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DIY SU carb rebuilding


ZXT_bean

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First I will start off with a little back history. The car is a 77 280Z, the carbs are from a 72 240Z that had been sitting for quite a few years. 

 

This morning I swapped the carbs onto the 77'. It did fire up, but not very well. It was popping and back firing thru the carbs so I didnt get any further with it.

 

I know everyones first response will be to order the Z-therapy kits and video. At the current moment thats not an option, as funds are kinda tight as I just bought the car. I already ordered the kits from my local auto parts store as well as a new intake/exhaust gasket. 

 

My question is does anyone have any write up's or guide to rebuilding SU's at home with out the Z-Therapy video? Ive searched and searched and searched and keep coming up empty. 

 

Any help is greatly appreciated!!

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First I will start off with a little back history. The car is a 77 280Z, the carbs are from a 72 240Z that had been sitting for quite a few years. 

 

This morning I swapped the carbs onto the 77'. It did fire up, but not very well. It was popping and back firing thru the carbs so I didnt get any further with it.

 

I know everyones first response will be to order the Z-therapy kits and video. At the current moment thats not an option, as funds are kinda tight as I just bought the car. I already ordered the kits from my local auto parts store as well as a new intake/exhaust gasket. 

 

My question is does anyone have any write up's or guide to rebuilding SU's at home with out the Z-Therapy video? Ive searched and searched and searched and keep coming up empty. 

 

Any help is greatly appreciated!!

 

My first response would definitely NOT be to tear down and rebuild the carbs. As long as nothing is sticking, I bet that you can get it to run well unless the shafts have severe leaks. It's not a simple bolt-on and go affair, the carbs must be adjusted to run on your engine. Go through the procedure outlined in the FSM, Haynes, or countless posts online.

 

How did you come to the conclusion that they need a rebuild? All I'm getting from your post is that you bolted on the carbs, it didn't run right, so now you've decided to "rebuild" them.

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Do a Google search as there are several "How to rebuild/tune SU carbs" threads on several Z car websites.

 

 

 

"This morning I swapped the carbs onto the 77'. It did fire up, but not very well. It was popping and back firing thru the carbs so I didnt get any further with it."

 

This indicates a too lean condition. Do a search  for SU  mixture adjustments.

Edited by Miles
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well I figured a rebuild was just part of the process. 

 

Maybe im not searching the right term. Ive come across countless threads that just conclude with them being sent to Z-therapy. Ill keep looking. 

 

The shafts does not seem to have play, but im no expert. I know the littlest amount of deflection in the throttle shafts is not good at all. 

 

One question I do have is how much oil actually goes above the piston? 

Edited by ZXT_bean
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I wish I could download it here at work, but our systems lock you out of saving any sort of files. when I get home tonight I plan to thoroughly read thru the FSM and if I have enough time ill make it out to the garage and see what I can do. 

 

Sorry for being such a NOOB, normally I have delt with EFI and MegaSquirt. This is my first time encountering SU's. 

Thanks again

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