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No Compression in One Cylinder

When we were near town and stopped for a light the engine was shaking badly. Acceleration was slow with lots of exhaust noise. Checked compression the next day. All were 180 dry except #2 which was 0!


No Compression ?

MVS Volvo Forum user waynej writes “Just took a trip of about 200 miles. Exhaust seemed a little loud. When we were near town and stopped for a light the engine was shaking badly. Acceleration was slow with lots of exhaust noise. Checked compression the next day. All were 180 dry except #2 which was 0!”

erikv11 » Burned exhaust valves are common on these engines as they get up near 200k. The valve stem seals get hard and inflexible, and leak. Oil gets hot, burns the valve.

The 93 head will fit the same, I sold my 98 head to someone with a 93, and it is doing great on that engine. He mostly wanted it to get rid of the VVIS though! Anyway, you will have to swap over the intake manifold too for the VVIS. If you do swap in the 93 head, be sure to replace the valve stem seals first. Victor Reinz or OEM (do some searches), or they won’t last long.

You can drive it on 4 cylinders for a while, just be sure to unplug the #2 injector so it doesn’t dump raw fuel to the cat.

rspi » I use to fear burnt valves and did some research on the causes. Here’s what I came up with:

1. Improper back pressure from the exhaust. This causes the valves not to seat correctly.
2. Running lean. Improper detonation causes the valves not to seat right.
3. Carbon build up from improper fuel mixture. I believe it’s from people running 87 octane in cars that are made to run 91+
4. Valve crack or chip from any of the 3 problems mentioned above. Also, if some buildup or something comes loose it can get stuck in a valve and chip it.

When a valve doesn’t seat right it builds up heat and makes it more prone to overheating and damage.

There is a slim chance that you have a slipped sleave on your piston or a hole in your piston. This is usually caused by knock or a messes up spark plug, like if it’s broken. The best way to test a cylinder wall is to wet that cylinder with a little oil. If the number climbs it’s likely the piston sleeve. But the sudden drop and no pressure usually points to a burnt valve.

http://www.dietersmotorsports.com/Compr … wntest.htm

http://www.wcengineering.com/articles/leakdown.html

No compression 96 850

2 Comments

Sadly I hate to say it. but i think your gasket is blown. i did the same thing and had the same problem. just got back from a mechanic he said that he thinks the gasket is cracked or about to blow.

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