1972 Datsun 240z with stock SU carbs stalling at intersections! How do i solve this?

[Stanley]

A fan shroud helps too, when you're stuck in traffic on a hot day.

Without the restrictor, coolant might go through the radiator too fast, not giving it time to get cooled off.

[Stanley]

Also, I expect The pitch of the WP impeller would have been designed to work most efficiently with the thermostat in the system.

Real Nissan thermostats look like they're made better than the chain store type.

Edited March 30, 2014 by Stanley

[ronlaw28]

I was having the same issue with my 71, stock su's when stuck in traffic here in Florida. There is a laundry list of issues it could be. However, I would start with the cooling system. Make sure you have proper coolant mixture/level. Thermostat is important as well. Clutch fan should be checked for proper function. Next is tuning carbs- correct mixture and air flow. Next is checking timing (if too retarded, you will run hotter). If still persists after all if the above, you might have to consider whether you are having fuel percolation and/or vapor lock (that is what I had. Fixed by switching to electric fuel pump and wrapping my headers...but this was AFTER dealing with cooling system, carb sync, air/fuel mixture)...

[jalexquijano]

I was having the same issue with my 71, stock su's when stuck in traffic here in Florida. There is a laundry list of issues it could be. However, I would start with the cooling system. Make sure you have proper coolant mixture/level. Thermostat is important as well. Clutch fan should be checked for proper function. Next is tuning carbs- correct mixture and air flow. Next is checking timing (if too retarded, you will run hotter). If still persists after all if the above, you might have to consider whether you are having fuel percolation and/or vapor lock (that is what I had. Fixed by switching to electric fuel pump and wrapping my headers...but this was AFTER dealing with cooling system, carb sync, air/fuel mixture)...

I checked the fan yesterday when the car was cold and it is not spinning freely. If you turn it, it does not spin the full cycle. If this is the case, should i order a new fan clutch and wáter pump with gaskets also? Who sells origina OEM Nissan fan clutch and wáter pump? My car was made in January 1972 and carries a plastic fan blade

[ronlaw28]

I checked the fan yesterday when the car was cold and it is not spinning freely. If you turn it, it does not spin the full cycle. If this is the case, should i order a new fan clutch and wáter pump with gaskets also? Who sells origina OEM Nissan fan clutch and wáter pump? My car was made in January 1972 and carries a plastic fan blade

Sorry for the delay.

Not sure whether its the fan. Give a little acceleration and see whether the fan clutch engages. At idle, the clutch won't engage fully.

Check out Welcome To Motorsport & The Z Store! Nissan-Datsun 240Z-260Z-280Z-280ZX-300ZX(Z31/Z32)-350Z-370Z Parts!, Datsun 240Z, 260Z, 280Z, 280ZX and Mazda RX7 Auto Parts & Accessories, or eBay for replacement parts. I found a rep!acement assembly a couple of months ago on eBay for less than 100.00 .. I'll try to get you the link.

[z boy mn]

I've never had overheating issues with my Z, but others here in MN have when it gets really hot and muggy, especially in Twin Cities traffic.

What my PO did as a precaution was install an electric fan with a manual and temperature-controlled switch and took out the stock fan and clutch assembly completely. He also installed a 3-row aluminum radiator with a 180 degree thermostat.

As I mentioned, I can drive the z on hot days, sit in traffic, run it in a parking lot, and it never goes above 190. Of course, we have 2 feet of snow on the ground still, so maybe it just so cold here in the winters it never really warms up!

[jalexquijano]

Just to let all of you know that i replaced the wáter temperature sensor, the old original thermostat housing and swapped the thermostat from 180° to 160°. I tested the car under heavy traffic on a hot day and the termperature in the gauge only raised to half and a Little bit to the right. Othewise it keeps under half. So this problem is solved!

[tetert1]

First put clear hoses on your fuel lines to the carburetor so you can see if there's air bubbles vapor lock. Vapor lock will make your engine run lean and will make it die and hot exhaust manifold, Muffler, fuel line ,carburetor bowl ..if there is. Check your distributor and timing.. loosen the bolt on your distributor. Turning toward advance will make  engine cooler.. I sent mine from the center of the dial on distributor to the left.. or get a timing light from Harbor Freight $25.. always check the basics first

Edited March 28, 2020 by tetert1