Coolant bypass conversion for SBC?

[BlouDon]

The fairly standard 350 SBC in my C10 has no cooling issues whatsoever.

I come from a Jaguar (and Land Rover) background where all the engines I've ever been exposed to, have coolant bypass systems that work as follows:

1) When the thermostat is closed, the bypass system is open allowing coolant to be circulated by the water pump through the engine only but NOT through the radiator;
2) when the the thermostat is open, the bypass circuit is closed and then all coolant is circulated through the engine and the radiator.

This concept has several advantages:
1) when the thermostat is closed, coolant can still circulate. Revving the engine while still cold (not that one should of course) allows coolant to circulate but the important thing is that the PRESSURE on the outlet side of the water pump (inside the block and heads) can not skyrocket;
2) Why should this be an issue? I once experienced an engine (where the bypass had been blocked off) blowing out its welch plugs (freeze plugs) due to excessive pressure resulting from too high revs while the thermostat was still closed. This could also blow coolant pipes;
3) the engine (and coolant within the engine) warms up more uniformly. Chances of a hot spot developing is less.

I have realised that my SBC does not have such a coolant bypass circuit.

It should be dead easy to implement such a bypass circuit by:
1) Fitting a bypass equipped thermostat housing to the current thermostat position along with a bypass port just before or at the intake port of the waterpump; I have not yet been able to find such an item off the shelf.
2) fitting an inline thermostat (my LR Discovery 2 has one of those) with a bypass port on the intake side of the waterpump.

[truckster]

The reason you don't find a bypass system for a SBC is that it's just not an issue. The iron block is quite durable.

If you really want one, I suspect you'll have to fabricate it yourself.

[geezer#99]

If it’s a standard 350 it already has a bypass.
If it’s a vortec headed 350 you need to install a bypass from the intake to the water pump.

Which motor do you have?

[68Gold/white]

Every SBC DOES have a bypass system, you are just not seeing it.

That small hole below the water pump bolt hole on the pass side is the bypass on a SBC. Heavier duty SBC's, like medium duty trucks use a hose out the top of the water pump to the intake (looks similar to a big block setup). THe SBC's that use the hose, have an approximate one inch long piece of rod that just slips in that hole to block it off...

[weim55]

Originally Posted by 68Gold/white

Every SBC DOES have a bypass system, you are just not seeing it.

That small hole below the water pump bolt hole on the pass side is the bypass on a SBC. Heavier duty SBC's, like medium duty trucks use a hose out the top of the water pump to the intake (looks similar to a big block setup). THe SBC's that use the hose, have an approximate one inch long piece of rod that just slips in that hole to block it off...

Picture:

[chewychevy67]

65-67 Chevy small block engines in trucks had factory bypass. It had a piece mounted under the thermostat and a hose that runs to the top of the water pump