spark delay valve

Discussion in '1974 - 1978 Mustang II Talk & Tech' started by 1970impala, Dec 22, 2011.


  1. 1970impala

    1970impala Please God, somebody find me some WHITE CARGO PANE Founding Member

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    Hi, can anyone tell me what a spark delay valve is precisely and what is its function? Is a 77 cobra II 305 stock supposed to have one?
  2. 1970impala

    1970impala Please God, somebody find me some WHITE CARGO PANE Founding Member

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    err, 302. typing too fast..
  3. 75mach1

    75mach1 New Member

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    I have been dealing in mustang ii parts for along time and i have never heard of a spark delay valve. There is a spark delay box that retards or advances spark on race cars that have computer controlled spark.
  4. 1970impala

    1970impala Please God, somebody find me some WHITE CARGO PANE Founding Member

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    Hi, thanks for reply. I found ebay auctions out there for them and their compatability cahrt shows all mustang II's with 8 cyl. I just don't know. :shrug:
  5. 1970impala

    1970impala Please God, somebody find me some WHITE CARGO PANE Founding Member

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    does anyone have a vacuum diagram for the dist. to the carb or around that area? thanks
  6. 75mach1

    75mach1 New Member

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    I looked at the valve you are talking about on ebay. My ford followers and I always called these a vacuum check valve. On page 82 of the Haynes Ford Mustang ii (owners workshop manual) it talks about this valve. It says that a spark delay valve is incorperated in the system to delay spark vacuum to the distributor diaphragm unit for a predetermined time. There is a vacuum diagram on page 81 that shows a SDV valve. It is just like a vacuum check valve. There is alot of information in this book that is very helpful.
  7. 1970impala

    1970impala Please God, somebody find me some WHITE CARGO PANE Founding Member

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    this may be asking too much, but can you put on here the graphic potion of the vacuum line that this delay valve goes to, or does it show exactly where it goes, does it go between the carb and the distributor? thanks much
  8. 75mach1

    75mach1 New Member

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    I can try to get a picture of it. Yes it goes between the distributor and carb. There is a special port for the delay valve and a different port for the vacuum advance. I will try to post a picture of that also.

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