Valve stem seals or Piston rings?
 

Hey guys,
​​​​I'm having a bit of an issue with my car (AP1 ~50k miles) and was wondering if you guys could help me figure this out.
So here's the deal, I get grayish smoke under very hard acceleration( mostly noticable in 1st and 2nd gears). I also get huge oil consumption (1liter/700ish miles). Tried not hitting VTEC for a few days, slowed the consumption down but still too much.
For me it seems to be that the noticable amount of smoke starts after 6k rpm. Trying to keep the story short, every reply is greatly appreciated.
T​​hank you for your time, have a great day.

P.S. Compression numbers are good

try new PCV first it might help a little. 50k miles isnt too much to have worn rings and guides unless its totaly abused car...

Compression can still be good but have bad oil control rings. Chances are pretty good based on my experience that when you have this much oil consumption on this motor, its typical valve seals/guides and rings. The only way to get clear confirmation on this is to do a leakdown test. That is your next step. With any luck the issue is all in the head- guides/seals.

Reports of possible pre-mature motor wear like this are more common then I would have expected. OP - please keep us posted on your progress with this. Also, once you have it diagnosed, if it turns out there has been pre-mature motor wear, any insight you might have as to the cause would be helpful. Are you the original owner?

Thank you all for your replies,
​​​​I'm going to do a leakdown soon.
​​​​​I am not the original owner sadly, could the motor be oil starved from a previous owner? Or maby even cracked retainers?
Will keep you posted on any further updates.

I dont think its the PCV valve, isnt it too much oil passing through it? It must be something else, but yet again, i'm not sure.
And as a stated above i'm not sure if the previous owner took great care of it, maby oil starvation or mechanical over-rev?

A sizable amount of F20 right off the show room notoriously burned oil at a rate that could starve an engine between oil changes if the owner was not privy to this. Its why buying an ap1 is such a roll of the dice. Later in 04 with the F22, Honda addressed many of the things that once caused this in group, such as improved cylinder machining tolerances using deck plate, improved piston skirt cooling when out of vtec from updated banjo bolt/oil squirters, improved valve guides and a lower rev limit. This is not to say the F20 is a bad design, but there were things that were addressed later that can be updated to the old engine, but the deck plating cylinder machining is a curve ball, and some engines were just bad from the factory and I happened to be a guy that got one. I bought my 01 with 22k miles on it from an old couple and it used oil the day I got it, but still above the ridiculously max recommended tolerance of 1Q per 1000 miles Honda deemed max ok spec. At roughly 80k miles however I started exceeding that amount to hitting 1Q per 800 miles. Thankfully the previous owner purchased an extended Honda care warranty which transferred to me, and with a bit of haggling with corporate they agreed to replace the entire short block with a brand new one and then replaced all the valve guides and seals in head. They found the cylinder bores were out of round and had what looked like manufacturing stress cracks in cylinder walls, guides were worn as well. Honda care covered the power train for up to 100k miles.

interesting info, always knew about ap1 oil stories but never knew why.... also been very lucky on my 3rd AP1 (have two right now one JDM and one EU) and neither uses oil at all.

is it possible the oil issue was US market only? like one lazy guy in engine factory somewhere :) ?

Who knows, but seems like the first couple years seem to be the worst culprits, before the upgraded banjo bolts were incorporated in mid year 02.

seems to be honda thing when they release new engines... 2008 CBR1000RR had oil burning issue from new. While the previous model 2006-2007 had no issues at all.