Burnt valve possibly?

Post by **jblackburn** » 02 Jun 2010, 14:43

They actually all look VERY low. Maybe it is just your gauge?

You did the compression test at wide-open throttle, right?

But for sure, at least one of the valves isn't shutting. It is also hard to tell whether or not it's burned or just stuck.

Take it out on the highway, and drop it into L and drive above 4000 RPM for 5 minutes or so. If it's just stuck, that should be enough to get it moving again. If it's burned, that won't help and you'll be looking at removing the head to figure out what happened.

Post by **FlyingVolvo** » 02 Jun 2010, 14:51

Try SeaFoam?

Cory · Post by **Cory** » 02 Jun 2010, 14:59

I have tried Seafoam and it did clean the cylinder tops pretty well! At least from what I can see with a flashlight through the spark plug hole. I did the treatment in the gas as well as through the vacuum lines.

And nooo...I didnt do the compression test at wide open throttle. The motor wasnt even running. I removed the coil wire and just cranked it over with the gauge hooked up. I also only hand tightened the gauge. The socket was a different size that I didnt have.

Ewww...that sounds like an awful lot of stress on everything to run it in low gear for a long period of time. I guess I can give it a try. How common are "stuck" valves though?

Also the misfire seems to go away at higher RPMs, like above 1800.

Post by **Ozark Lee** » 02 Jun 2010, 17:48

0/0 on cylinder 1 does point to a burned exhaust valve. If you have good service records on the original engine I would suggest either replacing the head or buying new exhaust valves (at least for cylinder 1) and lapping them in.

If the service records are sketchy you might want to consider a used motor - the money is about the same.

...Lee

Cory · Post by **Cory** » 02 Jun 2010, 23:35

Thanks everyone!

I agree Ozark Lee, I think I will just start looking for a wrecked one in the junkyard to pull a head from. Obviously one that is wrecked in the junkyard means that it was more than likely running relatively well when it was involved in that crash. This will provide me with the best donor head. I will then send it off to be checked and cleaned and repaired if necessary. Luckily I have a local place which I have used before and know to do good work.
The service records are somewhat spotty but I plan on being at Stage 0 after the head replacement (only need the timing belt service) and the motor looks and runs well. I cant really see replacing the whole motor with a used one because of the problems that may already exist before I ever install it (and yes, I would do the install). At least I know my motor runs relatively well, besides the burned valve obviously, and only throws a misfire code because of that. And I will feel more confident in my current motor knowing that the head and gaskets are in proper condition after the repair.

Has anyone done a write-up on cylinder head removal/replacement? Just wondering if it would be worth writing up when I do it.

beoutside · Post by **beoutside** » 23 Aug 2013, 17:47

Mt father in laws has the same issue in cylinder three, did you take your cam cover off to check if it was a lifter/spring issue?
thanks

Post by **erikv11** » 23 Aug 2013, 21:25

In all the posts I have read on the forums, I have only seen a couple broken valve springs. All the rest (dozens) were burnt valves. You can actually sometimes see a broken valve spring without pulling the head, just by pulling the cam cover.

beoutside · Post by **beoutside** » 23 Aug 2013, 21:40

Thanks just wondering if its a burnt valve that senerio may have effected others even though it doesn't show yet but trying to justify the cost of a total valve job on a car with 170000
. This I also based on the fact I have had our 1999 xc in my shop 75 percent more than any other vehicle we have owned. I'll pull the cover I guess and then go from there.

Post by **Ozark Lee** » 23 Aug 2013, 23:53

beoutside wrote:I'll pull the cover I guess and then go from there.

There is more to removing the cam cover than just unbolting it and taking it off. The timing needs to be lined up to the timing marks and the timing belt needs to be removed. You will also need a tube of the anaerobic sealer to put the cam cover back on. You also need to devise a means to slowly draw the cover down when replacing it so that the valves will open as necessary. The cover itself is the upper half of the bearings that the cams ride in and the camshafts and lifters come out in order to get to the valve springs, even to just inspect them.

It is also a good practice to keep track of the lifters so that they can be installed back in their original positions.

...Lee

beoutside · Post by **beoutside** » 24 Aug 2013, 08:52

Thanks so much that was my question after reading the manual and other posts needed to confirm it