TOPIC: Edelbrock

I think that with Edelbrock design it is more you can optimize than just the fuel pressure, Edelbrock standard design metering rods, jets and spring. I think that Edelbrock 1405/6 orginal design is made to match the standard vacuum range of an standard engine(and A/F ratio) and when you cut the groove and improve the vacuum everything changes. The vacuum controls the metering rods and spring when to open/close and the vacuum is also higher to the distributor for the vacuum advance. So if you can finetune all parameters correct I think that the fuel last longer and don`t forget to modify the sparkplugs and dont trust the PCV valve even if it is replaced, on my old Cadillac I removed the PCV valve and rerouted the hose direct to the air cleaner(Ron design . Is anyone thinking in my terms and maybe the needs for making special spring and other design to the metering rods, mods to the accpump spring and accpump jets and mods to the vacuum distributor advance curve??

I want one of Those gas analyzers for christmas but why are they so damned expensive

Best Regards
Peo Eliasson from Sweden

I am just now entering negotiations with both Edelbrock and Holley to see about their involvement by machining The Groove into their systems during the manufacturing process.

Part of my discussion with both will be what effect this alteration on the pressure curve will have on regulation by metering rods.

I suspect the spring power should be changed, but to what I am unsure. I believe Tracy Gallaway may be the best source on that data for now. He also lives a few miles from Summit Racing in Reno.

HI Peo and Ron. Yes Peo you're correct in your thinking. I've posted about this extensively before. Edelbrock Performer/Carter AFB is my favorite carb. I'm sure if you go to Edelbrock's website you will find loads of info about tuning kits for the Performer series carbs. Those kits contain primary rods, several sets of jets and several pairs of metering rod springs.
I dunno if there are any parts stores where you are that carry any of these, I use Summit Racing right here in Reno NV. Use the Edelbrock carb # like 1405 or 1406 to look for the tuning kits on Edelbrock's site. Peo it sounds like you already have good understanding of how these carb's work. One trick I found--take primary jet size# subtract first 2 digits of rod size# to get one number. Ex: .098-.073= 0.25.

.098 primary jet size
7347 rod size# (.073 thick step---cruise/idle vacuum conditions)
( .047 is thin step of rod, the tip end,WOT power
manifold vacuum low to zero)

So in this example I wind up w/ a single number, 25. I can do the same for the power step of the rod, that would be 49. Start with the stock rod/jet combo for whatever Performer you are dealing with or whatever is in there now. You can work with the charts Edelb. has for rod/jet combos, but once you "get" this idea you can do your own calculations as well. Point being--one reason Holley has dominated the 4 bbl. carburetor world is--they use jets with a single #. Easy to understand. So do this math trick and Edelb Performer (and older Carter AFB's, hey the Performer is based on the AFB, parts interchange physically) rod/jet combo's get MUCH easier to figure out, no?

Wow Ron that's awesome you are talking with Holley and Edelbrock!!

Tracyg Gadgetman Reno

Hi everyone! yes TracyG I know about Edelbrock tuning kits and tuning tips and I have done some tests with varios sets of rods, spring and jets but my experience is still that with the groove on a standard engine turns it in to a race car for example I have to modify the throttle linkage to another ratio to avoid burning rubber in every street corner it is fun but if your goal is to do a ecomodd...

I think that if you want to squeeze all the potential out of the groove maybe you have to do some hardcore mods to the carb and modify the ignition/vacuum advance curve.

My feeling is that there is a next level of tuning/optimizing an grooved carborator beyond Edelbrock tuning kit and their tuning tips and I Hope that many people can share Their experience on this forum

It is perfect that Ron talks to the carb manufacturer but that can take forever before they have done there own test and modify the manufacture process.

Thanks for your input TracyG

I'm just a curious amateur

Best Regards
Peo Eliasson, Sweden

Edelbrock carb heritage is from Carter
My suggestions is that don`t groove and modify your orginal Carter AFB for your old classic car get a newer Edelbrock instead, I think that Edelbrock has done some small design upgrade which is good so keep your old Carter AFB orginal.

Be carefull of your old classic orginal parts

Regard
Peo Eliasson, Sweden

Hi again Peo!

you are spot on about Carter/Edelbrock. You obviously know a lot more than the Average Bear here. Geez what vehicle/engine combo with a Performer carb did you Groove?

Must already have been hi Performance, or are there Traction issues:P ?! Is your carb setup to give a real big accelerator pump shot, for example?

I will admit I am still mystified why the Performer Ron Grooved on my buddy's huge '75 Lincoln 460 does so well--in contrast to the AFB on my Dodge 383 in my '68 Dodge 3/4 ton truck.I Grooved this one myself. Very different vehicles/engines to be sure. But my truck is 44 years old with 160 K miles, un-rebuilt. Still runs pretty strong, this truck I compare to a Battleship or a B-24 Liberator from WW2. Big strong tough, takes full attention to drive. Likes open country/roads, not congested tight situations.

I understand a fair amount about Carbs. The Carter/Edelb. design is the easiest freindliest most reliable one for 4 bbl's IMHO. Only big flaw is their electric choke's, again IMHO.

But other than the Groove, I'm not so familiar w/ custom mods to these carbs. What sort of ideas have you got, Peo? Im always ready to learn...

TracyG Gadgetman Reno

My setup is an old Cadillac -65 with a 429 Cubic Inch 340hk engine and a Edelbrock 600 (1406) and I try to improve my car over the years when I can Afford.
The summer in Sweden is short and I don't have much time to play with my Cadillac and I still testing different configuration from time to time.
So far
1.Replaced the original Carter AFB to a Edelbrock 600
2.Cut the Groove on the Carb(not Ron's grinding tool Sorry for that)
3.Test different metering rod, jets and spring
4.Lower the fuel pressure(with Edelbrock)
5.Removed the PCV valve and redirect the hose direct to the aircleaner
6.Replaced those crapy ignition wiring with a low resistant quality ones
7.Moved the Ignition coil from the original place on the intake manifold which is to hot for the coil(missfires only when to hot)
8.Changed the ratio of the gas linkage/throttle for better control with the gas pedal
9.Bigger gap on the spark plugs
10.Tested one time to disconnect the accpump linkage and to my surprise the car did run anyway(road test) not as good as before but without the groove I'm sure that the engine would have shut down or nearly when pressing the gas pedal.
11.Changed the old leakage Brake booster to a new one

Regard
Peo Eliasson from cold Sweden

Hey Peo! Wow that's a cool ride! I've been told that old Caddy's like yours had the engine basically "blueprinted" from factory. I.E. each cylinder bore measured, then pistons made in fractionally different diameters installed to match each cylinder. I've heard stories of old Caddy motors having monumental torque. Also I bet the compression ratio is well over 9 to 1.

So--dialing in that beast better than stock--no surprise you can break the tires loose on corners or otherwise!

I wonder how you Grooved that carb without Ron's bits. I know that off-the-shelf bits shaped like Ron's dont exist, I consulted w/ a master machinist, he'd never seen anything like 'em. I was wanting to Groove the iron throttle body from my Subaru carb w/o risking our valuable bits. In the end I had a certain industrial bit modified, used it to begin my Grooves, then finished with the small one from Ron. Interesting thing was how easy it was to cut iron! Mine was actually easier to control during cutting than any aluminum throttle body ( who woulda thought?)
I have a 5-cent question about the Groove and it's interaction w/ engines. Has to do with ratio of cylinder bore to stroke also rod angles. Would engines w/ bore legnths (swept area of cylinder-how far piston top descends in bore at bottom dead center) greater than bore diameter-also called "stroker" engines---would that be better than the reverse bore/stroke ratio. In other words does the greater distance pistons travel in "stroker" engines increase the vacuum pulse generated in the intake stroke, compared to the vacuum generated in an engine of same displacement with larger bore/shorter stroke?

I'm reasoning here that the longer piston stroke creates a faster piston acceleration since the piston must descend a greater distance during the same amount of time compared to an engine w/ shorter stroke. Seems to me since the intake vacuum is generated by that piston descending during the intake stroke--the faster it moves per unit of time the stronger the vacuum signal would be. But also the vacuum's intensity is also governed by how far open the throttle is. More the throttle is closed the stronger the vacuum is. So the long-stroke faster piston-speed engine should have stronger vacuum pulse off idle, so goes my guess here...?

If I remember correctly, Peo, I think those old Caddy motors had a longer stroke than cylinder bore diameter, plus they were basically factory-blueprinted. I don't know if anyone else knows their facts about the Caddy engines' specs. Or if anyone more knowledgeable can weigh in about my piston-speed to manifold vacuum ratio theory...I'm pretty sure other factors are involved like valve diameters, manifold design, etc. I do remember that those old Caddy's had gobs of torque, to rival anything else from Detroit in those days.

Another factor in engine dynamics is rod angle. In other words, when the piston is at the halfway point going down the bore, how far off vertical is the connecting rod? I remember reading in some Mopar-related magazine years ago, that the Chrysler 440 cu.in. engine had one of the very best rod angles, meaning that at 90 degrees after top dead center crank rotation, where piston is halfway down the bore, the point where the rod is at it's greatest angle offset from vertical straight up-and-down, the 440 had a shallower angle. Less angle offset from vertical the rod has here, means overall less stress on cylinder walls, pistons and rings. Meaning longer engine life, better ring sealing, etc. I'm gonna common sense guess here, therefore, better vacuum generation as well.

I dont know at all what the bore/stroke ratio or rod angle (or rod ratio, that's another thing) are for your Caddy. Whatever we have or are working on, that stuff is already "baked in". But things like this I'm sure are part of why some engines respond to the Groove better than others!

Well if you have made it this far and are still awake, thanks for suffering through my thinking with my fingers, Peo! PS-any pics of your Caddy project and of your Groove job(s) would be cool!

TracyG Gadgetman Reno

Hi TracyG!
What have you smoked
I respect Ron and his work, I would not talk about or show what I used for tools, but I can say so much that if you look through all the material that Ron has posted online so you can get an idea of ​​how to make and use, and if I only reaches 50% of Ron's fuel economy gain, I'm happy.

Anyone else here on the forum may be able to fill out your concerns about engine designs? I know that my Cadillac engine has 10.5 to 1 in compression ratio. But I thinking that with Ron's invention the engine runs cooler and maybe you can have higher compression without problem?

Objects of my thread was to try to see if anyone has managed to achieve some higher level of optimization of the Edelbrock carburetor with Ron's invention along with the ignition.

Thanks for your post TracyG and I hope you have a sense of humor

Regard
Peo Eliasson, Sweden

Hi again Peo!

LOL, well, I did drive for several miles behind a badly smoking diesel bus with my windows down the other day...

Yes I did wander off into wonder-land w/ my last reply! My sense of humor is quite varied and off the wall! No worries, it's all good!!

Ok, here is an idea for tuning your E-Brock carb: There is a tuning aid called the Colortune spark plug, basically a spark plug w/ a clear quartz or hi strength glass insulator. I have never used them but have read of using them on It allows you to view the color of combustion flame during engine operation. NOT to be used during driving, only in the driveway/shop. Try searching for this online, looks like some folks swear by them.

I'm sure you know about using a vacuum guage for tuning. There are only so many easy interfaces into altering the fuel delivery curve w/ the AFB type design. Carbs are crude compared to fuel injection of course. One could also use an exhaust gas analyzer if available.

You are also likely aware that to delay the onset of the power step of the metering rods, you switch to lighter strength piston springs.

It's cool that your Caddy has a high static compression ratio, that helps w/ efficiency!

Likely you are also aware of the many upgrades to ignition available...Better plug wires, cap/rotor, moving coil to cooler location are all a good start. Do you still use the stock point-style ignition? Personally I've always advocated beefing up the ignition first (ya gotta LIGHT that fire), then going into the fuel and other systems. Good ignition is the Foundation for a well-running engine.

Stay Warm up there, Peo!!

TracyG Gadgetman Reno

Tracy, you bring up an interesting point in the stroke aspect of the engine design.

I would suspect that indeed DOES have an effect on the wave formation, but am not a true expert in that field. It would be real cool to have more data from this perspective.

Way to go, amigo!

Tracy, Tacoma Carl (or any other guy), I finally installed the groved Edelbrock 1406 on my Chevy V8 350 Small Block with NO electronics onboard. Gaskets were changed on the engine, Sprark plug gapped 20% longer and grove perfectly done (Ron did it ). With stock fuel punp and metering rods and jets here are my problems: when trying to adjust the Idle Mixture Screws, I can alost screw both screws all the way in whithout having any effet (or just at the edge)on lowering the idle (I just followed the Edelbrock adjustment procedure on Youtude). Also, it seems, so far, the the exhaust is smelling as bad as before and that fuel consuption had not improved. Any comments on the next step for improving this setup ?
Much Thanks
Lapprentis