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Head/ rings / crankcase pressure??
by
Jet A
on 30 Oct, 2008 09:56
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In my quest to figure out why i am gettting oil out the dipstick tube, i have a couple of questions.
1. How are hydrualic cams adjusted? is it possible for a rebuild head to me so out of wack i am pressursing my block something fierece?
2. is the crankcase vented through the valve cover?
3. How else am i getting this much pressure in the oil?
4. when is the most pressure created in the crankcase? idle or high rpm (with boost)
I installed my aftermarket turbo. it is being drained via a bung welded high on the oil pan. i am getting enough pressure through the crank to push oil back up that line and out the turbine side of the turbo.
Could i have installed the rings inccorectly? would that cause this much bottom end pressure? (the gaps are not lined up)
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#1
by
zukgod1
on 30 Oct, 2008 10:24
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In my quest to figure out why i am gettting oil out the dipstick tube, i have a couple of questions.
1. How are hydrualic cams adjusted? is it possible for a rebuild head to me so out of wack i am pressursing my block something fierece?
2. is the crankcase vented through the valve cover?
3. How else am i getting this much pressure in the oil?
4. when is the most pressure created in the crankcase? idle or high rpm (with boost)
I installed my aftermarket turbo. it is being drained via a bung welded high on the oil pan. i am getting enough pressure through the crank to push oil back up that line and out the turbine side of the turbo.
Could i have installed the rings inccorectly? would that cause this much bottom end pressure? (the gaps are not lined up)
1. Hyd cams are adjusted by oil pressure in the lifter. There is a chamber that fills with oil in the lifter.
2. Yes
3. Compression is blowing past the rings, that's the only way to pressurize the crankcase.
4. Hard to say, At higher RPM the rings are loaded more but there is more pressure in the chamber. Same as with boost. There has to be more blowing past under boost. However when I had problems I REALLY noticed it at idle.
Yes you could have installed them incorrectly. Or broke one or more while installing.
I believe the rings are suppose to be install as, oil ring lower @ 7 upper@ 5, second compression ring @ 10 and top ring @ 2.
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#2
by
arb
on 30 Oct, 2008 10:42
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Long shot, are you sure you didn't plumb turbo charged air to the crank case / valve cover ? What is your intake manifold showing for boost pressure ? Is your blow off valve plumbed to the crank case / valve cover ? Maybe the valve is weak or bad is so.
You can easily check your rings this way: Remove the oil filler cap. Rev the engine to a couple 2k rpm's - if the rings are bad, you'll get a ton of smoke pouring out the filler hole - that is assuming nothing is wrong with what I have asked about above.
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#3
by
dieselweasel
on 30 Oct, 2008 18:35
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A failed/defective turbo will sometimes allow boost pressure to leak past the compressor side shaft seal and into the cartridge, therefore pressurizing the crankcase. Check the turbo shaft for excessive radial or any axial play. You can always isolate the turbo by disconnecting the drain line and letting it drain into a pail. Run the engine to see if the blowby changes. Obviously don't run the engine for too long.
If its not the turbo, the problem has to be either with the rings or valve guides.
Of course also check the crankcase ventilation system for kinks/restrictions...that would also explain the oil out the dipstick tube/turbo.
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#4
by
Jet A
on 30 Oct, 2008 19:36
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all excellent points. Turbo did not have excess shaft play when i checked it. will check again. Turbo is plumbed dirrectly from outlet of turbo to inlet of intake. valve cover tube port is open to atmosphere. I will check the smoke thing. Could my rings just not be seated causing all of these? this does seem excessive.
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#5
by
zukgod1
on 31 Oct, 2008 07:25
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How many miles on the rings?
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#6
by
Jet A
on 31 Oct, 2008 12:33
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How many miles on the rings?
4-6 miles...its freshly rebuilt. cant drive it cause i blowing oil out of every orfice....
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#7
by
arb
on 31 Oct, 2008 12:41
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Could my rings just not be seated causing all of these? this does seem excessive.
No, not enough to cause your dip stick to spout oil. New rings, if not damaged have more blow-by, but not excessive. New engines from most OEM's now have the rings already seated (production quality is that good now) and they fill the crank with full synthetic oil to get better CAFE numbers out the gate.
Did you open your oil fill cap and rev the engine ?
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#8
by
zukgod1
on 31 Oct, 2008 12:42
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Damnit!
It really sounds like a ring problem.
Maybe one or more are stuck to the piston?
Probably not but damn man you shouldnt be blowing oil like that.
I'm sorry but it really sounds like you need to tear it down
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#9
by
saurkraut
on 31 Oct, 2008 14:28
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Whats comming out of the valve cover tube? I assume thats blowing oil too.
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#10
by
Jet A
on 01 Nov, 2008 11:46
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Whats comming out of the valve cover tube? I assume thats blowing oil too.
air, there was some blue smoke for the first two min, now at every startup its just air. i have the oil baffle installed over the cam. little bit of oil at higher rpms but more of a mist.
As a side not, i do have a converted hydrualic head for a solid block. I dont hear any lifter tick, so i am asssuming all of that is working correctly.
My oil bung is located below the oil level. i need to investigate this a partial problem before the head but after that maybe i will pull the head, and pull out each piston, see if i cant find something, and then install another set of rings? i dont know what else to do?
I dont know if the head was pressure checked or not at rebuild i bought the head off ebay, from a pretty reliable fellow. Head looks like it was done right. correct valve seals, and bronse guides. head was decked and valves were new. Cant imagine the head issues to cause this. But i dont know where else to look.
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#11
by
gldgti
on 02 Nov, 2008 03:55
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the only thing i can think of that hasnt direcly been mentioned, is installing th compression rings upside-down... i'm sure you know they have a chamfer and a particular orientation.
i hope you find something!
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#12
by
zukgod1
on 02 Nov, 2008 12:11
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I can't remember if we've asked what your ring end gaps were at?
Did you check them?
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#13
by
Jet A
on 03 Nov, 2008 09:24
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I can't remember if we've asked what your ring end gaps were at?
Did you check them?
Yes, ring gaps were checked. also how i check the bore taper.
Orientation was noted on the compression ring. I believe they were also marked "up".
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#14
by
GTD0023
on 03 Nov, 2008 10:42
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i have this same problem!!
new rings, just 100km and oil spitting out the dipstick!!
the block was stil within spec, i used std Kolbenschmidt rings, new valve guides. i don't know what to do.
:cry: