Muncie Posted January 22 Posted January 22 Alright so ive just built my first engine from scratch a Holden L67 it runs nice after the rebuild has had run in oil through it and now on to synthetic ready to live its best life. The old engines that donated a few ancillaries both shat bearings so I used the best oil pump of the litter fitted new parts where available and reused it everything pulled apart cleaned like crazy. Suppose good thing is I have lots of oil pressure at idle I've got 55-60psi cold and doesn't change much once warm with a bit of a rev it climbs to 90psi. Would you call this too high? It has had new bearings lifters and balance shaft deactivated basically the balance shaft is there undisturbed but no longer drive off cam so I could fit a dual row timing chain. Quote
mjrstar Posted January 22 Posted January 22 Does it approach 90 quickly and then flatten off like the relief is working? If it does then I'd send it. If not I'd probably still send it. 5 1 Quote
sheepers Posted January 22 Posted January 22 1uz runs well over 100 psi whilst cold and around 80 most other times. 90 is good. Send it. Quote
RUNAMUCK Posted January 22 Posted January 22 I'm sure an old hot rodder mates rule of thumb was 30psi at idle and 10 psi for every 1000 rpms? /send it until ya end it! 4 Quote
Muncie Posted January 22 Author Posted January 22 Seems to peg at 90, its got 10/40 in it too. I'll send it but will make sure the pump keeps up once the turbo goes on and steals a bit of flow. Internet says its high but cant definitively find something whether its good or bad. Quote
HighLUX Posted January 22 Posted January 22 More oil pressure is better than less oil pressure 1 Quote
cletus Posted January 22 Posted January 22 One thing I'd be concerned about if that is more than it should have, is strain on the oil pump drive shaft (if that's what your engine has? Can't remember) Boss's 428 broke that just before xmas starting from cold 3 Quote
smokin'joe Posted January 22 Posted January 22 9 hours ago, cletus said: One thing I'd be concerned about if that is more than it should have, is strain on the oil pump drive shaft (if that's what your engine has? Can't remember) Boss's 428 broke that just before xmas starting from cold or in the case of my mates fresh 302W, no oil pressure, he dressed motor for a poser photo, by installing dissy, but no-one checked went they went to start it................... pump drive not installed, motor seized 7 Quote
Lord Gruntfuttock Posted January 22 Posted January 22 Man those are big numbers... Spoken as someone with an ironhead that runs at near zero. Like my old HQ ute that had a pressure gauge, all it did was worry you... Quote
RUNAMUCK Posted January 22 Posted January 22 It's easier to ignore an oil pressure gauge than an idiot light. 1 Quote
Muncie Posted January 22 Author Posted January 22 Found out my oil pressure switch is poked as well so glad I cranked it over first with crank angle sensor unplugged made sure pump had primed because I wouldn't have got any warning of no pressure. Heaps of oil pressure possibly to much I haven't revved it right out yet but it appears to bypass at 90psi and idles at 50-60psi on the gauge. Im using a calibrated gauge too not an old automotive shitter. Quote
ajg193 Posted January 23 Posted January 23 Two things to consider: 1. Bypass generates a lot of heat and also limits the amount of oil going through the bearings so could decrease oil life 2. Way too high pressure can supposedly erode bearings, but I guess that will be a self clearancing system 1 Quote
Muncie Posted January 23 Author Posted January 23 Hadn't thought about the heat side of things, so noted there thanks. Ive got another oil pressure reg body I could play with and there is an adjustable one out there i might consider buying so I can dial in. This may all drop back to normal with more driving too so I'll proceed and monitor, high is better than low for now. I do intend to launch this thing around Hampton downs at some stage so an oil cooler will be in next stage of development life after turbo and Cert. Quote
cletus Posted January 23 Posted January 23 Is the oil pump standard? Relief valve hasn't been shimmed? When I put the engine in my green car I took the high volume pump out and put a stock one in. When you think about it a high volume pump is not a great idea, if it makes more volume of oil move then it pumps it all upstairs and you end up with none in the pan if it cant drain back quickly enough. Also they might make more pressure at low rpm but the relief valve just opens earlier and the oil does laps around the pump And if the pickup is small the high volume pump can cause cavitation More oil flow might be beneficial if an engine is built with loose clearances but if its stock clearances I don't think they are a great idea 2 Quote
RUNAMUCK Posted January 23 Posted January 23 Shitloads more oil getting pushed up top can increase windage loads on the crank when it drains back to the sump too. Seen a few builds where guys block off the opening above the cam to control/li.it where the oil runs back down Quote
Muncie Posted January 23 Author Posted January 23 Its a stock pump only has a machined cover for dual row timing chain clearance. That would mean the cover is dead flat though so losses through shitty clearances would be way less. 1 Quote
morkster Posted January 24 Posted January 24 This might be Ling but anyway i build a kent 1600 xflow engine once with very tight cam bearings this caused so much oil pressure the oil filter oring would blow out and spew oil everywhere (mainly during attempted burnouts).. i just kept sending it until it clearanced itself (like someone else mentioned above) 3 Quote
SOHC Posted January 26 Posted January 26 On 22/01/2026 at 21:02, HighLUX said: More oil pressure is better than less oil pressure Not necessarily, 1 Quote
SOHC Posted January 26 Posted January 26 My Ford was using more oil when it had wrong spring in the plunger, Quote
kws Posted January 30 Posted January 30 On 26/01/2026 at 14:40, SOHC said: Not necessarily, Rover V8s run low pressure, but high flow, for instance. 10-15psi idle, 35psi @ 2000rpm 1 Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.