--- In [email protected], Michael Askin <mykas...@...> wrote: > > On Tue, Oct 13, 2009 at 5:55 PM, ap4098 <brook...@...> wrote: > > I have noticed some opinions in certain fuel topics that seemed a bit odd > > to me so I have added the diesel equipment part of the course notes I did > > for BT engineers to my website. They are under Technical Articles. > > > > I hope they will be of some use and if you want better pictures, text or to > > print them out then email me and I will send them as an attachment in > > MSWord format. > > > > www.TB-Training.co.uk > > Thanks for that Tony. Some good stuff there, even though I guessed > some of the more simple stuff, there is a lot a funny little things I > never realised (use of a fuel delivery valve to stop pressure > reflections for example)... and it's nice to know for sure about the > stuff I guessed about! > > Still trying to get to grips with the run-off from the injector - is > this fuel that has leaked between the needle valve and the tube it > sits in? If so why do relatively recent engines seem to leak quite a > bit of fuel back, surely modern manufacturing can produce a good seal > while allowing movement? > > Just thinking about it - maybe it's only a small amount each firing, > but with so many firings per minute it could add up quickly with 4 > cylinder engine? > > Also while I understand it's unlikely, I have a SR3 which is I believe > one of the engines prone to possible runaway from diesel in the sump, > and so I'll ask the question: > > What about using the compression levers to control a runaway? > > I assume it could damage the valves, but that would be the least of > your problems in such a case. > > Hope you don't mind me asking, but it's your own fault! :-) > > Cheers, > > Mike
First the runaway. By all means try the decompression levers (but its far better to prevent it happening in the first place by smelling and feeling the oil on the dipstick and noticing the level has started to go up) but the clearance between piston and cylinder head at top dead centre is only about 30 o 40 thou. so I feel there is a very good chance of valve, piston and head damage. The injector leak off should be very small but getting slightly more as the needles wear but on the majority of modern engines they also bleed fuel from the injector pump and fuel filter on two accounts. One is to prevent the build up of air in the pump or filter until it is sufficient to stop the engine. The second is to make at least the low pressure side self bleeding (as long as the battery is up to it). Tony Brooks
