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Discussion Starter #1
Arrgghh !

I did a bunch of work on my 73 Datsun 240Z. I re-did my valve clearences
(intake 0.25 , exhaust 0.30), then tightened the chain by removing the
gear at the front of the cam shaft and rotating it to the #2 position (yes,
I did jam something in the front of the engine to make sure the chain
did not drop). While in the engine I cleaned out the cam oiler.

Anyway, I fired-up the car and it seems to run just fine. But . . . .
Maybe I'm just FREAKING OUT but it seems like the engine
is much louder than before. You can really hear the cam / valves
ticking away. The valves were really, really tight before I adjusted them.
I wonder if something is worn out?

I removed the valve cover again and made sure everything was getting
oiled properly from the cam oiler. They all seemed oily enough.

My buddy has a 73Z and the engine is nowhere near as noisy.

Stephen
PS - Is it a pain to re-place the cam and valve hardware? Does the head need
to be removed and sent to a machine shop for this?
 

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Re: Valve Noise FREAKOUT !

You did adjust the valve clearances to .25 mm (.010 inches) hot on the intake and .30 mm (.012 inches) hot on the exhuast? Sometimes people mix up the inches and mm things and end up wiith a really noisy valve train as you describe.

Generally, I adjust the valvetrain to the cold numbers and then recheck/adjust after getting the engine really warm.

- John
 

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Re: Valve Noise FREAKOUT !

i have had this same exact thing going on for the past year or so, except mine has always been this way. it gets worse the higher the engine is revved, almost seems like its restricting the rpm's. the engine only has about 1000 miles on it straight out of the machine shop. my cousin has a 280z which is MUCH more quiet. i have adjusted the valves 3 times now because they seem to get better right after i adjust them but wane back into this same incessant valve noise eventually. the head had been shaved a bit and the cam is on spot #2.. if you come across anything, plz pass it along. this has been under my skin for too long now. gl!
 

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Discussion Starter #4
Re: Valve Noise FREAKOUT !

Hi Mach 280 and John,

I am going to invest in a go/no-go feeler guage today and try adjusting the valves again. I think my engine was not hot enough when I did my valve adjustments and maybe that is why it is so noisy.

It does get louder and more pronounced as I drive along a higher RPMs. It sounds like it is not going to blow-up engine or anything. And if it does, I 'll just re-do the head and timing chain completely with valves, new cam (drilled so I won't need the cam oiler anymore) and the associated lash pads / rocker arms / springs etc.

It is winter time here in New Jersey anyway, and who wants to drive their baby in the Snow (and the salted roads). Engine problems I can work with. Rust and no floors I can NOT. I'm not a body work guy.

Regards,

Stephen in New Jersey
The guy with the noisy 1973 240Z
 

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Re: Valve Noise FREAKOUT !

Here is an idea. Try doing like John said, and adjust them COLD. Here is the benefit. All the valves/rockers are at the same temperature. You will get a uniform adjustment all across the board.

The FSM gives hot and cold measurements for a reason. Nissan engineers already figured out the measurements for you. So, do them all cold, run the engine to operating temp, and THEN check a few while the engine is still hot (if thats your bag). Almost everyone that complains about noisy valves tries to do their adjustments hot. I have yet to see anyone fast enough to get them all done while the engine is at the specified hot temperature.

You may hear people tell you that doing it hot is the only sure way. BS. Do them cold, do them right, and forget about it.
 

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Discussion Starter #7
Re: Valve Noise FREAKOUT !

ur clearances are wrong
ex.....(.010)
in......(.008)

Those are in inches. In metric that is
ex .30 mm
in .25mm

for hot adjustments. I have to see what the cold ones are.

Also - I think all the noise is being caused by a flapping timing chain. I think the tensioner went "sproing" when I was re-doing the valve timing.
 
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