resurrecting a 1977 280Z

[MM569457]

42 minutes ago, SteveJ said:

Yep, it's not good when those are nasty. Don't forget about the last chance filters on the banjo fittings.

 

Where would the banjo fittings be that the last chance filter would be affixed to?

[SteveJ]

15 minutes ago, MM569457 said:

Where would the banjo fittings be that the last chance filter would be affixed to?

1. Make sure you have rebuild kits on hand. You need to replace gaskets and crush washers.
2. Attach the lid to the float bowl before you try to remove the bolt holding the banjo fitting in place.
3. Here's the filter: https://zcardepot.com/products/copy-of-fuel-filter-carburetor-oem-240z-260z-70-74?_pos=17&_sid=da1c07df2&_ss=r

[Racer X]

On 4/7/2023 at 6:52 PM, MM569457 said:

Could you adjust PSI on a mechanical pump? I’ll check the needle and floats

There isn’t any provision for adjustment to the stock mechanical pump, and electric pumps usually don’t have a regulated output. You need a fuel pressure regulator and a gauge (0 to 10 psi). The cheap regulators with the round adjustment dial aren’t worth the money or the trouble.

I recommend the Holley regulator (there are two, one for low psi settings, one for high psi, get the low psi one).

SU carburetors won’t tolerate pressure over 2 or 3 psi.

This is similar to what I have, 1 to 4 psi. The gauge can be plumbed into one of the outlets. 
 

[siteunseen]

Are you using a carb fuel rail, supply and return? That's where the reducer is. Small hole on return keeps it bottled down to 3-ish pounds.

[Patcon]

Maybe the return orifice is blocked?

[siteunseen]

This seems like a good regulator for not too much money. I ran a Holley blue low pressure pump and regulator on my boat and it was flawless for years, high cost up front though. This is one from amazon.com 

 

https://www.amazon.com/Universal-Adjustable-Regulator-Injection-Accessories/dp/B08S757C76/ref=asc_df_B08S757C76/?tag=hyprod-20&linkCode=df0&hvadid=507600687300&hvpos=&hvnetw=g&hvrand=15473091677829872037&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=200524&hvtargid=pla-1212457430535&psc=1

[MM569457]

7 hours ago, siteunseen said:

Are you using a carb fuel rail, supply and return? That's where the reducer is. Small hole on return keeps it bottled down to 3-ish pounds.

I am.

[MM569457]

I hope I didn’t mess the floats up too badly. There is a Z specific shop about 5 miles from the house I can drive to and have them install exhaust and carb work.

 

My primary concern/worry is leaking carb while driving.

[Mark Maras]

If I wasn't going to fix them myself, I'd remove them and take them to a mechanic to adjust the floats rather than risk a fire. My last resort would be drive it with a fire extinguisher handy.

[MM569457]

Exactly!!!! I’m waiting for rising sun performance to open this morning. I’ll call ahead and drop off the floats for them to set to an appropriate level.

They do exhaust installation work so I’ll have them tune the carbs when I return to drop the car off.

 

[Racer X]

20 hours ago, siteunseen said:

Are you using a carb fuel rail, supply and return? That's where the reducer is. Small hole on return keeps it bottled down to 3-ish pounds.

Pressure is the result of resistance to flow.

So, a small hole in the return line would only serve to increase pressure in the fuel system, and do nothing to regulate it. The pressure regulator needs to be inline before the carburetors to manage fuel system pressure.

Providing correct system pressure is important because excessive pressure will force the fuel past the needle and seat, overfilling the float bowls and increasing the risk of a fire.

[MM569457]

9 minutes ago, Racer X said:

Pressure is the result of resistance to flow.

So, a small hole in the return line would only serve to increase pressure in the fuel system, and do nothing to regulate it. The pressure regulator needs to be inline before the carburetors to manage fuel system pressure.

Providing correct system pressure is important because excessive pressure will force the fuel past the needle and seat, overfilling the float bowls and increasing the risk of a fire.

A few weeks ago the front carb did spit out fuel through the vent hose ontop of the float chamber. I'd assume the best place for a regulator would be after the mechanical fuel pump before going into the fuel rail?

Edited April 10, 2023 by MM569457