Hi all. I'm doing my first valve job. '98 N/A S70 that should have had a new timing belt. The exhaust valves in cylinders 2 and 4 were spared. But I pulled them out anyhow to clean them up. I did the valve seat lapping with the paste and suction cup stick. I have my doubts about the process though. To test the valve seals I turned the head on it's side and filled the cavities in the head with some kerosene. One of the four valves got a little wet after a couple minutes.

So do I pull the valve back out and do the lapping again, or is there something else I should look for?

Is there a better way to test the valve seals?

Even if there's no seepage can the valve to seat contact be dangerously inadequate? I of course don't want to end up with burned valves down the road.

I was also wondering if the valve to seat contact improves during the breaking period after the repair? A sort of looking for some piece of mind question.

Hello,


You can check the seat clearance with a vacuum gauge.

I would have the valves ground professionally. An experienced machinist will decern any damaged parts on the grinder.

If you have any question about the quality of your job, reread the line in your original post "I of course don't want to end up with burned valves down the road"


Goatman

I know there are better ways to approach this job. Economics is one of the determining factor too though. I'm not being cheap, I just don't have much to work with in that department.

I bought the car with the bent valves as a project car to learn from as I like Volvos and this is a very common engine. And also because my current car has over 225,000 miles on it and I want a second car should something really bad happen to it. Last spring I hit a bear with it. For an instant I thought I was carless. The 740 took it well enough though and with my donor car I made it right again. Had I not slowed down more or if it was a full grown bear I wouldn't have been so lucky.

I have thoughts though that I should have gotten another red block wagon. Next time...

Of the valve faces on these cars, B5254S, are they coated with something or are they "nude" metal? I was told these may be coated valves. Whatever it is softened up after soaking in CLR. I experimented with the bent ones.

Hello,


CLR is for cleaning toilet bowls and bathtubs.

I have used a bench polisher to clean mine donning a particulate respirator. Because tetraethyllead was used up to 1993, Letharge bromide salts are in high quanities contained in the valve deposits of vehicles operated during that time period

Methylmagenesetricarbonyl has been reapproved for use in motor fuel. Be aware that high levels of maganese damage the myelin sheath leading to permanent reductions in dystal nerve conduction velocities.

I prefer to have the valves renewed in a sandblasting cabinet.


Goatman