[leeklm]

Helping friend with 66 gto, new 389 build that likes to run warmer than it should at 65mph+, but fine at low speed around town.

Engine shop bolted on a cast iron flow cooler pump, but I doubt they checked plate clearance. I am not familiar with the internals of this pump, does it still need to be clearanced to the plate like a traditional pump?

Car has aftermarket aluminum top tank radiator, new "heavy duty" clutch, and 18" aftermarket steel 7 blade fan. Has an aftermarket shroud in correct position, does have a gap on top side to radiator, but that should not really matter at 65mph.

Problem was definitely worse with vacuum advance not working, but now have that setup and have tried a couple of total advance settings at 44 and another going back to factory position at 48/49. It likes the higher setting.

After all of that, car was hanging around 195 on his 30 mile drive back home. Not bad, but was only around 80 degrees outside and he was driving 63 mph with 355 gears and 27" tire. Using a 180 high flow thermostat.

Short of potential clearance issues with the flow cooler, or moving from the 8" pump pulley to a 7", I am out of ideas!!

On a side note, engine ran at 180 in 45 degree weather last fall, and the old worn out 389 ran cool all the time last summer with stock pump and all else the same. The new 389 build even used the stock pump for a short time. We switched to the flow cooler due to some original heating issues on the build.

I am open and appreciate any suggestions!!





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[Scott65]

Which design Flowkooler impeller? I don't think it could hurt to tighten the clearance up if it's really loose. I can see the newer closed face impeller being more sensitive to wide gaps.

[leeklm]

This is the pump... https://butlerperformance.com/i-2445...tegory:1234740

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[Scott65]

Looks like they've changed again or added another option. Either way, it can't hurt, but some people here will tell you they've never even checked it. Others will swear it's critical. Mine is ballparked... Somewhere close to .060 clearance with the closed face impeller. The one shown in your picture is an open faced.(at least semi open faced) Looks like they're afraid to commit to a design...

[ZeGermanHam]

I don't use the FlowKooler water pump, but the prevailing philosophy is to just get the divider plate as close as you can without causing it to contact the impeller. Like Scott, I just ballparked mine.

You say the engine is new. How many miles are on it since being rebuilt? Did the same temp sending unit and water temp gauge get carried over from the old engine to this new one? Any other changes?

[gtospieg]

I would certainly check the clearance but at the same time add the smaller diameter wp pulley.

[leeklm]

"Did the same temp sending unit and water temp gauge get carried over from the old engine to this new one? Any other changes?"

Maybe a couple hundred miles plus a handful of pulls on the engine dyno. The tri power carbs were rebuilt, otherwise everything else is the same as before the rebuild. The engine ran a little rich on the dyno, so definitely not a lean condition.

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[chrisp]

Originally Posted by leeklm

"Did the same temp sending unit and water temp gauge get carried over from the old engine to this new one? Any other changes?"

Maybe a couple hundred miles plus a handful of pulls on the engine dyno. The tri power carbs were rebuilt, otherwise everything else is the same as before the rebuild. The engine ran a little rich on the dyno, so definitely not a lean condition.

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Rich on dyno @ what rpm or @ idle ?