the dizzy and set the timing to 14deg BTDC? This will be better, or will there be alot of more modifications required?

Thanks

[sidecar]

Thanks for the info - will come in very useful!

I'm a little confused with the vac tho, so if I just blank off the vac in the dizzy and set the timing to 14deg BTDC? This will be better, or will there be alot of more modifications required?

Thanks

I think over all it is better without the vac system as long as you set the static to 14. You need to check that the all in is 36 and it needs to be all in by 3000 RPM. timing tape will help you check all of this. The link in my other post shows you how to make some tape.

You only need to block the ports in the carb, the one in the vac canister just goes to a diaphram and therefore can not leak or do anything dodgy if its left open.

You really need to re-calibrate the carb as well, not because of the ignition mods but just because it will never run right unless you get the air/fuel ratio's sorted out. The setup that I posted earlier is a good start.

I know that Kevin uses the RPI setup but it looks well lean in my humble! (19% leaner than base on cruise, 21% leaner on the powerstep)

[CastleMGBV8]

Pete,

Probably explains why I used to get 28-30 MPG with the old 3.5 engine!

Regards,

Kevin.

[sidecar]

Pete,

Probably explains why I used to get 28-30 MPG with the old 3.5 engine!

Regards,

Kevin.

Jeeze! 30 MPG, that's unholy!

I never got a 3.5 lump to run well when set that lean but I guess it depends on loads of things, Cobs tend to have noisy sidepipes with very little back pressure. Maybe with a more 'normal' exhaust the carb can be leaned out a bit more. Anyway all good stuff and is what the forum is all about.

[CastleMGBV8]

Pete,

Probably explains why I used to get 28-30 MPG with the old 3.5 engine!

Regards,

Kevin.

Jeeze! 30 MPG, that's unholy!

I never got a 3.5 lump to run well when set that lean but I guess it depends on loads of things, Cobs tend to have noisy sidepipes with very little back pressure. Maybe with a more 'normal' exhaust the carb can be leaned out a bit more. Anyway all good stuff and is what the forum is all about.

Should of said that that figure was on motorway cruise at approx 2300RPM, measured on a return trip from Sidcup to Santa Pod, with a bit of traffic once off the the motorway, I must admit it surprised me.

Kevin.

[Denis247]

That 500cfm carb is a bit too big for standard 3.5, especially in a heavy car like the SD1.

The Holley 390 will be much more suitable.

I use one on my 4.6, but even then it took a lot of setting up, taking into account camshaft, head mods etc, even the weight of the car and gearing has an effect.

I had a 3.5 (modified) engine before that and found the 390 Holley suited that perfectly (for the road).

[sidecar]

That 500cfm carb is a bit too big for standard 3.5, especially in a heavy car like the SD1.

The Holley 390 will be much more suitable.

I use one on my 4.6, but even then it took a lot of setting up, taking into account camshaft, head mods etc, even the weight of the car and gearing has an effect.

I had a 3.5 (modified) engine before that and found the 390 Holley suited that perfectly (for the road).

loads of 3.5 lumps run well with the Eddy 500, the primary venturies are smaller than the Holley ones so you still get good engine response at low RPM. The actual diameter of the venturi looks large but the 500 boosters block most of it off. The secondaries have an air valve so that ensures that you don't "flame out" when you boot it. (I tried my carb with the valve removed, I could kill the engine stone dead just by booting the throttle)

The Eddy certainly needs re-jetting/roding from the out of the box setting though!

[Denis247]

That 500cfm carb is a bit too big for standard 3.5, especially in a heavy car like the SD1.

The Holley 390 will be much more suitable.

I use one on my 4.6, but even then it took a lot of setting up, taking into account camshaft, head mods etc, even the weight of the car and gearing has an effect.

I had a 3.5 (modified) engine before that and found the 390 Holley suited that perfectly (for the road).

loads of 3.5 lumps run well with the Eddy 500, the primary venturies are smaller than the Holley ones so you still get good engine response at low RPM. The actual diameter of the venturi looks large but the 500 boosters block most of it off. The secondaries have an air valve so that ensures that you don't "flame out" when you boot it. (I tried my carb with the valve removed, I could kill the engine stone dead just by booting the throttle)

The Eddy certainly needs re-jetting/roding from the out of the box setting though!

Still say it's overkill on a standard 3.5.