wrote:

>
> "mbjj" > wrote in message
> link.net...
>> Before I go taking off the head of this 1.0L Metro engine I'd like to
>> know how a burnt valve acts in relation to the performance of the engine.
>> What
> it
>> is doing is acting like a bad miss. Like it even has water in the gas. It
>> sputters and misses when it's under load [like climbing a hill or
>> mountain]. On straight roads when the load is reduced it straightens out
>> and runs well. I'm going to do a compression check here in a little bit
> and
>> also change the plugs, wires and distributor cap before I get into the
>> head. We just bought this thing knowing it has a problem and the seller
>> seems to think he burned a valve. It also produces a puff of oil related
>> smoke out of the exhaust just after you start it [cold] and put it into
>> gear. It quickly goes away when shifting out of 1st and doesn't come back
>> again until it cools off and restarts.
>
> The puff of blue smoke after a cold start often indicates worn valve
> guides and/or
> degraded valve guide seals. These seals are often easy to replace without
> pulling the
> head.
>
> If you have a burned valve, it often shows up as a dead or nearly dead
> cylinder.
> At higher RPM the effect of a dead cylinder is less noticeable, but the
> loss of power is
> obvious. The engine may miss, or sometimes even backfire.
>
> You can listen for a burned or poorly seating valve by disconnecting the
> spark plugs so the engine
> wont start, and turn the engine over with the starter. If every cylinder
> is sealing about the same, you should have a consistent rhythm. If one, or
> more, valves are burned, you will hear something different....like wa -wa
> - WAH-wa-wa-WAH
>
> A compression test is a better way.


Thanks for the info. The compression test showed an even 175 PSI across all
3 cylinders. The plugs were in need of replacement. The bad miss was in all
liklihood due to a bad plug in #3. I replaced all 3 plugs and put on new
wires, cap and rotor button. The miss is gone so I guess I can breathe a
little easier on the valve. I still have to look for the puff of smoke to
see if I took care of that too. After I run it awhile I'll keep a close eye
on the smoke and react accordingly.