[ctrcreek]

What heater hose connection brings water to the heater core on a pontiac 400 ? The one off the timing chain cover or the passenger head ?

[LPete]

The cylinder head connection is the outlet to the core, and coolant returns to the water pump.

[ctrcreek]

thank you

[Tom Vaught]

If you are doing heater hose work on your pontiac, do yourself a favor and either bend the edge of the inlet tube to the heater core so that it has a small small 1/4" square hole for the water to pass thru. (Inlet Hose will go from the passenger head to this nipple).

What this does is restrict the tube enough so that when you accelerate hard you do not damage the heater core with the "slug of water" that the water pump creates when the engine accelerates quickly. That "slug of water" can easily damage a heater core over time if you like to go to WOT very often with your pontiac.

Another member uses a small plastic restrictor with a 1/4" hole drilled in it to restrict the flow. He makes the restrictor from a piece of plastic rod to the inlet hose inside diameter and drills a 1/4" hole thru the center of the plastic. The length only needs to be about 1/2"-3/4" long.

Tom V.

[AdamIsAdam]

X2! I did both, bent the metal connection and put a restrictor in the line. I like WOT.

[Tom Vaught]

NOTHING wrong with "Both"

Tom V.

[dataway]

Jeez, I should turn up some HDP plugs that would fit into the core nipple with a lip the same as nipple OD and a 1/4" hole drilled in them. Slide it in, reattach hose. I could make a FORTUNE

[Tom Vaught]

I think that you could buy a very similar plastic piece right from the Ford dealer, as some years ago, the Mustang "Cop Cars" were having heater core failures, a suggestion was made, and the 'Powers to be at Ford' started installing the restrictor plastic part in all of the "Cop Car" vehicles, be it Mustangs, Trucks, or other cars. No more issues.

Tom V.

[TedRamAirII]

Find a cheap chinese 1/4" socket that fits the hose and stick it in. Usually free from your scrap pile. The Ford piece is a overpriced $45 piece of plastic with a hole in it. I can imagine the engineering that went into that. ; )

[wovenweb]

Originally Posted by TedRamAirII

Find a cheap chinese 1/4" socket that fits the hose and stick it in. Usually free from your scrap pile. The Ford piece is a overpriced $45 piece of plastic with a hole in it. I can imagine the engineering that went into that. ; )

American engineers are more expensive...

[AdamIsAdam]

I just remembered what I used for inside the hose. Went to home depot, found a piece of scrap galvanized pipe, they cut an end off for me and have it to be for free. I squared off the end and installed it.

[Tom Vaught]

Originally Posted by TedRamAirII

Find a cheap chinese 1/4" socket that fits the hose and stick it in. Usually free from your scrap pile. The Ford piece is a overpriced $45 piece of plastic with a hole in it. I can imagine the engineering that went into that. ; )

I was just giving Dataway a place to do some compare shopping.

If Ford (With all of their Engineering) figured the thing out for $10 then by the time it made it to the consumer you are pay $40.00 seems about right with the typical supplier network.

I bought 10 RAM AIR IV camshafts from the OEM supplier one time $17.37 each. (actual piece cost)

The dealer price book at the time was over $140.00 for the camshaft. I sold them for less than $70.00 and sold all of them in a weeks time. $700 minus $173.70 = $526.30 profit.

The Pontiac buyers were very happy to get the parts.

So the point is there is ALWAYS mark-up on parts vs what the piece actually cost to make. Be it a solid plastic rod with a 1/4" hole drilled thru it, a Home Depot deal, even the cheap chinese solcket but a 1/4" drive socket does not flow as much as a the same as a 1/4" drilled hole. I could make 50 parts from a stick of 5/8" diameter plastic rod for $10.00

The Ford "over-priced" comment and the "engineering comment" were expected

Tom V

[TedRamAirII]

Originally Posted by Tom Vaught

I was just giving Dataway a place to do some compare shopping.

If Ford (With all of their Engineering) figured the thing out for $10 then by the time it made it to the consumer you are pay $40.00 seems about right with the typical supplier network.

I bought 10 RAM AIR IV camshafts from the OEM supplier one time $17.37 each. (actual piece cost)

The dealer price book at the time was over $140.00 for the camshaft. I sold them for less than $70.00 and sold all of them in a weeks time. $700 minus $173.70 = $526.30 profit.

The Pontiac buyers were very happy to get the parts.

So the point is there is ALWAYS mark-up on parts vs what the piece actually cost to make. Be it a solid plastic rod with a 1/4" hole drilled thru it, a Home Depot deal, even the cheap chinese solcket but a 1/4" drive socket does not flow as much as a the same as a 1/4" drilled hole. I could make 50 parts from a stick of 5/8" diameter plastic rod for $10.00

The Ford "over-priced" comment and the "engineering comment" were expected

Tom V

Yep Tom, just razzing the cost of "engineering". Ford has a lot of UAW workers to pay, so its all figured in. Its just tough when you hear about a fix, and its $40, so you think its worth it, then when you get it in your hands, you think you got ripped off. $40 IS cheaper than a heater core PLUS having to replace it. I was told once that, as a rule of thumb, it you bought something for $100 it cost the manufacturer $10. Don't know if that's true or not? Maybe it used to be? Of course the 1/4" square hole old socket more matches the end of the crimped heater nipple than a 1/4" round hole does. But I think a 1/4 square hole flows more than a round hole. But no one is going to argue the flow of coolant through the heater core needs to be slowed down, hence the smaller orifice. I like your idea of drilling a hole in plastic rod though, that is the answer.

[Tom Vaught]

I think Dick Boneski was one of the first to do the plastic rod piece in the heater hose that was posted on the forum.

I always did the "crimp the inlet tube on the heater core to 1/4" square shape" after being told to do it by one of my uncle's Pontiac mechanics in the very early 70s.

Ford blew out a bunch of heater cores (before the mod) when the cops first got the Mustang cop cars and liked the acceleration not knowing the slug of water was going to take the heater core out at some point and the vehicle out of service.

Tom V.

Dick B has posted he blew out more than one heater core before he figured the deal out. (just like me).

[rexs73gto]

Tom , it would seem that if you necked it down to a smaller opening right at the nipple you would be getting a spray similar to what you get at a car wash always hitting the back of the heater core when you accl. Instead of having a soft larger amount of water going through the core you would end up with a small very hard spray going into the core which seems like it would be harder on the core then the larger amount coming in the core at a slower & larger amount of spray. ?????

[AdamIsAdam]

Originally Posted by rexs73gto

Tom , it would seem that if you necked it down to a smaller opening right at the nipple you would be getting a spray similar to what you get at a car wash always hitting the back of the heater core when you accl. Instead of having a soft larger amount of water going through the core you would end up with a small very hard spray going into the core which seems like it would be harder on the core then the larger amount coming in the core at a slower & larger amount of spray. ?????

I put my restricting thing inside the hose just after the water pump, plus I bent the heater core inlet, so hopefully i don't have that garden hose effect you describe.

[STEELCITYFIREBIRD]

It's about pressure, it increases @ the restriction, and drops after the restriction, due to decreased volume after it. Think of it as a surge protector, protecting the heater core.
Interesting, as I have noticed it on many replacements I have put in over the years and only recently learned why.

[rexs73gto]

I don't understand because it's going to act as a garden hose when you pinch the end it make the water come out harder which will put more pressure on the heater core case as it sprays harder on the case as it comes through the hose thus putting extra pressure on the case as it comes through it under more pressure , what am I missing ???

[dataway]

See... I'll make CUSTOM plugs with an orifice to your spec ... with a counter sunk ramp to the hole to SMOOTH that flow and further dampen that pressure spike.

$60 in solid brass, $40 in HDP $39.00 if you order 1000 of them

[dataway]

Originally Posted by rexs73gto

I don't understand because it's going to act as a garden hose when you pinch the end it make the water come out harder which will put more pressure on the heater core case as it sprays harder on the case as it comes through the hose thus putting extra pressure on the case as it comes through it under more pressure , what am I missing ???

You are missing the fundamentals of hydro dynamics ... all things being equal, increase in velocity of the fluid means decreased pressure. For a given volume of water to flow through a smaller orifice means an increase in speed, since total energy must remain constant, increase in velocity means increase in kinetic energy which is provided by a decrease in pressure ... and pressure is what damages the heater core.

In the example of a water hose ...when you are trying to clean something it is the velocity of the water .... or speed of the water exiting the nozzle which does the work for you ... the kinetic energy of the water striking the surface of what you want to clean is what is doing the work. The pressure is actually greater BEFORE the nozzle, but the velocity .... or SPEED of the fluid ... exiting the nozzles is increased ...which applies the force to the surface to be cleaned. You are trading pressure (before the nozzle) for Kinetic energy (after the nozzle) because the kinetic energy is what removes the mold from your vinyl siding.

In any system with a constant flow rate .... an increase in pressure is accompanied by a decrease in velocity, and any increase in velocity is accompanied by a decrease in pressure. Which is known as the venturi effect.

Total energy of a fluid system in movement is calculated with pressure + kinetic energy (kinetic energy = mass flow x velocity) .... so if one is increased, the other is decreased.

Of course it gets more complicate when you add head loss (nothing to do with long term marriage), pump efficiencies at different outlet pressures etc.

But ... suffice to say... with a heater core with a 1/2 outlet, and a 1/4" inlet ... the pressure seen by the core will always be less than seen with a 1/2 outlet and a 1/2 inlet.