RP Tappet noise

[Graham O]

Many thanks everyone for your advice.

I never gave thought to the guides when effectively shortening the followers.  I guess when I check the tappet settings I should make sure that the tappets do not hit the top of the guides.

I will probably have to leave things for a while before I get back to this issue, but I promise that I will come back and update this thread when I have made the adjustments.

Cheers Graham

[Graham O]

An update:
My good friend Graham Barker kindly brought his 37 Ruby so that we could compare engine noise levels from our cars.
Both engines were well warm and were idled at about the same rate.  I measured the noise using my uncalibrated phone microphone app and held it exactly a half meter from the manifold side with the bonnet open.
The results were: 
RP 83dB  Ruby 81.5dB.  I assume these are dBA measurements, but it does not really matter being just a rough relative test.  This means that there was almost half as much extra noise coming from my RP. At these high noise levels the ambient noise had no affect on the results. Our subjective decision before the test was that my RP was a bit louder and sounded a bit harsher.

So time will tell if I have tappet issues.

[John Cornforth]

Hi Graham

A difference of 1.5 dB is pretty small given some measurement uncertainty. I doubt if the ear can percieve a difference much less than this.

If your phone app can give an audio spectral display that might tell you more about the noise character.

[Ian Williams]

Backlash in the timing gears and/or end float in the front cam bearing can also contribute to the noise Graham. Did you get both of these spot on during the rebuild? Have the tappet clearance's changed significantly after the first 100 miles? If not I think we can safely eliminate the guides from the equation.

[Graham O]

Thanks for your comments John and Ian
Yes I agree that the measured difference in noise level is about the point where a difference can be noticed.  I think the slightly harsher sound of my car catches the ear more.
Ian I did not measure the end float or timing gear backlash.  So that may be a contributor.  The sound appears to come from the tappets rather than the gears.
When I get time I will measure the tappets, but that will have to be a while away.
 Graham

[Ian Williams]

Both are very important Graham, if you have more than 3 thou end float the cam will kick back an forth making all sorts of clatter, it will wear the front bush quickly and eventually cause an oil leak around the locating pin. Others may have differing opinion about lash but I find 4 to 5 thou about right, its important when mixing and matching gears that you stone off high points or you will point load the teeth which in bad cases will cause fast wear and inevitable chipping of the gear.

[dickie65]

The other possibility is a split cam follower which will jam if the locknuts are overtightened.
I have a collection of split followers somewhere.

[Ian Williams]

This is true Dickie but also likely to hold one of the valves off its seat which will affect running. Graham seems to be saying that the car is running well its just noisier than he expected.