429/460 Overheating Issue

[cycleguy55]

Originally Posted by Speedwaypj

Update:
- I R&R intake gasket with Fel-Pro which block the exhaust cross-over.
- I used the "Cooling System Vacuum Purge And Refill Kit" to try to eliminate any air pockets.....it actually worked pretty well.
- I did add the bleed lines to the intake. I drilled a hole in each intake side matching the (blocked) head water ports. Tapped (1/8 NPT) for small hose fittings and connected them with a "T" and then ran it to the gooseneck.
As I mentioned previously the radiator is new; but I have taken it off again and back flushed.....seems to flow fine.

- Results. ( 80+F) ...not much difference.....(I have an in-line radiator cap - no surge tank yet - on order)....I used a "Spill-free-funnel" to be able to monitor it.
- It pushed out about a pint+ or so....it started from about 5 minutes on.
- Also notices very tiny bubbles occasionally....from 15 minutes and even some at 45 minutes.
- I also ran a Strong garage fan on the radiator the whole time....at 40 minutes it was at 195,....when I turned the Fan off for 3 minutes, it went to 210; turned fan back on and it went down to 205.
- When I revved the engine for a minute it would drop a few degrees.

My goal is to keep the mechanical fan, build a better shroud and add two front fans (ERA type). (yes I'm sure the Mark VIII fans would work best).

Next - integrate the expansion/surge tank (and overflow tank);
- Maybe get an undersize water pump pulley.

Again, thanks all!
PJ

Perhaps I missed it, but I haven't seen any posts about the normal expansion / contraction of coolant in the system. Coolant expands at about 7% per 100°C / 212°F of temperature rise. That's why coolant recovery bottles have separate marks for Cold and Hot.

If your engine is 'cold' at 70°F, then going to 210°F, that's a rise of 140°F, and the coolant will expand about 4.6% (140 ÷ 212 x 7% = 4.6%). Assuming a total coolant volume of 15 quarts, the amount of expansion will be 0.69 quarts, or about 22 ounces or 1.38 pints (15 x 4.6% = 0.69).

It would appear the "pint + or so" amount of coolant being pushed out is quite typical - certainly well within the range of 'normal'.

BTW, running a 21# cap is okay if your system is designed and built for that level of pressure. Many cooling systems, OTOH, were designed for 15 PSI or lower and won't handle that pressure reliably. You have a new radiator, so may not have any issues running that kind of cap, but I would be cautious about using a higher pressure cap than the system is designed for.