Burnt valves will cause power loss. Another symptom will be the engine will run hotter than normal and use more antifreeze.
Engine cylinder head valves admit the air/fuel mixture and release the burnt gases.
a burnt rubber ball in the cardorater
The fuse has burnt out.
This could be any number of things... a slipping belt, burnt valves, old bearings. Try plugging some of the car symptoms into this search engine... it's handy: http://findzer.com/searchengines/000017.html
timing off,base timing not set,dist. not set in right position, timing belt about to break, low fuel pressure,burnt valves,leaking head gasket.need more symptoms.
Burnt valves need to be lubricated where the valves move up and down there is alot of friction and whats to keep it lubed is oil if you dont keep that up that is where the blue smoke coming out the tail pipe.
blue smoke can be caused by sticking valves or burnt rings
You can have a compression test done on the engine to determine the condition of the rings and valves.
Exhaust valves open at the appropriate time to allow the burnt gasses to escape.
The valves in a car engine are opened and closed by a cam shaft driven by the engine crankshaft. they allow the flow of gases and fuel into the engine and the burnt gases out of the engine into the exhaust system.
The bulbs are burnt out.
First of all, it's not 850cc, it's 805cc. You want to adjust your valves when they get noticeably louder or quieter. Louder = loose. Quieter = tight. Loose is better than tight. Too tight can lead to burnt valves and low compression. I adjust my valves at the start of every season.
a burnt valve looks like a wide crack in a valves' head. when a motor runs too lean, the cylinders heat up too much, causing the head of the valve to heat up faster than it can dissipate the heat, causing the valves' head to crack. once the valves' head starts cracking or melting away, you lose compression in that cylinder, and the engin will vibrate and it may not idle at all.
That happened to me. I had to go the hospital and the emergency room. I actually was pregnant, too.
Vacuum leak, low compression, burnt valves, low fuel pressure, weak spark, bad transmission....
The engine will have low compression and misfire, especially at idle. The misfire will seem to disappear at higher RPM.
if its burnt out, replace it, if not, check the wireing
Bad plugs or plug wires. Blown head gasket or burnt valve. A compression test will eliminate burnt valve or blown gasket.
Engine miss, poor fuel economy, loss of power, and low compression on the cylinder with the burnt valve.
Water in the oil Burnt oil Oil in the water Loss of power.
Could be burnt out. Same thing happened to my caddy.
If the pistons are bad it should be smoking a bright blue color out of the exhaust. Are if a piston skirt is broken it should be knocking all the time. If there is a whole burnt in the piston you will not have any compression on that cylinder. Most of the time pistons just don't go bad.
Since the compression is good I would not expect it to be a burnt valve. It could be timing if the timing chain has excess play. I would also check the ignition module and the engine control module. We had a 1986 Chevy Celebrity that had an ignition problem that cause it to run badly and backfire. The service engine soon light was blinking but not posting a code. We changed the engine control module and it fixed the problem.
Well that depends on whose money, and what his work order said to do, and the cause for the valves to have been burnt, if hey burnt due to a lean condition that caused them 3 to fail earley then sure it is ok, some purest would insist on have all the valves done at once, but if it is alow mile car or a tigh budget you could get another 100,000 miles out the head the way it was fixed. I would say, overall yes and the proof is in the pudding, IE it runs fine.