#4 cooling done differently

[85glht]

If you go from high side of the pump to the freeze plug, in theory, the corner of the head behind #4 is still starved; this assumes that the coolant turns left and dives to the T-stat box and does not swim up stream toward the corner.

If you go from the low side of the pump to the freeze plug, then, you are more likely to pull stagnant coolant from the #4 corner of the head. And, if you are going to pull coolant from the pump low side, then why not just drop straight down to a Tee on the low side heater by-pass hose and avoid the complication of drilling/tapping/hosing from the pump.

I prefer to drill and tap for a 1/4" NPT elbow right into the driver's side of that #4 corner. Freeze plugs really aren't engineered to stay put when there are hoses being pushed and pulled off of hose barbs that are tapped/brazed/welded to the plug. An awful lot of this kind of "I'm gonna make it better than stock" stuff actually is a step backward in terms of reliability and risk.

I had the head off the engine and I removed the freeze plug and had the machine shop weld in a bung (1/2 npt thread), this eliminated the freeze plug.
Now I have a fitting screwed into the head instead of just using the freeze plug. I did tap into the top of the waterpump and ran a #6 line (3/8) from there to the new bung/fitting.
It has to be better that what I had. Only time will tell.

[Shadow]

Freeze plugs really aren't engineered to stay put when there are hoses being pushed and pulled off of hose barbs that are tapped/brazed/welded to the plug. An awful lot of this kind of "I'm gonna make it better than stock" stuff actually is a step backward in terms of reliability and risk.

5 cars with the #4 frostplug mod over the last 5 years. Never had a problem. I've had it on the Charger for the two years it's been running, had the hose on and off 3-4 times, never a leak, it's never moved. Stepping backwards in reliability has more to do with the person performing the mod, than the mod itself, in most cases. (unless of couse, your willing to do any mod that anyone brings up, just because)

[overlordsshadow]

Putting my head back together this week or next and going to do this mod. I'll let you guys know how it goes. Shadow, did you also drill the 1/16th hole in the tstat?

[Shadow]

Putting my head back together this week or next and going to do this mod. I'll let you guys know how it goes. Shadow, did you also drill the 1/16th hole in the tstat?

Always!

[overlordsshadow]

I just got my head tapped and the turbo on and noticed that my hot pipe goes right where i want the coolant mod to go. I got a bronze fitting, will that work? I need to get a 90 of something to go into the 1incher i just put in.

[Shadow]

I just got my head tapped and the turbo on and noticed that my hot pipe goes right where i want the coolant mod to go. I got a bronze fitting, will that work? I need to get a 90 of something to go into the 1incher i just put in.

Bronze should be fine, just make sure you use a good sealant on the threads. My hot pipe follows the trany and runs below the mod.

[overlordsshadow]

Would it be a problem to thread a piece of cast into the bronze?

[Shadow]

Would it be a problem to thread a piece of cast into the bronze?

No, but cast rusts over time, might wanna try galvanized.

[overlordsshadow]

good idea. Just getting pieces to get it together for now, will look for aluminum and such once it's up and running.

[knownenemy]

A bit of an old thread but, interesting ideas and actual proof of their validity.
I like it!

Subscribed!

[glhs875]

Also, when you guys get the right NPT tap for the end of the head, run it till it hits the back inside chamber. Go slow and keep it straight. The whole is actually a little big, but if you tap it that deep it will work good. The water pump is a little more tricky, as it's thin and on an angle. If you tap it and use a fitting, use some serious grey anerobic sealer and it should be good. I've started tigging ends on now.

I have seen water pump housings with what looks like a 5/8" outlet on them at the rear of the pump area on them already.

[Ondonti]

Since headgaskets are disappearing I would create one that balanced flow through the block to head making modifications needless and making every motor happier no mattery how much of a race car it was. Very basic oldschool tech. Cometic etc did you no favors when they mindlessly created each gasket they sell. V motors tend to come with universal gaskets but they should be made cylinder bank specific if they were properly designed. Absolutely no reason to make a universal style headgasket for an inline motor.

[Shadow]

I have seen water pump housings with what looks like a 5/8" outlet on them at the rear of the pump area on them already.

I believe what your describing is the return for the heater core on 87 and newer models? That would be on the suction side of the pump.

[glhs875]

I believe what your describing is the return for the heater core on 87 and newer models? That would be on the suction side of the pump.

Okay, I couldn't remember exactly!

[black86glhs]

Was racing this wknd, so I just saw this now. I plug the H/C hole in the front of the head with the apropriate size plug, leave the thermostate untouched, pull the frost plug out of the end of thr head and the hole is the perfect size for the tap I use. I think it's 1', but I'd have to check. Then I put a 1' down to 3/4 adapter and wind the 3/4 brass 5/8 barb fitting in. Just make sure you use some good sealer and make it tight! I'll snap some shots today and get them up tonight.

Bringing this back from the dead....lol. Bob, I had not seen this when I modded the last head on my car. I had seen the other mods like the VW housing and drilling the freeze plug. I ended up doing the same thing you did with the tap and adapters just due to pieces I had lying around.
The only thing I did different is to put a plug in the 5/8" fitting with a hole drilled through the plug to reduce the flow. Main reasoning for that was without it, I didn't get good heat through the core after performing the mod.
Just thought it was interesting that we both did the same thing without seeing what the other one did.