There was a post some time back that this helps cooling on the T-Birds. I believe they said use a 3/8 pipe plug with a 1/8" hole drilled in it. Do I have this right? Not sure of the hole size.

1/8 inch diameter - that will do just fine - the brass 3/8 pipe plug will then screw into the short 5/8 hose coming out of the t-stat housing. Simply changes the amount of water that bypasses the radiator and recirculates "hot". Works on any of the engines - not just the T-birds.

 
 Steve Metzger       Tucson, Arizona

Worked for me, Along with a smaller water pump pully off a 302 Mustang...


56 Vic, B'Ville 200 MPH Club Member, So Cal.

Thanks. Thought I was right but better to double check than to be wrong. Wrote it down and lost the note.

Hmm this sounds interesting and I may try this when I put my new motor in since I will be generating a lot more heat with my higher compression. My only concern, is a 1/8 hole large enough as to not dead head the water pump until the thermostat opens? 

I love the smell of burning rubber in the morning!

Dead heading is not much of an issue due to the centrifugal nature of the pump but some degree of hole in the bypass is needed simply to bleed the air from the top of the timing cover housing before the coolant flow goes back down to enter the block.  I’d be happier with a 3/16” or 1/4" hole size just to insure a piece of debris doesn’t clog the smaller sized hole.

Lorena, Texas (South of Waco)

I don't think you'll have a problem, Rob.  I think the restrictor is accompanied by a few extra holes in the thermostat, so a little coolant is flowing through the radiator right off the bat.  These modifications make it take longer to get up to temp, which may not be favorable in your cooler climate.

I've been observing pulleys recently and the Y Block cars tend to have quite large diameter pulleys.  More modern cars tend to have smaller pulleys. Y Block trucks have smaller pulleys, similar to those of modern cars.  Larger pulley = less pump rpm = less coolant flow at idle and less airflow at idle since the fan is attached.  My temp does creep up in summer, if I get caught in traffic.
I'm running a car pump and pulley, which is about 7 1/4" dia and that works out to about 10% underdrive for the pump.  I'm working on a project now that requires new pulleys so I will make the crank to pump ratio 1:1 to speed up the pump and fan and we'll see this summer what that does.  When I race, I set the idle speed at 1000rpm and I don't notice that issue at that rpm, so it does suggest that the pump is simply turning too slowly at my normal idle speed.  No restrictor, yet.



Lawrenceville, GA

my opinion is leave the bypass alone,refer to the post of the 55bird that found haveing all the original shrouding and a new rad or recored  cured heating isues in hot weather conditions.to have heads survive you need circulation when stat closed, when you have hot spots you have steam ,when you have steam the temp guage does not register. nothing wrong with a slightley smaler pulley,but with smaller pulley  and restricted bypass you will most likeley get cavitation,which is airiated watter which is cracked heads . or fresh engine scored piston ,blowen head gasket. modern engines have water punps with better impellers that work ok with higher speeds.. Ihave rebuilt 2 55 tbirds over several years,1st 1 was powered with a 312and some goodies. recored rad proper shroud,never got hot,even on hot summer days. 2nd one 292 bored to 312 bore,iskey cam no heating isues. my sugestion is service your rad and shrouding,and be aware of modern rad cleanig is poor at best. costic tankes ar not legal hear in bc,rad shops use sonic meathed which is ng. recor is the best .

I personally wouldn't recommend restricting the bypass tube.  That is just asking for trouble as that is what allows water to circulate through the block till the thermostat opens.  Now if you have a heater that does not have some form of hot water valve either manual or vacuum then you could block off the bypass completely and not have a problem as the heater core is operating as the bypass to keep water circulating in the block.

When it comes to temperatures air flow is what you want.  If you are not pulling enough air through your radiator then you wont do much cooling.  Then throw in the fact that not all of these Y-block equipped cars came with fan shrouds you are now having more low rpm cooling issues.

I personally don't think there is a problem with the factory setup long as you are stock.  Ive let mine idle at 600 rpm for almost an hour and the temp gauge just would not get past the low side of normal.  This is also including the fact that I have a radiator that has four tubes separated from the top tank and a 30+ year old belt that might be allowing some slippage.

I would also recommend if you are going to be making more power or you just want more cooling they sell reproduction radiators that has more cores per inch resulting in better cooling over the oem stock radiator.  I would go with one of theses personally but all of them have cooler hook ups in them and mine is air cooled, I am too picky to just plug the fittings, so that is something else to think about if someone is picky like that as well.


1956 Ford Fairlane Town Sedan - 292 Y8 - Ford-O-Matic - 155,000 mi

THANKS for coming in on this, Cliff and Rusty_S85,

A cooling system overheating issue has haunted the '55-'57 'Birds as I recall.  I wonder if it is related to the water pump bypass discussion, though.

My recollection of an entry on a thread some time ago was that Ted Eaton made the point that the cast iron spacer used between the 'Bird water pump and the timing chain cover diminishes the ability of the 'Bird water pump to work effectively, particularly in low speed (parade type) vehicle operation. 

It seems like there was also a comment that the SS (?) fins added to the 'Bird water pump impeller by CASCO Supply did help the apparent low speed vehicle operating temperature problem.  Again, this is IF you were using the 'Bird-only water pump-to-timing chain cover cast iron spacer. 

A suggested alternative (IF I remember right, from Ted) for the '55-'57 'Bird was to eliminate the water pump to timing chain cover cast iron spacer and instead use an appropriate water pump pulley spacer to align the pump pulley with the 'Bird crankshaft damper pulley.

Can someone confirm my recollection?


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York