StuartW Posted February 9, 2012 Share Posted February 9, 2012 Hi All. i had to remove the oil pump relief springs (x2) to fit the wing plate into drag supra, After cleaning out the hole the springs came from i found a M6 nut sitting in there I wonder if this is their 'special spring rating mod' as i have just compared the springs against stock and they are identical. it is about 1% possible that the nut dropped into the hole whilst it was all apart but i suspect not..would just love clarification on this please. Many thanks Stu Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 9, 2012 Share Posted February 9, 2012 Interesting one, i fitted one of their pumps, and never checked the pressure relief valve, i think:blink: i did however strip the pump vain plate, in order to check just why it was almost immovable, cleaned it and re meshed the vanes and all was OK. It does make you wonder if the nut was indeed an attempt to up the maximum oil pressure, but don'tnt see why, the std pressure is quite adequate, and there is nothing whatever special about the pump that i could find, it was identical/in fact was a std pump! other than the oil drain holopenednd up to 6mm. Quote Link to comment Share on other sites More sharing options...
Mr Ree Posted February 9, 2012 Share Posted February 9, 2012 (edited) Pretty sure the reason that the spring is "uprated" is to allow higher pressures at higher revs, and the relief hole is bored out so theres no undue risk of blowing out your FMS. Edited February 9, 2012 by Mr Ree (see edit history) Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 9, 2012 Share Posted February 9, 2012 Pretty sure the reason that the spring is "uprated" is to allow higher pressures at higher revs, and the relief hole is bored out so theres no undue risk of blowing out your FMS. The (enlarged)drain hole which carries away any oil leakage from the pump rotors/vanes which bleeds into the void behind the FMS is simply just a measure to stop oil build up, which is a prelude to a worn oil pump, and eventual seal failure. just why would you need to run higher oil pressures at higher RPM? system pressure is more than adequate, high oil pressure is not always a good thing. Quote Link to comment Share on other sites More sharing options...
Mr Ree Posted February 9, 2012 Share Posted February 9, 2012 Thats interesting info, I always thought the enlarged relief was to avoid FMS ejection at high revs/OP. I hear you re: high OP not always being a good thing, but from what I can gather, its used as a safety for highly stressed engines, that rev alot higher than the stock 6800rpm limit. Stock system pressure is adequate for stock revs, but if you are doing 10k rpm, 75psi isnt going to cut it. Quote Link to comment Share on other sites More sharing options...
Hellstrom Posted February 10, 2012 Share Posted February 10, 2012 Its alot more technical than 10psi/1k of rev. It comes down to bearing clearence, oil thickness etc, the more bearing clearence the more pressure and less bearing clearence less pressure. High oilpressure is more parasitic loss. I would say that if someone is not hunting for ever little bits of gain having roughly 10 psi/1000 rev is going to be enough. --- I am here: http://maps.google.com/maps?ll=57.729242,11.786078 Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 10, 2012 Share Posted February 10, 2012 Its alot more technical than 10psi/1k of rev. It comes down to bearing clearence, oil thickness etc, the more bearing clearence the more pressure and less bearing clearence less pressure. High oilpressure is more parasitic loss. I would say that if someone is not hunting for ever little bits of gain having roughly 10 psi/1000 rev is going to be enough. --- I am here: http://maps.google.com/maps?ll=57.729242,11.786078 Some of us know all that, however sometimes its just too much trouble to go into detail;) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 11, 2012 Share Posted February 11, 2012 This sounds like a typical American oil pump "upgrade*, done in a typically stylish American way Let's up the oil pressure (and heat the oil up more, wear the pump out faster, add parasitic drag, do unknown things to the hydrodynamics of the bearings....) Pass me some 6 mm nuts.... Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 11, 2012 Share Posted February 11, 2012 LOL! I can remember "shimming" oil pressure relief valves on old Triumph and BSA twin motors, but thats because they run abysmal pressure even when running all new bearings and new oil pump, however, there is just no need on the 2JZ, pressure is high enough as std, if you're going to try and run 10,000RPM then you will chose the correct bearing marital and journal treatment beforehand, not try and bang the oil pressure up and hope for the best. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 11, 2012 Share Posted February 11, 2012 Of course the nice way to do it is to make a new cap for the pressure relief valve with a threaded rod and lock nut in it to allow external, manual setting of oil pressure, like most dry sump pump pressure relief valves have. Or at least make a turned stepped internal shim, not a bloody 6mm nut.... Quote Link to comment Share on other sites More sharing options...
StuartW Posted February 16, 2012 Author Share Posted February 16, 2012 so shall i remove it then? I had confirmation from a simirlar supplier that they 'DO' shim them with what 'could' be the 'same' thickness as an M6 nut, i would have thought it would be a 7/16" nut though lol! My motor runs 2.4 bar and chucks out around 1400hp, ran for 20Hrs or so with newly rebuilt engine by myself and you Chris wilson, i run stock supra shells and so far the crank and journals look fine, so loathed to remove it really? Stu Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 16, 2012 Share Posted February 16, 2012 If it was me, i would check cold start oil pressure with and without, and see if the is any difference in pressure, as cold start should see oil pressure at max so relief valve operating, As a side note after fitting my new "uprated" pump the overall max oil pressure was actually less than the oid worn pump which definitely didn't have the reliefe spring shimmed, work that one out. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 16, 2012 Share Posted February 16, 2012 If it's not caused an issue and it's running OK I'd leave well alone, but I wouldn't rev it much at all when it's cold as it may have a LOT of cold oil pressure as T-R says. If it's a real lot of pressure cold it could rupture an oil filter casing. Is this the engine I did the ring gapping for, that came on a pallet? Quote Link to comment Share on other sites More sharing options...
StuartW Posted February 17, 2012 Author Share Posted February 17, 2012 I'm always careful when warming up my baby ;-) Yes Chris it's the engine you did the ring end gaps on, She never breathed a drop of anything all season!! I would highly reccomend that anyone with aftermarket pistons have CW do the ring end gaps. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 17, 2012 Share Posted February 17, 2012 Yep, it's one of THE most important parts in building a good reliable high power motor. Buying my expensive digital ring gapper has been one of my best investments in years, does a super accurate job with 100% square ring ends, beats all the years of hand filing I did previously. All the best Stuart, thanks for the plug Quote Link to comment Share on other sites More sharing options...
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