Recurve a Dizzy?

[Jason82FJ60]

JimC seems to be the master at this as i see him referred to when discussing this procedure. So I sure hope I can get him to answer this or anyone that knows the answer to my question. So here goes....

What exactly is done when you recurve your dizzy? Step by step would be great.

I plan on desmogging my rig as i have hesitation while driving during mid throttle. it sputters and falls on its nose then picks up again...and quite frankly i dont feel like trying to decipher all that spaghetti under there. unless someone knows whats wrong with it.

at any rate, i have the PDF downloaded, saved and printed out for a reference, i just dont understand what is meant exactly by recurving my distributor.

Thank you very much in advance. this site is the foremost knowledge base for these awesome rigs. I find myself coming here many times in my day to search for an answer. thank you again.

Jason

 

[TS888]

Recurving is adjusting the rate and or amount that the mechanical advance changes the timing relative to engine speed. It is done by changing the resistance of the springs, the mass of the weights, or both.

It's possible to do it yourself, I read an article once about a guy who even wound his own springs to get just the right tension. All the same, I'd suggest having the work done by someone with A) the right tools and B) experience. Probably cheaper than FUBARing your dizzy and having to buy a new one.

 

[SDFJ60JFK]

Tony is right.

As I Understand it Jim C has a distributor machine that allows him to do this the correct way. I think that the experience he has would be worth the $100 or so that he charges.

FUBAR > $100. Just a guess

John

 

[Jason82FJ60]

Tony is right.

As I Understand it Jim C has a distributor machine that allows him to do this the correct way. I think that the experience he has would be worth the $100 or so that he charges.

FUBAR > $100. Just a guess

John

fubar is always greater than $100.

thanks for the insight in this matter. now to get the ministry of finance (the ) to allow me to allocate funds. lol. i need to come up with a good story.

 

[Jason82FJ60]

one more question. is it absolutely necessary to get this done? or can i scrounge up an electronic dist?

i just not very knowledgeable about dizzy's. or carburetors. suspension is my thing.

 

[klinetime574]

I have been running my 2F desmogged for some time now. Haven't re-curved. Although I probably should. Running factory timing also. Maybe I should this summer...

 

[gregnash]

I have heard that while it is not adviseable to leave the vehicle running like that for years on end it will not necessarily damage anything (other than your wallet in the means of gas). From my understanding your engine will just not be running at the most "optimal" until the dizzy is recurved and the carb is rebuilt for the desmog (like I said, my understanding).

 

[1911]

one more question. is it absolutely necessary to get this done? or can i scrounge up an electronic dist?

Like my dear departed mom used to say, "you don't HAVE to do anything except die, and pay taxes".

It isn't a question of it being electronic or not; all (U.S. anyway) stock 60 dizzys are electronic already.

But to answer your question, it's not strictly necessary but it is worth it. One of the effects of the stock EGR system is to slightly retard the timing; the stock advance curve compensates for this with a faster advance curve (it reaches full advance sooner than it would on a non-EGR engine). So when you remove the EGR, now the existing advance curve is too aggressive. This can manifest itself by pinging under load (up a hill, etc.). If you don't want to re-curve the dizzy, you can just retard the base timing by a couple of degrees, until the pinging goes away. Sometimes you can get by with just running mid-grade gasoline. But by retarding the base timing you're going to lose a little power and efficiency on the top end, plus the option of advancing the base timing if you're taking a trip to the mountains (high altitude).

I ran my de-smogged 1980 40 for about a year with the stock dizzy retarded a hair and burning mid-grade gas. It ran fine, but it was a noticeable improvement in mileage and smooth running when I installed my Jim C.-rebuilt and re-curved 60 dizzy.

 

[TS888]

Huge disclaimer -- I did not start with a stock setup, the PO had done a half-arsed desmog when he installed a Weber. Perhaps ignorantly, because there are no symptoms of a problem, I have not validated that my dizzy is functioning to factory spec, other than confirming the vac advance works. And, no recurve.

That said, once I cleaned up the desmog, I set the base timing to around 10 degrees btdc, and performance is better. Given there is no sign of pinging at all, I'm planning to add a bit more advance. The gas(ahol) we get now is quite resistant to preignition. I may have to dial it back come summer.

 

[Spike Strip]

It's far easier to spend the $100 and have Jim C. do it with the dizzy rebuild. In addition to having the correct springs and being able to recurve (and check the specs) to your application, as well as knowing the proper rate of advance, he also replaces the almost always missing plastic bushings on the advance weight arm with custom brass ones.

 

[Jason82FJ60]

thank you for all the replies. i cannot say enough good things about this website and the people who frequent it.

since i only get a day off every once in awhile, first im gonna remove the carb and give it a good cleaning/rebuild/adjustment verification. then re-install it and see what happens. it wants to stumble during acceleration.

if that doesnt solve the issue, then i am definitely going to desmog and totally remove that out of the equation. i have almost all of the vacuum line replace with new quality line (i didnt buy enough, so gotta get more....dang this thing has alot of vacuum line lol)

to be frank, i just do not feel like trying to track down a smog issue. i prefer a simplified motor.

 

[gremlink0]

Jim C still doing recurves and Carb rebuilds?

Does Jim C. still do Re-curves and Carb rebuilds? I tried to email him a couple times with no response. Man-a-fre sells them re-curved but I hear such good things from the forum about Jim C's Work. I would much rather give him the work if he is still doing it. He might just be to busy because he does such good work.

Thanks

 

[Spike Strip]

Only if you pay him money.

FJ40Jim *AT* gmail dot com ....

He's prolly been busy or on vacation or on MUD or ... PM him.

And I'd much rather have Jim's rebuild and recurve; if you have a desmogged engine, only way to go.

http://tlcperformance.com/

 

[gremlink0]

Thanks Spike Strip,

Seems like the consensus is Jim C is the only way to go! I will be patient.

 

[Cougar cruiser]

I just picked up my cruiser after getting a Jim C dissy and carb put in. Waited roughly 3 months for it and it was worth the wait. De-slogged and recurred runs great. Can't say enough about the improvement. Also Tor in Mukilteo does great fast work.

 

[dorcom]

..... i have hesitation while driving during mid throttle. it sputters and falls on its nose then picks up again...

Jason

The probable culprit is a hole in the dual membrane vac advance . I had the same issue until one day I discovered that there was a leak between the primary to secondary membrane!

Quick solution: cap one port (the secondary with the blue VTV in the line). Plug the latter as well.

She'll roar....(again...?)

 

[dorcom]

PS Take your dizzy out and spin it on a bench drill or so with known or controllable RPM.
If you have a strobe light you can then tinker the advance-to-rpm.
(The ratio of cam to crank is 1:2 or half a cam rotation per a full crank rotation.
The dizzy to crank ratio is also half per full crankshaft rotation)
With the strobe light you can see how it/should advances in degrees from its original position.

 

[gremlink0]

Still no word from Jim C I was really hoping to get it mailed out sooner than later.

 

[fj60dave]

yes, what everyone has said...

I have performed all work/maintenance on my ride, except for a few items. Thinking that I know when to say when...I took my head to the local machine shop for valve work,etc...and shipped my carb and distributor to JimC for some love. It has been enough years that I forget exactly when it happened - but, i can recommend JimC or someone having intimate knowledge of these machines to perform this critical task. No way I could ever hit the learning curve on this one just doing my own. The price is fair and the results are solid.

 

[FJ40Jim]

Still no word from Jim C I was really hoping to get it mailed out sooner than later.

Sorry I missed your earlier email. Found it and responded.