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Hot or Cold Valve adjustment


I have a 1982 BMW 323i. It has the m20 engine which was common in all of the 3 series BMWs from the 80s. This is a rather tappity engine with a lot of valve chatter. I’ve read that you can reduce this chatter by adjusting the valve “hot”.

The specs for my valve adjustment are .25mm cold or .30mm hot.

What do you guys think?

Thanks for a great show!

It means you can set them hot or cold.
Do not know what you are asking?

Will it make them quieter? Are there are any downsides to doing them hot? Is there a recomended procedure? How quickly does the engine cool down? Will I be able to finish them before they start to change size?

I have owned a 86 320 (Eupope only) with the m20 and as a mechanic I have adjusted the valves on hundreds of m20 engines. I would never give them a lable of being tappity. I don’t think you are going to reduce your valve train noise simply by using a "hot’ spec. Any of the adjustable valve engines will tick if you don’t adjust them correctly. Even BMW’s wear out, and you could be looking at a wear issue in the valve train.

Suprising that there is a group out there that lables the engine “tappity” all mine were virtually silent.

The downside to doing them hot is you burn your hands. I could adjust all the valves in under 5 min,is this your first time? What are you going to turn the eccentric with?

I did run the question by my Master Tech friend and the m20 does have a reputation for both valve noise and loud injector clicking and the injector noise is often mistaken for valve noise. The m20 also has a reputation for using up camshafts,not really early but at higher milesge.

are you sure about those specs. they seem to be reversed the way I see them?

Yes, the specs are correct, see the attachment

I would do them cold.
When plugs are hot they are more likely to damage threads when you take them out.
No worry about burning hands.
Book will give you step by step, Take plug wires off so not to damage them, mark them so you are sure where they go.
Take off valve cover, turn motor by hand until valve is all the way closed, do it the way book says. set it then go to next one.The way I like is set each one then recheck, this is important.
Reason for this is something after going up and down it will give a different reading.