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How To Re-Curve Toyota 4Kc Distributor


redvalkyrie

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I'm looking to have my distributor re-curved. It's a stock 4KC dizzy in good working order. Engine currently features a Weber 38/38, carb base plate port matched for carb adapters and intake manifold carb opening. The dizzy is electronic but features a vacuum advance and retard.

 

I am using the big port intake manifold--it's been cleaned up on both ends.

 

I am also using a set of extractors.

 

As it's sit now--is it worth it to re-curve the dizzy's timing advance?

 

When I add my performance camshaft and reworked cylinder head?

 

I'm still under the assumption that Toyota ignition systems work just fine for most application. So, it seems like just re-curving the vacuum advance would be a good way to get some more power and throttle response.

 

Is this some I can do myself or do i have to send it out?

 

Thanks

JP

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People don't tend to touch the vacuum advance. I'm not 100% sure how you'd modify that, or even if it would be worth it. Generally re curving is done by change the springs and weights in the unit, but you need to know where you want to head with it. Generally with modified engines you have more initial advance, less overall advance, and it comes in sooner. You achieve this by heavier weights or lighter springs and by modifying the limits of the weights' movement. All up, it's a lot of research and experimentation, or just send it to someone with experience and the right gear to test it. Tell them your setup and save yourself a hell of a lot of hassle.

 

If you have the time and love experimenting, have a go. I love experimenting, but have no time, so I'd be getting someone else to do it :)

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Been there, done that-

 

http://www.rollaclub.com/board/topic/42407-the-girls-ke70/page__st__45

 

The vac advance is only to advance the timing at cruising speed when the mixture is running lean. It helps with fuel efficiency and emissions. The moment you accelerate it collapses and you run on the springs and weights.

 

Mark out the crank pulley and generate your own advance curve, and see how it compares to mine.

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