oil pressure (ha ha) relief valve

1660bob

Well Known and Active Forum User
VOC Member
Hi All, installing the oil pressure relief valve in my timing cover today I noted that the OP11 spring compression is next to nothing( well certainly on my bike it is).In went the OP37 plunger, nice and free, spring(new-1&3/4" free length), and then the OP38 nut.I screwed this in expecting it to meet at least a little resistance as it began to compress the spring, but it was still possible to shake the casing and hear the plunger rattle until the nut shoulder was about 1mm from the casing.In other words, the spring pre-load is about that-1mm...... I know the Vincent pump is not noted for high pressures, but surely there is more pre-load on the relief valve? Am I missing a shim or something?? Bob.
 

Ken Tidswell

Well Known and Active Forum User
VOC Member
Phil Irving said that the only thing they got wrongin the design was the pressure release valve. The pressure in the feed to the big end is about 2 psi hot. Do not worry. I found an the plunger OP32 jammed in on a Comet , and needed some persuading to come out. It must have been there decades. As long as roller and ball bearings have some oil they will last along time: as demonstrated by the Vincent, too much oil absorbes power and overheats the bearings.
 

david bowen

Well Known and Active Forum User
Non-VOC Member
most of the vincents I have through my hands the op32 is jammed a wheel spoke bent to a angle will push it out free.
 

1660bob

Well Known and Active Forum User
VOC Member
Looking at the set up again today, I note that although there is not much pressure needed to lift the release valve off its seat initially,the plunger has to travel over 1/4" or so against increasing spring pressure, until the drain hole back into the crankcase is reached and excess oil can escape freely, thus the design is perhaps a little more clever than it initially appears...........it pays to study closely and ponder these things....Bob
 
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