Noisy Valve Gear 323i

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e21Keith
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Noisy Valve Gear 323i

Post by e21Keith »

Still waiting for my bottom end to come back from rebuilding, so in the meantime I'm thinking about the top end.

I've had many M20s over the years, some have had very quiet valve gear, some have been noisy. In general the lower mileage ones have been quieter but that's by no means the rule. Sometimes adjusting the valves improves matters and sometimes it doesn't.

So what's the secret to quiet valve gear, do I have to replace everything?


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Jeroen
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Re: Noisy Valve Gear 323i

Post by Jeroen »

Perhaps wear on rocker arms where they move over the rocker shaft, and the rocker shaft? Sometimes you adjust valves real tight and they're still noisy, must be freeplay on the other side of the rocker I reckon?
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e21Keith
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Re: Noisy Valve Gear 323i

Post by e21Keith »

OK I'll add a little background.

When I rebuilt the head (first time before it cracked) I used original camshaft with new rockers and shafts (pattern parts, believe they were Febi) . It was noisy as hell.

Second rebuild I used a matched set of camshaft, rockers and shafts that came with the head, still noisy.

Having sorted through all my bits I have the following:
Unused pattern Camshaft (manufacturer unknown)
Full set of pattern rockers (500 miles)
I don't have a pair of shafts so could buy new ones.

So for the third rebuild I could use the parts above which would all be new or close to new but all pattern parts. I don't want to go through this a fourth time, particularly as it involves removing the head again. Genuine BMW new parts are really expensive.
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Duracel79
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Re: Noisy Valve Gear 323i

Post by Duracel79 »

Check the eccentrics have not got worn flats they may cause some noise, you only mention the rockers not sure if you had new eccentrics in them.
1982 323i (S54 "Test Mule" - to be rebuilt into M20 powered track car)
1983 316 (Taiga Thunder - The refined S54 Race car)
1982 635csiA (New project)
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e21Keith
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Re: Noisy Valve Gear 323i

Post by e21Keith »

The eccentrics are all new (pattern parts I suspect).
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Jeroen
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Re: Noisy Valve Gear 323i

Post by Jeroen »

Really weird if you have a noisy valvetrain while pretty much everything is new, and while noisy valvetrains are pretty rare on M20 engines as far as I've experienced, a lot better compared to S14 engines for example.
Regards/groeten, Jeroen
e21Keith
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Re: Noisy Valve Gear 323i

Post by e21Keith »

The machine shop called me today and the bottom end is rebuilt, I'll collect it on Tuesday, I expect it will take me about 2 weeks to get the old engine out, build up the new engine and get it installed (mainly because I am old and decrepit).

The top end I'm going with new cam (genuine) new rockers and eccentrics (done 500 miles, pattern), new rocker shafts. I'll check everything carefully and see how it works out.
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Duracel79
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Re: Noisy Valve Gear 323i

Post by Duracel79 »

Just a thought, make sure you clean out the cam spray bar, lack of lubricant will make the valve gear noisier and let it wear more.
1982 323i (S54 "Test Mule" - to be rebuilt into M20 powered track car)
1983 316 (Taiga Thunder - The refined S54 Race car)
1982 635csiA (New project)
1985 728iA (For Sale)
2004 330d Touring (The Daily Hack / Tow Car / Load lugger)
e21Keith
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Re: Noisy Valve Gear 323i

Post by e21Keith »

I'm thinking of a new spray bar as well just to be belt and braces
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BertjeConti
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Re: Noisy Valve Gear 323i

Post by BertjeConti »

And install the excenters the right way around. Wrong way installed excenters ruin the valve stems.
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e21Keith
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Re: Noisy Valve Gear 323i

Post by e21Keith »

Install the eccentrics the right way round, could you explain this to me as I didn't know there was a right/wrong way?
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BertjeConti
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Re: Noisy Valve Gear 323i

Post by BertjeConti »

Check out this topic i wrote about the excentrics a few years ago:
http://www.bmwe21.net/forum/viewtopic.php?f=61&t=23266
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