edelbrock tunning tip

[fdbdw]

tried this out today and it worked good so I thought I would pass it on.
start the motor and let it warm up, at idle speed and warm loosen the screw that holds the rod and spring door shut, the idle vacum should hold the door, shut if it doesnt you already know your spring is to strong. From there use a magnet to pull the door up giving you a view of the rod and piston, then you can use different throttle positions and watch the response. Ive also thought about cutting out a little piece of plastic to fit and screw it down so I can watch and tune. Hope this helps someone

[Wrenchbender Ret]

That sounds like a good idea. You could use a vacuum gauge to find what vacuum releases it.

[Sinister]

That's a pretty cool idea. Thanks.

[Hottrucks]

great tip but I have no clue what your talking about

[fdbdw]

Ya , I use a vacum gauge also , but watching it work is kind of cool and informative,

[oldblue1968chevy]

no idea what your talking about but sounds like ya know what your doin! lol

[Hottrucks]

Originally Posted by fdbdw

start the motor and let it warm up, at idle speed and warm loosen the screw that holds the rod and spring door shut, the idle vacum should hold the door, shut if it doesnt you already know your spring is to strong. From there use a magnet to pull the door up giving you a view of the rod and piston, then you can use different throttle positions and watch the response. Ive also thought about cutting out a little piece of plastic to fit and screw it down so I can watch and tune. Hope this helps someone

Originally Posted by oldblue1968chevy

no idea what your talking about but sounds like ya know what your doin! lol

I'm not sure what he means by the rod or door...I have always just used a vacum guage to adjust it with the 2 mixure screws on the front to get the highest vacum level...I understand jetting and such but this is unclear to me and I am always open to learn new stuff

[Sinister]

The primarys have metering rods and springs. There are little doors on the top of the carb to access them. This is a great tip for trying to figure out which springs to run.

[Hottrucks]

I looked at miine and see what he's talking about..I guess one of the reason I love the Edlbrocs is that they run very well out of the box..so I never fussed with it

[leddzepp]

Originally Posted by Hottrucks

I looked at miine and see what he's talking about..I guess one of the reason I love the Edlbrocs is that they run very well out of the box..so I never fussed with it

X 2. They also run very well even after sitting on a shelf for 10 yrs.

[fdbdw]

The metering have two stages, power and cruise, if you look at the rod it should be stamped (example 73/47) 73 would be the cruise mode which is the fatter portion of the rod plugging more of the jet letting less fuel flow through the jet, the 47 would be the power mode wich is the tapperd lower portion of the rod that plugges less of the jet letting more fuel flow though. Now the position of the rod in relation to the jet is controlled by vaccum that wants to pull the rod down into cruise mode and a spring under the piston that the rod is hooked to that wants to push the rod up into power mode. The spring and vaccum work against each other. At low rpm or cruising speed vaccum is high wich overcomes the spring pulling the rod down putting the cruise mode of the rod into the jet allowing less fuel flow. At hard acceleration or WOT, vaccum is low and the spring overcomes the vaccum pushing the rod up and putting the power mode portion of the rod in the jet allowing more fuel flow. If your spring is to strong it can overcome the vaccum and put your rod in the power mode at low rpm causing a rich mixture, or if your spring is to weak it will not overcome the vaccum leaving you in the cruise mode causing a lean stumble. Now all that being said you can and should still use a vaccum gauge when determining which spring is right for you, but the tip I posted is just that, a tip , I like many others like to tune and tinker. I had an idea, tried it and I thought it worked pretty well so I passed it on. If you like to take your carb out of the box mount it and trust that it is calibrated perfect for your application thats fine. I dont disagree that your carb is running fine but if you havent tuned it to your motor and elevation, I guarantee you are leaving some performance and economy at the table.

[Hottrucks]

thanx for taking the time to type that all out it makes a ton more sense now...

I take it you can buy diff springs to fine tune it

[Wrenchbender Ret]

Yes you can buy a kit from Edel. that has different springs, rods, & jets. You have to disasemble the carb to change the jets but the rods & springs can be change from the top.

[MESS-HALL]

Originally Posted by Wrenchbender Ret

Yes you can buy a kit from Edel. that has different springs, rods, & jets. You have to disasemble the carb to change the jets but the rods & springs can be change from the top.

The guy I bought my 67' from said he had "down-tuned" the motor to get better gas milage.(14 mph AVG.).....What he should have said was "I changed the springs, rods and jets in the carb". Now it is lacking power and not very responsive. So, I dont' need a new carb, I just need to get a new set of springs, etc....

Why would you put an RV cam in a 350 and then "down-tune" the carb?
Does not make sense to me. Anybody got an idea?

[COACHMEASON]

It would be SWEET if someone did a very detailed thread with many pics fine tuning a Edelbrock carb (of course b/c I have one)...I heard Edelbrocks are suppose to be pretty straight forward but I bet a thread by someone who KNOWS what they are doing would be very beneficial to members like myself...FAQ worthy possibly!!

[FLEET72]

Originally Posted by COACHMEASON

It would be SWEET if someone did a very detailed thread with many pics fine tuning a Edelbrock carb (of course b/c I have one)...I heard Edelbrocks are suppose to be pretty straight forward but I bet a thread by someone who KNOWS what they are doing would be very beneficial to members like myself...FAQ worthy possibly!!

How about some instructional VIDEOS, in particular Additional tuning part 1 and Additional tuning part 2. There's even a whole book about it.

[Hottrucks]

^^ nice I'm sure to make my truck run like junk when I'm done..LMAO

[FLEET72]

Originally Posted by Hottrucks

^^ nice I'm sure to make my truck run like junk when I'm done..LMAO

[COACHMEASON]

That will work too!! Thanks

Originally Posted by FLEET72

How about some instructional VIDEOS, in particular Additional tuning part 1 and Additional tuning part 2. There's even a whole book about it.

[FLEET72]

Originally Posted by COACHMEASON

That will work too!! Thanks

[lt704]

Hi fleet 72, thanks for the video link, very helpful