Oil Control In Rb's For Circuit Drag Or Drift

[accel junky]

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...

Edited February 26, 2020 by accel junky

[GTSBoy]

The dipstick is so small that it can only offer a tiny improvement.

[burn4005]

I run a -12 vent from the sump so the dipstick ain't doing shit

[KiwiRS4T]

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...

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.

[burn4005]

I used to get a lap or two around QR at full tilt before I start filling the can (before all the oil control mods). You must be driving like a mad man on the street.

[accel junky]

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 February 28, 2020 by accel junky

[djr81]

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/

[KiwiRS4T]

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.

[Duncan]

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

[accel junky]

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.

[KiwiRS4T]

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).

[GTSBoy]

Yup. Piece of corflute will fix it.

[Duncan]

I don't know if it will fix the problem in your case, but the oil cap vent is the quickest bandaid way to improve things to find out....

[accel junky]

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 March 11, 2020 by accel junky

[Unzipped Composites]

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+?

[KiwiRS4T]

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

[Unzipped Composites]

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.

[Unzipped Composites]

No one?

[R32 TT]

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.

 

[fatz]

You only need to worry about weakening the block of going over 450-500rwkw
 

eg drag fags