Forum

[Les H]

Hi John. That is it...if one uses the word vacuum, then one should qualify (quantify?) the actual amount of relative lower pressure by adding the words "partial" if there is not a complete zero filling of atoms, but in practice this is never possible not even in outer space. As it's therefore impossible to achieve a perfect vacuum we generally describe any strong low pressure in everyday language as a vacuum. The dictionary suggests these meanings: a. Absence of matter....b. A space empty of matter.....c. A space relatively empty of matter....d. A space in which the pressure is significantly lower than atmospheric pressure. So if we use "vacuum" with the meaning as shown in c or d then, as you say, vacuum is correct and acceptable. However, I guess everyone would understand the everyday commonly used word "suction" as the perceived action and effect that a vacuum can provide or create. Everyone is familiar with the effect of sucking (be serious now!) such as drinking from a straw where one moves liquid against gravity by creating a lower pressure in the mouth. We also have the description "vacuum cleaner" and no one questions the term or suggests it should be called a “suction cleaner”. I have to agree though with Trevor, that using the word suction would have been the better word as it describes the action I was describing rather than the scientific pressure difference which then also requires a second thought as to mentally picture the process of moving the oil along the oilways to the pump. Many thanks and best regards....Les
PS just noticed your new post Trevor,before posting the above and coincidently you've mirrored some of my same points..never mind ATB...Les

[another Allan]

Ok, back from the theoretical to the practical..... I've just managed to get around to fitting the new 'weak' springs to my oil pump. With two gaskets in each end, it is possible to turn the spindle with heavy thumb pressure, so that will do for me. I am sure that ChrisD has a point about further lapping of the new discs may have helped it to turn more freely, but the fact that the pump frees-up in use anyway made me happy to put it all back together. Once it's been up and running again for a while, I plan to go back to one gasket at each end. Thanks for the useful tips.

[Les H]

Hi Allan. Once again the position you are in with your pumps is how I ended up with my ones before fitting and forgetting; they could be moved but left the shape of the spindle imprinted on the flesh of the thumb. I would just keep the revs down for a few tens of miles and thats it. If you think about it, one would imagine that the force to turn the pumps would need to be quite large with two disc being pushed quite hard onto flat surfaces and having to also twist the springs that have the pressure pad to be turned as well. Somehow though they do get looser, which sort of doesn't make sense does it? Chris says the final polishing makes all the difference but it doidn't in my case. Another thing to consider is that the pumps are turned indirectly by the piston not by the spindle pins directly. So the pistons not only have to slide in and out they have to bear sideways and turn the pump body. There is going to be some friction on the sides of the piston and this will be on the very top and bottom of the piston against the pump bores as the action is a sideways rocking action. It makes me wonder if the settling-in of the pump piston is what eventually frees up and lowers the turning friction.... maybe the top of the bores becomes very slightly radiused and thus reduces the side friction on the piston as it turns the pump sideways. Just an idea and something to look at closely when you have a chance the view the old pumps or pumps that are known to turn with less force...Good Luck.

[Alan R]

GENTLEMEN------------ if, at your age you still can't tell the difference between a vacuum and a good SUCK then you really ought to get out a bit more--------oops !! Shoot me someone.

[Les H]

Hi Alan R, I reckon we could ALL do with some fresh air!...Weather's improving now, the rain has stopped and the sun is starting to shine. Time to turn off the PC and turn on the ignition. CU.

[Alan R]

I'm with you on that one LES H, check-out the thread "Wots rong wiv da byke"

[Chris]

BIG-END - Does anyone know how long the floating and the roller big-ends last? Mine lasted about 40,000 miles and the failure was not "wear" as such, but what appeared to be the thing de-laminating in one area (the inner surface). Other than that the surfaces looked fine.

FEED-PUMP - I don't think that there is a problem with the feed pump recieving oil, once it is primed because the oil level is higher than the pump. I could see this when I had the timing cover off and topped up the oil and it drained out of the feed pump supply after I'd put little oil into the tank. I don't think the oil drains back, but, when stopped, can actually drain through to the big-end and into the crankcase.

[Chris]

OK I get it now, I didn't realise there were numerous pages - I was scrolling down to the bottom and wondering where my posts went. Sorry if I've repeated myself.

[Les H]

Hi Chris. Just to ask, where is anyone saying the feed pump needs priming? This statement has been made a couple of times now and I can't find where that has been written?
Apart from that Chris, nice to hear from you again, I note from your last post you mention the WDCO and I realise who you are but I cannot think what your previous USERname was, Was it Chris (Stockport)?
Best regards to you anyway Chris.

[Chris]

Hello again Les, I think I have always been Chris with no other appendage! I think it was you who guided me on the WDCO crank repair with balancing AND the gaps for the floating bearing.