So on the trucks, the heater core flow is exit the intake to the core, exit the core to the waterpump. Is it possible to do the same on the Z28s? I hate all of those hoses and that fluid diverter (whatever you want to call it, that has a vacuum on it). Plus, one of my hoses is busted, and the core is leaking. So, i want to replace the core, put on a truck pump, and then have 2 hoses to keep it simple (and then cap off the nipple on the radiator). Think it would work?

 

While not exactly sure what you're describing (or I'm missing it) I never liked the heater hoses running along the valve cover/intake manifold area.
I picked up two 90° plastic fittings, one 5/8" and one 3/4" and connected them to the heater core nipples sticking out of the firewall. That orientated the hose direction towards the passenger fender. From there it was a broad sweep towards the strut mount (where I fitted a clamp to secure the hoses) and then back to the engine. One hose ends at the water pump. The other to a fitting on the intake manifold. No diverter valve in this case. Looks clean. Works great.

 

I agree with skinny z. I routed mine away from the carb on my 1986.

 

The plan for my tbi build is to run the heater inlet directly from the intake manifold, and use the factory return to the radiator, capped/sealed off where the heater valve bypasses to. I don't have a tpi car to look at right now but that's the plan for my tbi. A pre-Vortec sbc shouldn't be a concern as they have an internal bypass system. I'll also have some form of a restricter in the heater core inlet. Those plastic heater valves are failure prone, and I don't want anything to do with them either.

 

Ok cool. This is the way I did it on my truck. TBI has the quick disconnect crap on the back of the intake, and an inlet on the top of the pump. So moving the outbound water from the back on the intake to the front when I put on the TPI was easy. But with the camaro, I see 2 inlets underneath the waterpump. One coming from the radiator and one from the outlet of the heatercore. So, if the truck waterpumps will fit the camaros, then ill swap a truck one on there that has the 1 inlet.

 

Interesting topic, my '87 IROC has the added feature of the factory oil cooler so I have some other 3/4" coolant lines to contend with. I still have the TPI setup which I'm keeping for looks but if anyone has done something similar to what you guys are showing but with TPI and the oil cooler I'd be curious so see what you did.

In addition I'm 90% sure I can't get the rubber "U" hose that comes from the intake base (intake manifold) and goes to the throttle body.

 

The rubber "U" shaped hose is still available. Go to Ebay and do a search. Also TPIparts.net may still have it. You can also try Jims Performance. When I did my TPI conversion on my Monte Carlo SS, I kept the Monte plastic heater control valve. It has one inlet and one outlet. I only run two heater hoses. One hose goes from the heater core to the nipple on the passenger side of the radiator. The other goes to the intake manifold. I deleted the "U" shaped hose that heats the throttle body since I do not drive the Monte in the winter. I also have a thermostat with three 5/16 holes to allow some coolant flow when the thermostat is closed and not calling for heat.

 

https://www.rockauto.com/en/catalog/...se+/+pipe,6892

 

If you have (3) 5/16" holes, then you no longer have a thermostat. One 1/8" hole is all it takes.

 

I could be wrong on the hole diameter. I installed it several years ago. It is a EMP Stewart No. 301. The car warms up normally, maybe slightly longer. Temp stays between about 180 and 195 degrees during summer driving. I run electric fans.

 

Getting rid of the heater diverter valve will cause hot coolant to flow freely through the heater core at all times. The vacuum hose you see connected to it shuts off the flow or reduces the flow of coolant into the heater core when the hvac controls are in the off position. I did this on my last car and I could feel hot air in the cabin area even when the heat was off

 

My car is an 84 and did not come with a diverter valve.
But whether people chose to have the valve or not, shouldn't there be a door that closes so that the heat from the heater core does not freely flow into the cabin?
Or did the bean counters at GM decide that a door was not needed to save a few more cents?

 

So you run fluid from the intake thru the heater core then back to the radiator? I would think pressure from the radiator and intake would fight each other. If not, then ill do that and then just plug the hole on the water pump.

 

In my setup, I do have the heater diverter valve. I used the diverter valve from my Monte Carlo SS (one inlet, one outlet), instead of the multi port TPI valve. Looking at the heater core from the front of the car, the left side heater hose goes to the passenger side of the radiator. The other heater hose goes to the heater diverter valve then out the diverter valve to the port on front of the intake manifold.

What happens is that the water pump sends coolant into the engine around the cylinders, that coolant flows thru the cylinder heads to the intake manifold. Part of that coolant goes thru the nipple on front of the intake manifold then goes thru the diverter valve (if calling for heat) then into the heater core. Coolant then flows from the heater core into the passenger side of the radiator. My TPI swap manual did state that coolant flow through the heater core actually bypasses the cooling of the radiator. To improve cooling, the book suggests to restrict the amount of coolant that goes to the heater core. That does make sense since the flow from the heater core goes to the passenger side of the radiator instead of the driver's side.

When not calling for heat, the multi port TPI heater diverter valve causes coolant to flow from the intake manifold to the passenger side of the radiator without going thru the heater core. I'm guessing that GM did that to keep the flow from dead-ending at the diverter valve when not calling for heat.

In my swap I used a high volume TPI water pump sold by TPIparts.net, no longer available. I do not have a port on top of the water pump to use. If you have that port on top of the water pump then you should use it as the return from the heater core. You just would need to install a two port diverter valve in the hose that goes from the intake manifold to the heater core.

Fred

 

Thanks for all that schooled me on the "U-hose" from the manifold base to the TB. I guess was being lazy I looked a few places but clearly not all...

Speaking of the diverter valve. I'm not sure if this is the same for everyone but I think the other path the water takes is through the oil-cooler if your car is equipped with one and as such there are also lines for that, I would like to consider taking the TB out of the loop but it tight in that area so leaving it might be the easiest.

Thanks again.

 

So then the Monte SS one in - one out "diverter" valve is really just a shut-off to stop the flow of coolant in the heater core when not called for. Right?

Oh crap, I started another sentence with the word "SO". Stuart will let me know about this.

 

My 86 has no valve. The only issue with this is efficiency of the AC, and the degraded foam "seals" on the diverter doors and ducting inside the dash, etc. The old crumbled foam makes the doors not very effective which makes the AC efficiency issue even more difficult.

It's definitely preferable to have the valve - I'm assuming that's why GM added it later in production. Certainly not absolutely required though.

GD

 

Totally a different vehicle platform but in our '56 Chevy pick-up we installed 90 degree plumbing ball valves in the heater line so we didn't heat the cab in the summer. The valves are sort of hidden up by the firewall and it's a pretty simple solution. I'm going to stick with the factory diverter on the IROC but just thought I'd share.

 

For me, I want coolant going through the heater core for more even cylinder cooling. But I don't want to heat the cabin when not called for. I have modified my carbed intake to be like the factory TBI intake. I take the coolant (going to the heater core) from the rear water ports on the intake. I drilled and tapped for fittings and a hose to connect the two rear ports together. From there, the coolant goes to the heater core inlet. You can see it in the picture below (black hose).


The intake gasket has restrictions already built into the gasket, 3/32" I believe.

 

NoEmissions84TA, yes the "Monte SS one in - one out "diverter" valve is really just a shut-off". Your setup is just like the stock Monte Carlo SS, with coolant outlet ports on the rear of the intake manifold going to the heater core, via the diverter valve.

 

For years I was trying to find a nice way of taking the coolant from the rear, and it wasn't until the intake gasket blew on my 1995 GMC 305 TBI truck that I got to see that GM already did it. So all I had to do was copy what the factory did.

 

Anyone have a thought on how to tighten the hose clamp that comes out of the firewall and immediately turns 90 degrees down? It is only about 5 or 6 inches down but there is soooo much other stuff running the same route between the firewall and engine block, that I have fought it for hours, cutting the crap out of my 74 year old hands with no success. Looking for any help, do I need a special tool? Thanks, George

 

Anyone have a thought on how to tighten the hose clamp that comes out of the firewall and immediately turns 90 degrees down? It is only about 5 or 6 inches down but there is soooo much other stuff running the same route between the firewall and engine block, that I have fought it for hours, cutting the crap out of my 74 year old hands with no success. Looking for any help, do I need a special tool? Thanks, George

 

Find someone with smaller hands that knows how to turn a wrench, socket, whatever tool can reach that hose clamp.
It might even be easier to reach from the underside of the car.

 

Made mine from different pieces of aluminum tubing. I kinda borrowed the idea from 3rd gen tpi cars so should work back around.

 

That's sweet man. I am planning on doing something similar

 

84 1LE, did you bend that pipe too? Or did you find enough pre-bent pieces that worked?

 

I didn't, but i did have to tweak them a bit.