For the second time in 2 months I removed the cylinder head on my 92 Accord DX. Cylinder 4 had a hole burned in the exhaust valve and after replacing the head I found excessive oil consumption (1 qt/100 miles) and a black spark plug in cyl 4.

After pulling the head again I hand cranked the engine a few times and noticed a heavy oil film on the #4 cylinder wall after the downstroke, but cyls 1-3 were clean. I also noticed some light vertical scoring on cylinder 4... I was able to feel it with my fingernail, but not with my fingertip. There was a very light ridge of carbon at the top of the cylinders but it didn't seem like the metal was worn to a sharp edge so I didn't bother using a ridge reemer. I removed pistons 3 and 4 to check for differences. The ring end gaps are supposed to be 8-14 thousandths, with a service limit of 24.... (I think... memory is a little fuzzy).

Piston 4 ring end gaps were around 60, while piston 3 end gaps were closer to 30. This seems to jive with the carboned plug on #4.

It seems like I should replace all of the rings since even the non-oil-leaking rings are beyond the service limit. This brings up many questions and considerations that I'm somewhat clueless on. This isn't going to be a race car... just needs to get me to work without smoking out everybody behind me.

Vertical scoring:
do I need to hone the cylinder? the scoring is so light (and it's only on one section of the wall) that I'd like to try using emory cloth. bad idea? If I don't fix the scoring will I end up with oil leakage or strange ring wear?

Piston rings:
I'm confident in my end gap measurements, but I don't know how worn the cylinder walls are. It could be that the rings on cyls 1-3 are just fine, and cylinder wear is giving me the beyond-service-limit end gap. I got the same end gap measurements in cyls 3 and 4 when I used the same ring in each cylinder, so I don't think cylinder 4 has worn to a larger diameter than the other cylinders. Is the purpose of oversized rings to accomadate for 250k miles of cylinder wall wear?, or are those only to be used when the cylinder has been honed to a larger diameter and oversized pistons are also needed? I've checked multiple sites for ordering new rings and my options are 'standard', 'oversized .020"', '1.00mm oversized', and .50mm oversized. I'm not even sure in which direction the rings are oversized... diameter? end gap?

I'm so deep in this engine that I really don't want to miss something important... any help is greatly appreciated! Even a link to another site or thread would be helpful.

-Erik

 

Since you have the head off, you can rent a bore micrometer (mic) and check each cylinder for wear. Do not worry about th top ridge. Need to read up on the web on using the mic, however if you're careful enough you'll get an idea of the wear. You'll need to know the max wear limit for this engine to compare to.
However, the main problem is that scoring, and how bad it is. Best scenario: scoring is not bad and you find cyl 4 has more wear but less than repair limit. You can re-ring the engine and drive for a while, (dump the car).
Worst case: you mic cyl 4 more than wear/repair limit, you need to bore the block. That's where you need the "oversized" rings. Pistons as well. If you get there it gets complicated.
If you're mecanically inclined, you can piece-meal the job (engine rebuild) and save some. If you never done it, it takes a lot of reading, tools, friends, money and work. To do it right money will be first.
Or you can shop for another engine.

 

I'll bet you can still see the original plateau hone marks in the cylinder walls.
It wasn't until 98 that Honda changed the cylinder walls to be softer than the rings.
[ I'm sure Soichiro Honda rolled over in his grave when that happened ]
Depending on the miles of the engine I'd say replace the rings with 'standard' and new rod bearings.
Check a couple of the mains to see how deep they have worn, or if the engine has been run low on oil replace the mains; FWIW......... you don't have to drop out the crank to replace mains.
I'd just lightly scuff the cylinders with a 'dingleberry' hone and wash down the cylinder walls with WD-40.
Be sure to super clean the ring grooves and also the oil holes behind the oil wiper rings.

 

Can I use chemicals to clean the ring grooves? I have acetone, denatured alcohol, carb/choke cleaner, brake cleaner, etc. Also, would a brass brush be too abrasive or should I stick with nylon? I hear you don't want to nick or gouge the grooves.

 

LOL I've tried it all...even "easy off" oven cleaner.

Here's the way to do it....grab off one of the oil wiper rings twist it into an 'S' shape; wrap a rag around it [for hand padding] and use the end of it to clean out the other grooves.

That old carbon behind the rings has been cooked in there by a few billion high temp explosions.

 

Considering the amount of money I've already dumped into this high mileage vehicle and my lack of future income... I'm debating on using rings from the other accord I'm scraping out (same engine code) assuming they don't look horrible and have decent end gap measurements. I'm just not prepared to invest yet another $80 for brand new parts that will outlive the rest of the vehicle. My not-so-great Haynes repair manual says "Do Not Reuse Rings"... but at this point I just want to get the car running without falling behind on bills and rent.

Is this the dumbest thing you've ever heard... would I be totally nuts to cheap out on something this deep in the engine... but most importantly... will I regret this in 6 months? Do previously used rings destroy themselves if reinstalled?

-penny pincher

 

Used rings have worn themselves into intimate contact with the cylinder bore that they WERE installed in. Moving them is asking for serious problems of compression & oil burning. Having said that, I don't really know how bad that would be, and (like you say) it's not a brand new car that you're gonna keep for the next 20 years...

 

NO WAY...... DON'T DO IT...... Cheap out on rings and wind up right back where you are now?
"It's the stingy man that pays the most"

Whats the story with the 'other' engine?

And why is the current engine burning valves? Is the timing way off, or valves adjusted too tight?

 

The 'other' engine is mated with a body that has been in 2 accidents... one of which required replacing both driver side doors, which now don't close perfectly because the frame is ever-so-slightly bent. Also, it smoked like a son-of-a-gun when I started it cold... even after replacing the valve stem seals. Smoke would blow in through the vents in the morning unless i turned off the fan and hit the recirc switch. I know... bad idea to take rings from a car that already has oil burning problems, but...

I just pulled a piston from the 'other' engine and the end gap is actually within the service limit. Perhaps I'm obsessing over end gap when it's not the issue... I can imagine a million micro flaws on the cylinder walls that these "better" rings have mated too... and if I transfer the rings to my other micro-flawed cylinders I'll probably be worse off than before. I was kinda hoping someone would yell at me... talk some sense into my impatient self.

I haven't been able to figure out what caused the burned valve, since it was like that when I bought the car. I fell in love with the body but failed to imagine all the hours I would spend fixing every last removable part.

I thought the engine was running on three cylinders when I bought it... I replaced the wires right away and it made such a dramatic improvement I thought it was all good. When I finally discovered the burned valve I realized it was actually running on two cylinders the first time I cranked it over. I can hardly believe it ran at all now. (I had it towed to my house.)

I suspect that the wires were bad for such a long time that carbon built up on one side of the valve until a gap formed and it burned through. I'm no expert on engine internals, but I've talked to a bunch of people and this seems like the most likely chain of events... but that's just speculation. It has a different head now and I adjusted the valve clearances... even swapped injectors from the other car just for the heck of it. I sure don't want to find another burned valve in a few months...

 

Hooray! My parents floated me some cash for fixing their Pontiac... now I'm ready to buy some NEW rings.

It looks like I can save some $$ on ebay...
http://cgi.ebay.com/ebaymotors/90-96...Q5fAccessories

but I'm a little hesitant to buy internal engine parts online. I can get them from Napa but it's over twice the price.

Has anybody dealt with http://stores.ebay.com/Performance-Engine-Parts before? Their feedback looks good, but I'd feel better if anybody can vouch for them or recommend a good vendor.