1916 Buick D45 water pump impeller

[Hubert_25-25]

Sorry - Going to drag you thru some of Buicks early development work.   

I received the 2 drawings in the mail from Dean Tryon.  Both are original Buick drawings.   Same part number 33754.  The white background impeller (calling it the A vane) is "revised 1-5-15".  The black background (B vane) is revised 12-6-15. 

 

  The early impeller (white background) seems to be of conventional design to what I see today in all searches on the internet as being correct.   The 1916 Dseries water pump is a "front " inlet flange,  clockwise spinning impeller.  It matches my 1916 Book of parts printed October 1915, with the same part number.   What it is missing is short vanes on the back side of the impeller if I were to say it was lacking anything relative to a modern impeller in design.  

 

To me, the odd impeller is the later one on the black background.  It does not follow convention for how they draw curved vanes on an impeller.  I have never seen an impeller with vanes drawn this way.  Adding short vanes on the back side says that there was some development work going on.   There were also six 3/16 holes drilled thru the casting that were removed 1-17-16.  So they were working on "pressure balancing" the impeller as short vanes, and drilling holes are common practices.

 

Dean also sent this note

1.  For 1916, I have a parts book dated Feb 1915 shows #33754 and the "A" vanes.  Another one dated April 1917 shows #33754 and the "B" vanes.  Both for D series 6 cylinders.  Must be a running change but it tells me that both vanes will pump.

2.  For 1915.  The C-30 series (larger engine) is the same as the 1916 BigSix as a "B" vane and a new number.  This makes sense since the BigSix (6 cyl) was 3 sets of jugs whereas the  1915 4cyl had 2 sets.  (#30367)

 

On the 1915 4 cylinder cars, the inlet flange is on the back of the water pump, which means that the impeller spun in the opposite direction.  This assumes the  vanes are on the cover side.  I do not know what  part number they used for the 4 cylinder water pump impellers.   

 

The straight vane impeller came out in the 1922 4 cylinder, and adopted  for the 1924 6 cylinder.   They used the same impeller raw casting and flipped the rotation since the 4 cylinder water inlet was on the rear of the pump, and the 6 cylinder water inlet was on the front.  The straight vanes went into the 30's.  

 

Dean Tryon has all three styles of impeller casting replacements available.  

Hugh

[dibarlaw]

Hugh:

Here is the straight vane example I received from Dean during machining for my 1925-45 pump.

As the pattern I prepared for Dean to have them cast.

[Hubert_25-25]

Larry, 

   That looks really nice.  A big improvement over steel with JB weld to fill the holes.     Hugh

[27donb]

We're the Buick engineers trying to regulate flow with those different vane designs, as in too much flow and the coolant doesn't have time to remove the engine heat, and too little flow and the engine runs hot? 

[Terry Wiegand]

I have said this before and I will say it again - at this period of time Buick was incorporating changes almost on an hourly basis.  From 1915 to 1925 saw more changes than at any time before or after.  If you look at the radiators on the 1916 Light Six models and follow the progression up through 1923, you will see that they increased in height.  This resulted in a larger cooling system capacity.  In order to keep the cooling system at a rather constant range, the coolant had to be moved accordingly.  A pump that moved the coolant too fast was as much of a problem as a pump that moved the coolant too slow.  At either end the engine was going to run hot.  I am sure that Buick Engineering was playing with several different versions of pumps to get the desired results that was needed.  donb hit it right in his last post.  Too much or too little - that is the dilemma that was facing the engineers.

 

Terry Wiegand

South Hutchinson, Kansas

[Mark Shaw]

23 hours ago, Terry Wiegand said:

I am sure that Buick Engineering was playing with several different versions of pumps to get the desired results that was needed.   Too much or too little - that is the dilemma that was facing the engineers.

It is also important to know that impeller diameter & speed determines the pressure produced.  Since the early cars had low pressure cooling systems, GM could not significantly increase pump size without changing pressure sensitive components like the radiators used to cool the engine and passenger compartment heaters. 

Basically, the same size pump body was used with different impeller designs in early Buicks.  Straight vane pumps in early 4 cylinder cars are not as efficient as pumps with curved vanes.  So, I believe GM curved the vanes for better flow efficiency in later years to compensate for larger engines without changing overall pump size.  

[Terry Wiegand]

Mark,

I agree with everything you stated in your posting except for one wee little point.  You stated "Since the early cars had low pressure cooling systems".  That's the wee little point that I cannot agree with.  The early cars like your and my Buicks have a NON PRESSURIZED COOLING SYSTEM,  meaning one could drive the car with the radiator cap off and have no issues.  I also believe that the reason behind the radiators being so thick was directly tied to the heat transfer in the cooling system.  I'm thinking that our friend, Mr. Heil, could probably explain this so that everyone could understand the goings on in an engine cooling system.

 

Terry Wiegand

South Hutchinson, Kansas

[DonMicheletti]

You guys are confusing pressure with flow rate

[Brian_Heil]

There is delta P Terry W or there would be no flow. 
 

Don’t confuse system pressure as in a closed system with delta pressure created by the pump which in turn creates flow.  
 

I spent half of 1983 designing and testing impellers for the Buick 3.0L which carried over into the 3800.  The impeller looked very similar to the top drawing you shared.  
 

Has anyone seen an impeller in a Buick like the second drawing?  I have not.  Perhaps it was a drawing for a prototype tested and then rejected?

[Brian_Heil]

Is Part Number 33754 (the second impeller) in any of the parts books indicating is was released for production?

[Brian_Heil]

Scratch that. 

 

Not sure why and it makes no sense but both designs have the same part number. 

[Hubert_25-25]

3 hours ago, Brian_Heil said:

Scratch that. 

 

Not sure why and it makes no sense but both designs have the same part number. 

That is what is so interesting about these impellors.  The early drawing looks like they had things figured out.  The later impellor kept the part number, but it is very different.  There is science, politics, and economics in much of what we do not understand.  

[Mark Shaw]

22 hours ago, Terry Wiegand said:

You stated "Since the early cars had low pressure cooling systems".  That's the wee little point that I cannot agree with.

Terry, 

     The early Buick pumps are located near the bottom of the engine and therefore must lift coolant to the top of the radiator and overcome significant friction losses through the water jacket.  You might be surprised to see 2-3 psi if you put a pressure gauge on the discharge side of an early Buick pump.  Pressure will vary with the overall height of the engine/radiator and how much crud is restricting flow within the engine's cooling jacket and radiator.