Moore

What oil weight should I run with acl standard size bearings? I just finished rebuilding my sr with acl mains and rods and have had it out for a couple drive's now. I put in 10w30, oil pressure is lower than it was before I rebuilt it and I am wondering if this has to do with larger bearing clearances.

@ 160F oil temp
13psi idle,
35-40psi 3200rpm.

I would like to see those higher as I know my oil temp will get a lot hotter. I am thinking of changing to at least 10w40 but I am interested to know if what I am seeing is normal.

Croustibat

read the FSM and chose the oil weight according to recommended pressures hot & cold, at idle and at 3500-4000rpm.

Although your pressures seems way too low for a rebuilt engine (unless you did not change the oil pump - which mean you now have to). I highly doubt it has to do with larger clearance, unless again they are way too big.

nissan recommends 11psi min for idle oil pressure when hot, and 160°F is not "hot", 200-210 is. I cant remember the hot running window, but 15psi per 1000 rpm up to 4000, then 60psi is the way to go on most engines.

TBH i would not run the engine with such low oil pressure. I think your engine has a problem, not one caused by loose clearance, more like dead oil pump. What is the idle pressure when cold ?

Moore

Not the response I wanted to hear but this is why I asked.

Cold idle seemed good, around 70.

I was thinking it was more like 10psi for every 1000rpm so I thought my pressure was in spec but on the low end.

I did not put a new pump in, but I did take the time to remove the cover and check all the tolerance's. The pump measured in spec and looked in good shape, no visible scars pitting or anything that I thought required replacement.

TheRealSy90

I'd go up to 15w50 Mobil1 or RotellaT6.

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Moore

I found that chart for temp vs oil weight. It was 30C out yesterday so if I'm reading the chart correctly I should be running at least 10-40.

Is there any way to check for a bad oil pump, other than obviously pressure? And what cause's an oil pump to go bad besides wear?

Croustibat

That chart applies to standard engines used as commuters. You can find it on numerous car driver manual.

The oil pump may have its regulator damaged, it just is a ball and a spring. Maybe you could preload the spring a bit more. The pump seal may be leaking too. It could be a lot of things ... when i changed my oil pump, it looked good too. I hesitated to buy a new one, but then i thought i had oil pressure and temperature problems, and i did not want to pull the engine again, and i changed it. That really was the source of my problems, i had to run 10w60 to have a good pressure when hot. The problem is that when using a pressure regulating system, the more pressure you get, the less flow you have.

Now i am running 10w50, and am near the maximum pressure window when hot. I also have no temperature problems anymore ( new pump gave more flow and more pressure). I probably can try going 5w50.

Now, 70psi when cold indicates the pumps does a good job when oil is thick. Mine did not, so it may be just a sealing problem, or a thin oil problem. I don't live in the same place so it has to do with usual driving temperatures, but here nissan (and most car builders) recommend 10w40 as standard thickness, and it is nowhere near 30°C.

But again, this is for a normal use of the engine. The real recommended thickness is whatever fits the pressure window given in the FSM.

Try just with a thicker oil, see if the problem goes away. Acheap 10w40 will do for a bit of testing. It might be all you need (although i am a bit skeptical)

Moore

Well I am agreeing with you skepticism. I put in 15-40 last night and saw no change in oil pressure. Still sitting around 13 at idle when warm and 35psi at 3200rpm which I am not okay with. I guess the contact area of the pump gear's has worn, it was difficult to measure that area. Either way I'm going to put a new pump in. This looks like a pain in the ass job to do with the motor in the car

Croustibat

That is another reason i changed it. I did not want to find out

Good luck, and i hope it solves your problem. 15w40 should have given way more pressure though, i find it strange it did not even go up. It should have, even with a worn pump. It should not have been enough, but it should have gone up.

Before you disassemble your engine, try with another pressure sensor and gauge ... maybe the pressure is good but the sensor is not.

pacotaco345

I run 20w 50 in my car and I see about 5-6 bar cold start idle (70-85 psi) and about 1.3 bar warm idle (19-20 ish psi). Cruising at 3000 rpm I see about 4 bar (56-60 psi) and it kinda levels off around 70 psi.

Sorry about using bar, I'm not a jdm fanboi but that's what my gauge reads in lol. Try putting thicker oil in it and see what happens. I spun a bearing running mobile 1 10w 30 and now I don't think I'll ever drop below 15w 40 as far as oil weight. I'm running ACL race bearings btw

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Moore

Your numbers are what I would be comfortable with but I've never had to run that thick of oil before. I've always use 10w30 and then 15w40 for summer/track season.

I did see higher oil pressure when it was cold with the 15-40, but once it warmed up it went back to being low. There could also be a leak between the pick up.

My car isn't running very well since I rebuilt the block so changing the pump also gives me the chance to confirm my chain is correct on the crank sprocket. If I put the brand new pump in and see the same numbers then I'll go up in oil weight and have to relate it to the bearings.

Moore

update. I put in a brand new s13 front cover with pump last weekend. I put 15w40 back in. Oil pressure is a bit higher but still lower than I had before my rebuild.

Good pressure at idle,19, but at 3200rpm on the high way I'm around 45. My car is running well so I've been breaking in the motor and not to concerned about the lower pressure but I still haven't seen very high oil temp - 170 max, my oil cooler kick's in at 160.

After 800km of driving this week I have no oil leaks and haven't used up a drop of oil. I can only think the lower pressure is due to the bearings so I'll try 20W 50 before doing any tracking.

Croustibat

Seriously guys, please think about what you are doing instead of blindly following stupid people. do NOT put 20w50 in these engines, seriously ... that kind of oil was used a long time ago because oil was shite, and a 20w50 would transform nearly into water in one race ... We are NOT at this day and age, stop fucking believing crap without giving it a thought...

Moore

So whats your opinion then? Just leave it be?

TheRealSy90

I've been running 15w50 in my daily driven sr for 6 years... How is that bad oil?

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pacotaco345

What are you talking about? You use thicker oil for turbo motors and even thicker oil at that for motors that have slightly larger clearances (I.E. acl bearings). There's a reason why companies like GReddy, HKS, Eunos, etc all formulate their turbo race engine oil to be 20w 50. Next time think before you blatantly call people stupid.

France.. apparently the Florida of the world

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pacotaco345

Oh and @Moore, I live/drive in Texas where its routinely 90+ degrees and humid during the spring, fall & summer. I'm not sure what the weather is like where you are but if temps are > 60* I'd say 15w40 and > 85* I'd say (whatever)w50

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Croustibat

Use your head, and not by banging it on a wall. Learn how a lubrication system works, how hydrodynamic bearings work. Then talk, voice your opinion. But repeating what you read or heard like a parrot ? that just is plain stupid. Just like it is stupid to put 20w50 oil in these engines. Which you'd know if you even knew the clearances in your engines and the pressure they require. You'd also know what i am talking about if you had read THIS DAMN THREAD.

I guess you also consider a lowered car with rock hard suspension has better handling than with working oem suspension at stock height, because all the cool kids do it, and in formula 1 the cars are low too

pacotaco345

@Croustibat, he specifically asked you a question and instead of spending 10 seconds to answer it you just sling insults at me and another member. He's currently running 15w40 without enough pressure AND a new pump, so whats wrong with stepping up to 15 or 20w50.

OP I would step up to 20w50 or what TheReaySy90 said and run 15w50. Just don't rail your car until you see the oil warm up and the pressure drop to normal levels. If you really feel the need to spend $70 on oil changes and buy 5w50 I'm sure your motor won't complain but your wallet will. My car works perfectly well with $25 VR-1 oil changes lol.

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quickdiversion

We all forgot to ask him a very important question.

ACL makes over and undersized bearings.

Over sized; if you have have crank work done and want to bring it back into stock or pre-determined clearance.
Undersized; Some people run undersized a little with a tad heavier oil weight to free up the rotation mass and keep heat down at very high RPM say drifting a 4 banger at 6-8k rpm often, keeps the crank a tad looser and better heat dissipation.

You can have any setup you want,
Did you just use the standard SR20DET size, or did you get a different size?

Croustibat

The fact is I already explained why, numerous times, and even on this very thread. You want to know what is wrong with that ? That is quite easy: READ MY DAMN POSTS and you will.


5w50 is actully cheaper than 20w50 or 10w50, so yeah, that is so going to ruin his wallet. "lol" .

BTW how about using an oil that actually gives the desired pressure level ? To me it sounds DAMN STUPID not to, and even more when you know it beforehand.

I am quite sure your camshafts and rocker arms will reward your use of cheap, ultra thick 25$ oil too. While you are at it, why not piss into the oil filler ? Maybe it will thin that 20w50 enough, and that sure could take 50% off of the cost of an oil change !

dorifto_demon

i normally use 10/60 or 20/50 on built engines with looser clearance..

so far oil pressure and temps is A ok..

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Moore

I figured I should take the time to update this thread with what I have done/learned. In regards to the question about the bearing size, they are standard size, there was no machine work done, but the bearings are the hx size which has 0.001" extra oil clearance. I have them on mains and rods.

Before switching to a 50 weight oil I did disconnect my oil cooler and remote filter to make that wasn't the issue. I saw the same pressure. Pressure was also confirmed with a different mech oil gauge. Since then I switched to castrol 5w-50, it was all the local auto store had at 50 weight and I had plans to do some fun driving that weekend - I will be changing to a 15 or 20w-50 next oil change. With that oil in the car I drove it for around 40mins with rpm's > 4000, oil temp was up to 200-210, idle pressure was 15, red line rpm 50-60.

The redline rpm still concerned me so I spoke to ACL directly about the bearings and the oil pressure. ACL confirmed that the larger clearance will drop oil pressure which makes sense.

http://lubricants.s5.com/oil_pressure.htm not sure how creditable the link is but it is interesting, made sense to me and was inline with the discussion I had with ACL.

ACL Tech support looked up the sr20det specs, greater than 11psi at idle, and 47-57 @3200rpm. He said because there is no high end spec that my oil pressure was adequate for the bearings at high rpm - take that as you will but he seemed to be knowledgeable. Also recommended full synthetic oil - so redline or high end equivalent but warned the high teflon levels can cause issues with clogging oil screens and filters so you should be changing oil more frequently than with conventional... not something I plan on doing. I said i'll run mobile 1 or castrol which he said would be fine.

I went with the ACL's because they were recommended to be by someone that's been into sr's for over 10 years. It was also my first motor build so I was fond of the 1 size fit's all for reducing the difficultly. If I were to do this again I would likely go with oem nissan because it really isn't that difficult to size and my oem bearings looked great when the came out. On a positive note the engine is running great so I'm going to live with this and just keep beating on and hopefully it last a couple years before something fails.