: Hi, Just wondering if anyone can help with my overheating problem in my model A.
:After driving for about 5 miles or so the radiator temp.
: climbs to about 210 deg and water starts pouring out the
: overflow pipe.I have ajusted the overflow hight but no different.I allso replaced the head gasket as I was getting a
: bit of water leaking up one of the head studs and thought
: may be a blowin gasket was the cause but still the same.
:Dont think it is a water pump problem because I fitted a
: new one 3 months ago.[hoping that was the problem]
:I allso had the radiator core checked out and cleaned and
: that appeared ok.As I am now about stumped would anyone
: have any ideas???
:ThankMurray Le BretonG'Day Murray & all others with hot A's,
If you look back a little on this page there was a similar question posed with most of the same answers. I'd like to now get my viewpoint of not enough circulation off my chest, so if all & sundry reading this page will bear with me through a small theory lesson, here we go as a while back I asked about water pump impeller to headclearances but I think the gist of my question was missed, so, out with the soap box.
For a water pump to effectively transfer liquid from one area to another, it must create a low pressure area from where the liquid is to be drawn, & then force it through the required outlet. On a motor vehicle pump this is achieved by a vane type impeller, belt driven by the engine through the water pump shaft. The centrifugal force created by the spinning impeller tends to throw the water outwards (to the outlet neck) whilst at the same time drawing more water towards the centre of the impeller (from inside the head) to replace it. Unfortunately this little water pump Utopia can only occur if there's no Goliath in the form of the laws of physics standing in the way, which brings me to my point (almost).
During my apprenticeship, older & wiser men than me were able to pass on, along with the normal useful snippets ofinformation, all sorts of unenjoyable tasks to their apprentices, one of them being the re-conditioning of water pumps, & I can clearly recall their paranoia about having the correct clearance of 0.020" between the impeller vanes & housing face once everything was pressed back together.
This is now the crux of the matter. As I've seen all sorts of answers to counter pump shaft float, from brass bolts in the end of the shaft (impeller end), to spacers behind the fan pulley, none of which are condusive to good impeller to head clearance. Now, due to fair wear & tear taking place, the pump shaft has normally worn itself a nice little burrow into the head, allowing the impeller to slowly wear away at its vanes & the internal head face. If this float is compensated by the above means, a quick peek down the top of the head with the radiator outlet neck removed will reveal Goliath in the form of a major gap between the impeller vanes & the face of the head. This is fine if you intend using the impeller as a food blender, but it ain't going to pump much water until the gap is greatly diminished to approximately 0.020".
The above clearance must first be corrected by either, building up the end of the shaft, fitting a brass bolt in the end of shaft, having the cylinder head thrust area built up, or moving the impeller on the shaft & re-drilling the dowel hole. The shaft float (+/- 0.015") can then be corrected by fitting a spacer between the thrust washer (A-8513-A) behind the impeller, & the pump bush (A-8520, I silver soldered mine together), or if the bush is a tight fit in the housing, it can be knocked back a little as long as you feel it'll stay there & it's not closing the lubrication hole.
There now, I feel much happier. (Is that snoring I hear???)
Regardz
DJ.
OutOfAfrica A's
|
E-Mail Comment to Webmaster