fw_walty_ek

hey guys just need some help maybe diagnosing a problem! my built b20v is smoking on acceleration light blue and will stop around 4k and once I hit VTEC will then start smoking again. it's burning oil too I believe since I'm losing some and I have zero leaks on my garage floor. any help will be appreciated guys thank you!!

Wankenstein

To confirm do you mean blue smoke from tail pipe?

Possibly, burning oil via cylinder oil rings stuck (melted to piston) or cracked OR valve seals are worn/broken and need to be replaced. Since you stated it's during acceleration and not constantly points to the valve seals as the likely suspect. I'm sure others will chime in to confirm, differ or add to.

Oil leaks don't always end up on the ground..can leak onto any part of the exhaust including manifold and burn off before reaching ground. Check for smoke in engine bay while at idle after driving around for 20 minutes.

fw_walty_ek

Wankenstein

I said it may be the valve seals but others may say different or provide you with test methods to perform that will isolate the cause.
If, it is the valve seals then should be possible to replace them with head still on as shown in this video:

DSMHondaguy

Blueish smoke is oil being burned. Since it's doing it under heavier load it's most likely the piston rings. When valve seals leak and cause smoke it's normally on start up after the vehicle has been sitting for a bit.

A compression and leak down test will confirm if it's the piston rings. Make sure you do the compression test with the engine warm, throttle all the way open with the spark plugs removed from all cylinders and if you can easily disable the injectors by removing the MPI fuse or something similar do that as well. Look up instructions on how to do a leak down test, I only mentioned the above because there common mistakes when doing compression tests....also make sure your battery is fully charged.

fw_walty_ek

Wankenstein

I may be wrong but an engine could have good compression (top and middle) rings yet have failed oil control bottom ring. So, could pass a leakdown or compression test for ring yet still burn oil.

fw_walty_ek

DSMHondaguy

Pretty unlikely, but I'm sure if it can happen it has to someone somewhere. (I have personally never seen or heard of that happening) regardless of if it's possible doing the tests will give him more information about the state of things than he has now. Also OP if you get low compression numbers and want to test if it's the valves leaking the compression or the rings, (but could be both) pour a single cap of motor oil into the cylinder from the spark plug hole and re-test that cylinder. if the compression doesn't change significantly, the valves are leaking, if it does jump up a good bit, it's the rings leaking the compression.

ETA: White smoke is coolant.

ezone

Compression test cannot evaluate oil control rings, only compression rings.


The oil control rings could be completely MISSING and you will still have great compression test numbers.

The top two rings alone will provide nearly perfect compression test results, but those rings don't control oil.


Smokes at high RPM and high load is usually caused by rings.
Valve stem seals typically smoke worst during periods of high vacuum (deceleration, long periods of idling then blip the throttle), and after shutoff

DSMHondaguy

I agree it can't evaluate oil rings, but it's reasonable to assume that if the compression test is low, and it's the fault of the rings, (not a valve, cracked cyl etc.) that the oil ring is also worn and causing the issue. However, yes you could in theory have good compression (or more likely just decent) and a bad oil ring. Regardless doing the test will tell us more information about the state of the engine.

Wankenstein

Here's a related thread: https://honda-tech.com/forums/all-mo...s-bad-2314064/

ezone

This is what I expect to see in just about any of our engines with a bunch of miles and some oil consumption issues......
Stuck oil rings should be obvious in this pic, click for full size if necessary



Carbon buildup in the groove is what makes the oil rings stick, they can't float freely to conform to the the cylinder walls anymore.

These are from an 07 Fit I bought with 200k on it. (it's my GFs car now)
I tried soaking the rings......After the 3rd day of being submerged in combustion chamber cleaner, they kinda started to loosen up but were still full of crap and not freely moving.....I replaced the complete set anyway.




I have been running 0w20 in this since I went through the engine....
I change oil when the maintenance minder says to change the oil and I have not needed to add oil between changes (7-9k miles per) and she's put almost 40k on it since I got it. Honestly, I don't even worry about checking the oil at this point....because it's 2 hours away from me most of the time