recurving distributor
Thread Starter
Instructor
Joined: Jun 2001
Posts: 188
Likes: 0
From: nova scotia canada
recurving distributor
What is involved in recurving a distributor? My L-48 4-speed is completlely
redone except for the distributor (hei) and it sounds like i could really wake
up my mods with some work in this area.As far as iginition i do have an msd
6al box and blaster 2 coil but no one in my local area works on distributors.
what's involved?
thanx wade
redone except for the distributor (hei) and it sounds like i could really wake
up my mods with some work in this area.As far as iginition i do have an msd
6al box and blaster 2 coil but no one in my local area works on distributors.
what's involved?
thanx wade
Burning Brakes
Joined: Oct 2001
Posts: 1,241
Likes: 4
From: Okinawa Okinawa
Re: recurving distributor (Mystery Machine)
Lars is the one that needs to chime in on this. I am planning on doing the same thing or send it to him this winter.
Email lars at lars.grimsrud@lmco.com for information on his recurve kit. Can't remember how much but it isn't much for the increase in performance.
[Modified by scottw, 1:15 AM 9/24/2002]
Email lars at lars.grimsrud@lmco.com for information on his recurve kit. Can't remember how much but it isn't much for the increase in performance.
[Modified by scottw, 1:15 AM 9/24/2002]
Le Mans Master
Joined: Feb 1999
Posts: 6,807
Likes: 0
From: Hoosier
Cruise-In III Veteran
Re: recurving distributor (wadey)
The basics come down to having about 36 degrees of mechanical advance in at about 2700 rpm. The distributor usually has 22-24 degrees of mechanical built in. So if you set the full mechanical advance in at 2700, it should read 12-14 degrees at idle. If this is not acheivable you would want to change the springs to a lighter tension spring(s).
Use ported vacuum advance.
You should also check out the Tech Tips section, click the link at the top of this page.
[Modified by AlwaysWave, 7:16 PM 9/23/2002]
Use ported vacuum advance.
You should also check out the Tech Tips section, click the link at the top of this page.
[Modified by AlwaysWave, 7:16 PM 9/23/2002]
Drifting
Joined: Mar 2001
Posts: 1,514
Likes: 1
Re: recurving distributor (Mystery Machine)
Go to Corvette FAQ http://www.bokonon.net/corvettefaq
Under the "Engine" section there are some articles written by Lars.
Those should get you started. Recurving distributors is becoming a lost
art. But I can't believe all those Sun distributor machines are gone already
there must be someone in your area with one and someone who knowa how to use it.
Recurving a distributor involves setting up the centrifucal weights and springs
to get the spark to advance at the RPM and total advance thats optimum for your engine. A typical small block chevy likes a total of 36 degrees advance at the crank, that's intial + mechanical. Intial advance is what you set at idle with the vacuum advance disconnected, mechanical is what the weights add as RPM comes up. Vacuum advance adds even more, up to 52 degrees total(intial+mechanical+vacuum)at cruise and partial throttle to increase gas mileage.
That's just brief description, Lars' paper explains it in depth.
Scott
Under the "Engine" section there are some articles written by Lars.
Those should get you started. Recurving distributors is becoming a lost
art. But I can't believe all those Sun distributor machines are gone already
there must be someone in your area with one and someone who knowa how to use it.
Recurving a distributor involves setting up the centrifucal weights and springs
to get the spark to advance at the RPM and total advance thats optimum for your engine. A typical small block chevy likes a total of 36 degrees advance at the crank, that's intial + mechanical. Intial advance is what you set at idle with the vacuum advance disconnected, mechanical is what the weights add as RPM comes up. Vacuum advance adds even more, up to 52 degrees total(intial+mechanical+vacuum)at cruise and partial throttle to increase gas mileage.
That's just brief description, Lars' paper explains it in depth.
Scott
Melting Slicks
Joined: Feb 2000
Posts: 3,052
Likes: 0
From: Vancouver BC, Canada
Re: recurving distributor (wadey)
Simply put, recurving is altering the rate, start point, and end point of the mechanical advance. Factory settings are bias towards fuel economy and reduced emissions. There is significant room for performance gain.
Alterations are done by using different springs, weights, and bushings. Also, the internal parts of a distributor will be checked too minmize any errors.
Alterations are done by using different springs, weights, and bushings. Also, the internal parts of a distributor will be checked too minmize any errors.
Safety Car
Joined: Aug 2001
Posts: 3,685
Likes: 202
From: Waterford Mi
Re: recurving distributor (Turbo-Jet)
There is alittle more to it than changing the weights and springs. The lenght of travel is limited to around 14 degress. The stops need to be moved to allow for the needed travel to start at 8-10 degrees and get to the 36 degrees at 2700-3000rpm's. I had Lars check my distributor out for any neccesary repairs and adjustments. He then put it in a motor on a Dyno to make sure everything was perfect.
Drifting
Joined: Jul 2002
Posts: 1,855
Likes: 0
From: Cocoa Beach FL
Re: recurving distributor (Scott78)
Thanks for the link...that's a cool site with lots of good info. So, is it necessary to "recurve" an HEI setup? I have a brand new ZZ4, should I just drive it for a while? The only reason I ask is because I saw that Lars is going to be in my town in about a week. Maybe I should ask if he has time to check it out. :confused:
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