1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Carb question

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Old 08-21-21, 01:15 PM
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Carb question

On a Nikki on a 79, is there a manifold or spacer between carb and engine?
Long story short, sent carb to a “rebuilder” that never returned it a couple of years ago. I’ve got a carb now but can’t remember if there was a manifold on it with vacuum ports.
If so guess I’ll need to hunt one up. Stripped Nikki, emissions gone except for choke stuff, so will I even need it?
Thanks.
Old 08-21-21, 03:01 PM
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yes, 79-80 is different from 81-85. i think Mazda still has them, its kind of pricey
Old 08-21-21, 03:14 PM
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Thanks, I’ll start searching. And no gaskets needed am I correct?
Old 08-22-21, 07:48 AM
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Correct, the phenolic spacer is the gasket.
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Old 08-25-21, 06:13 AM
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The only source of vacuum I need is for the distributor advance. There’s a couple of ports on the carb. Can I use one of those and do without the spacer?
Old 08-25-21, 02:20 PM
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No, the spacer is needed for spacer reasons, also it contains the proper vacuum ports. IIRC there are no ported vacuum sources on the carb.
Old 08-25-21, 11:39 PM
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There is one vacuum port on the carb that works for vacuum advance but it may not be present on the SA carbs. I know it's on the FB carbs because I use it for vac advance with my setup. It originally serves some purpose with the PCV system but works well for advance if the carb is stripped.

Depending on the carb model/year there are up to three accessible, timed vacuum ports that can be used for various things like vac advance. I can only remember the nipples for two of them off the top of my head though.
Old 08-26-21, 03:29 PM
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You need the spacer and the vacuum advance port is the second from the front of the spacer on the drivers side. The rest need to be capped. Use new silicone caps or if you use rubber ones, replace them every 5 years cause they will disintegrate and leak over time.
Old 08-26-21, 07:54 PM
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If I'm not mistaken, the spacer serves a heat dissipation function in addition to being the vacuum manifold.
Old 08-26-21, 08:19 PM
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Thanks guys I’ll start searching for one.
Old 08-27-21, 08:41 AM
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if you find a 81-85 part works shoot me a PM, i have a couple. if you have emission controls still it wont work for sure, but if you don't, then maybe
Old 08-27-21, 07:23 PM
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Originally Posted by j9fd3s
if you find a 81-85 part works shoot me a PM, i have a couple. if you have emission controls still it wont work for sure, but if you don't, then maybe
Thanks, I can’t see why it wouldn’t work but I’ll try to find out.
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