So, my oil consumption is going up slowly, and I'm getting some noticeable smoke out the back under open throttle in 1st. (noticeably, vtec) - this is a 00 Prelude.

I'm trying to assess exactly what needs doing - if it's just valves, I'll pull the head and have that done. Belts need doing anyway. If it's the rings, the bottom end has to come out too, so I might as well pull the whole deal and be done with it.

Are there any rules of thumb for determining if it's the valves or the rings?

Also, has anyone re-ringed their stock H22A4 with a light hone to Honda's specifications successfully?

 

Do a leakdown and compression test to see where the leak is coming from.

 

is the smoke black or blueish ? black indicates a rich mixture and blueish would mean your burning some oil.

Do determine the problem i would do a compression and leakdown test. Start with the compression test. Look in the helms for your specs. Generally around 190-200+ with less than 10% variance between cylinders. Do a dry test and wet test. A wet test involves adding a few drops of oil and then doing the compression test, if numbers go up it could indicate a ring problem. Regardless of your results you should follow that with a leakdown test. Listen and look where air may be escaping and that is likely where your oil is entering the combustion chamber from.

 

ive experienced increased oil consumption with inadequate pressure relief to the head.

either the pcv or the hose that runs from valve cover to intake pipe. once the pcv went bad and once i decided not to use that hose and both times my car started drinking more and more oil.

dunno if this is your case tho good luck!

(ps compression / leakdown test is always a good idea)

 

all that hose goes from the intake to the valve cover does is pull in air for the pcv system, it will not pull oil out.

 

no i dont mean it will pull oil out. somehow pressure builds up and forces oil into the cylinders as well as the sparkplug holes. you shouldve seen my car... oil started seeping from the valvecover studs and the spark plug holes (or whatever you want to call them) were filled with oil. ive never seen anything like it... BUT when i fixed those 2 things alone it went back to normal..

 

Unfortunately, I don't think my problems are going to be solved that easy. I'll do a compression and leakdown on the weekend, the plugs look good - no oil.

Just wondering if there were any rules of thumb and if people have had luck redoing the piston rings without resleeving the motor. If it's gotta be sleeved, I'll probably try and locate a type-S JDM motor instead.

 

you dont have to resleeve. You can rehone the cylinder walls.

start with a leakdown. Its the most precise measurement.

If you are leaking oil through the valves, then you need to replace your valve seals...not the valves.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by xtal &raquo;</TD></TR><TR><TD CLASS="quote">Unfortunately, I don't think my problems are going to be solved that easy.
</TD></TR></TABLE>
A bad PCV valve is commonly overlooked item that causes smoke...

 

Does the smoke appear if you've been idling a while, then go?

 

Blake, the problem is that a leakdown doesn't necessarily tell you the condition of the oil control rings.

My track car burned a bit of oil until I ditched the PCV system completely. Since then, I haven't really noticed much, but I don't have the catch can plumbed back into the oil system, so I lose a bit of oil through the catch can. Fortunately, it's not being burned.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98vtec &raquo;</TD></TR><TR><TD CLASS="quote">you dont have to resleeve. You can rehone the cylinder walls.

start with a leakdown. Its the most precise measurement.

If you are leaking oil through the valves, then you need to replace your valve seals...not the valves.</TD></TR></TABLE>

 

If his problem is only in 1st gear, his valve seals might be bad. He probably isn't describing the situation properly. PCV is too easy and cheap, to not start with though.

 

Why would it happening in 1st gear only mean the valve seals are bad?

 

Not relevant to gear position, but he probably just sees it in 1st after the car has been idling. No one starts from a stop in any other gear.

 

Right, after the IM has been under a vacuum condition for some period.

Another way to test this theory would be to run the engine up to 7,000 RPMs in any gear (probably 2nd would work best), then let off of the accelerator completely. Let the engine slow the car to say 3,000 RPMs, then accelerate again to see if you can see any oil burning. There's a ton more vaccum at 7,000 RPMs with the throttle completely closed than there is a idle, so if the intake valve seals are leaking at idle, they should leak more when there is more vacuum in the IM.

 

Just of curiosity, how do you distinguish between faulty valve guides v. seals? Wouldn't bad guides lead to seal failure? So how do you know if only the seals failed, or if failing guides caused the seals to fail?

 

The only way I know of to check the guides is to take the head apart. You can check the "wobble" of the valve in the guide at a specific lift or you can mic the stems of the valves and use a split ball gauge in the guide to measure the clearance directly.

 

From what I read I think your valve seals are leaking. If you had leaking rings you would "most likely" burn oil all the time not just in when you get on the gas. Valve seals are a cheaper fix then going with rings anyways.

 

Bad guides will eventually cause valve failure itself, I'm not too sure if they would ruin the valve seal, just because the part that rides the stem of the valve is rubber and has a spring, so it can flex but stay tight.

If the guides allow the valve to move around a bunch, it will stop hitting the seat squarely and probably crack on the side and bend/break off eventually.

Guides don't fail often unless you mess with them.

 

The way I understand it, wouldn't out of spec guides allow excess heat past and harden the seals? I imagine this would happen before valve failure.

 

On the S2000 that I'm doing right now, the margin on the valve was very thin, almost like the valve was being pulled through the valve seat. This was on the exhaust side, and you could wiggle the exhaust valve a good 1/10" with the valve only 1/8" off the seat!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vinuneuro &raquo;</TD></TR><TR><TD CLASS="quote">The way I understand it, wouldn't out of spec guides allow excess heat past and harden the seals? I imagine this would happen before valve failure.</TD></TR></TABLE>

I didn't think about that, good point

vtak

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vinuneuro &raquo;</TD></TR><TR><TD CLASS="quote">The way I understand it, wouldn't out of spec guides allow excess heat past and harden the seals? I imagine this would happen before valve failure.</TD></TR></TABLE>

If you're talking about the exhaust. Heat wouldn't be a factor on the intake side.

 

Yep

 

How do you do a "leakdown" test? I have done a compression test before and it came out as 190, 200, 210, 210 respectively. So I already know I have a small compression problem and I also know that I burn about a quart every 750 miles. So how do you do a leakdown test and what does it prove?

Thnx