Well I burned a valve over the weekend . .

[PetesPonies]

in my '89. I was out of state as well. Little engine that could drove over 800 miles on 3 cylinders. I ended up removing the injector wire on #3 once I was sure of the diagnosis. She got 17 .5 MPG running about 65-75 mph on three cylinder I'll post some pics once I get it apart today. This engine just turned over 200K miles . . and I'm hoping for more. It seems #3 or #4 are cylinders that have this problem the most. Once I get it apart I'll see which way I want to go in fixing it . . how much damage.

 

[PetesPonies]

Almost have head out. I was impressed at how clean the upper head area was. 200K on this engine and not a single spec of sludge, spotless.

 

[Mark_88]

I'd be interested in seeing what a burnt valve looks like...and hope that is the problem since it's probably easy to fix...

My #2 plug gets fouled up with gunk and I'm hoping it's just the valves...won't know for sure till I pull the head...but post up more pics if you can of the bottom of the head...thanks!

 

[PetesPonies]

Ok, so I tore into it today. When I removed the head I was shocked . . no burned valve. So Mark, I do have a couple examples of what a burned valve looks like.

or

So then I was scared . . . . I didn't want to look at the piston. When I was away this weekend, I borrowed a compression tester and saw I had basically no compression on #3; why I thought I had a burned valve. I had 30# of pressure which quickly went to zero in #3. So if the valve wasn't burned, I figured detonation must have broken the head of the piston. But again, nope! Piston looked fine with no signs of detonation damage ( of course it detonates, it's a 2.3 Ford engine ). But the piston top was very clean compared to the other 3 pistons. That is usually a sign of water getting into the combustion chamber.

The ring on the head gasket didn't look compromised, but it must have been. That could explain the low/no compression and the clean top of the piston. The other interesting fact of this "mystery" is that both plugs for cylinder #3 were damaged. These plugs were less than 2 weeks old and about 250 miles on them. One center electrode had burned completely away. You couldn't recognize it at all. The other plug ( dual plug head ) had started to burn away the center electrode. Other 3 cylinders the plugs looked new. And the plugs that were removed from that cylinder 2 weeks earlier looked decent, considering they were 84K miles old. So trying to figure what may have happened here. It's possible I had an injector that was partially clogged and making the mixture very lean. This could have burned away the electrode. This also could attribute to detonation in that cylinder. Or, perhaps I had a head gasket fail and that water vapor created havoc in the cylinder ( although many times some water is a deterrent to detonation ). I'm not totally sure here, it's a head scratcher. So the head is getting rebuilt. Valve job on all 8 valves. new seals, milled, cam bearings etc. The camshaft looks great ( roller followers ). It's a good time to replace a lot of things on the engine. I ordered a fresh set of injectors.The timing belt has 60K on it along with the water pump, so I have to replace those items. The oil pressure switch is original, etc. Time for a mini rebuild you might say. If any of you have had a similar condition with your 2.3, shoot some ideas of what you think might have happened here that caused the end results. I was hoping for a bad valve and not hoping for a damaged piston. It looks like I have neither . . just so head scratching

 

[Milton]

Broken ring(s) cyclinder #3?

 

[PetesPonies]

I doubt it . . there would be blow by. This engine didn't burn any oil . . didn't have any blow by . . .even at 200K miles. Even driving it 800 miles broken, I wasn't smoking. So I doubt it . or more so I hope not

 

[Milton]

Just a guess, when you thought the valve burned you actually broke the #3 compression ring explaining the compression test results. The two oil wiper rings remain intact so you had minimal smoking. I guess your post assembly compression test will tell all.

Can you drop the oil pan, unbolt the #3 piston rod and then pull the #3 piston through the top?

Also dropping the oil pan would allow to to view the insides from below and allow looking for damage.

Be a real pain to reassemble everything to find the problem was not fixed or damaging any of the work you are doing.

 

[PetesPonies]

I'm not going to say it isn't possible, however the top two rings are compression rings. The third ring is the combo oil control ring. If one or both of the compression rings had broken, compression would be effected for sure. But not zero compression. That happens from something catastrophic, like a valve or blown gasket. As for looking at the piston, can't be taken out with engine in truck. You can't get the oil pan out to access it.

 

[Milton]

Good luck!

 

[RonD]

If there was a leak in the head gasket into the cooling system your drive home would have been more an issue of overheating then gas mileage.
Coolant would have been blown out the cap and overflow.

No compression is a puzzler without obvious leak.
valve not closing?
piece of the spark plug "temp" welded to a valve edge could have held it from closing all the way, seems like you would have seen that.

Yes injector failure could have caused the problem with spark plugs, stuck open would wash cylinder even after you unplugged it for the drive home.

 

[PetesPonies]

yep all good possibilities. I thought of something holding the valve slightly open. Maybe on the ride home it came loose. The injector was hooked up for the trip going . . so raw fuel could have washed the piston top as well.

 

[Mikel89us]

Take extra meat off the head! .075" minimum (from factory thickness)! This is a must on an N/A 2.3. I would suggest .100". I run .150 on my 8 plug ranger and my 4 plug mustang, and the ranger gets spark knock even with 93 in it. but .100" will improve drivability, torque and HP.

 

[RonD]

yep all good possibilities. I thought of something holding the valve slightly open. Maybe on the ride home it came loose. The injector was hooked up for the trip going . . so raw fuel could have washed the piston top as well.

yup, gasoline is a good cleaner, coolant is only a good cleaner if it is changed to steam, and with the no fire on that cylinder you would have expected to see beads of moisture in that cylinder after head removal, if head gasket had failed.

 

[PetesPonies]

Mike I would never take that much off this head. I'm going to clean it up, probably .010-.020, that's it. All I want it reliability from this truck. I have plenty of other vehicles if I want some real power.

Ron, what I don't know is how long this problem has been there possibly at a low level. I lost about 2 mpg the last couple trips and figured it was just a general tuneup situation. The plugs and wires had 80K on them, O2 sensor as well.But maybe there has been a gasket leak all along . . but it finally "went" this weekend. It's all conjecture I know. I was hoping to find something definite.

All I did today with it was clean things. I got the deck clean and the piston tops. Everything looks great. The ridge in the cylinders are small, even can still see a few cross hatch marks . . . and after 200K miles. Probably have the head done by Thursday and then back to working on this.

 

[Mikel89us]

Trust me, you will NOT decrease reliability. You will make it perform better, and get better fuel mileage. Every N/A 2.3 i have ever built has had at least .075" taken off the head. This is the best thing you can ever have done for the little price tag it has. It should cost you little to no more money to have the machinist take the extra material off. Most of his time is invested in the setup anyway. If you mill the head that much you will be happy with the results. If you are used to v8s that you cant take more than .010" off of before things get messed up, then get your mind out of that. These are not v8's and they are much better with a bit more compression.