914-V8 coolant system questions Options

[MM1]

To any of you current and former V8 conversion owners, I would appreciate your advice.

I’m nearing the end game of my coolant system overhaul (1965 Chevrolet stock, carbureted 283 in.³ V8) and I spoke with Don, the veteran at Renegade Hybrids, the other day for quite some time.

Don said he has done V8conversions on 914’s for 40 years.

He suggested two things for my current project:

1.) Cut two or three 1/8 inch holes into a 160° thermostat . I prefer to go with the OEM 180 and I’m wondering if I should cut one, two or three holes in it - my veteran Ford tech neighbor thought perhaps I should cut one ( he’s going to help me pressure test the system and then pull a vacuum to fill it if the radiator doesn’t leak after I removed those 30 year old hoses ).

2.) Burp the coolant system with the car nose down. Part of the reengineering/overhaul here is that I am adding Moroso expansion tank/coolant tank next to the engine as high as I can get it. The engine is actually nose down a bit so the Ford tech thinks that with the vacuum system we should be able to get every bit of air out of it but if we nose it down then maybe steam pockets or air will stay in the back of the heads since they are already higher than the front when the car is level on the ground.

Any thoughts/suggestions/experiences regarding the above?

Thank you all!

[FL000]

My memory is sketchy on the subject but I think the suggestion for drilling holes in the thermostat may have more to do with reducing cavitation on the mechanical water pump than getting air out of it. The original SBC wp has in internal bypass that the renegade setup does not. I drilled 2-3 small holes in my thermostat when I was running that setup.

I also sometimes would raise the rear of the car when adding fluid, but settled on checking and topping off the overflow tank as my routine for getting air out. After 3-4 heat cycles it should be free.

[MM1]

@FL000 , did you run an expansion tank in the rear?

This old conversion had an old round style Corvette expansion tank (Harrison - now DeWitts) in the front which makes no sense since it should be the highest point in the system which would be in the rear near the engine and above the thermostat housing .

I also plan on putting a three-quarter inch bleeder at a point just past the thermostat housing (still in the engine bay near the firewall -i.e. before the radiator) that I can keep lower than the expansion tank. When I want to bleed it I have enough slack to raise it up higher than the expansion tank and open the valve .

Based upon the system used in (modern) GT 40’s, I will not be routing a small line for overflow from the radiator because it would have to go down to the rocker and back up - apparently the GT 40 guys suggested just blocking that small hose and using it to purge any air from the top of the radiator if necessary .

Any thoughts on that ?

My memory is sketchy on the subject but I think the suggestion for drilling holes in the thermostat may have more to do with reducing cavitation on the mechanical water pump than getting air out of it. The original SBC wp has in internal bypass that the renegade setup does not. I drilled 2-3 small holes in my thermostat when I was running that setup.

I also sometimes would raise the rear of the car when adding fluid, but settled on checking and topping off the overflow tank as my routine for getting air out. After 3-4 heat cycles it should be free.