[DeTomaso] water pump

[JDeRyke at aol.com]

In a message dated 12/22/08 5:13:56 PM, bwerner at live.com writes:
snip.....
> I have a new Weiand,  I have heard that you want to put a plate on the back 
> of the impeller on this pump and this style of pump doesn't allow water to 
> be circulated through the engine, it has to go to the radiator.  What is the 
> purpose of this design??
> 
Adding a plate on the impeller back cages the water being pumped, slightly 
increasing the efficiency of the pump since the small space between the back or 
the impeller and the pump case then no longer allows water to leak backward. 
The aluminum Weiand 8209 is in my estimation one of the best made. I have one 
now 19 years old on our much-modified engine and it has had exactly one problem 
in that time. There are two small bosses for the heater hose (bottom) and the 
stock thermal switch (top). No one uses the thermal switch any more so this 
is usually plugged. Over-tightening a plug -or any pipe fitting into the upper 
boss will spilt the casting, which is made too thin. TIG-welding the split 
corrected my mistake- be careful here. Also, the pump has no recirculation 
passage so you can use any thermostat, not just the special one for the 351C. 
Suggest any thermostat you choose should have bleed holes drilled to increase water 
circulation, IMHO. The Weiands are also rebuildable if someone gets a seal 
faiure. Welding a plate to the impeller will wreck the seal if too much heat is 
used; I TIG'ed mine on. It made no difference in engine temperature. Matter of 
fact, NOTHING in the entire cooling system makes any measurable difference in 
engine temp except:
1)- a bigger more efficient radiator and big shrouded fans for low speed 
operation. I use an aluminum Fluidyne with Flexilite sucker fans. There are other 
choices that also reportedly work but I have no experience with them.
2)- completely removing the thermostat radically increases water flow thru 
the system, and drops engine temp way-too-far- to around 120 F degrees when 
cruising and possibly 160F during track events when high rpms and low gears are 
used a lot. Some sort of restrictor will be needed in place of a thermostat. 
Good luck- J Deryke



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