| : Starting with the impeller and shaft : 1) the tear drop washer goes on and seats in the impeller.
: 2) shaft goes into the rear bushing
: THEN
: without the gasket, assemble the pump to the head tighten lightly and see if there's end play. : What should happen is that the end of the impeller shaft should contact a cast boss inside the head.If there's end play with no gasket then there's probably wear on the inner boss, or the shaft end. : What is best is to replace the shaft with a unit that's longer than standard (available from everybody) and re-assemble the shaft/impeller with enough shaft sticking out inside to contact the boss.That way you don't have to fool around with thrust washers on the fan end.If the inner boss is worn in an irregular shape you should flatten it out to give a good surface for the shaft to seat onto.I used a small cylindrical stone in an electric drill to true mine up. : With the gasket installed the end play should be 0.010" : Bob Carabbio G'Day water pump detectives,
I'm sorry to harp on about this subject, but I just don't seem to be able to get down off this soap box yet. Having read (& understood would you believe!) all the cures & modifications to compensate for pump shaft end float due to wear in the cylinder head where the end of the shaft contacts the casting, my question remains, where are the impeller vanes in relation to the corresponding working face inside the cylinder head?.
FACT: If the end of the pump shaft has worn its way back into the head, the impeller vanes must have also been rubbing on the corresponding head face causing, not necessarily the same, but definately a certain amount of wear.
FACT: Increasing the length of the pump shaft beyond the impeller will decrease or eliminate excessive end float of the shaft, but will NOT compensate for any wear of the impeller or the head face.
This brings me back to my original question of impeller to head face clearance which if too great, could be a primary cause of many overheating problems due to poor or no circulation. Logically, the distance from the impeller face tothe end of the shaft should always remain the same, IF both faces inside the head have worn at the same rate. However this is seldom the case, so by leaving the impeller in the same position relative to the front of the shaft, & merely extending the rear of the shaft, the clearance between the vanes & working face in the head will be too large for efficient circulation to occur.
To correct this problem on the longer shaft, the impeller should be moved on the shaft closer to the head face to obtain the correct vane to head clearance, then the dowel hole re-drilled to suit. It will then be necessary to increase the thickness of the thrust washer between the back of the impeller & the pump body to obtain correct end float. If this is done correctly & the impellor vanes are in good condition, adequate circulation will be achieved. Runnning with a thermostat would also guard against any chance of too rapid circulation which wouldn't give the water time to cool when passing through the radiator.
I'm open to criticism in any form on the above ramblings, constuctive or otherwise.
Regardz
DJ.
OutOfAfrica A's
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