Do you have to run the hose that connects the water pump to the intake ?
CK5
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Intake bypass in a BBC
- Thread starter kgblazerfive
- Start date
Did some Googling and some searching and got no real answers.
Kain
3/4 ton status
when i had my bbc it ran cooler with it,but no you dont have to.
Yes you need it, the BB does not have a built in bypass like the old small blocks. You have to have something there for water to flow through when the thermostat is closed. I put my heater core in between those two hoses. If you don't you can get hot spots in the engine, the water has to flow, even if its not flowing through the radiator.
If you want to plug the bypass you could drill a few holes in the thermostat to allow partial flow when it's closed, but it will take a little longer to warm up in the winter.
If you want to plug the bypass you could drill a few holes in the thermostat to allow partial flow when it's closed, but it will take a little longer to warm up in the winter.
I think the answer depends on how the heater hoses are or can be run on the BBC, which I am not intimately familiar with.
If you can run the "hot" side of the heater core from the intake (or head) then out to the radiator or water pump, you have a bypass. This would be no different than the Vortec setups that claim you need the specific bypass (again, not if you run the heater as I've described) and no different than the small block as originally setup, GM just used the heater core outlet as the bypass.
The bypass is nothing but a leak from the engine, to the side of the cooling system "past" the thermostat.
Edit: Also, if there is a flow shutoff valve in the heater core lines (which GM used early on in cars, and probably later in trucks) then obviously it's not usable as a bypass.
If you can run the "hot" side of the heater core from the intake (or head) then out to the radiator or water pump, you have a bypass. This would be no different than the Vortec setups that claim you need the specific bypass (again, not if you run the heater as I've described) and no different than the small block as originally setup, GM just used the heater core outlet as the bypass.
The bypass is nothing but a leak from the engine, to the side of the cooling system "past" the thermostat.
Edit: Also, if there is a flow shutoff valve in the heater core lines (which GM used early on in cars, and probably later in trucks) then obviously it's not usable as a bypass.
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yep you need it.
Make sure you get the hose with a bend it, a piece of straight hose will have a short life. I can get the PN if you need it, I recently replaced mine.
Make sure you get the hose with a bend it, a piece of straight hose will have a short life. I can get the PN if you need it, I recently replaced mine.
You really should. As has been noted there are ways around it, but it seems like running the bypass hose is the easiest of those solutions.
This is what's done on the 650hp BBC that's in my brother's M-37. Motor shop told him to do this
My issue is I need three temp sender spots. Four if run a heater which I do not have right now. Five if I run the factory gauge. One for the MPFI, one for the fan sender, one for the gauge is the least I need.
My heads have the ones on them but look like they have never been out and I am pretty sure the drivers side is not ever coming out, not even going to try it the plug is cracked on the top.
So my intake has three one is filled with the sender for the MPFI the other would be where the heater core line would go. The third is for the bypass.
I have the one for the bypass hose in the pump. Next to the one in the pump I have a plug.
The one in the water pump that goes to the bypass is not coming out.
My thought was to run the line from the radiator to that. Is that a pressure out from the pump or a suction?? I am thinking its a suction. Which means it wont work.
So I guess I could put the bypass in. Block the line from the radiator. Put a sender in the water pump, and then the other two in the intake. That's not going to work. The water pump will give me a bad temp reading.
ahhhhhhhh
My heads have the ones on them but look like they have never been out and I am pretty sure the drivers side is not ever coming out, not even going to try it the plug is cracked on the top.
So my intake has three one is filled with the sender for the MPFI the other would be where the heater core line would go. The third is for the bypass.
I have the one for the bypass hose in the pump. Next to the one in the pump I have a plug.
The one in the water pump that goes to the bypass is not coming out.
My thought was to run the line from the radiator to that. Is that a pressure out from the pump or a suction?? I am thinking its a suction. Which means it wont work.
So I guess I could put the bypass in. Block the line from the radiator. Put a sender in the water pump, and then the other two in the intake. That's not going to work. The water pump will give me a bad temp reading.
ahhhhhhhh
What temp sensor does the MPFI use? GM two wire?
I've not done it yet (but I have a couple of them for the eventuality) but for a fairly short period GM used a 3 wire temp sensor/sender combo...2 wires for CTS, 1 wire for gauge. All appear to have the same resistance as the earlier ones, just decreases the components by 1.
If your MPFI will control a fan, you could get rid of the temp switch I would assume.
I've not done it yet (but I have a couple of them for the eventuality) but for a fairly short period GM used a 3 wire temp sensor/sender combo...2 wires for CTS, 1 wire for gauge. All appear to have the same resistance as the earlier ones, just decreases the components by 1.
If your MPFI will control a fan, you could get rid of the temp switch I would assume.
hmm not sure, I have a Spal fan controller to run them.
I stopped buying the temp senders but I've got the part number somewhere, if it turns out you might be able to use it. Get them for ~$10/shipped off ebay. Just have to find a 3 pin connector for it.
If MPFI will control the fan(s), I'd consider that approach strongly anyway...at least with GM injection, you can program the on/off temps to whatever you want. Set it and forget it.
Just ideas, hopefully something works for you.
If MPFI will control the fan(s), I'd consider that approach strongly anyway...at least with GM injection, you can program the on/off temps to whatever you want. Set it and forget it.
Just ideas, hopefully something works for you.
Its a Edelbrock so we will see.
Not that I can tell from the instruction manual. So still going to need three.
So I am thinking that I will have to get the plugs out of the heads and use them. It may get ugly but cant figure out another way.
So I am thinking that I will have to get the plugs out of the heads and use them. It may get ugly but cant figure out another way.
I wouldn't resign myself that quick. Running the Pro-Flow? http://www.summitracing.com/parts/edl-3589 That's the CTS for it. That looks IDENTICAL to the CTS GM used forever on all their applications since they started using ECM's. I'd be real surprised if they used anything other than a proven OTS piece, which means the three wire should solve it.
I can't tell if the pro-flow will control an electric fan or not, that would have to come from the manual I suppose.
I can't tell if the pro-flow will control an electric fan or not, that would have to come from the manual I suppose.
Well the plugs in the head are not coming out. Unless I do some drilling, which is not happening.
So the temp sender for the spal and the MPFI are the same looking.
Going to go find a thermostat housing that has a threaded hole in the top. See if the spal controller sender can go into that. If not that Summit one looks rather enticing.
So the temp sender for the spal and the MPFI are the same looking.
Going to go find a thermostat housing that has a threaded hole in the top. See if the spal controller sender can go into that. If not that Summit one looks rather enticing.
So the SPAL uses a two wire temp sender? That seems odd, but I'm not real familiar with those things...most aftermarket fan setups (and even GM early on before the computers controlled them) just use a single wire I thought?
Anyway, if the temp sender can be swapped for a 3 wire, that would free up a port, which is what you need, no?
Anyway, if the temp sender can be swapped for a 3 wire, that would free up a port, which is what you need, no?
I would put the heater core in the bypass hose, use the top two intake ports for the MPFI and the gauge, and then either control the fan with the MPFI, or put the fan switch in the head.
You can also use an autometer gauge with an output side, some of the high end full sweep electric gauges have stepper motor movements and you can program them to output a signal to the MPFI so it has the temp as well.
If you haven't already bought the MPFI, I would definitely buy one that can control the fan.
You can also use an autometer gauge with an output side, some of the high end full sweep electric gauges have stepper motor movements and you can program them to output a signal to the MPFI so it has the temp as well.
If you haven't already bought the MPFI, I would definitely buy one that can control the fan.
MPFI is bought and almost all the way in.
Went and talked to a neighbor down the road who is into BBC a bunch.
He said for sure to run the bypass. Decided to buy a thermostat housing that fits a temp sender.
Put the fan controller into the thermostat. The temp gauge in the passenger side of the intake and the MPFI controller in the drivers side.
Went and talked to a neighbor down the road who is into BBC a bunch.
He said for sure to run the bypass. Decided to buy a thermostat housing that fits a temp sender.
Put the fan controller into the thermostat. The temp gauge in the passenger side of the intake and the MPFI controller in the drivers side.
