I adjusted the old valves today. All of the exhaust valves were tight, and only one intake was tight, the rest were ok. I took it out for a test drive, and there was a noticeable louder rhythmic pffft-pffft-pffft sound in the cabin. Also, I managed to create a rhythmic base sound that's kinda like a pah-pah-pah. Here are two wav files of the sounds. In the first one, I put the mic right up to the intake scoop. That's were the pah-pah-pah sound is most audible. The second is a recording of the engine bay in general.

http://cbjukraine.home.comcast.net/Sounds/DSCN2937.wav
http://cbjukraine.home.comcast.net/Sounds/DSCN2938.wav

Some general valve adjustment questions:
1. Is it bad if the valve rotates when you are trying to adjust it. I don't have the wrench that holds the valve spring collar.
2. If the clearance is too tight, does that mean the valve is opening too little or too much?

Thanks, I know you guys will have the answer!

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cbjukraine
'84 300D

Did you recheck the clearance after you tightened the adjusters?

1. If you don't find some way to hold the collar, you're not actually adjusting the clearance. The nut is just rotating against the valve and not adjusting its position. You need to find some way to hold it. I either wedge it with a screwdriver or use channel locks since I refuse to waste money on the wrenches.

2. If the clearances are too tight, correct me if I'm wrong, then the valve doesn't seat all the way and can lead to lower compression and possible burning of the valve. It could be the other way around but I think that's how it goes. Also I think it does something to the amount of time the valve is open, decreasing the amount of time and thereby allowing less fresh air in and less exhaust out.

You need to make sure you recheck all the clearances before you button everything back up. Also make sure to check that you tightened all the adjustment nuts back down. Once I left one completely loose and I noticed a loud rhythmic thumping noise coming from the rear of the engine. Tightening the adjustment nuts on cylinder number 5's exhaust valve made the noise go away. Go figure.

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Seth

1984 300D 225K
1985 300D Donor body
1985 300D Turbo 165K. Totaled. Donor Engine. It runs!!!
1980 300SD 311K My New Baby.
1979 BMW 633csi 62K+++? Dead odo

I checked each valve clearance after adjusting it and tightening the nuts down. But I did not run through each valve again before putting the cover back on. Let me run my predure by you guys to see if I'm doing it right.

First I get the cam lobe pointing 180 degrees away from the rocker pad. If the valve needs adjusting, I break the bond between the two nuts by applying CCW torque to the cap (top) nut and CW torque to the lock (bottom) nut. That breaks them apart, so they can be turned independently, without turning the whole valve. Assuming the clearance is too tight, I then tighten down the lock nut so that I can bring the cap nut down too, increasing the clearance. When I get the right clearance, I hold the cap nut in place and bring the lock nut up to it. I try my best to not turn the cap nut while applying as much CCW torque as I can to the lock nut. After getting them tight, I check the clearance to make sure it hasn't changed. If it did, I repeat the whole process.

This is just what I did today, and now I get these wierdo noises! Guess I need to recheck the clearances tomorrow...

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cbjukraine
'84 300D

Well, you did it right. Recheck to be sure. You might have accidentally swapped measurements

I've done it, I accidentally set an intake valve to exhaust clearance (way loose for an intake) and I didn't catch it until the next adjustment.

What specifications did you use for the valves?

It's very easy to make an error with the clearances..........exhaust and intake valves are different............and you're not doing them in order. Without a paper sheet with the valves listed..........you'll definitely make an error.

0.1 mm intake, 0.35 mm exhaust on a cold engine. I did all the exhaust valves first, then intake, so I don't think I adjusted an exhaust valve to 0.1 mm or vice versa. I did them in firing order, that is, I adjusted the valve whose cam lobe was next in line, saving me from having to wear out my arm rotating the crankshaft.

The only thing to do now is recheck them, which I am about to do. Could the noises be an intake valve that is too loose (too much clearance). On one or two, the 0.1 mm feeler slid in very easily, but I didn't want to mess with it, so I left them alone. But then, I never got these noises before...

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cbjukraine
'84 300D

From the front of the engine..........counting valves from front to rear.........which are the exhaust valves?

from front to back: 1, 4, 5, 8, 9
intakes: 2, 3, 6, 7, 10

I printed out the FSM page that shows the layout and marked off the ones I had completed. I wasn't flying blind...

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cbjukraine
'84 300D

Yep, you've got them right.

There still must be some error..........it's easy to do.........I made a mistake on the sequence when I put the head back on the 617. It had a funny tapping sound that was surely abnormal. Setting an intake to .35 can do that.........

On your situation, it almost appears that an intake is not fully closing.........meaning the adjustment is way out of spec. Are you positive that you're placing the feeler gauge between the camshaft lobe and the rocker arm?

the reason you adjust valves.

1. too little clearance will cause the rocker to be constantly wearing on the cam lobe causing increased wear and heat.

2. too little clearance will cause the valves to be open during the combustion cycle causing lower compression and possible valves being burnt.

3. too much clearnace will cause increased cam wear and additional noise.

4. too much clearance will cause less valve lift. meaning better idle but much less proformance.

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Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac?

As long as they would add one additional commandment for you to keep thy religion to thyself.
George Carlin (Wonder where he is now..)

1981 240d (engine donor 1983 240d) recently rebuilt engine hurray! - No more.. fought a tree and the tree won.

pearl black 1983 240d 4speed (Converted!@$$%) atleast the tranny was rebuilt.

Pretty much all the valves were way loose. I guess my interpretation of "the feeler gauge should slide between the cam lobe and rocker arm with some resistance" was a bit skewed. Some of the exhaust valves were so loose, the thickest gauge in my set (0.65 mm) fit in the gap. I figured out how to do it right, however. I made sure the right feeler could slide in, but the next thickest one couldn't. Much better sounding engine...

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cbjukraine
'84 300D

Good job.

It had to be something amiss with the adjustment. Don't feel bad........it happens to all of us...........