[slo_eg8]

Can High Crankcase Pressure Can Be Caused by Worn Piston Rings?

 

[Swaggles]

Can High Crankcase Pressure Can Be Caused by Worn Piston Rings?

I've read that article before. Seems unlikely that my rings would be toast after just 3000km right?

Healthy compression (still waiting in leakdown tester) very nice oil pressure (1.2 bar idle at 800rpm, 5.3 bar at 3000rpm, oil at 90c) 0 oil burning, it just leaks

Note: the pistons are new. Rings are new. Basically everything inside the engine is new except the crank, rods, valve guides (checked ok), and pcv system except for the catch can

 

[slo_eg8]

"Other Possible Causes
A few things can cause excessive blow-by apart from worn cylinders or rings. Powerful spikes in crankcase pressure are a classic sign of a blown head gasket, or a cracked engine block. This is especially true if the gases coming out of the breather hole carry with them a strong stench of raw gasoline."

 

[mattliston]

Find a hill, run up it all the way, turn around, grab a low gear, run it high into the rpms, then coast down the hill while in gear.


Burp the throttle when you get to the bottom. If it shoots out a lot of smoke, your oil situiation is coming from stem seals or guides.

 

[Swaggles]

Find a hill, run up it all the way, turn around, grab a low gear, run it high into the rpms, then coast down the hill while in gear.


Burp the throttle when you get to the bottom. If it shoots out a lot of smoke, your oil situiation is coming from stem seals or guides.

Its leaking oil, not burning it.

"Other Possible Causes
A few things can cause excessive blow-by apart from worn cylinders or rings. Powerful spikes in crankcase pressure are a classic sign of a blown head gasket, or a cracked engine block. This is especially true if the gases coming out of the breather hole carry with them a strong stench of raw gasoline."

No gas smell. Headgasket is fine. Did a leak test on it. Liquid stayed blue

 

[mattliston]

Its leaking oil, not burning it.

I get that. But any time the valvetrain is able to leak oil into the intake tract, fuel vapors can get sucked in as well, and eat seals up.

Front main seal and camshaft front seal are prime targets for this reaction, and love to leak first. Though technically all rotating surface seals get the axe first when seals/gaskets start to deteriorate

 

[Swaggles]

I get that. But any time the valvetrain is able to leak oil into the intake tract, fuel vapors can get sucked in as well, and eat seals up.

Front main seal and camshaft front seal are prime targets for this reaction, and love to leak first. Though technically all rotating surface seals get the axe first when seals/gaskets start to deteriorate

Ooh okay. Sorry for my somewhat harsh reaction. I've posted this issue on multiple forums and most people assume its burning oil, so I've been saying it like 25x already.

I will test it. Cam and distributor seal are fine tho. Seems to only affect the seals in the bottom of the block.

 

[mattliston]

Ooh okay. Sorry for my somewhat harsh reaction. I've posted this issue on multiple forums and most people assume its burning oil, so I've been saying it like 25x already.

I will test it. Cam and distributor seal are fine tho. Seems to only affect the seals in the bottom of the block.

I dont always cover my thoughts or view points. I wasnt bothered at all.

Just trying to spit some ideas from the chaotic mess inside my head, thats all.

And I can be totally wrong, so verification is always recommended lol

 

[Swaggles]

I dont always cover my thoughts or view points. I wasnt bothered at all.

Just trying to spit some ideas from the chaotic mess inside my head, thats all.

And I can be totally wrong, so verification is always recommended lol

Yea thats true. Better to double check then to keep guessing.

Im on holiday at the moment but will be back in a week. I can go test that stuff out when I'm back. Will post an update

 

[Georgia Eg]

Your First post is going to be repeating what someone else said earlier in the thread?

 

[Swaggles]

Your First post is going to be repeating what someone else said earlier in the thread?

Sorry I dont understand what you mean?

 

[Georgia Eg]

There was a post above that, mods removed it

 

[Swaggles]

Find a hill, run up it all the way, turn around, grab a low gear, run it high into the rpms, then coast down the hill while in gear.


Burp the throttle when you get to the bottom. If it shoots out a lot of smoke, your oil situiation is coming from stem seals or guides.

DING DING DING
Well shit now that Ive paid extra attention to it and tested it, yes it smokes. Even when just revving it in neutral and blipping the throttle it does it. This really frustrates me as this was the reason I rebuilt and built the entire thing. How could this be with brand new valve stem seals. The shop that I took the head to said the guides were fine.

Im at a loss now. Even with my upgraded pcv system it still has lots of crankcase pressure. I even added the an10 adapter to the block.

 

[drtalon123]

DING DING DING
Well shit now that Ive paid extra attention to it and tested it, yes it smokes. Even when just revving it in neutral and blipping the throttle it does it. This really frustrates me as this was the reason I rebuilt and built the entire thing. How could this be with brand new valve stem seals. The shop that I took the head to said the guides were fine.

Im at a loss now. Even with my upgraded pcv system it still has lots of crankcase pressure. I even added the an10 adapter to the block.

I'm still not convinced you have massive crankcase pressure, maybe just high blowby.

What are your compression values again? Have you done a cylinder leak down test?

What is the actual crankcase pressure? Its one thing to have higher crankcase gas flow, which is pretty typical if you've upped compression, its another thing entirely to build pressure. Have you put a pressure gauge in the dipstick tube to see what it is?

Usually a manometer is used for this because pressures arent that extreme, using an inches of water column scale to indicate pressure:

One inch of water = 0.036psi

But if pressure is massive as you say, a gauge that reads vac/pressure like those for testing engine vacuum usually have a pressure side to read like up to 10psi.

Stick the hose in the dipstick tube and tape it off. Close the oil cap and leave your pcv setup like it is.

Then test pressure, at idle, and while revving. If pressure is as massive as you say, you'll see positive pressure values easily.

If you never see the gauge barely go positive (<1psi), you don't have excessive crankcase pressure.

With as much ventilation as you've provided the crankcase, I highly doubt you are building any significant pressure, more likely you just have a lot of blowby.

The only time I've ever experienced "massive" crankcase pressure symptoms was on large worn out diesel engines, and their customers complained of oil leaks. One I worked on had 20+psi actual crankcase pressure non loaded while revving before every main seal rolled over and bled off pressure, and 8psi at idle. This was enough idle pressure to blow the oil cap off the valve cover about 10ft in the air if you unscrewed it, slowly, with your eyes covered and your arm fully extended to unscrew it lol. Me and the guys at the shop did this about 20 times because it was fun, and went even higher if you revved it up haha.

THIS is what high crankcase pressure looks like. Anything less than 1psi is just blowby.

 

[Georgia Eg]

Well, obviously you're leaking pressure, if it's not a seal or ring(s), then you have a fail in metallurgy.
Does it blow air when the engine is cold and hot? Does it get lower or higher intensity when the engine warms to temp?
What is the static compression ratio? I'd say if you're getting 250 psi, and the gauge is accurate, You're over pressure rating for seals or the ring end gap is incorrect.
*DrTalons post is a good way to test.

 

[Swaggles]

I'm still not convinced you have massive crankcase pressure, maybe just high blowby.

What are your compression values again? Have you done a cylinder leak down test?

What is the actual crankcase pressure? Its one thing to have higher crankcase gas flow, which is pretty typical if you've upped compression, its another thing entirely to build pressure. Have you put a pressure gauge in the dipstick tube to see what it is?

Usually a manometer is used for this because pressures arent that extreme, using an inches of water column scale to indicate pressure:

View attachment 142366

One inch of water = 0.036psi

But if pressure is massive as you say, a gauge that reads vac/pressure like those for testing engine vacuum usually have a pressure side to read like up to 10psi.

View attachment 142365


Stick the hose in the dipstick tube and tape it off. Close the oil cap and leave your pcv setup like it is.

Then test pressure, at idle, and while revving. If pressure is as massive as you say, you'll see positive pressure values easily.

If you never see the gauge barely go positive (<1psi), you don't have excessive crankcase pressure.

With as much ventilation as you've provided the crankcase, I highly doubt you are building any significant pressure, more likely you just have a lot of blowby.

The only time I've ever experienced "massive" crankcase pressure symptoms was on large worn out diesel engines, and their customers complained of oil leaks. One I worked on had 20+psi actual crankcase pressure non loaded while revving before every main seal rolled over and bled off pressure, and 8psi at idle. This was enough idle pressure to blow the oil cap off the valve cover about 10ft in the air if you unscrewed it, slowly, with your eyes covered and your arm fully extended to unscrew it lol. Me and the guys at the shop did this about 20 times because it was fun, and went even higher if you revved it up haha.

THIS is what high crankcase pressure looks like. Anything less than 1psi is just blowby.

Compression test resulted in 250psi across the board

Still dont have the leakdown tester sadly.

And now that you mentioned it I probably misinterpreted it as pressure.

See the thing is when the engine is cold, its fine. Take the oil cap off, no real "wind" pulses coming from it.

Heated up on the other hand. Wow does it blow some wind from the oil cap. Never enough to blow the dipstick out but its noticable. It does leak oil past all the seals now, hence my thought that it would be pressure.

Well, obviously you're leaking pressure, if it's not a seal or ring(s), then you have a fail in metallurgy.
Does it blow air when the engine is cold and hot? Does it get lower or higher intensity when the engine warms to temp?
What is the static compression ratio? I'd say if you're getting 250 psi, and the gauge is accurate, You're over pressure rating for seals or the ring end gap is incorrect.
*DrTalons post is a good way to test.

Metallurgy? Sorry english isnt my native laguage.

Basically no blow when cold, once heated up and driven it blows. Ring gap was set to 0.25mm on the top rings and 0.35mm on the bottom rings. Oil rings I havent touched.

Seals that I bought were from Elring. Thinking of switching them to OEM Honda or something like skunk2 if they have it

Video of the smoke. Note that the car sat idle for about 20 seconds. Stomping the pedal and driving it to redline it after engine braking produces some smoke aswell

 

[Oldcivicjoe]

How could this be with brand new valve stem seals. The shop that I took the head to said the guides were fine.

They ALL say the guides are fine, but they rarely are. they are usually at the very loose end of the specs on hondas by about 200k miles, with hondas large exhaust valve lift and vtec intake lobes there is a lot of lateral force applied to the tip of the valve stem, so the guides tend to taper from top to middle and bottom to middle. For some reason 95% of machine shops don't see this as needing replaced.

 

[Swaggles]

They ALL say the guides are fine, but they rarely are. they are usually at the very loose end of the specs on hondas by about 200k miles, with hondas large exhaust valve lift and vtec intake lobes there is a lot of lateral force applied to the tip of the valve stem, so the guides tend to taper from top to middle and bottom to middle. For some reason 95% of machine shops don't see this as needing replaced.

Hmm okay

Yeah I'm driving the car to a machine shop who has over 40yrs of experience to see what he says aswell. Ive lost the trust in the previous shop.

So that would solve the oil burning problem, but what could the issue for the oil blowing past the seals be?

 

[slo_eg8]

Most common cause of crankcase pressure, especially with higher compression, is bad valve stem seals, next is valve guides in addition to stem seals.

Pull the intake manifold off, grab a small mirror, and remove the valve cover. SPray carb cleaner at the valves and see if anything makes it into the intake port

32hrs later he was right. only took an extra 30 days to confirm. someone get matt a cookie

 

[Swaggles]

32hrs later he was right. only took an extra 30 days to confirm. someone get matt a cookie

Yeah. Damn time constraints, sorry for taking so damn long. Will do a leakdown test. I refuse to believe my rings are shot haha, but I do think the valve guides we're shit after all. If thats the case, I will NEVER trust any random shop in my area again. More updates coming soon. I won't leave this unanswered since others need to know what went wrong aswell.