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No bubbles coming up in the swirl pot. That is the only fan as was fitted from the factory. A bigger fan will be fitted but for now a bigger fan will just cool the cool water in the radiator as the hot water from the engine never gets that far.

Tomorrow I'll pull the swirl pot and start the car to see if water gushes out of the open flange.

I can get water through the head and up to the swirl pot flange by simply pouring water into the top of the radiator. There is no obstruction. Same for the drain stop cock, no problems draining or flowing out when pouring water into the top of the radiator.

Nice looking swirl pot. Mine is similar but not near as nice.

Video of the swirl pot in action, or inaction. trim.C9CEA96F-7C19-4E29-9FA2-778830B4A255.MOV

Larger pulley and new (used) pump installed and same result. Under 5 minutes from cold engine to over 200F water temp while driving at 25-30mph, nose cone on, fan running. After engine shutdown, lower hose was very hot, upper hose was cool. Swirl pot was cool to the touch. There was some heat in the radiator but not much Before driving I noted no flow in the swirl pot, just some surge when lifting off the throttle. 2000-3000rpm, no flow in the swirl pot. I'm out of ideas.

I was able to get the crank pulley off. It came off surprisingly easy. The pulley only measures 3.8". I would need 2500rpm's to match the speed of the water pump with a 4.75" pulley at 2000rpm. Fingers crossed a new pump and pulley will resolve my issues. Otherwise, I'll be left with the head gasket and port cleaning, which doesn't excite me.

Found a spare pump and 4.75" pulley from my local club member. Will pick up tonight. How hard is it to pull the crank pulley off with the engine int he car? Near impossible I assume.

If my math is correct there is a 353rpm difference at the water pump between the 4.0" and 4.75" pulleys at 2000rpm on the tach. This would explain the higher rpm's I'm seeing regarding water flow in the swirl pot but should eventually move water through the radiator which I'm not seeing. So, I may have a combination of issues. This smaller crank pulley aligns with what the previous (2nd owner) told me, and some of the other things I'm noticing about the car, related to the car being used for racing by the first owner. - First gear is very different from a normal road going car, it's more for speed - hard to start from stopped and picks up speed quickly. I may need to address this later. - The lack of wiring for high beam, front running lights, and turn signals all around. - Windshield wipers but no motor or drive cable. - Seat back was cut in half so only seating for the driver.

Now that makes more sense. I doubled checked the measurements now that the water pump and V-belt are off the car. I can't get a caliper into the space to measure the crank pulley so that one is eye balled with a tape measure. Both numbers are confirmed with water pump pulley at 4.25" and crank at 4.0". And that crank measurement is generous. It might be a 100mm metric (3.94"). SENC, from the pictures of your engine it looks like your crank pulley overlaps your timing marks. Do you have any trouble timing the engine? My pulley has the timing notch on the outside of the pulley which, given the angle I have to hold the timing light, would make it difficult to see both marks.

Unfortunately, I can't remove and fill from the top hose. My spacing from radiator to swirl pot is very short with an 8" flex hose. So I have to remove the swirl pot to remove the top hose. The last time I filled the system that is what I did. Removed the top hose (and swirl pot) and filled the from the radiator until water cam out the thermostat opening. Put the swirl pot and top hose on and topped off the swirl pot. Made no difference. Swirl pot water cold, cylinder head water very hot. I think the pump doesn't have enough oomph to overcome the head pressure to reach the swirl pot. Pushes the water around the cylinders but not up into the swirl pot. I'll put the pump back on tomorrow and try the nose up filling.

My largest feeler gauge .75mm can just squeeze in. There is no slippage of the vanes to pulley. No bearing movement in any direction. Just can't see any issue with the pump.

These things are pretty simple. Just can't see what could cause this pump not to pump. Shaft is intact, seals are good, no damaged vanes. I'll pull the pump again and take another look. It's much easier when the radiator is not in the car

Mine looks like the one on the right. Are the new after market pumps better? If I'm going to change the pump I want to best one I can fit.

I just checked the thermostat opening again and a Thermostat won't help. There's nothing for the secondary valve to seal against so the thermostat would just open the passage to the swirl pot which is what I already have. It's starting to look like a bad pump.

I have done about a dozen flushes now. Water flows freely out all of the ports including the drain stop cock. The water has a redish tint but you can still see through it. No crap, sludge, or bits or rust coming out. It just doesn't seem to be pushing any water through the radiator. I just pulled the swirl pot again. The water in the swirl pot isn't even bath water temperature but the water in the head is smoking hot!

The impeller blades are cast and are open towards the pump.

Crank pulley is about 4" and the water pump pulley is about 4.25"

A bunch of update: For the previous test above I filled the coolant system from the swirl pot. Test results were as previously mentioned. When I opened the drain at the bottom of the radiator very little water came out. When the engine was run the water level stayed at the top of the swirl pot indicating a full system. I couple understand a little air but the radiator was nearly empty. Temperature probe test: I pulled the probe an placed it in a cup or boiling water along with a digital thermometer. I took data every 10 deg. while the water cooled. The end result is; 178deg on the digital thermometer = 178 on the dash gauge 90 deg on the thermometer = 105 on the gauge Next I filled the system from the top hose of the radiator. Took a lot more water this time. Filled until I saw water coming out the thermostat opening. Placed the swirl pot back on along with the top hose of the radiator and completed the fill from the swirl pot. So I know the system is now full of water. Started the engine and took it for a short drive <1mile at 25 to 30mph, nose cone on, fan running. The temp gauge continuously raised until I shut off the engine at 210deg. The faster I went, the faster the temp raised. The top hose is cold, the bottom hose is warm and both the top and bottom of the radiator are cold. There is no water flowing through the radiator! Could this just be a thermostat issue? Do I need the thermostat to shut off the re-circulation flow internal to the pump and force the flow through the radiator? If so, what part number is the correct thermostat?

The radiator was removed for cleaning. The bypass hose was temporary for engine flushing. I expected the temperature to rise in that scenario. What I did not expect was high water temperature and cool hose. Block was very hot where the probe is but the swirl pot water was lukewarm. The last test was done with the radiator back on, nose cone in place, and fan running. Still can't keep the temperature from running away. Bliping the throttle I could see flow in the swirl pot but also seemed to make the temperature rise faster. Once it cools, I'll try taking it out for a drive to see if normal driving can keep the temp under control.

Timing has been triple checked sine I was having trouble getting first fire. But worth a check.

Thanks SENC for the video. Mine appears to be about the same. I don't see "flow" until about 2500rpm and then it gushes when I lift off the throttle. Even with keeping the rpm's up between 2000 and 3000, temperature still rises pretty fast when standing still, nose cone on and fan running. I'm trying to tune the carbs but the coolant temp keeps shutting me down. My pump has the cast impeller. I'll try the air bleed stop cock and see if that helps.

My swirl pot bolts directly to the head where the thermostat would normally be. This is also where the temp probe is (in the head). I have had this open many times. It's wide open in this area. I can not see any restrictions. Because the home made swirl pot bolts directly to the head is why I don't think I can get a thermostat in there, the tube ID looks too small to go over a thermostat. Water flow freely from the swirl pot out of the pump inlet so I don't think there is much restriction in the block. I'm without a phone today otherwise I would shoot you guys some pictures.

SENC, I have a similar issue with my Elan S4. I don't see a lot of traffic where I am but when I do, A quick increase in rpm usually drops the temp. Everything on that car is stock too so no high efficiency fan, no electric water pump, etc. This seven seems to run much hotter.