Ive got a 22re that has always smoked a little when you start it. It also uses quite a bit of oil probably half a quart a week. The other day I drove it to the city and back, about 250 miles on the interstate. By the time I got home it had developed a miss that was really noticeable at idle. It still runs good at 65 mph. I started pulling plug wires one at a time and isolated the dead cylinder. I pulled the plug and it was black and crusty so I replaced it and it still misses. I did the paper trick and it sucks the paper at the tailpipe. I assume it is a bad valve? I thought I might try to adjust the valves but I don't see why that would help considering how bad it smokes at idle. It will sit and smoke like a train at idle, if you rev it, it blows smoke but quits at higher RPM. Any thoughts?
If it is a valve and I pull the head, should I just rebuild the head and leave the short block alone? The reason I ask is because the PO said he had the motor rebuilt. I assume given the oil burning that was a lie but if it wasn't then I assume the rebuilder didn't do a good job and I'm going to have more problems down the road. I have read that if a 22re is not broke, don't fix it, that a rebuild most of the time will not be aas good as the factory build.
So how could I check the motor to see its condition? I hate to pull it apart rebuild the head and it still drink oil and have problems later down the road. Nor do I wanna toss a short block that still has 100,000 miles left in it. The truck shows 300,000 on the odometer.

 

Rebuild has several different meaning from previous owners now a days. I would run a compression test and see what the results are. I have replaced or rebuilt many heads on motors with out doing a full rebuild. With 300k miles on it and if it was actually rebuilt in the past who knows what you are dealing with. See what your compression numbers are first is what would determine which way I would go. It could be as simple as needing valve seals but I would not hold my breath on that.

 

It would be tough to do a compression test on cyl #3 if it has a bad valve but if the other 3 cylinders test well would it be safe to assume the truck is not going to burn oil with a new head?

 

Do a leak down test on all 4.

 

A bad oil seal would cause the smoke. If the valve or rings are bad your compression is going to be way lower compared to the other cylinders. Assuming it is just a bad valve, I would repair or just replace the head myself. A full rebuild on a motor jacks the cost way up. I have done several top end only and full compete rebuilds from block to the head. My wallet likes just a top end rebuild a whole lot better then a complete rebuild.

 

How do you do a leak down test on a cylinder with a bad valve?

 

The leak down test will tell you if it is a bad valve, or bottom. It'll also tell you which valve it is- intake or exhaust.

Adjust the valves and run it a little first before testing.

 

Like Millball said and leak downs are for detecting the condition and location of problems like bad valves.

 

I watched a few youtube videos on leakdown tests. It makes sense, Ill do it tommorow. Thanks for tje help guys and I will post what I find.