Avispa

Anyone know of a source for a radiator overflow reservoir that can be used in a big block C2 without cutting too many holes?

I have a continued burping problem on my '66 in hot weather, and now I remembered why my '65 didn't have that problem, even though it ran a bit hotter - I had an overflow reservoir on that car and it worked perfectly.

Thanks.

Ron Champe

Ebay has numerous recovery cans in various sizes and materials. Should you decide to go that route, buy one that is vented for air pockets and one that is also recirculating. Be Cool, although a little high in price is a good recovery can #70003 ? with a one tab install.

Ron Miller

I couldn't see why you couldn't use the small block reservoir on a big block, take a filler cap for the big block and weld a fitting into it the same size as is on the small block radiator. You might also have to change or modify the water pump, I believe (from memory again) that one of the smaller hoses on the small block connects there.

But, before I did that I believe I'd try and find the source of your problem. Big blocks weren't designed with the overflow reservoir and most have worked well for many years. I'm not a big block expert, but I expect you'll get some input regarding correction of your problem. I'd keep it as is and correct whatever's wrong, just me!

Mike Ward

I'm guessing that you have a radiator with an integral cap. If so, and this is the correct rad for your car, there is no benefit in adding an expansion tank to the system.

Check for a weak rad cap or overfilling of the system before trying to re-engineer things. There's a fill mark on the side of the rad, full is considered to be a few inches down from the neck.

BTW, no Corvette prior to 1973 had an overflow (coolant recovery) tank, they were all expansion tanks, different animal completely.

Vogie

I took a replica C2 expansion tank to a welding shop and had it converted to a recirculating recovery tank with a pressure relief filler neck and vent tube. Connected it all together with braided stainless. It looked really cool under the hood of my 67 Camaro next to the ZZ502 and aluminum radiator.

Avispa

I appreciate the recommendation. What I need is a true overflow reservoir with associated sealed-lip radiator cap. I have a correct radiator with cap on the tank for a big block. In fact I had it recored about 10 years ago with a five row, 3/8 tube spacing, 14 fin per inch core. That knocked 25 degrees off the "sitting in traffic" temperature, but I've never been able to solve the coolant pressure problem.

jim lockwood

Not true. The top tank radiator used on solid lifter '60s and some '61s was a true coolant recovery system. GM even patented it.

In the early '70s, GM went looking for owners of Corvettes with top tank radiators as part of a patent infringement case (not against the Corvette owners, obviously).

Jim

midyearvette

if you have a cap on the rad i would use the stock fill tank and convert it to a recovery system by capping off one nipple on the bottom and using the other side for a line connecting the over flow nipple at the rad.....then use the top nipple on the surge tank for the ground hose.....all you do then is install a VENTED cap on the rad and you have a true modern recovery system made from a part that belongs on a vette....i have used this for years on my big block and it runs mostly with no pressure in the system...

Mike Ward

You're right-:o. I was thinking only of the '73 and up type system where a plastic recovery tank was used.

There is still confusion in some of the posts above- the OP wants the function of a coolant recovery tank, not an expansion tank. Plumbing in a C2/earlyC3 style expansion tank as per factory hook up will not achieve that.

midyearvette

....yes you have to change the plumbing.....very easy to do as i outlined in my post and thought the pic would help.....

Mike Ward

I'm still wondering why the OP has a problem with coolant puking on the ground. Always best to go after root cause rather than to re-engineer.

midyearvette

...he could be running a vented cap and not know it....i see that constantly....

jim lockwood

A vented cap? On a radiator?

JohnZ

The photo below shows how the midyear pressure/vacuum-relief radiator cap works. With a hot engine, in pressure relief mode, if the system pressure exceeds the cap's rating, the pressure on the bottom of the cap exceeds the strength of the large coil spring, and the rubber primary cap seal lifts off the lower seal surface in the filler neck, allowing coolant to escape through the overflow nipple and dribble on the ground. When this occurs, the metal gasket in the top of the cap (which seals to the top of the filler neck) prevents coolant from leaking out under the cap.

When the engine is shut off and the system cools down, the cap is in vacuum relief mode. A slight vacuum is created in the cooling system as the coolant contracts; that vacuum opens the small circular vacuum valve in the center of the bottom of the cap, and the vacuum pulls in air through the overflow hose.

If you add a coolant recovery bottle (as on '73-up Corvettes) connected to the overflow hose nipple on the filler neck (with the end of the hose going to the bottom of the bottle), any purged coolant will go into the bottle (instead of on the ground), and during cool-down, the vacuum in the cooling system will draw coolant back into the radiator instead of air. The coolant recovery bottle isn't under pressure - it's vented to atmosphere at all times.

Avispa

John Z has it right. No, I'm nor running a vented cap. I'm running a repro stock 15 PSI radiator cap, and it DOES hold all 15 PSI.

I have had problems with radiator pressure since putting the current engine in the car in 1997. It's .040 over and two cylinders are sleeved, but the block has been pressure tested (no leaks), the cylinder leak down is close to zero, compression is perfect (175#) on all 8 cylinders and the engine dynos at 454 HP. Having said all that, the upper radiator hose gets hard as a rock even before the thermostat opens (160). For some reason this motor makes cooing system pressure that I've never seen in another motor. It doesn't overheat (runs on the thermostat if the outside temperature is below about 70) but puking is a constant problem. An overflow reservoir seems like a good solution to a problem whose source isn't yet identified.

midyearvette

try my method......it will work...a corvette tank would not look out of place on your vette and it won't start building pressure until it needs too, just like a newer system....good luck
ps....look my post #8 pic and the 5/8 hose connection reduced to 3/8 just on top of the battery,also the cap on the other nipple is visible too....simple to do ...you have to change the rad cap to a newer ,automatically vented style...

Mike Ward

Are you running the coolant at the recommended level? I think the line is about 4" down from the filler neck.

CorvetteMikeB

I just replaced the radiator hose on my 1965 Corvette. I filled the radiator overflow reservoir tank to maximum capacity. I think I might have put in too much radiator fluid in the reserve tank.
Will this be a problem?

Nowhere Man

yes it will puke out once warm. The tank is only to be filled half way. Just like it says on the side

phil2302

No.