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Mikes Z car

intake mainfold to carb spacer gaskets

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Pulled the carbs off of my 240Z today to have them reworked.  There is no gasket between the spacer on the intake manifold and the intake manifold, is one supposed to be there?  More directly can the lack of a gasket there cause an air leak?  My car seems to have variable mixture making me think there is an air leak somewhere though I never tried the carburetor spray test.

IMG_3439 phenolic spacer text added.jpg

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21 minutes ago, Mikes Z car said:

is one supposed to be there?  More directly can the lack of a gasket there cause an air leak?

Yes and yes.

Most noticeable at idle, and could possibly be affected by temperature.

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Thank you siteunseen, Captain Obvious and 7tooZ, very helpful information.  I was having fairly severe idle issues.  I now see the missing gaskets on eBay.  My car needs the insulator to intake manifold gasket with no holes as there are no holes in the intake manifold surface that mates to the carbs.  I guess some intake manifolds actually put hot water through the carbs but not on my car.

IMG_3461 Water tube on my car but no holes.jpg

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9 hours ago, Mikes Z car said:

some intake manifolds actually put hot water through the carbs but not on my car.

72 does that. That's the only year that pushes coolant from intake manifold into the carbs.

Good luck and here's to hoping the fix was as easy as a couple new gaskets!

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The block with a gasket on each side is a little pricey, but you can also just get paper gaskets for the block you have.  They are the same as Austin Healey carbs.  Gaskets are a dollar or so apiece.  If you can't find any, try Z Therapy.  I think they're listed on their web site.

Dennis

Edited by psdenno

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9 hours ago, 7tooZ said:

My July 71 did!

Cool. So you had the three screw round tops?  Was it titled as a 72 being built that late in the year, and you think the carbs were original?

Maybe a transition period at the end of the 71 run? Everybody talks about the mid-year changes in 74. Maybe they did that kind of stuff in other years too.  :)

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No it was titled as a 71. My understanding is that dealers in each state titled them differently. Also I heard that in our state because there was no MSO (manufacturer’s statement of origin) from Japan the title work was loosely controlled. I have always considered it to be a Series II. No hatch vents, non solid steering wheel spikes, second gen seat belts, storage boxes instead of storage compartments. Etc...

 

 

Sent from my iPhone using Classic Zcar Club mobile

 

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On 26/10/2017 at 7:36 AM, Captain Obvious said:

72 does that. That's the only year that pushes coolant from intake manifold into the carbs.

Good luck and here's to hoping the fix was as easy as a couple new gaskets!

I removed this inline intake manifold and place some brass nuts at the ends of bothe carbs. Does this have any effect on then performance of the car once started? I live on a tropical weather country were no heater is needed.

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1 hour ago, tzagi1 said:

PS, leave the water system alone, removing it will hurt drivability on warm up and gas millage.

 

I'm sorry but I disagree. If I lived in a colder climate, maybe but my carbs are cool to the touch after a good drive since I plugged those coolant lines. 

Gas mileage in my situation is I must drive the car to keep the fuel from losing octane.  It's my favorite chore I have, driving my Zs to burn the flat gas.  Life is tough at my house. ROFL

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  Thank you for taking the time to type in the gasket making information.  I wondered what type of cardboard might work.

  siteunseen,

   Not knowing a lot about carbs I left the carb water heating hooked up with my only reasoning being that the manufacturer knows more about carbs than I do, though I am willing to do independent thinking too, and to take advice from forum members to possibly remove carb water heating.  I live in a warm Arizona climate.  I should be able to evaluate carb performance in this climate better once I get them reinstalled on the car and have an opportunity to drive the car when it is really hot.  Since I recently relocated, I haven't been here for the hot part of summer yet.   

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I ran the factory design for years.  After I rebuilt the motor I read up on what I could delete to simplify the engine bay's looks.

It'll run fine in my opinion with the coolant flowing. I eliminated potential hose failure is all.  Nothing to do with performance. 

Hopefully you'll have it on the road soon. :)

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That was my thought for water heat removal, get rid of hoses that might fail.  Should get the carbs back from Z therapy around the end of December.  Can't wait for that!

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