Since October I have been doing work to my '91 crx Si D16A6.

I broke a timing belt, so I decided to replace / upgrade a lot of items while I had an excuse.

I pulled the head, and replaced the HG with the D16Z6 metal one. I did a very mild port & polish (just cleaned up castings). I cleaned the carbon from the combustion chambers and the pistons, as well as the head and valves (the valves were not bent from the timing belt break). I replaced the valve seals, the various gaskets & o-rings on the head, the cam ends, the valve cover, and under the rocker arm assembly. I installed ARP headstuds. I cleaned up the castings on the IM, and cleaned the TB. I replaced the IM, TB, and EM gaskets with new ones. I replaced the timing belt, tensioner and spring, and water pump. I replaced all the various coolant hoses that run in and out of the head. I replaced the plug wires, cap, rotor, and plugs. I also got a used IACV off of ebay and installed it in the hopes of fixing a bad idle it had prior to the belt breaking. I cleaned the mating surfaces between the head and the block with a brass brush, and they were completely clean. There we no scratches or gouges on either the head or the block. I did not have the head decked, because it never overheated, and I wasn't losing any significant oil or any coolant.

After I assembled the motor it started up and ran very strong, except it smoked pretty badly. I wrote it off to being associated with all of the solvents and stuff I had in the cylinders when I was cleaning it, and from having the head off for over two months.

I ran the vehicle for about three miles and the smoking continued. I was starting to get worried, so I ran a compression test, as well as a leak down test.

The results of the compression test were between 195PSI, and 205PSI. The results of the leak down test were between 5% - 9%.

Considering that the compression, and leak down tests both came up good, and I wasn't losing any coolant (nor was the exhaust white, it's blue) I assumed that I mis-installed a valve seal.

I bought 16 new valve seals, and I replaced them all. None of them looked messed up. After I got everything assembled, it still smoked.

I used all Honda parts, and I followed all of the specifications in the US Factory Service Manual.

SHORT VERSION: Car smoked and loses oil after a complete head rebuild - compression is mint, HG is new, and valve seals were replaced, twice.

Any help will be greatly appreciated.

I'm located about 1/2 hour north of Scranton PA, and I will be happy to have anyone come and take a look at it. I'll provide pizza and beers (although I don't drink).

I'm completely stumped here, and I'll be happy to answer any questions - ask away.

-Des!

I'm stumped. You pretty much checked everything I would check.

Is the z6 gasket ok on the a6?

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The Z6 HG is now the official replacement for the A6 motor (says Majestic Honda). The original A6 head gasket was a composite paper gasket - Honda discontinued that gasket, and replaced it with the three-layer metal (Z6) gasket.

So yes, the Z6 gasket is the correct gasket.

This is a tough one - and I'm completely stumped too. What would you do if you were me at this point? I don't even know what the next step should be.

Oh, by the way, I checked the PCV hoses, and all of the breather hoses, and they're not filled with oil.. so it's not coming in that way. (I don't think so, anyway)

-Des!

Not sure about the oil burning but as far as the smoking...... could it be that after the head rebuild your rings decided they were tired?

exactly what i was going to say.

Story time. Had a 93 Civic LX, limped it around for a while and didn't have shit for power. Pulled the head and found 2 exhaust valves with holes in them. Replaced those, all the top end gaskets, valve seals, etc. Got it back together, let it warm up, drove it 2 miles and it looked like one of those skywriter planes at the air show. Replaced the rings and drove it 30k miles without issue.

Only thing i could figure was everything being new on the top end just had too much compression and the rings let go.

You can also use the y8 gasket. Little thinner, little higher compression

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That was my first thought too, but the compressions tests make me think otherwise.

If the rings were bad they would show poor performance under the compression test, and leak down test, right?

-Des!

Did you remove the oil jet when you did the head swap?

There was no head swap - A6 head, A6 block.

-Des!

My bad.

I saw the Z6 and thought head swap.

No problem. Any more ideas?

-Des!

my only thought is maybe some carbon got in between the compression rings and maybe stuck in the oil rings, did you check the cylinders with a bore gauge for taper and out of roundness? I have had two a6's with 4 thousands of cylinder taper before, its kinda hard to get accurate readings with the pistons in there but you can see if they are starting to. With taper you can still have good compression #s but burn oil.

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I'm thinking rings, the leak down test really isn't that great. I mean it's acceptable but not stellar. Plus it all depends on how much the car is smoking. Is it super noticeable or just slightly? Also, if you leave the car idling for 3-5 minutes and then rev it does the smoke billow out of the exhaust or it's just as bad as usual? In other words does leaving it idle for a few minutes make the problem worse?

In short think of this. Oil can only enter the combustion chamber in 4 ways.

1) Piston rings
2) Valve stem seals
3) Blown head gasket
4) intake track (such as PCV or blown turbo seal)

Leak down test can tell you about rings and head gasket. My idling question helps determine the valve stem seals. PCV valve blow by is usually cause by bad rings and excessive blow by. Finally the turbo seal, well you obviously don't need to worry about that.

How do your plugs look??

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When I start the car it smokes like a guy in a biplane skywriting. After it idles for 5-10 mins the smoke dies down (it's still bad, but it's not obscene), and if I rev it after it idles for 10 mins the smoke plumes out really badly.

Meaning, it smokes when it starts, then dies down.. if I rev it after it's been idling for a little while the smoke plumes out badly.

I've replaced the plugs twice since the head rebuild. They're black, with oily residue on them, but they're not dripping oil.

Jadkar, you read that I've replaced my valve seals twice, right?

I'll try to get a video of the smoke tonight - if the sun stays out.

It runs really strong, idles great, and starts better than it ever has before. It just smokes like crazy.

I did not check the bore and taper of the cylinder walls. There were no gouges at all, but there was no crosshatching visible.

The motor has 114,000 miles on it.

-Des!

How much oil do you have in the engine? I read that you replaced your valve stem seals but I didn't read that you did it twice. Are all four plugs equally as bad?

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I have a little under 3.5 quarts in it. It's directly in between the two holes on the dipstick.

Yes, my plugs are equally bad. I wouldn't say that the newest ones are fouled, but they're grimy. I rebuilt the head, and changed the spark plugs - it smoked, and I replaced them again to the ones that are in there now.

I failed to mention before, if I do drive it (although I shouldn't, the smoke is bad) eventually the CEL will come on and indicate a faulty O2 sensor. At that time it will also begin to misfire between 3000 and 3500 RPM's, only if I hold the throttle there. (meaning if I rev through 3000RPM I won't feel anything.. but if I hold it at 3300 it will sputter and buck) I assume the CEL is because of the quantity of smoke has the O2 dirty as hell. The CEL will only come on if I drive it.. I can let it idle forever, and I won't get a CEL.

Since the rebuild I may have three miles of actual driving time on the car.

-Des!

Double post, sorry.

Be sure and change out the 02 sensor after all this. When my 02 sensor set off the CEL my car would run crappy.

Hmmmmm, now I'm wondering if it's really oil that you're buring and not just running really rich. Did you mess with anything on the fuel system while doing all of this? Do the plugs smell of fuel or oil for sure? It would take a hell of a lot of oil to make the O2 sensor read incorrectly and then throw a CEL and mis-fire. I think maybe you have fuel problems that maybe making the car run like crap and mis-fire. You need to be certain it's oil you're burning.

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As promised, here are some pics of my plugs as well as a few vids of my exhaust.



FULL SIZE



FULL SIZE



FULL SIZE

And the vids:

First Started

Another

Five minutes later

RIGHT CLICK SAVE AS

My server has nearly no bandwidth, so be patient.

-Des!

The only thing I did to the fuel system was removed the 'fuel rail side' banjo fitting from the fuel filter, and remove the fuel rail and injectors from the intake manifold. I didn't lose any of the o-rings or 'filters' that are attached to the injectors, and I kept everything sealed in separate zip lock bags when I was working on everything else. I only did the things detailed in the factory service manual. I didn't swap injectors, or mess with anything else.

Is there a procedure for checking the fuel system to see if I'm running rich?

I'm currently letting the vehicle idle after thoroughly checking the oil level to ensure that I actually am losing oil. I'll let it idle for two ours or so, and I'll report back.

I would not stake my life on saying that I'm losing oil for sure - I thought I was low on oil after the first time I changed it, and ran it for awhile. That's how I determined that I was 'losing oil'.

For the record, my exact compression test results were as follows:
(I did two tests, just to be sure)
#1 200PSI
#1 199PSI
#2 201PSI
#2 201PSI
#3 198PSI
#3 197PSI
#4 211PSI
#4 211PSI

-Des!