I believe you are confusing copper and brass. Copper conducts heat better than aluminum and aluminum conducts better that brass. Most radiators are either brass or aluminum, not copper.

Good thing too, otherwise every idiot around would be trying to steal your radiator $$

"The Master Cylinder"

Enjoying life at the beach in SOCAL

show me a engine manufacture ,or car builder that has no bypass to acomidate flow when stat closed,close the bypass and see how quickley you crack a head,or on a fresh eng you scuff a piston. re cavitation the concern is not damagto water pump, but ariated water
creates hot spots not shown on tempgauges(as theyrequire water to function).The other reason for a bypass to the water pump is to ensure the water pump has a consistent head of water as thrm opens and closes,hear again no airiated water(cavitation) if you own a boat with a outbord motor you can se cavitation on abrupt turns,engine over speeds etce. most yblockes that have cracked a cyl head have cooling isues and cavitation. look at the 2x4 alum intakes for sale on e bay,they badley eroded due to no anty freeze and cavitation.
I wont coment again on this topic as A # of ideas seem of the cuff with no factual info. cliff

The bypass is only restricted, not blocked and that restriction is accompanied by a few holes in the thermostat to allow more coolant to the radiator. This is a warm climate modification. The flow is not blocked off entirely. It just takes a different route.

I don't know if that is off the cuff, but several have done it and it achieved the goal.


Lawrenceville, GA

What size holes? Something like 3/32""? Maybe 3 or 4?

Drill three 3/16 holes, one on each side. You need to have a Robert Shaw/Mr. Gasket type thermostat.



Here is my previous post in this thread with a link to an old(er) discussion;



"The Master Cylinder"

Enjoying life at the beach in SOCAL

Link to other forum; http://forums.y-blocksforever.com/Topic83884.aspx?



Sorry if I hi-jacked you... I tend to wander...

"The Master Cylinder"

Enjoying life at the beach in SOCAL

MC thanks. I get everything from sub zero to 100+ here in the Pac NW. I've installed a 3 row aluminum radiator, a 195 Tstat and a 16" pusher fan. Is this bypass/Tstat thing something I should wait & do only if needed??

You may want to wait because I did notice the engine took a little longer to warm up because you have more coolant going thru the radiator before the thermostat opens and less recirculation thru the bypass. I live in SoCal where the temp doesn't fluctuate so much and never sees freezing ~45 to 80°F.

"The Master Cylinder"

Enjoying life at the beach in SOCAL

This has been discussed on here any number of times - and there are more than a few that have made these modifications and found them to their liking. I believe in performing functional tests (an engineers disease) and tried the "hose on the manifold bypass port" test as soon as a guy mentioned it to me. Thunderbirds are particularly sensitive to heating (small radiator and inefficient WP mounting) and Tucson has heat to spare. Letting that much hot water constantly bypass the radiator (even after the engine was warm) wasn't to my liking.

I know that my T-bird responded immediately to changing to the high flow thermostat - as predicted by the CASCO test you see on their site. It amounts to simply putting more water through the same radiator. Charlie has recently reported that to get a good one - the thermostat that Milodon now markets, seems to have a quality edge. I've been using the Mr. Gasket parts - and the 160º has worked well - the 180º stutters a bit. You could also drill the auxiliary passages in a large poppet style T-stat such as sold by NAPA (170º) - probably have to fit them around the edges.

The "three hole" (drilled) Robertshaw style thermostat can be seen on the Stewart waterpump site - and yes they are unfortunately, Chebbie oriented - but they are very competent. They use the drilled thermostats with a performance engine set-up to have NO bypass. When I asked about this, Ted advised using an orifice that still allowed a small free bypass passage. For the good reason of allowing any bubbles to exit the water pump cavity when the engine was stopped. Fact is - engines with the two modifications purge quite nicely when you are filling them with fresh coolant.

Yes the modification slows down the warm-up period - again, no big deal in SoCal or Arizona or points south - but noticeable in Michigan. Ford also used a small initial spark advance and ported vacuum advance on these engines - which leaves them clunking along quite retarded at idle - which also speeds warm-up. Most of us have added more initial advance - which makes for better performance of the engine in general - but the increased advance also slows warm-up. The sum of this could make an outfit pretty "cold blooded" in the extreme - but I've had some pretty nasty engine combos in cold climates - and enthusiasts live with it. I know I did - it wasn't my wife's car.

I put the smaller WP pulley on my engine after realizing that at hot idle - water flow into the top tank was (to be polite) very sluggish. My last restoration project was a '67 Cougar (289 automatic) and at idle it easily showed twice the water flow as the T-bird. The remedy was to use the 289 size upper pulley - yes it jacks up the WP revs, but it didn't hurt the Cougar and it had a higher hot idle speed in drive. What then occurred was the fan speed was too high to suit me - so I went looking for a thermostatic clutch (Hayden). They fit nicely on a T-bird - not so nicely on a sedan.

The sum of this is - that making the car behave to suit ME - required some thought and testing and "re-engineering" to get what I wanted. This sure isn't the total number of changes I've made in the name of reliability or performance - and there are more to come I'm sure. If some of the things I've tried or tested can help another of us - I'm going to share them.

 
 Steve Metzger       Tucson, Arizona

GB your info here is good to know. I signed up here to learn. And boy am I doing that! The W/P pulley I'm using is for a Chebbie big block. It's a bit smaller, haven't measured the difference yet. I'll be running two belts even though I only have an alternator to start with. Good place to keep a spare belt and it will look way cool. If any of you say you haven't done some mods just due to the cool factor, well, no I don't wanna buy a bridge.
OP have you given thought to using a smaller w/p pulley? Could be all you need