What do you mean by a 'one off rod'?
64x54 is not on the edelbrock chart of rod and jets. Where do these come from? The 3.9 rod/jet combo seems quite a lot leaner than stock. If the carb runs the rv8 that rich it makes a mockery of what RPI says about the carb. They claim it runs perfectly out of the box.
Wet or Oily Plugs RV8
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What Mike says is true, Paul, the chap who has the rods and jets (we combined all the stuff that we have gathered over the years). He even spoke to RPI with regards to what we have found when setting up RV8 lumps with these carbs. (We must have done around 10 engines now plus a few small block chevvy lumps). RPI did not want to know, they usually just try to sell you their ignition box regardless of what problem you have. (Even if that problem is a flat tyre!)
One off rods = rods that I have either made from scratch or a standard rod that I have modified.
I can tell you that the rods are critical down to 1 thou of an inch so it takes some doing to modify them. I have been in a car which will run fine with a 69 thou rod in the cruise circuit, we then stuck 70 thou rods in the carb and we could not get the car off the drive. I would call that quite 'jet' fussy personally and why shouldn't it be? Real Steel hate these carbs because most engines will 'seem' to run OK even when very rich, what then happens is that the bores and piston rings get worn out after a couple of thousand miles. Again not really the fault of the carb, It just needs to be setup properly!
Also when they are setup well its quite surprising what MPG you can get out of them. Pauls SD1 runs a 4.6 with an Eddy 500 and a decent programable MSD system (including a programmable vac advance). On a recent trip up North doing 50 to 100 MPH he got 37 MPG!!!! (The MPG computer stated this and he manually calculated it to confirm the figures).
One final thing for this post, the setting that I gave for a 3.9 is that setting that the 3.9 that I worked on needed, it certainly is not 'the' 3.9 setting!
One off rods = rods that I have either made from scratch or a standard rod that I have modified.
I can tell you that the rods are critical down to 1 thou of an inch so it takes some doing to modify them. I have been in a car which will run fine with a 69 thou rod in the cruise circuit, we then stuck 70 thou rods in the carb and we could not get the car off the drive. I would call that quite 'jet' fussy personally and why shouldn't it be? Real Steel hate these carbs because most engines will 'seem' to run OK even when very rich, what then happens is that the bores and piston rings get worn out after a couple of thousand miles. Again not really the fault of the carb, It just needs to be setup properly!
Also when they are setup well its quite surprising what MPG you can get out of them. Pauls SD1 runs a 4.6 with an Eddy 500 and a decent programable MSD system (including a programmable vac advance). On a recent trip up North doing 50 to 100 MPH he got 37 MPG!!!! (The MPG computer stated this and he manually calculated it to confirm the figures).
One final thing for this post, the setting that I gave for a 3.9 is that setting that the 3.9 that I worked on needed, it certainly is not 'the' 3.9 setting!
Last edited by sidecar on Wed Nov 11, 2015 4:24 pm, edited 5 times in total.
All, Sidecar,
Thank you for your patient advice regarding this. I completely understand that you can't suggest a rod jet combo that will suit my engine without testing the engine yourself. I think the only way forward is for me to try and get myself a wideband sensing kit. Something like a LC1. Sounds like it might pay for itself regarding fuel economy!!!!
Please could you put me in touch with your friend who has the jets. I have found a place that sells the calibration kit for £45. It might be worth me doing that.
Thank you for your patient advice regarding this. I completely understand that you can't suggest a rod jet combo that will suit my engine without testing the engine yourself. I think the only way forward is for me to try and get myself a wideband sensing kit. Something like a LC1. Sounds like it might pay for itself regarding fuel economy!!!!
Please could you put me in touch with your friend who has the jets. I have found a place that sells the calibration kit for £45. It might be worth me doing that.
You are totally on the right lines getting a wideband exhaust gas analyizer, there is a really good one which has data logging including vacuum that is all enclosed in a 52mm dial, the name of it escapes me at the moment! You can just mount it in an ABS box if you don't want it fitted to the car. remember to remove the Lambda probe too when you are not using it, they get knackered if they are left in the exhaust but not powered up.irony wrote:All, Sidecar,
Thank you for your patient advice regarding this. I completely understand that you can't suggest a rod jet combo that will suit my engine without testing the engine yourself. I think the only way forward is for me to try and get myself a wideband sensing kit. Something like a LC1. Sounds like it might pay for itself regarding fuel economy!!!!
Please could you put me in touch with your friend who has the jets. I have found a place that sells the calibration kit for £45. It might be worth me doing that.
45 quid for a calibration kit is OK BUT the problem with them is that if you are lucky there is 2 sets of rods that you can use and maybe 2 sets of jets! So in terms of value for money they are pretty crap! My mate will probably sell you the stuff a bit cheaper and the big deal is that you can then keep returning the stuff to try other stuff. PM me you mobile number and I'll past it on. Or you can just PM him actually. (MuscleManta on this forum).
PM me an email address and I'll send you my spreadsheet, you can use it to compare any jet and rod combo with any other.
Just before you splash any cash are you sure that the choke is not causing a rich mixture and also are you running a decent air filter? (Not one where the top is too close to the mouth of the carb?)
Where do you live?
