Jump to content
SAU Community
  • Welcome to SAU Community

    Welcome to SAU Community, like most online communities you must register to view or post in our community, but don't worry this is a simple free process that requires minimal information for you to signup. Be apart of SAU Community by signing in or creating an account.

    • Start new topics and reply to others
    • Subscribe to topics and forums to get email updates
    • Get your own profile page, build reputation and make new friends
    • Send personal messages to other members.
    • See fewer ads!

    Consider joining our newsletter for the latest content updates

    Click here to register


Oil Control In Rb's For Circuit Drag Or Drift


Recommended Posts

Read backwards from pages 81-49. Wish I'd seen this before my 26 had to be pulled and rebuilt. I have a 1.5mm restrictor with N1 pump, stock sump w/ Tomei baffle, Hi-Octane baffles, oil cooler. Builder (here in the states no so experienced with these oil control topics I guess) talked me out of head drain which at this point after reading I'm not upset about any more. I tried leaving cam covers tied together and routing one to a small vented catch can which did nothing but blast my bay with oil spray (whilst overfilled to the hump...probably aerating). So I have a Hi-Octane 3 liter can incoming with 12AN fittings for each cam cover. At this point for various personal reasons pulling the motor again soon is not an option for me but otherwise being now-educated I eventually plan on extended sump with vent fittings and a smaller restrictor.

Therefore, I'd love to know if anyone has had any practical experience running the dipstick to a catch can. I saw some bare mention of it a few times but it looks like few have noted ever trying it. My thinking is that if I weld a Y off the tube, I can still use the stick to check the oil level. The tube appears to terminate even further up than the sump vent fittings I've seen pictured which should be even safer for preventing oil sloshing up. I have no issues blowing out the dipstick currently. Obviously this is not the most optimal idea (fairly small opening and all...) but I'm not going on the track (very sadly) until I can pull the motor for the extended sump anyways, so I wonder if this will at least provide some worthwhile benefit for my street blasting in the meantime? My hunch is that it can only help.

Crude drawing attached...

dipstick-vent.JPG

Edited by accel junky
Link to comment
Share on other sites

10 hours ago, accel junky said:

Read backwards from pages 81-49. Wish I'd seen this before my 26 had to be pulled and rebuilt. I have a 1.5mm restrictor with N1 pump, stock sump w/ Tomei baffle, Hi-Octane baffles, oil cooler. Builder (here in the states no so experienced with these oil control topics I guess) talked me out of head drain which at this point after reading I'm not upset about any more. I tried leaving cam covers tied together and routing one to a small vented catch can which did nothing but blast my bay with oil spray (whilst overfilled to the hump...probably aerating). So I have a Hi-Octane 3 liter can incoming with 12AN fittings for each cam cover. At this point for various personal reasons pulling the motor again soon is not an option for me but otherwise being now-educated I eventually plan on extended sump with vent fittings and a smaller restrictor.

Therefore, I'd love to know if anyone has had any practical experience running the dipstick to a catch can. I saw some bare mention of it a few times but it looks like few have noted ever trying it. My thinking is that if I weld a Y off the tube, I can still use the stick to check the oil level. The tube appears to terminate even further up than the sump vent fittings I've seen pictured which should be even safer for preventing oil sloshing up. I have no issues blowing out the dipstick currently. Obviously this is not the most optimal idea (fairly small opening and all...) but I'm not going on the track (very sadly) until I can pull the motor for the extended sump anyways, so I wonder if this will at least provide some worthwhile benefit for my street blasting in the meantime? My hunch is that it can only help.

Crude drawing attached...

dipstick-vent.JPG

Have you even got a problem with "street blasting"? Problems usually occur only with extended bursts at high revs which you will normally only manage on a track. And no dipstick won't do it.

Link to comment
Share on other sites

Appreciate the responses. Engine isn’t coming out again so soon due to life so I’ve got to try to make the best of what I can get to or else park the car for a while. I figured it was probably not going to offer much but can it be worse? I’ll give you an example of street blasting: 30min drive, warm up then about 3-4 WOT high rev (8k) straight line pulls consisting of 2-3 gears each, everything logged, 25psi with meth. 100ml in the 250ml can (aware that is far too small) some of it meth or water and oil sprayed out the filter into the left side of the bay. I figure that is probably a bit much for a few quick pulls but I’d filled to the hump to sort out straight line pressure drops I’m having, so maybe aerating. I have a bigger catch can coming from hi-octane as soon as they finish the coating and with much bigger lines from the cam covers. I don’t dare take the car on the track until I have it sorted on the street. There is a possibility the engine builder left me with the blow by problem but I’m not sure yet. I have a cylinder at 10% below the highest cylinder and full improvement with a wet test but the car was shut off for 3 hours with adjacent plugs all in so not exactly a proper operating temp test.

Edited by accel junky
Link to comment
Share on other sites

This is one of the most popular threads on SAU but for my 10 cents worth it is the rings that are the issue not the rest of everything.  So before building an engine please think long and hard about the rings and dont just get whatever comes with the pistons.... 

As an example and for those in Oz I found these folk very good:

http://pacificengineparts.biz/

Link to comment
Share on other sites

5 hours ago, accel junky said:

Appreciate the responses. Engine isn’t coming out again so soon due to life so I’ve got to try to make the best of what I can get to or else park the car for a while. I figured it was probably not going to offer much but can it be worse? I’ll give you an example of street blasting: 30min drive, warm up then about 3-4 WOT high rev (8k) straight line pulls consisting of 2-3 gears each, everything logged, 25psi with meth. 100ml in the 250ml can (aware that is far too small) some of it meth or water and oil sprayed out the filter into the left side of the bay. I figure that is probably a bit much for a few quick pulls but I’d filled to the hump to sort out straight line pressure drops I’m having, so maybe aerating. I have a bigger catch can coming from hi-octane as soon as they finish the coating and with much bigger lines from the cam covers. I don’t dare take the car on the track until I have it sorted on the street. There is a possibility the engine builder left me with the blow by problem but I’m not sure yet. I have a cylinder at 10% below the highest cylinder and full improvement with a wet test but the car was shut off for 3 hours with adjacent plugs all in so not exactly a proper operating temp test.

Yes 250ml is way too small needs to be 2L at least. Maybe do a leakdown test to see if you have a major problem.

Link to comment
Share on other sites

Also, if the engine is super new, give the rings some time to bed in before being too worried. Make sure you run it pretty hard rather than just idling or driving at low load.

One quick fix that will work better than a dipstick vent is to vent via the oil cap. Just put on a alloy cap and weld a large dash fitting on

  • Like 1
Link to comment
Share on other sites

10 hours ago, Duncan said:

Also, if the engine is super new, give the rings some time to bed in before being too worried. Make sure you run it pretty hard rather than just idling or driving at low load.

One quick fix that will work better than a dipstick vent is to vent via the oil cap. Just put on a alloy cap and weld a large dash fitting on

I’ve got 2000 miles on it and honestly I have been punishing it pretty regularly. The only thing I’m concerned with about break in is that the builder did not honor my request for a oil thermos stat with the cooler so I struggle to get temps much above 160F (especially with it being the winter). He insisted I didn’t need it but seeing the temps on the street I should’ve held my ground. So I plan to rip all that out and run new lines with a thermostat. I did see some other manufacturers with OEM cap vents. Would the oil cap vent be of particular use even with the 12AN cam cover lines to the catch can? I’ve moved my splash shields back for the cam cover baffles too, not sure if that makes a difference for the cap.

Link to comment
Share on other sites

17 hours ago, accel junky said:

I’ve got 2000 miles on it and honestly I have been punishing it pretty regularly. The only thing I’m concerned with about break in is that the builder did not honor my request for a oil thermos stat with the cooler so I struggle to get temps much above 160F (especially with it being the winter). He insisted I didn’t need it but seeing the temps on the street I should’ve held my ground. So I plan to rip all that out and run new lines with a thermostat. I did see some other manufacturers with OEM cap vents. Would the oil cap vent be of particular use even with the 12AN cam cover lines to the catch can? I’ve moved my splash shields back for the cam cover baffles too, not sure if that makes a difference for the cap.

In the mean time some people just make a cover for the oil cooler and remove it for the track (or the summer).

Link to comment
Share on other sites

  • 2 weeks later...

Just a quick update for future readers in case it is meaningful: while I'm still awaiting my 3 liter catch can to come to the states, I tried a few experiments to manage this blow by on the street.

First, I dropped down to my 19psi, no meth/water pump gas map. Then I drained out my overfilled oil (was to the bottom of hump, now back to the top of the hash marks).

I cleaned all the oil that pissed out of my tiny atmo 250ml catch can and then covered it in a loosely fitted clean ziplock bag so that I could watch for oil vapor coming out, mitigate oil spray while testing.

I drove the car to work and back with a detour, all totaling about 3 hours with quite a bit of WOT pulls mixed in. Got home and the ziplock bag was pristine, just some water vapor. Drained the catch can. 17ml, mostly runny doubt much oil. I did a compression test again this time as fast as I could after shutting the car off. 177F oil temp is as high as I could get without a tstat. Compression was between 172-179 across the board. No more cyl at 10% difference. Guess these Mahle's are loose when not fully hot. Conclude that there is not a ring issue at this point.

Then I did another drive next day after switching back to my 25psi meth/water map, changing nothing else. Drive was shorter...about 1-1.5 hours and full of WOT pulls. Drained catch can: 3ml, mostly runny/watery again.

So that is all with a 250ml atmo catch can, factory oil level on dipstick, and the Hi-Octane baffles.

I therefore must conclude that the standard practice of overfilling to the hump was sending oil back to get aerated by the crank hence my earlier issues with overwhelming the catch can and before that filling my piping/intercooler.

At this point, I still have 40+ psi oil pressure drops (to lows of 40-50psi) under acceleration Gs and the only way to fix that looks like engine pull with sump extension or Accusump, as the Tomei baffle seems to not be enough. But it is not like the overfilling really helped much. I logged it at around a 5psi reduction in pressure drop to the hump vs standard oil level.

I don't know how this would play out on track but I'm postponing taking it to the track until the oil pressure drops are dealt with and the larger catch can is in place. I am going to run a line from the dipstick tube to the smaller catch can in the meantime since I am getting very little in my can now.

 

Edited by accel junky
  • Like 2
Link to comment
Share on other sites

  • 2 months later...

82 pages in 2 days, what a wild adventure. It's like reading of the rise and fall of several different dynasties throughout time - except interesting.

 

One thing I didn't find a mention of anywhere: is it a drain or a vent? Haha. Jokes.

 

Seriously though, enlarging the oil returns. I know of a few experienced engine builders who would say touching the block at all is a bad idea. Is this only true of very high horsepower applications? Ie. 1000hp+?

Link to comment
Share on other sites

8 hours ago, Unzipped Composites said:

82 pages in 2 days, what a wild adventure. It's like reading of the rise and fall of several different dynasties throughout time - except interesting.

 

One thing I didn't find a mention of anywhere: is it a drain or a vent? Haha. Jokes.

 

Seriously though, enlarging the oil returns. I know of a few experienced engine builders who would say touching the block at all is a bad idea. Is this only true of very high horsepower applications? Ie. 1000hp+?

Its not to do with horsepower. Its a number of factors including  that some people put in super high powered oil pumps that may actually empty the sump (or at least leave the pickup exposed) under certain conditions. In particular a long period at WOT which you will not likely encounter on the road but more likely on a long straight or sweeper (especially the front straight at Hampton Downs (in NZ) which is uphill so foot flat all the way).  I did not drill out my oil drains but did fit restrictors and a couple of vents in the sump because pressure can build up which impedes the flow of returning oil. I also think that souped up RB30s (I had one) are also more prone to this problem for some reason.  But with the baffles, oil restrictors and sump vents running through two catch cans (and no rear "drain" or "vent" )I did solve my problems.

BTW if I had anywhere near 1000hp I would seriously consider a dry sump set up

Link to comment
Share on other sites

No i understand the enlarged oil returns and why it is done, I meant is it considered bad practise to weaken the block by drilling out the holes on big horsepower builds. I know of a few engine builders who would say doing anything that makes the walls of the block thinner is not a good idea. 

 

Just hadn't seen it discussed in this thread at all.

Link to comment
Share on other sites

I can't say I have done it - but I am of the same opinion - I wouldn't do something that weakens the block.

An external drain is attempting to get the same result - just like a jerry can has a breather.

 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Latest Posts

    • Hey I have a spare CAS unit if you wanted to borrow or buy
    • All issues mentioned are mitigated by running billet gears and a long nose crank. My question pertains more to the oil pump housing differences. I already have an RB25 pump housing I wanted to put billet pump gears in. I was wondering if there's any advantage if I purchase an N1 pump instead and put billet gears into that. Even stranger is I found a link (One in OP) that states the RB25 pump housing is actually preferable which I'm wondering why.   Thanks
    • In the middle of the rb25 upgrade on the rb20. Its actually a Arashi bolt on. Its in and lined up perfect First question is can I use a standard hose as my oil return line? New turbo fitting is shorter and having to  change the line/hose The oil supply/intake hose has a smaller hole than stock. Not sure I should go back with the old one   Any other tips would be appreciated   
    • So just to update: I changed the brushes over and polished the commutator using a 1500 grit sanding sponge; it was super easy to polish being copper. A power tool wasn't necessary, although could have made it easier if you have the finesse to use it well.     Yet this was to no avail, the motor worked as it did before, stop, start, stop start, etc. Today I went to my mechanic's shop to do a few things. I showed him the motor and asked in broken Japanese "who can fix this?", he took it from me and had a crack, was able to fix it-ish. From what I could understand (which is very little), the problem with the motor was with the clutch disc located amongst the gears, I saw it whilst he was working but couldn't identify any issues. I say he fixed it-ish, because now the motor will run continuously when free from the rack, which is great. But once I had reinstalled it, the tilt function would work but the sliding function sounded off, like the motor was under more load than before and the motor was struggling. We're going to pull apart the rack in the new year and see what we can find.  Hopefully this is of some help to others that get sunroof motor issues with their R34, S15 Silvia, or highly unlikely the Z10 cube. I will update this when more progress is made.
    • AFAIK in the RB26 section of the service manual it explicitly says not to take apart the AAC valve. If you took it apart once there's no harm in taking it apart again to see if you can save it.
×
×
  • Create New...