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Seeking info on the correct design for the water distribution tube installed in the 1937/120 Packard motor.
It appears to me that a lot of 120 owners must have modified the tube to what they thought best suited their needs.
Since buying our 120 16 months ago we have from that time experienced unexplained high engine temp. In fact it will boil & throw all the water out. Having gone through all the usual fault finding problems eg blown head gasket/ cracked head / block radiator / problem with water pump / timing out etc etc. All this checked out OK. Now the brass flow tube in this motor had 3 parallel rows of holes with the larger holes tapering back to smaller holes at the other end. With the tube in the motor the larger holes were up the front. This didn't seem right so we removed the tube & cut the blind end off, rebraised the blind onto the other end & reinserted the tube. So now we have the smaller holes to the front with the larger holes to the back. Instead of distributing water to the valve seats / around the cylinders & facing up at the head, it is still pointing at the valve seats & around the cylinder however it now shoots water down to the bottom of the block instead of up to the top of the head.
After going for a run today in the car, & if I didn't know better, I would say that the mystery overheating problem has been solved. None of this makes any sense to me! Anyone care to comment?

G'day upsidedown,

to PackardInfo. Little did you know, when you phoned me earlier this evening(Aussie time), that I'd respond to your post. Reason being I'm the Owner Registry 'Nazi' here who requests, cajoles, encourages, twists arms or whatever for PackardInfo members to include their Packards in the Packard Owner's Registry. I therefore cordially invite you to include your '37 120 Convertible Coupe in the Registry.

Regarding your query I'll leave that to the real experts here to comment on, and just post some pic's of the WDT in my '41 120 when it was removed in 2015 for inspection. As far as I know it's correctly orientated.

And I'll post a pic of your Packard taken at last years National Rally!

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It appears to me that a lot of 120 owners must have modified the tube to what they thought best suited their needs.

Can't say it hasn't happened but in 50+ years around Packards I can't say I've ever heard of anyone modifying a distribution tube for any reason, and especially to direct coolant away from the valve seats. If the tube was damaged you usually bought a new one, they only install one way.

Let me quote from Glenn's manual, a respected text on basic automotive engine service: "DISTRIBUTION TUBES. Distribution tubes are used to direct the flow of relatively cool output from the pump to the chamber around each exhaust valve seat." Glenn goes on to note that cracked valve seats can be the result of distribution tube failure.

PS - I urge you to return to the correct installation of the tube - I recognize you will then have your overheating problem to contend with, but the exhaust valve seats will likely eventually crack without proper cooling, and when they do the crack will invariably extend across the block and down a cylinder wall. Then you are in for a valve seat insert, "stitching" the crack across the top of the block, and sleeving - in short, you'll be looking for another engine block.

Here is a bit from Packard re design and hole placement in the distribution tube.

As to the size of the openings I vaguely remember something from physics class having to do with water flowing out of openings in a pipe. It has something to do with linear flow past an opening vs forced flow thru an opening where it cannot go any farther and also something about total volume available.

My vague memory and many years since class remembers water flowing past an opening such as it would be if going out the openings directly behind the source or the pump in this case will not flow out as fast as it would be if being forced thru an opening such as when going thru the rear openings near the closed end of the tube. I believe the total volume of water available also comes into play since a lot of the water will be gone by the time the rear of the tube is reached. There would be a need for smaller holes to "squirt" the remaining volume harder to reach the seats.

I believe that is the reason for the larger openings in the front -- equalize flow so relatively the same amount of linear flow water reaches the front valves as the remaining water which is being forced out the closed end of the tube thru the smaller openings to the rear valves.

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Geoff & Anne,
for including your '37 One Twenty Convertible Coupe in the Packard Owner's Registry.