Tyler06 266 Posted July 14, 2013 How much oil pressure should a crossflow have on idle? 1 mcfly94 reacted to this Share this post Link to post Share on other sites
mcfly94 169 Posted July 14, 2013 the lowest mine gets to is about 13psi on 650/700rpm idle, that's at temp. 10w-40 in a 300k motor Share this post Link to post Share on other sites
Clevo120Y 815 Posted July 14, 2013 I like to see 25 to 30. They can live with 10 but your running a fine line. Share this post Link to post Share on other sites
mcfly94 169 Posted July 14, 2013 but what idle mate? as soon as mine gets up to 900/1000 its at 25 psi Share this post Link to post Share on other sites
Clevo120Y 815 Posted July 14, 2013 800rpm, this is with a reasonably fresh engine, 20/50 oil Share this post Link to post Share on other sites
mcfly94 169 Posted July 14, 2013 what oil is best to use? I use 10w/40 Share this post Link to post Share on other sites
Clevo120Y 815 Posted July 14, 2013 I use penrite oils mate, 10/40 I generally use for new engines that have had there tolerances checked and more performance orientated, 20/50 for general use and older engines. Others may disagree with me and the debate on oils will rage forever 1 slydog reacted to this Share this post Link to post Share on other sites
mcfly94 169 Posted July 14, 2013 I use penrite oils mate, 10/40 I generally use for new engines that have had there tolerances checked and more performance orientated, 20/50 for general use and older engines. Others may disagree with me and the debate on oils will rage forever Yeah I use penrite too, my engine is 300km old, had clean bores and was healthy looking when I got hold of it so I used 10/40. Share this post Link to post Share on other sites
Tyler06 266 Posted July 14, 2013 1300 rpm idle once warm mines sitting at 13psi with all tolerances checked and thats with 15/40 running in oil. Share this post Link to post Share on other sites
Clevo120Y 815 Posted July 14, 2013 You probably pick up a bit of pressure going the thicker oil mate but if your engine is happy and consistent then stick with it, I find the penrite more stable than any other oil so good choice. 1 mcfly94 reacted to this Share this post Link to post Share on other sites
Clevo120Y 815 Posted July 14, 2013 My comment was to Mcfly Chris. I wouldn't be happy with that personally Chris, did you check the oil pump clearances? 1 mcfly94 reacted to this Share this post Link to post Share on other sites
Clevo120Y 815 Posted July 14, 2013 What was the initial pressure when cold? Share this post Link to post Share on other sites
Tyler06 266 Posted July 14, 2013 Yeah oil pump was spot on and 50psi but wen i put my racing oil (its a heavier oil for high temps) in wednesday night ill see how it goes but the engine was fairly warm too Share this post Link to post Share on other sites
winton 399 Posted July 14, 2013 I rebuilt my 250 in my pre internet days and wasn't aware of the issue with fitting a high volume pump to a xflow so I fitted one. cold 50psi. worm 25psi. at about 800/900 rpm. think its got 15/40 in it atm. last build was about 3 or 4 years ago now. don't do many ks in it. when I pull it down to increase HP will probably go back to standard. Share this post Link to post Share on other sites
thunderbolt 150 Posted July 14, 2013 my 250 in my ute  gets 20psi hot at 900rpm and and 40 when cold Share this post Link to post Share on other sites
Thom 6,651 Posted July 14, 2013 As a general rule of thumb you don't want your oil pressure any less than 10psi per 1000rpm Share this post Link to post Share on other sites
slydog 7,873 Posted July 14, 2013 Mine has a E series pump and pick up to suit my sump of course,here it is at idle...   The engine was still cold (I only ran it for like 2 minutes) I couldn't confirm it's real operating window.Was was built for my engine for my RPM window so it will start to by-pass @ 72 PSI when warm @ RPM.  And yes Thom is right,the rule of thumb is 10 PSI per 1000 RPM.Having said that I have never had a x-flow die due to low oil pressure,only even been dead pistons or camshafts.I use to get 15ish @ idle and around 50 @ RPM but with my new combo and new pump it's cranking pressure is higher than the old 1's total @ RPM.If your concerned bro stick a thicker oil in it and check or whip it back out and I can get my guy to build you a pump to suit.I know it's a pain to do but it's peace of mind.  Good luck with it bro... Share this post Link to post Share on other sites
Tyler06 266 Posted July 14, 2013 Cheers guys im gonna stick my racing oil in tomorro night (50w made for higher temp) and see how it goes as id be happy with 15psi warm if no better ill get a new pump built by your guy rob :-) Share this post Link to post Share on other sites
ando76 4,354 Posted July 14, 2013 does the oil pressure go up when the revs increase? if so is it 10psi per 1000 rpm, hot or cold? what is its peak pressure?  Oil is the life blood of your engine. That is why a good sump, good windage tray, enlarged oil return holes, smoothed castings in the lower block, smoothed oil filter area with radiussed galleries, supplementary oil returns from the back of the head, good std volume oil pump and enlarged oil capacity should be a part of every serious x-flow build.  I like to fit a hobbs switch set at 30psi connected to a big light so that you have half a chance of shutting down and saving the engine if you see the light come on under full power.  most of the hobbs switches are adjustable as well so you can bump that up a bit if u like.  suggestions only  Share this post Link to post Share on other sites
Tyler06 266 Posted July 14, 2013 Yeah peak pressure is 45 psi at about 4500rpm as i havent revved past that yet but does go up with revs and i like the sounds of a hobbs switch Share this post Link to post Share on other sites
ando76 4,354 Posted July 15, 2013 Your hot oil pressure at idle scares me a little. I usually see about 40psi hot after a 15 lap feature race. My guess is that you are running a flat tappet cam with solid lifters that have the disc style restrictor plate. These are the most common ones. You can buy big brand name (c. cams etc)and they are the same as the cheaper ones. They are all made in China. The only solid lifter to use in a x-flow is a isky lifter IMHO. they are made in America and are a true edge orifice lifter. they restrict oil to the top end and don't screw with the oil as much as the disc design. they are not cheap but neither are screwed engines. they will increase your hot oil pressure by 20psi. You can try reducing your valve lash to improve oil pressure. Do you have a decent volume sump? Share this post Link to post Share on other sites
Tyler06 266 Posted July 15, 2013 7.5ltr high energy sump but wat clearance do you run on your mains and bigends? Share this post Link to post Share on other sites
ando76 4,354 Posted July 15, 2013 2.5 and 3 with Fuchs Race 60 Share this post Link to post Share on other sites
ando76 4,354 Posted July 15, 2013 that is big ends and mains respectively in thou of course. Share this post Link to post Share on other sites
Tyler06 266 Posted July 15, 2013 Yeah my mine are 2.5 and 3 as well gonna try my 50w brad penn tomorro night and see but if its still no good i will be ripping it out and ill get robs guy to build me a pump. My previous issue was only lost pressure when applying brakes and pickup had 28mm clearance but now has 6-7mm. That was with a mellings pump and this is a new JP pump with the clearances checked and at 2 thou. But no other mods... Share this post Link to post Share on other sites
