C2: '66 BB bypass w/AIR & AC

[Dan Pepper]

The smog pump on my '66 BB L36 runs out of belt adjustment because the AIR pump bumps into the H20 bypass hose. This causes the AC/AIR belt to rub a little on the underside of the hood brace when the hood is closed. It has worn a small groove into the hood brace. Both AC pump and AIR pumps are adjusted to max lowest belt clearence and the belt is a bit more loose than it should be.

Paragon offers a "L" shaped bypass fitting and "U" shaped bypass hose to allow more clearance/range of motion between the pump and the hose. The fitting is supposed to be pressed into the pump. First question:

For the "L" fitting to and "U" hose to create more clearance (I assume it's the same design as in some L79 bypass configs I've seen), the bypass fitting on the intake manifold needs to be turned from pointing straight fwd, 45 degrees to the left to accept the "U" hose. Does this make sense/sound right?

The waterpump bypass oulet is threaded with a standard fitting. Does this need to be reamed to a smooth surface in order to press fit the new "L" shaped fitting?

Finally, this is a mid-production car #15521 and is pretty much original w/54k miles, and it doesn't appear to have come with this elbow-type bypass fitting. Althought the car had a replacement H20 pump when I bought the car, the original intake fitting is pointing straight fwd like a standard BB bypass. Is there anyone else out there that can confirm whether or not the "L" fitting & "U" shaped hose were used on ALL '66 BB smog cars?

[mike mccagh]

Re: C2: '66 BB bypass w/AIR & AC

Dan: what i'm about to pass on is 67 big block K-19 info and i suspect that many on the 67 parts are configured like your 66. first of all, the H2O pump fitting and the intake fitting (coolant) aren't on a 45 degree angle but rather both are on a 90 deg angle.also note that the fittings are bent to produce a smooth 90 degree radius, not a squared off 90 deg bend. they press into the water pump and intake manifold.the 67 smog pump had a triangular piece removed from its main body, either on the line or at the mfgr's asembly line to allow more clearance between smog pump and the upper radiator hose. this triangular piece was not removed on the 66 smog pumps and the 66 pump wore away material from the upper radiator hose with use. gm recognized the interference problem and removed the triangular piece by 67.when i restored my 67 435/K19 15 years ago, i got the u-shaped rubber coolant bypass hose from richard fortier who then owned Paragon. the only 66 big block with K-19 that i'm aware of belongs to gary whitting, the owner of Quanta reproductions. they ad in driveline and gary is K 19 knowledgable. good luck, mike

[Joe L.]

Re: C2: '66 BB bypass w/AIR & AC

Dan-----

What is the casting number of the waterpump? I don't think that any GM casting #3856284 waterpumps, the only one ever originally used on any 1966 Corvette big block, used a threaded style bypass fitting. There's no practical way that I know of to convert a threaded style bypass fitting pump to a press fit type.

[Dan Pepper]

Re: C2: '66 BB bypass w/AIR & AC

This is a 284 pump. I assumed the fitting was threaded since it has a wide hex shoulder (just like most H20 pump fittings) above where it enters the pump body. But maybe it's not threaded...

As Mike mentioned in the previous post, I have seen a bypass fitting on ebay recently that had a radiused bend rather than a sharp bend. Can't remember if it was threaded though. I'll try pinging the guy from Quanta as well.

This car has AC, AIR, & PS, so there are a lot of hoses, belts and pulleys. I haven't seen any other cars like it for comparison, so I'm not sure what is "correct". According to Noland Adams, this is one of 23 with that combo, so I'm not sure what effort was given - if any - in St. Lou to engineering special parts for so few cars.

[Joe L.]

Re: C2: '66 BB bypass w/AIR & AC

Dan-----

The 90 degree bypass fitting used for 66-67 big block with AIR was a press-in type fitting. If your current fitting has a HEX fitting at the base, then it's definitely a threaded type. I've never seen a '284' pump with a threaded bypass fitting. I'm sure that none were used in PRODUCTION during the 65-68 period. It's possible they were in later SERVICE, but I don't think so.