karl head Posted September 25, 2012 Report Share Posted September 25, 2012 while waiting for my main bearing to arrive I have be cleaning up and painting some of my parts and accessories. I noticed that although I have a bypass head, the water pump is the external bypass type. I was wondering if I could simply drill a hole in the back plate to match the one in the block and convert it to a internal. I have notice that others say the new replacement pumps can be used either way so I am guessing the only major difference between these pumps is the back plate. Am I right in this guess. Karl Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted September 25, 2012 Report Share Posted September 25, 2012 Do you have the external bypass thermostat housing to go along with that pump? If so there's no need to change. If you have the later model thermostat and housing then you need to have the proper pump. And I believe you'd be correct in adding the additional hole to convert it. That's the only difference that I know besides that the dual purpose ones have both threads for the heater hose fitting as well as bolt holes for the bypass neck. Merle Quote Link to comment Share on other sites More sharing options...
karl head Posted September 25, 2012 Author Report Share Posted September 25, 2012 I do have the external housing Merle, I was just hoping to clean up the engine area and I think the internal looks a lot cleaner. Thanks for the quick replay Karl Quote Link to comment Share on other sites More sharing options...
karl head Posted October 15, 2012 Author Report Share Posted October 15, 2012 (edited) First of all I will say I am sorry about the picture quality. I hope this helps clear up the question of whether a external pump can be switched simply by switching the back cover or as I did drilling a hole for the internal bypass. The answer from my experience is no when I drilled the hole in the back plate using a new gasket as a template the hole did not line up with cavity in the pump .in fact part to the volute blocks the hole. # 1 shows the back cover with internal hole drilled in it. #2 shows the blockage with the help of a wire nut. # 3 shows the section of the volute with the nut in place, I cannot see how you could remove material here without weakening the pump. Edited October 15, 2012 by karl head Quote Link to comment Share on other sites More sharing options...
Guest P15-D24 Posted October 15, 2012 Report Share Posted October 15, 2012 It is an article I want to add to the new tech tips but I'm not knowledgeable. Look for a volunteer to write up a short article and pics. Not a gifted writer, just get me the facts and I will edit it together. PM me if interested. Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted October 16, 2012 Report Share Posted October 16, 2012 Karl, here's a thread I started a few years ago on this same topic. My pump was for internal bypass and at the time it appeared that the one that Napa sold was dual purpose. http://www430.pair.com/p15d24/mopar_forum/showthread.php?t=6316&highlight=water+pump Merle Quote Link to comment Share on other sites More sharing options...
karl head Posted October 16, 2012 Author Report Share Posted October 16, 2012 Thanks Merle I had read it previously and remembered it. I was wondering if you had a picture of the internals of the Internal pump. I am thinking it must be a different design. Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted October 16, 2012 Report Share Posted October 16, 2012 I'm not sure if I even have it anymore, but I'll have a look. I never took the back off for pictures. Merle Quote Link to comment Share on other sites More sharing options...
Young Ed Posted October 16, 2012 Report Share Posted October 16, 2012 I've got 2-3 water pumps laying around that I just came across while sorting junk in the garage. If you need me to take them apart for photos or whatever I can. Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted October 16, 2012 Report Share Posted October 16, 2012 junk in a garage...never!!!!!!!!!!!!!!!!!!!!!!! Quote Link to comment Share on other sites More sharing options...
karl head Posted October 16, 2012 Author Report Share Posted October 16, 2012 I've got 2-3 water pumps laying around that I just came across while sorting junk in the garage. If you need me to take them apart for photos or whatever I can. That would be kind of you, if its not to much trouble. Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted October 17, 2012 Report Share Posted October 17, 2012 This might or might not help. Quote Link to comment Share on other sites More sharing options...
karl head Posted October 17, 2012 Author Report Share Posted October 17, 2012 Thanks for taking the time to post the pictures and its good to see someone has a good camera Don , I was hoping for a internal view I wanted to see how the bypass is plumbed on the inside of the pump. Quote Link to comment Share on other sites More sharing options...
Fernando Mendes Posted October 17, 2012 Report Share Posted October 17, 2012 Karl,a picture is worth a thousand words. Quote Link to comment Share on other sites More sharing options...
Young Ed Posted October 17, 2012 Report Share Posted October 17, 2012 Here are the two water pumps I had. The one with the shiny back originally had the non bypass hole. When I put the new pump on my p15 I swapped the backs from the new one to the old one. I believe the one on the left is my old one and the one I swapped backs with was some other random one I had laying around(and Tim wondered why I said I was sorting junk in the garage) They are in the same order with the backs removed. Quote Link to comment Share on other sites More sharing options...
karl head Posted October 18, 2012 Author Report Share Posted October 18, 2012 That's intriguing because it looks like the bypass hole on both pumps is partially obstructed by the volute. Quote Link to comment Share on other sites More sharing options...
HanksB3B Posted October 18, 2012 Report Share Posted October 18, 2012 Mr. Gambini, would you mind explaining to the court, exactly what is a Volute? Hank Quote Link to comment Share on other sites More sharing options...
karl head Posted October 18, 2012 Author Report Share Posted October 18, 2012 From Wikipedia, the free encyclopedia Jump to: navigation, search The volute of a centrifugal pump is the casing that receives the fluid being pumped by the impeller, slowing down the fluid's rate of flow. A volute is a curved funnel that increases in area as it approaches the discharge port.[1] The volute converts kinetic energy into pressure by reducing speed while increasing pressure, helping to balance the hydraulic pressure on the shaft of the pump. [2] The name "volute" is inspired by the resemblance of this kind of casing to the scroll-like part near the top of an ionic order column in classical architecture, called a volute. What I was speaking of is the area that looks like a small triangle in the lower right in the pictures. Quote Link to comment Share on other sites More sharing options...
JBNeal Posted October 19, 2012 Report Share Posted October 19, 2012 (edited) In my opinion, that external bypass water pump (which has been out of production for decades) should go back on the shelf and a new internal bypass water pump should be installed on your motor. There is a seal in that pump that most likely will fail from its age, and that's if the impeller shaft bearings don't give out first. The new pumps are lubricated by the coolant like modern water pumps, so there will be no need to grease the bearings. And if those shaft bearings fail, the fan will carve chunks out of the radiator as the vibrations will cause the blades to fly apart...very messy and inconvenient. The new internal bypass pumps will fit external bypass motors as the bolt pattern is the same, and the bypass port on the pump can be blocked off by a supplied gasket and the engine block, as DC's & Ed's photos show. The difference between internal & external bypass pumps is not so much the back plate but the pump body casting. Drilling a hole in the back plate will not access the flow from the pump impeller as the casting will not allow this, and to do surgery on cast iron with a hand drill can be a 'creative' waste of time. As much as I'd like to keep my old flathead original looking, the newer style water pump looks close enough to the original for me, and it gives me the peace of mind of knowing that water pump won't fail anytime soon. More information can be found in Merle's thread on water pumps Edited August 24, 2013 by JBNeal Quote Link to comment Share on other sites More sharing options...
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