Guest osrocket Posted April 26, 2004 Report Share Posted April 26, 2004 wondering if anyone has some suggestions for the below::: did a rebuild on my tr6, everything is fine, but very little oil pressure from new pump, before i tore it down pressure was always in the middle, renewed main bearings, end thrust bearings, rod bearings and plasticguaged all of them and they were fine, replaced the spring in check valve, and primed the pump, started up and pressure initially was at near 50/60 at idle,(perfect) then after running it seemed to fade, suspected the higher pressure may have jarred the relief valve??, but pulled it out and checked it, seemed ok, and just stiffened the spring to rule out the pressure valve for now, going to pull the pan off tomorrow and reinstall the old pump which was fine, the one that i got to replace it had the round filter on the pickup?, and my original one had the square pickup, i guess my main question is had anyone ran into a new pump that had no pressure, or is maybe that pump(which said 2000 on the box the wrong one?) thanks for any input< john bohland email me at osrocket@neo.rr.com Quote Link to post Share on other sites
Andy Moltu Posted April 26, 2004 Report Share Posted April 26, 2004 I have had a new pump that didn't deliver the pressure as well as expected. I guess one or two with excessive clearance sneak through to the market. What oil are you using - some go thin when they warm up. Quote Link to post Share on other sites
tim_trinda Posted April 26, 2004 Report Share Posted April 26, 2004 John The oil pressure on my engine is 60-70psi at idle when cold, when hot the pressure drops to 15-20psi. I thought these figures were fairly 'normal'. What is the oil pressure at 2000 rpm when hot? ======== Tim Quote Link to post Share on other sites
Guest osrocket Posted April 26, 2004 Report Share Posted April 26, 2004 i put new oil in and its 10w-40 and it only runs at approx 20-30 at 2000 rpm, which with the old pump it was always at 40-50, at 2000 area, i never really paid attention before, but after getting hot now and idling its not showing much, the oil is valvoline, maybe i should try a straight weight oil? i may drop the pan off tonight and stick the old pump back on just to see, but i don't really want to run it much with the low pressure, jb Quote Link to post Share on other sites
marvmul Posted April 26, 2004 Report Share Posted April 26, 2004 Thicker oil (20w 50) will not show much difference. When hot, 10w - 40 has the same viscosity as monograde40 oil. Swapping the oil pumps will prove if the oil pump is at fault and you can take some bearing caps off when you are there.You can look at the new oil pump : tolerance of inner/outer rotor and end plate. What was the reason for the engine rebuild? If the new oil pump is ok, can it be a blocked oil way? : spilled plastigauge, silicone...but then this must be before the oil pressure line. Quote Link to post Share on other sites
tim_trinda Posted April 26, 2004 Report Share Posted April 26, 2004 The oil pressure should be 40psi @ 2000rpm (hot) at a minimum. Its probably worth checking the clearances on your old pump before you refit it ( and the new one!), you may find it is perfectly servicable. the one that i got to replace it had the round filter on the pickup?, and my original one had the square pickup, The square pickup is the early cast iron body pump, the one with the round filter is the later alloy body. I think they are interchangeable but the mounting bolts are different. ====== Tim Quote Link to post Share on other sites
Guest osrocket Posted April 26, 2004 Report Share Posted April 26, 2004 ok thanks, i did the rebuild because it was smoking, had the head done and had them put new style ford valve seals and hardened seats in there and i also had the flywheel ground and replaced the clutch and all the seals, rings, etc. i started it this morning with the oil cooled down and it has oil pressure of 70? so now i wonder maybe the pump is ok and i am getting a loss of pressure somewhere else? ((thinking)) lol jb Quote Link to post Share on other sites
Guest ron Posted April 26, 2004 Report Share Posted April 26, 2004 The only thing I can add is that within reason the cold oil pressure is not important it's the hot oil pressure that matters. My engine has done 3500 since rebuild, hot oil pressure is 75psi at 3000rpm and 25psi at tickover using Castrol 15/40. I think you should be looking for 50psi+ at 3000rpm on a newly rebuilt engine. Another obvious question, are you sure the pressure gauge is OK? Ron Quote Link to post Share on other sites
Guest osrocket Posted April 26, 2004 Report Share Posted April 26, 2004 seems to be ok, after oil was all down and added new oil, started engine and after the pump picked up the oil it went up to 70 area and looked stable, and it has always seemed accurate before and when the pressure drops after warming you can almost tell the way the engine sounds then i shut if off right away to avoid any damage, when i take the pan off i will pull a couple of the brgs out and check them(main,rod) jb Quote Link to post Share on other sites
Tom Fremont Posted April 26, 2004 Report Share Posted April 26, 2004 The TR250 owners manual states " 45-65 psi at 2000 rpm when hot ". My rebuilt motor with 60,000 miles using Castrol 20W-50 will produce 70 psi with cold oil using the starter motor only, then when hot 55 psi @ 2000 rpm, 85 psi @ 4000 rpm, and 20 psi when idling @ 700 rpm. I think it was a little higher before it ate a couple of camshafts...... A few more data points for your consideration Quote Link to post Share on other sites
Guest osrocket Posted April 26, 2004 Report Share Posted April 26, 2004 ok i got home from work at 3, and pulled the pan off and dropped the pump out and it has almost .010 play on the outside area and the top is only .003, but my cast iron one that i took out had .008 to .0085 roughly, so i may try and locate another cast-iron one or just put that one in and see how the pressure is with that one, because it was fine before the rebuild, ?? jb Quote Link to post Share on other sites
Guest osrocket Posted April 30, 2004 Report Share Posted April 30, 2004 pulled the pan back off, rechecked a couple of rod and mains to make sure they were not showing any wear, put the old cast-iron pump that was on there back on and pressure is awesome, when hot and idling at 30 area but as soon as throttle is applied goes over 50 right away, measured the aluminum one that was brand new and it had .009/.0095 outside play, thats more than the old cast iron one, does anyone know where you could pick up a cast-iron pump, or maybe some kind of repair parts? thanks for any info johnb Quote Link to post Share on other sites
JohnC Posted April 30, 2004 Report Share Posted April 30, 2004 If memory serves, the Leyland manual gives acceptable tolerances for the oil pump clearances. I rebuilt my engine 5000 miles ago, but re-used the old pump (which to the best of my knowledge has done ~150,000 miles). I did do the full rebore/regrind thing. When hot, I'm getting a tad under 50psi at idle (800rpm), 80-85psi at 2000rpm, and about 90psi at higher revs. I've set the oil PRV to limit the pressure to about 90psi. Before the rebuild, it had a couple of packing washers behind the spring (I didn't put them there). That resulted in over 100psi when hot at 3-4000rpm. FWIW, YMMV etc., John Quote Link to post Share on other sites
Guest osrocket Posted April 30, 2004 Report Share Posted April 30, 2004 john, the manual that i have states that anything less than .004 top clearance is ok, and if the outside is .010 or more replace, and a guy in virginia that restores the cars told me that if it is not .006 to .008 on the o.d. the pressure will be lower / shakey, thanks johnb Quote Link to post Share on other sites
Cinnobar Posted April 30, 2004 Report Share Posted April 30, 2004 Standard rule of thumb for oil pressure is 10PSI for every 1000RPM anything else just wastes power driving the oil pump. Just a thought as it's a long time since I was involved with Straight sixes but I'd have thought 10/40 was too light as they must have been designed around 20/50. The thinner oil will give lower oil pressure and unless the clearances are good and tight possibly too low an oil pressure. Final point is when rebuilding check the cam bearings, I've been involved inseveral engine rebuilds where they kept knocking out B/E bearings which turned out to be excessive cam bearing clearance starving the ends of oil. Jim Quote Link to post Share on other sites
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