eddy 500 running rich

[sidecar]

I have quite clearely stated that my jetting & rods have been set up for track use, johnny asked me the question,i have answered..
Bish

When you first posted up your jet and rod combo you did not state that it was for track use only, you only stated that later on in another post when you also stated that you were not interested in the cruise mode.

Im presuming as hes running stage 3 heads and a fast road cam he must be doing track use. Not sure what manta's or sidecars motors are used for so cant comment..
Bish

Why must he be "doing track use" just because he has a fast cam and stage three heads?
I have all of the above and NOS yet my car is only used on the road.

[Johnny Rotton]

I only bought the Westfield in June this year and will be using it mainly on the road with perhaps a 2 or 3 track days per annum. Yet to venture on a track due to finding chassis cracks around the diff cage and 2 dizzy gear failures.
Replaced the gear wheel myself first time, only to have it fail again within 200 miles ! Got John Eales to do the job second time around. His verdict was extra stress caused by the uprated oil pump and poor lubrication. He fitted the front cover that has the oil pump driven off the crank, so should not suffer any more failures. He also fitted one of his baffled sumps.
Once I have sorted my air filter out, will try the 65-47 rods and see how she feels. Have measured the gap between top of carb and top of filter housing and it is only around 50mm. A 3" filter will definitely not fit under bonnet, so considering a half inch spacer under housing. Has anyone tried one of these ?
Cheers
JR

[sidecar]

I only bought the Westfield in June this year and will be using it mainly on the road with perhaps a 2 or 3 track days per annum. Yet to venture on a track due to finding chassis cracks around the diff cage and 2 dizzy gear failures.
Replaced the gear wheel myself first time, only to have it fail again within 200 miles ! Got John Eales to do the job second time around. His verdict was extra stress caused by the uprated oil pump and poor lubrication. He fitted the front cover that has the oil pump driven off the crank, so should not suffer any more failures. He also fitted one of his baffled sumps.
Once I have sorted my air filter out, will try the 65-47 rods and see how she feels. Have measured the gap between top of carb and top of filter housing and it is only around 50mm. A 3" filter will definitely not fit under bonnet, so considering a half inch spacer under housing. Has anyone tried one of these ?
Cheers
JR

Hi JR,

The spacers are nothing 'clever' I bet you could make something out of a strip of ali. You can get a new filter stud from Real Steel. I think if you can raise the base and fit an extreme filter top your airflow will be fine, the jetting should then work. If it does not it will more than likely be the cruise circuit that has just gone too lean so don't despair, I'll be able to find another jet and rod combo that is slightly richer. Really the way to get the cruise up is just to keep going leaner and leaner until the engine won't run properly, you then just go one stage richer.

If it was my lump I'd also check the timing, it can be quite a job to sort it out if its wrong but its worth doing. Go for something like 14-16 at idle, 28-30 all in at 2700-3000 RPM and ditch the vac system as it does not really work with this carb. (You MIGHT get a Mallory vac system to work in some small way because they are adjustable)

All just my humble!

Regards,

Pete

[Johnny Rotton]

Thanks Pete.
John Eales set the timing at 12' at idle and ditched the vacuum. By the way have you tried different plug gaps ? John Eales recommends 27.5 thou, which doesn't seem that wide to me.
Cheers
JR

[sidecar]

Thanks Pete.
John Eales set the timing at 12' at idle and ditched the vacuum. By the way have you tried different plug gaps ? John Eales recommends 27.5 thou, which doesn't seem that wide to me.
Cheers
JR

Plug gap very much depends on the ignition system that you are running, remember that it is better to have a small gap rather than a big one if the system can not cope with it. It also depends on the CR and the fuel that you are using. I would have thought the 27-30 thou is about right for a standard system. (if that's what you are running?)

I run an MSD system with a 40 thou gap, I could even push it to 50 thou but for the sake of the NOS I've gone for 40.

[mgbloke]

Sidecar
Really interested in this thread.
As Bish V8 says we have been using the calibration kit and have ended up with .086 jets and .067x.055 rods with the secondaries being 0.092. Which seems to be about right for best power according to the Innovate.
However I have recently stripped my engine down and was surprised to find that the carbon buildup was not what I would expect. Instead of being hard and well baked on, the deposits are more like tar. You would expect to have to scrape it off but I could wipe 30% off with a rag. This must mean that my mixture is way too rich.
I have ordered the 0.083 jets and 0.065x0.047 metering rods to give them a try. It seems quite a big jump from 0.092 secondaries down to 0.083 but you have obviously spent a lot of time on this.
I will give it a go and report back.
Thanks
Mark

[sidecar]

Sidecar
Really interested in this thread.
As Bish V8 says we have been using the calibration kit and have ended up with .086 jets and .067x.055 rods with the secondaries being 0.092. Which seems to be about right for best power according to the Innovate.
However I have recently stripped my engine down and was surprised to find that the carbon buildup was not what I would expect. Instead of being hard and well baked on, the deposits are more like tar. You would expect to have to scrape it off but I could wipe 30% off with a rag. This must mean that my mixture is way too rich.
I have ordered the 0.083 jets and 0.065x0.047 metering rods to give them a try. It seems quite a big jump from 0.092 secondaries down to 0.083 but you have obviously spent a lot of time on this.
I will give it a go and report back.
Thanks
Mark

Hi Mark,

Thanks for the reply, you know that I used to say that the jetting seemed to be similar for all RV8 engines and that is what I've quoted on the "How to build a Sumo (Cobra) wiki" site but I no longer think that, I must change the contents of the site one day!

Anyway Muscle Manta and I were working on a another 4.6 in a Lambo replica the other day, I don't know the spec of the engine but the jetting was not the same as my car or Mr. Muscle's.

The Lambo ended up with the pilots out 2.5 turns, silver rod springs, 65-47 rods, 83 primaries and 98 secondaries. That lot gave the following figures:-

Idle=12.5-13:1, cruise=14.5-15:1 Acceleration=11.5:1 WOT=12-12.8:1

We also noticed that the throttle had to be open quite a long way before the vacuum dropped enough for the silver springs to lift the rods, you should bear this in mind if you still have the standard springs as they are weaker than the silver ones.. The above setup is just about as lean as the cruise can go, as soon as 15.5:1 flickers up on the LC1 the throttle response goes very bad in my experience! (With a carb, I'm sure that you could go leaner on cruise with EFI)

The acceleration is a bit rich as is the WOT, 95 secondaries placed the WOT at 13:1 which is getting just a touch lean (12.8-13:1 being ideal)

We are going to try 83 primaries with 65-52 rods, this will leave the cruise at 16% leaner than base but rather than the acceleration being 0% leaner it will be about 10% leaner than base, hopefully this will get the acceleration to around 12.5:1. Also the WOT should lean off a touch even with the 98 jets, hopefully this will be around 12.5-13:1.

Really an LC1 or something similar is the way to go when setting up one of these carbs, I reckon you can get it done in a day if you have all of the jets and rods!

BTW, Muscle Manta can supply, jets, rods, and springs for a good price!

I guess the other thing to bear in mind that if you are only using your car on the track (drag racing?) then really only the acceleration and WOT figures are going to be important, the cruise does not need to be as lean as possible but there is no point in running it rich either!

Cheers,

Pete

[mgbloke]

Thanks Pete
Will let you know how it turns out. Mine is now 4.8 so likeley to be slightly different.

Mark

[mgbloke]

Trying to do the maths.
If I change to 0.083 jets and 0.065x0.047 rods I think the cruise will be 4% less and the Power to be 1.3%more than I have now.
If I go to 0.083 jets and 0.065x0.052 rods I think the cruise will be 4% less and the power 1.12% less.
Cant remember what my LC1 reads so will take fresh readings with my current setup and then experiment with secondary jetting before trying new combinations.

Mark

[Muscle-Manta]

Hi Mark,

Hope you don't mine me answering for Pete.

The maths equation for working out the percentage differences between the different rod and jet settings is a bit involved. Pete sent me a copy of his spread sheet which works it all out for you when you put the different rod and jet sizes in.

If you take stock setting of .86 jets and 65-52 rods as a zero. Using the .86 jets with 67-55 rods you will be running 8.325 % leaner than stock in the cruise mode and 6.841% leaner than stock in the power/acceleration mode.

If you make the change to .83 jets with the 65-47 rods you will now be running 15.989% leaner than stock in the cruise mode and .0256% leaner (effectively zero) in the power mode.

By changing the .86 jets and 67-55 rods to the .83 jets with the 65-47 rods you alter the % leaner than stock for cruise from 8.325 to 15.989 which is a further 7.664% leaner. The power mode changes from 6.841% leaner to zero -stock.

Making the change from .86 jets and 67-55 rods to .83 jets and 65-52 rods the cruise is leaner by another 7.664% and power is leaner by a further 3.965%. I would try this setting first as you will already have these rods - they are the stock (originals) fitted to the eddy 500 carb and the kit you have will have .83 jets included. If this doesn't work out ie too lean in the power mode then try the 65-47 rods. I can supply you with a set for £8 with postage if you need them.

Paul.

[mgbloke]

Thanks paul

I remember when I changed from 4.0L to 4.6 I was using the 0.083 jets with 0.065x0.052 rods which were RPI's setting for a 4.0L engine. It hesitated under acceleration. I naturally assumed that the 4.6 would need more fuel so started with the stock calibration and went from there.
Hopefully get it back on the road in a few weeks, looking forward to doing some testing.

Mark

[sidecar]

Thanks paul

I remember when I changed from 4.0L to 4.6 I was using the 0.083 jets with 0.065x0.052 rods which were RPI's setting for a 4.0L engine. It hesitated under acceleration. I naturally assumed that the 4.6 would need more fuel so started with the stock calibration and went from there.
Hopefully get it back on the road in a few weeks, looking forward to doing some testing.

Mark

Hi Mark,

I'm not sure that you can use the theory of a bigger engine needing bigger jets, for one thing the bigger engine could generate more vacuum and since the vacuum in the venturi is more or less what causes the fuel to flow through the jets they might actually need to be smaller! The one thing that all the engines have in common is that they need similar AFR's for each mode of operation. The difference is just the jetting required to obtain it.

For example the cruise AFR needs to be around 14.5-15:1, the 3.5 engine generally needs the cruise mixture leaning off at most 10% whilst the 4.6 needs the cruise jetting leaning off around 16% in order to get the same AFR figures.

The thing that goes against the 'bigger engine, bigger vacuum' theory is that I've measured the vacuum of difference sized engines, even when the vacuum levels are the same between two engines the jetting may still have to differ between them!

If you want a copy of the spreadsheet that Paul is using in order to post up the different percentages of various jet and rod combos just PM me an email address!

Cheers,

Pete

[Johnny Rotton]

Thought I would provide update being as this thread has been resurrected. I got Paul to send me 83 and 86 jets and 65-47 rods. It was only when I compared these jets to my primaries that I discovered I was running 80 primaries with 62-52 rods and 95 secondaries. These are a lot leaner than stock, so have switched to 83 primaries, 65-47 rods and 86 secondaries. This should richen it slightly on cruise and alot on power.
Have also ordered a new filter from ITG, which they are going to custom make at 65mm high. This will give an extra cm of clearance from top of carb. I have also removed the choke flap to aid flow further.
Can't wait to try the car out once the weather improves.
Cheers
John

[sidecar]

I was running 80 primaries with 62-52 rods

Hi John,

The above setup is 19% leaner than base on cruise and 21% leaner on the power step!....Well lean.

The secondaries Paul has sent you may well be OK you but after the work that Paul and I did on the 4.6 Lambo you may have to keep the 95 secondaries. It's hard to say, really an LC1 would tell you!

Cheers,

Pete

[mgbloke]

More feedback.
Today I fitted 83jets with 65/52 rods with silver springs and 92 secondaries.
Briefly drove the car and it was immediateley apparent that there was a big flat spot coming onto part throttle. Once the engine picked up again it felt good. AFR was around 16 on cruise and flicked to 18 momentaerily as the engine stumbled before going back to around 15.
Didnt try WOT for obvious reasons.
Going to try same setup with 62/52 rods when the rain stops.

Mark