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Valve noise?

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desmo900rider

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I noticed today a ticking coming from what sounds like under my valve cover on my 79 Spit...the speed of the ticking increases with RPM's, and at idle, with the bonnet up, it really sounds like its coming from right under the valve cover...I noticed it after an about 15-20 minute, 70-75 mph freeway jaunt...anything to worry about? Anything to check for? Just never noticed it before today...

Thanks!

Mike
 
If you can't get the valves to adjust properly, check for wear on the underside of the rockers and rocker shaft. Triumphs often lack good lubrication to the rockers and tend to wear in these places.
 
I feel better if I can hear a slight clicking, kind of like a sewing machine running. Then I know the valves are closing completely. It does get louder when the engine gets warmer because the oil gets thinner and the valve train parts do not have as much cusion.
I would be concerned if I could not hear them at all. That would indicate that they may not be completely closing which would mean they could be leaking which would burn the valves.
In any case, when in doubt check the valve adjustment.
 
Well, this AM on the way to work I really coudn't hear the noise, so it seems to be happening when the engine is very warm...I'll try to get myself trained on how to check the valve adjustment...and Tom, your sewing machine sound is a very accurate description...

Thanks!

Mike
 
Except Mike has a 1.5 /ubbthreads/images/graemlins/grin.gif

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Hi Mike,

A little valve noise is not uncommon on these old engines. Especially at startup when cold, before oil gets fully circulating and parts expand due to heat to reduce valve lash. After a hot run, when oil is thinned a little due to heat, it's common too.

What oil are you using?

If not already doing so, I'd suggest that in summer heat you might want to use something heavier, particularly if your engine has some miles on it. Maybe 20w50?

Synthetic or non-synthetic?

Opinions vary a lot, but I personally prefer to use non-synthetic oils in these old engines and change it every 3000 mi./3 months minimum. This is the type of oil these engines were designed to use. Synth oil might make things a little noisier (plus can lead to more leaks, is expensive and often has too much detergent in it, IMHO).

Other causes/solutions for valve noise:

- Valve seat recession due to unleaded fuel. I think this is unlikely on a '79 car, but am not certain. Usually it can be spotted by frequent need to adjust, particularly the exhaust valves. The real/final solution is to rebuild the head with hardened valve seat inserts on at least the exhaust side, and use Stellite valves. Again, I'm not sure this is likely on your car, due to it's age.

- Weakened/soft/old valve springs. Again, head rebuild time.

- Worn rocker assembly: bushings, rocker shaft, etc. Pretty easily and inexpensively rebuilt without pulling the head from the engine.

- An oil cooler can help prevent oil from thinning under hard driving use and in high summer temps. If installed, it should have a thermostatic control, too, to prevent over-cooling at other times and to keep cold, thick oil from over-pressurizing the cooler at startup.

- Not a cause, but a possible solution: Install an aftermarket cast aluminum valve cover... muffles some of the valve noise... and it looks cool too!

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A little valve ticking is normal. These are solid lifter cars that require some gap (slop) in the valve train to allow for slight expansion of the parts as the motor heats up. This ensures that the valves are not being held slightly open which results in loss of compression an valve burning.

If you have set them all with a feeler guage (about 5 times) and you still have a couple valves that are much louder than the rest, my experince has been that it is a worn rocker arm or two. This can fool you because what happens is that the end of the valve wears a pocket in the rocker arm. When you put your feeler guage in to set the gap the face of the feeler covers the pocket, like laying a board across the top of a bucket.

Pulling the rocker shaft and inspecting the rocker arms for pocketing and play on the shaft is quick and easy.
 
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