I'm in the middle of a motor swap and doing all the things I've been wanting to do while the new (used) motor is out of the car before it goes in. One of the big things on that list is eliminating all the superfluous coolant lines. I have everything cut down to what I think is the bare essential but wanted to run it by you guys in case I misunderstand how the system works. Don't want to ruin the thing. Among a million coolant/reroute related threads out here, there's so much unrelated information I'm having trouble finding the answer I'm looking for.

This is for a 1.6 mind you.. essentially everything is removed/blocked off except for the main coolant path from back of head through GM hose to radiator then back to water pump/block. The water neck on the front of the block is completely removed replaced by a block-off plate. This means no more water lines to throttle body or intake manifold and the hard line that runs under the exhaust manifold is gone (no heater core).

At this point, coolant has only one flow path. As I see it, with thermostat closed the water pump just circulates water through the head with nowhere else to go. Then when it opens, the only path is out the head, through the reroute to the radiator, then back into the water pump.

Is this acceptable or is it necessary to have some other path for flow when the thermostat is closed? If so, should the thermostat be gutted?

Thanks
-Ryan

 

Small hole in the Tstat maybe (which makes warmup longer), otherwise it's a trusted old design of cooling.
You will warm up without load anyway (because racecar) so there should be no risk of getting hot spots before the Tstat starts to regulate flow.

 

Yes, you'll want a hole in the thermostat to allow water to flow. Otherwise, the thermostat will basically be the bouncer at your local club. The guy in front is have a nice chat with the thermostat, while the back of the line around the block (get it?) is getting pissed and hot headed (get it?).

Basically you'll have hot(ter) spots.

Once you've blocked off the two idle valves (one below the throttle body and one on the side of the intake manifold), you'll just have the feed for those lines on the back of the head, the side of the intake manifold, and the mixing manifold.

All of them can be twisted/pulled out with a set of vice grips, then drilled and tapped for 1/8 NPT plugs. Much better than rubber caps clamped on that like to leak after a season of tracking.

 

I've got pictures of each of the locations Curly mentioned with a brass NPT plug in my Silver car build thread.

About to do the same to the Red car.

The way to tune the permanent hole in the thermostat is to observe temp gauge behavior during warmup. If the hole is too small, then you will notice that it seems to get too hot and then all of a sudden drops to normal temp once the thermostat opens and starts regulating. If the hole is too big, then it will just take a long time to warmup. In for your results!

 

Thanks for the input guys. Don't really want to repeatedly pull the thermostat off the back of the head to "tune" the bypass hole size once everything is back in the car.. going to err on the side of going a little bigger, probably 1/4" or so, not concerned about warming up too slowly - one warmup lap should do it

 

Went with a 1/4" hole, will try to remember to report back here once the car is up and running with how it behaves.