Paul,
Pleased to hear that with the right combo of coil and dizzy that the engine is starting and running better.
Before doing anything check that the no, 5 and 7 plug leads are not next to each other in the combs or touching at the dizzy end as this can cause crossover firing problems.
With a mild cam the standard step up springs should be ok but what cam is it?
I was never happy with the rod and jet combo that RPI!!! recommended so follow sidecars advice.
Kevin.
MG V8 Conversion help required - 3.5 - Eddy 500 etc
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Kevin,
I've kept number 7 and 5 apart, heard that from other people too.
The cam is the Viper Hurricane Hydraulic Camshaft from Real steel, pretty mild by most accounts, still able to use hydraulic lifters so can't be too wild.
I'm considering having it setup on a rolling road as I'd like to get out on a few track days over the next couple of months. Didn't want to thrash it round a track at anything less than almost perfect setup.
I've brought it into work today so it's had 40 miles this morning of mixed driving, seems to be pulling better than it was, not as hessitant as before. Timing is currently set about 10 degrees before, I do have the vacuum advance connected as I'm not that keen on pulling the dizzy apart yet.
Is there a really massive difference between non vac and vac when set up properly? Is anything like a vacuum delay module possible for use with the Edelbrock or does it not work with vacuum advance full stop.
What does everybody end up with their mixture set at? I'm going to get it on an exhaust analyser for setup but not sure where the figures should end up for ideal running? (in terms of CO and HC etc)
Paul
I've kept number 7 and 5 apart, heard that from other people too.
The cam is the Viper Hurricane Hydraulic Camshaft from Real steel, pretty mild by most accounts, still able to use hydraulic lifters so can't be too wild.
I'm considering having it setup on a rolling road as I'd like to get out on a few track days over the next couple of months. Didn't want to thrash it round a track at anything less than almost perfect setup.
I've brought it into work today so it's had 40 miles this morning of mixed driving, seems to be pulling better than it was, not as hessitant as before. Timing is currently set about 10 degrees before, I do have the vacuum advance connected as I'm not that keen on pulling the dizzy apart yet.
Is there a really massive difference between non vac and vac when set up properly? Is anything like a vacuum delay module possible for use with the Edelbrock or does it not work with vacuum advance full stop.
What does everybody end up with their mixture set at? I'm going to get it on an exhaust analyser for setup but not sure where the figures should end up for ideal running? (in terms of CO and HC etc)
Paul
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CastleMGBV8
- Top Dog
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- Location: Sidcup, Kent, UK
poor running
Hi Paul i used to run the same carb as yours on my v8 and it was always a pain to start when warm alot of my mates had the same prob on theirs,try holding the throttle pedal to the floor when cranking it over, poor running could be down to low fuel pressure mine was set up on the rolling road at tvr specialists Austec who refused to touch it till it had a Facet red top pump fitted as the su and equivalent ones only run at 1.5psi where as the red top puts out at least 6 turned down to approx 4 on pressure regulator,just check your fuel lines are up to it as old rubber could be sucked flat,did you say you had a mollory dizzy?hope this helps im now on fuel injection bliss ,Doug
V8Paul wrote:Thanks for all the advice so far...
Biggest issue was the 12v DLB120 coil running a ballast resistor. A well known 'v8 specialists' didn't even pick up on this, Should have been DLB102 and they sold me that combination!
Fitment of DLB198 with the new Lucas dizzy has transformed the car, starts on the button and even when hot only requires minimal cranking (little fuel evap i feel). Car is currently running about 10 degrees static advance on idle.
The carb now really needs to be setup 'properly. I'm going to order a set of step up springs to trial as I think it's running lean on part throttle. Who stocks them in the UK? I've roughly set the idle mixture by ear, better than it was (way too lean) although car still smells of unburnt fuel on idle so may be a little too rich.
Primary Jet and rod combo is the 6252 rods with .080 jets. Springs are standard. Secondary jets are standard. Accel pump set to middle hole.
Car feels flat on acceleration, slightly jerky on part throttle and off idle. Only eventually feels quick once you're flat out in a gear.
What should I look at swapping first?
Paul,
The 80, 62-52 combo will give you a cruise setting that is 19% leaner than base and an acceleration setting that is 21% leaner. Like I said before, RPI settings are rubbish! Your car will feel as flat as a fart with the carb set like this. Your 'flat out' is OK because its running off the secondaries at that stage. (Although they will be a bit rich).
I'd bung the 80's in the secondaries, fit 86's in the primaries and fit 67-55 rods. Really silver springs would be good too.
The secondaries don't seem to be very sensitive, I'm currently aiming for 13:1 at WOT using my Lambda probe, I can barely see a difference between 77 jets and 83 jets.
Muscle Manta (on this Forum) actually spoke to Chris at RPI the other day about the duff Eddy settings that he insists on using, Chris just did his normal thing of trying to sell Mr. Muscle an RPI sparky box! He clearly did not have a clue about these carbs either!
I think that you could run more timing at tickover, you need to check the all in figure, it wants to be 36 degrees all in around 2700-3000 RPM. This may well give you a tickover figure of 14 degrees which is fine. Even 16 is fine as long as your starter motor does not complain.
You could buy a calibration kit as it will have most of the stuff that you need, the problem is that you are also buying loads of stuff that you don't need! It won't have the 86 jets in it either as they are the standard 'base' jets. The 83 63-47 combo will be in the kit but that is not quite as good as the 86 67-55 setup. You could try JRV8 for the jets, rods, and springs, You could try Repower although the bloke that runs it in my opinion is Obnoxious (And he charges 10 quid to deliver anything!). You could try John woolfe racing, V8 Tuner or Muscle Manta!
I'd also fit an insulation plate under the carb to help with hot starts.
All just my humble opinion!
Pete
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Muscle-Manta
- Forum Contributor
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- Location: Thatcham Berkshire
The Edelbrock 1404 500cfm carb has orange springs as stock parts. Examine your springs very carefully for traces of Orange paint as it tends to come off and the springs look silver.
If you do have silver springs installed this should work in your favor as it will push the rods up onto the rich step quicker than the stock orange ones and will help get rid of any lean cut on initial acceleration.
The setup springs are sold in sets of 10 -5 different grades- I have a set for sale for £12 if you are interested.
I would also recomend switching the .80 jets from your primarys to your secondarys and refitting the .86 jets to your primarys and using them with a set of 67-55 rods. I can help with the rods for £10 if you require them.
Sidecar -who has posted above- and me have done a lot of testing with a wideband airfuel ratio meter and are running .80 jets in our secondarys on Rover 4.6 engines and they are not lean. They will be fine on your 3.5.
The setting recomended above (.86 jets 67-55 rods) works out on Sidecar's spread sheet as 8.325% leaner than stock jetting in cruise. Your current (Rpi setting) is 19.3% leaner than stock in cruise.
On the power side -this is the low vac condition with the springs pushing the rods up onto the thin end in the jets- the above setting will give you a 6.841% leaner than stock setting. The Rpi setting on power is a wopping 21.28% leaner than stock setting!!! I don't find it surprising you are getting hesitation on acceleration.
If you do have silver springs installed this should work in your favor as it will push the rods up onto the rich step quicker than the stock orange ones and will help get rid of any lean cut on initial acceleration.
The setup springs are sold in sets of 10 -5 different grades- I have a set for sale for £12 if you are interested.
I would also recomend switching the .80 jets from your primarys to your secondarys and refitting the .86 jets to your primarys and using them with a set of 67-55 rods. I can help with the rods for £10 if you require them.
Sidecar -who has posted above- and me have done a lot of testing with a wideband airfuel ratio meter and are running .80 jets in our secondarys on Rover 4.6 engines and they are not lean. They will be fine on your 3.5.
The setting recomended above (.86 jets 67-55 rods) works out on Sidecar's spread sheet as 8.325% leaner than stock jetting in cruise. Your current (Rpi setting) is 19.3% leaner than stock in cruise.
On the power side -this is the low vac condition with the springs pushing the rods up onto the thin end in the jets- the above setting will give you a 6.841% leaner than stock setting. The Rpi setting on power is a wopping 21.28% leaner than stock setting!!! I don't find it surprising you are getting hesitation on acceleration.
Last edited by Muscle-Manta on Sun May 08, 2011 10:23 pm, edited 2 times in total.
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Muscle-Manta
- Forum Contributor
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Thanks for all the comments.... I gave up trying to mess about myself and took it to a rolling road. Welded in a wideband receiver hole.
Ignition was putting 55 degrees on full advance so had to trim that back for starters.
Once the ignition was in trim we did an inital run, it made 118bhp at the wheels. Torque curve was all over the place.
AFR was very rich on idle, lean on cruise and lean on secondaries.
Swapped out the rods and primaries (not sure what to but will check), leaned out the idle mixture and went up to a 92 secondary.
Mid and low was was but better, full power still lean, made 136bhp at the wheels.
Went up to a 98 secondary and blue springs to get rid of a slight dip off early on.
Ended up with a completely smooth torque curve peaking at 3800rpm at just above 200lbs/ft, power peaked at 5200 142bhp at the wheels.
Car is far far better to drive now, no hessitation and flat out literally roars along. Only concern is that current fuel pump is not up to flat out for too long (have a replacement 7psi Webcon to bolt in)
The only slight quibble now is a jerk hessitation off idle when you snap the throttle back on. I'm thinking idle mixture or idle speed might help with that?
Accelerator pump is on lowest setting.
Ignition was putting 55 degrees on full advance so had to trim that back for starters.
Once the ignition was in trim we did an inital run, it made 118bhp at the wheels. Torque curve was all over the place.
AFR was very rich on idle, lean on cruise and lean on secondaries.
Swapped out the rods and primaries (not sure what to but will check), leaned out the idle mixture and went up to a 92 secondary.
Mid and low was was but better, full power still lean, made 136bhp at the wheels.
Went up to a 98 secondary and blue springs to get rid of a slight dip off early on.
Ended up with a completely smooth torque curve peaking at 3800rpm at just above 200lbs/ft, power peaked at 5200 142bhp at the wheels.
Car is far far better to drive now, no hessitation and flat out literally roars along. Only concern is that current fuel pump is not up to flat out for too long (have a replacement 7psi Webcon to bolt in)
The only slight quibble now is a jerk hessitation off idle when you snap the throttle back on. I'm thinking idle mixture or idle speed might help with that?
Accelerator pump is on lowest setting.
V8Paul wrote:Thanks for all the comments.... I gave up trying to mess about myself and took it to a rolling road. Welded in a wideband receiver hole.
Ignition was putting 55 degrees on full advance so had to trim that back for starters.
Once the ignition was in trim we did an inital run, it made 118bhp at the wheels. Torque curve was all over the place.
AFR was very rich on idle, lean on cruise and lean on secondaries.
Swapped out the rods and primaries (not sure what to but will check), leaned out the idle mixture and went up to a 92 secondary.
Mid and low was was but better, full power still lean, made 136bhp at the wheels.
Went up to a 98 secondary and blue springs to get rid of a slight dip off early on.
Ended up with a completely smooth torque curve peaking at 3800rpm at just above 200lbs/ft, power peaked at 5200 142bhp at the wheels.
Car is far far better to drive now, no hessitation and flat out literally roars along. Only concern is that current fuel pump is not up to flat out for too long (have a replacement 7psi Webcon to bolt in)
The only slight quibble now is a jerk hessitation off idle when you snap the throttle back on. I'm thinking idle mixture or idle speed might help with that?
Accelerator pump is on lowest setting.
All good stuff, it shows that really on each car the jet and rod combo is not set in stone. The big secondaries definately over fuel the bigger engines (well mine and Muscale Manta's)
The jerk maybe beacuse of the vac advance, assuming that its connected.
Please post up what primary jets and rods you used!
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CastleMGBV8
- Top Dog
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- Joined: Sat Aug 18, 2007 5:09 pm
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It's not a plug at all but it's Atspeed racing in Essex http://www.atspeedracing.co.uk/ he carried the full stock of weber/eddy jets and needles and actually spent as much time as it needed until he was happy with the car.
Video http://youtu.be/b3BYw45f-N8
On the jerk after idle it feels like a brief hessitation before the carb gets the fuel in. I might richen the idle mixture a touch and see if it's that. Feels like it's not quite onto primary jets but not off idle.
Video http://youtu.be/b3BYw45f-N8
On the jerk after idle it feels like a brief hessitation before the carb gets the fuel in. I might richen the idle mixture a touch and see if it's that. Feels like it's not quite onto primary jets but not off idle.
