Oil pressure relief valve

[mgcjag]

Hi All.....looks like im forgetting more than i remember Oil pressure relief valve in the filter housing....nothing clear in the service manual on its operation......does it just open under a fault condition of high pressure due to a blockage etc.......or does it also act more like a regulator at higher pressure to maintain a steady rate....a bit like the instrument voltage regulator switching on/off to maintain 10v....Cheers.....Steve

[flatfloor 3.8]

I think it's more of a pressure relief and by-pass if the filter gets blocked.

[mgcjag]

There are 2 valves...one a pressure relief....the other a balance valve to bypass the filter if it gets blocked...its the pressure relief info im after....Steve

[flatfloor 3.8]

Sorry !

[mgcjag]

No need to say sorry.....all answers welcome

[Bob.]

Hi Steve,
This description was given by Jaguar's Chief Engineer Bill Heynes in a paper to the IMechE in 1953 so, unless there were changes in later years, hopefully answers your question.
Bob

[mgcjag]

Hi Bob...thanks for posting..interesting artical but not sure what its relating to....does it mention the XK engine in any other pages of artical....the pressure relief valve it mentions is in the pump ...in E type engine its in the filter housing....so not sure the description of how it works is relevant...but i could be wrong....any more info...cheers...Steve

[Bob.]

Hi Steve,
Yes it is the XK engine but as it was in 1953 so in the XK120 and MKV11 I think. Apart from turning the filter from the vertical to horizontal to fit the E I don't know what other changes might have been made.
Heynes' paper gives a fascinating and detailed account the design intent and development of the engine but only up to 1953.


You can access the full paper here: http://www.myds420.info/motor/m.01.m.html
Bob

[mgcjag]

Hi Bob...that is fantastic info....im assuming that even though much later in the XK engine the valves were moved into the filter housing... they were designed to do the same job as in the artical you post......so not just a simple valve to open in the event if a blockage but to also control flow as well as pressure...think i understand it Cheers....Steve

[PeterCrespin]

‘Our’ engines have not got gear pumps. As noted, our post XK120 engines have the pressure relief venting oil back to the sump via the external pipe. The filter bypass should never operate in a well-maintained engine but the PR valve operates every cold start.