Tinker219

OK, I have a question. Could excess positive crank-case pressure cause oil backup in the oil return line? Even if its a ONE ******* INCH Inner DIamter line?
TIA

DaveF

how much pressure are ya talking about?

anyway, i have doubts about possitive crankcase pressure causing the oil to back up in the return line.

ScrapinSi

you didnt blow another turbo did you?

ahobbs

Man I wouldn't think so..That has to be alot of positive pressure...I mean alot. The whole oil pan should pop off if that's the case.

Tinker219

well, ya, im still smoking. I would think it was the engine, but NA the thing rocks. SO, I was wondering if perhaps the positive pressure from boost could be causing this? I seriously have a 1 inch ID oil return line, as well as a 3-an feed. Should I pinch the nipple a little bit to restrict some oil flow TO the turbo or what!?
I have a catch can w/a line going to the inlet of the turbo when boost snaps the stock PCV valve shut, so I would think this would aleviate this. BTW, cylinder # 4 has under 100psi compression, (but no smoke WHATSOEVER NA) so Im wondering if the ringlands are letting THAT much air through, and its causing backup? Im going to try a 1" ID to 1.5" ID, and the 1.5" ID part will then fork into TWO lines going back to the pan. If this doesnt work, then I dont know WTF is goin on

DaveF

how much oil is in the pan?

Tinker219

lower line, I already tried running a lower level, but the oil pan is starting to get caved in a lil bit(h22 in eg, LOW LOW), and I dont want to starve the thing.

omahaturbocivic

Maybe the pressure is not actually pushing oil up the line but just escaping out of the turbo seals through the drain and then taking some oil out with it.

kpt4321

It doesn't really matter what size the return line is, the pressure restricting the oil will be the same.

You only need a big line so that the oil itself doesn't cause backpressure on the bearings.

I bet it's smoke being caused by the turbo, but not because of a restricted return line.

Do you have good crankcase ventilation under WOT?

It's not very likely that it is crankcase pressure coming out the turbo, unless the crankcase pressure is greater than the boost pressure (or the backpressure in the exhaust mani, which is probably even more....).

Tinker219

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by omahaturbocivic &raquo;</TD></TR><TR><TD CLASS="quote">Maybe the pressure is not actually pushing oil up the line but just escaping out of the turbo seals through the drain and then taking some oil out with it.</TD></TR></TABLE>
Ill post pictures later, but I think its adequate. I know that #4 cylinder is completely toast, like under 100 psi of compression, and being an h22, the ring lands are history.
SO, your theory is the best bet as of yet. It only smokes actually in BOOST, and as soon as boost is gone, it doesnt smoke.
Again, in NA trim, the engine DIDNT puff a wink. Put the turbo on, and instant smoke in boost ONLY. So, I think youre right bro. If theres a solid 12 psi in the engine(which there probably is), it might cause the air to blowby. BUt one thing, the oil pressure going INTO the turbo is 100 psi or so at WOT/redline. The turbo seals could take more then 12 psi then correct? Ill be trying the monstrous return line tomorrow while cutting collectors for all the customers out there.

BROOD

I feel that moving to a 1.5" ID return line will only be more work and will not yeild any results for you. In most applications using an 8AN-12AN return line, the oil travels through the line along the walls for the majority of the length. Oil has a sort of cling to the walls of its travel path. The 1" ID return line you have now should be more than enough.

This makes me start thinking. Even though I may catch some heat from this....I'm really not seeing any solid results backing up feed and return line sizes being the main factor in turbo oil leakage. **Besides the obvious problems (severe angle fittings, collection dips in the line, etc.)** Changing sizes has shown to improve the problem, but is it really just covering up something else???
There are alot of high HP turbo engines running fine with as little as 8AN return lines (EVOs) and have no oil issues. So what gives?
Large bore diesel turbos have weaker shaft seals and usually have larger feed lines than 3AN, no restrictors, and see more EOP than we try to get. They live fine...why?

Was the engine built for n/a or for f/i?
Are you seeing any oil in the exhaust downpipe or intake track/compressor impellers???
I would have to say that the dead cylinder you mentioned should be addressed before diagnosing other systems on the engine.

Tinker219

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BROOD &raquo;</TD></TR><TR><TD CLASS="quote">I feel that moving to a 1.5" ID return line will only be more work and will not yeild any results for you. In most applications using an 8AN-12AN return line, the oil travels through the line along the walls for the majority of the length. Oil has a sort of cling to the walls of its travel path. The 1" ID return line you have now should be more than enough.

This makes me start thinking. Even though I may catch some heat from this....I'm really not seeing any solid results backing up feed and return line sizes being the main factor in turbo oil leakage. **Besides the obvious problems (severe angle fittings, collection dips in the line, etc.)** Changing sizes has shown to improve the problem, but is it really just covering up something else???
There are alot of high HP turbo engines running fine with as little as 8AN return lines (EVOs) and have no oil issues. So what gives?
Large bore diesel turbos have weaker shaft seals and usually have larger feed lines than 3AN, no restrictors, and see more EOP than we try to get. They live fine...why?

Was the engine built for n/a or for f/i? </TD></TR></TABLE>
Maybe its the oil pressures that our hondas put out? Im not sure what other presssures are present in other engines, but its a possibility.
The engines stock, but is well on its way to a killer FI build...

BROOD

Are you seeing any oil in the exhaust downpipe or intake track/compressor impellers??? If nothing is seen there..then the oil seals are most likely working correctly.
I would have to say that the dead cylinder you mentioned should be addressed before diagnosing other systems on the engine.

**hmmm, I can understand you frustration Cody. **


Modified by BROOD at 5:20 AM 10/17/2003

Tinker219

Yes, there is oil out the DP. Not alot, but the bumper is fairly damp(side exit in the front). BUT, at idle, the oil does not flow anymore. So, it has to do with high rpm pressures.
On another note, this engine has gone through 4 turbos. I pulled my t3/60-1 off after a day of intermittent smoke, and I decided to run my t4/60-1 with this monstrous line.
Then why wont the engine smoke AT ALL in NA trim? Im not being an ***, Im asking truthfully. My buddy blew his ringlands on his b16a, took it for a drive in NA trim, and SMOKE EVERYWHERE.
Ive been back and forth about 5 times because everytime this happens, I think the engine is completely toast. Go NA, and is beautiful, no smoke, pulls hard, etc etc. Maybe I should recheck the compression, because it doesnt run like it has a dead cylinder. It only has to last another 2 weeks, and its goin iunder for the RWD conversion

Overblown-Teg

is it possible the smoke is left over oil in the exhaust.. I know it can take a while to burn it all out and have the smoking stop.

Tinker219

I spose it could be, but my exhaust is ALL downhill, and a whopping 2 feet long...