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Point 1. Valve seat recession - Valves do need adjustment but not often due to seat erosion. My 240 has 518,000 km and last had valve shims adjusted 10 years ago at 370,000 km. Since the job is very tedious you can get away with only doing the exhaust valve shims as they get most erosion. For example my cold clearances for valves 1 (front)to 8 (rear) in sequence were less than 1.5 thou(smallest feeler gauge leaf), 12, 6, 12, 4, 11, 12, 13 thou. Note the huge difference in recession between exhaust valves for cylinders 1 and 4. Also worth noting is that I ran my 240 on LPG since 1991 which is supposed to cause more valve seat erosion than gasoline. Compression on cylinder 1 is fortunately OK (100 psi (cold)) but I think I came too close to burning #1 valve and having the car towed to a head shop for an expensive fix. BTW I have never used upper cylinder lubricant (eg Flashlube) with LPG. Although there are horror stories about valve recession on the Internet at least Volvo (240) valves and seats must be tough to do 300,000 km on LPG and still work.
Point 2. Adjustment tools - Its possible to use homemade tools to replace shims. To depress the cam bucket I used 2 screwdrivers, one to initially depress bucket and then the other to hold it down at the edge of the bucket after removing first screwdriver. The main hassle with this is that inserting the first screwdriver rotates the bucket sometimes "hiding" the slots that are used to grab the shim, so use another screwdriver in the slots to rotate bucket to get the slots in a good position. To remove the shim use a small pointed screwdriver and bend its end 90 degrees to poke in the bucket slots. Since the oil between the shim and bucket provides some suction against shim removal I found that it was easier to get better shim extraction with a tiny flat blade screwdriver than a pointed one, though I used a stone to grind the blade edge very thin to get into the gap between the shim and bucket.
Point 3. Cam rotation limitations. To remove several shims its necessary to rotate the camshaft but rotation is very limited since the cam lobe goes right down into the bucket and then the top of the cam lobe will jam against the edge of the bucket limiting rotation. Nevertheless I extracted 3 shims with this partial rotation though I found it necessary to turn the engine both forwards and backwards to do so.
Point 4. Mechanic cost - After doing this job (at no cost but considerable stress) I spoke to the local mechanic about his cost of doing this job. He said it would take him two and half to three hours for all 8 shims at $100 per hour labor - presumably with Volvo special tools. The he said why dont I do it myself because the job is not easy, and then he said sometimes he pushes this job out to a "head shop" - I guess he has a gofer drive the car to the head shop then takes his cut for doing nothing. Before you start this job make sure you are in a good mood with plenty of patience as you'll need it.
sutherml @ Adelaide, Australia
1979 244 @ 518,000 km
Converted to LPG in 1991
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