Water pump for an L31?

[garyd1961]

If you have just a heater and no ac the heater can serve as the bypass.

[msg]

Originally Posted by Tom

They are all fine, water pumps last forever on these things. No need for hi volume unless you have a massive HP build which it seems you don't.

Thanks Tom, I guess the AC Delco then.

Originally Posted by sweetk30

yes that hose .

and the port might be in the block to the water jacket area but the head surface to head hole is not there . this is why you need a bypass hose . the true vortec L31 installs from gm the water pump has a hose and the intake has the spot for it .

The AC Delco I was looking at on Rockautos has a port like what I had before so I think connecting that to the manifold is the bypass I would run.

The Edelbrock intake manifold I bought is this one

https://www.summitracing.com/parts/EDL-2116

Originally Posted by garyd1961

If you have just a heater and no ac the heater can serve as the bypass.

The Vintage Air Surefit AC system will be added this time removing the heater from the firewall so it sounds like the water pump smaller port connected with a hose to the intake is what I need to do.

[sweetk30]

Originally Posted by garyd1961

If you have just a heater and no ac the heater can serve as the bypass.

some get away with this some dont . . . mine did NOT like it .

and the intake the O.P. posted from edelbrock has the bypass port in the front just under the t-stat . its a 3/8" pipe thread . i used a 3/8" pipe to 5/8" hose barb fitting from these guys in the intake . https://www.ebay.com/itm/5-8-HOSE-BA...72.m2749.l2649

then a molded 45* hose from the local napa / carquest rack to the water pump port on top almost dead in line with the intake port . hooked them up and ZERO problems ever since then .

here is my thread on this problem and lots of people posted info and pics to back it up . and post #42 on 2nd page has my exact fix and hose part# . http://67-72chevytrucks.com/vboard/s...d.php?t=778518

[msg]

Sweetk30, looks like the bypass parts were included in the intake kit. There is a straight type barb though not the 45 degree type and a plug which I guess is in case you arent using the bybass hose to the manifold.

Question on the water pump install, do you guys use rtv at all on the metal surface and then stick the gasket on it or gasket only? Ive seen a spec of 30 ft lbs of torque used for the bolts, sound right?

[sweetk30]

i do a super thin skim or use red & tacky thats it on both faces that get a gasket .

[msg]

Looks like the 45 degree hose barb fitting is what I need just like you said. The instructions on this intake assume the user knows anything about them. No listing of what the holes are for in the manifold. Compared to my original 350 setup the only ones I recognize are the thermostat housing large port and the water pump I assume is the port I threaded the barb they supplied into. The other 2 I think were for heater hoses? I guess I need plugs then if thats the case since the vintage air system is self contained.

How do you mold the hose to get the angle right?

[tdangle]

I could not get the bypass to fit on mine using the fitting on top of the water pump and the manifold fitting you show in the picture. I ended up with a 90 degree fitting for the fitting on top of the manifold water passage and a 90 at the water pump. The top radiator hose just barely clears the bypass hose, but it worked. This was with a short water pump. I think you might get away with a straight fitting on the water pump and a 90 at the intake manifold

[garyd1961]

Originally Posted by sweetk30

some get away with this some dont . . . mine did NOT like it .

As long as your heater core isn't clogged and you have it plumbed right it should work. All you need is a bypass from your intake below the thermostat to an intake on the water pump. It doesn't matter how far the water has to travel as long as it circulates.

[sweetk30]

Originally Posted by garyd1961

As long as your heater core isn't clogged and you have it plumbed right it should work. All you need is a bypass from your intake below the thermostat to an intake on the water pump. It doesn't matter how far the water has to travel as long as it circulates.

i tried this first and had problems .

and i did NOT use a straight barb fitting . i used a 45* i had to order off ebay and a molded hose i got off the rack at the parts store .

[msg]

Ive got the 45 barb you linked to on ebay ordered. The molded hose Ill need to go look for as well as the pumps fitting too which I think then is a 3/4 fitting to the pump and 5/8 barb like this?
https://www.amazon.com/Straight-Pipe.../dp/B06XSMD83X

[garyd1961]

Originally Posted by sweetk30

i tried this first and had problems .

and i did NOT use a straight barb fitting . i used a 45* i had to order off ebay and a molded hose i got off the rack at the parts store .

Been running mine for over 3 years now, no problem at all. A bypass is a bypass.

[sweetk30]

It's a crap shoot I guess . Some of us win and some of us have to do the bypass hose trick .