Tapping cam follower 1500 Spitfire

[houlio]

I recently had to drop a replacement engine into my 1500 spit, (the big end shells went on my old one went - apparently)

So I have this second hand engine dropped in, it seems fine except for an infernal knocking sound that speeds up and slows with the revs, the sound increases in volume and quietens of its own accord. I'm told its not the tappets, that it is a tapping cam follower?

Now if it is a loose tapping cam follower, what damage is it doing? and is a relatively inexperienced mechanic (me) going to be able to fix it?

thanks for any bright ideas,

Jules

[tr3a]

houlio said:

I recently had to drop a replacement engine into my 1500 spit, (the big end shells went on my old one went - apparently) So I have this second hand engine dropped in, it seems fine except for an infernal knocking sound that speeds up and slows with the revs, the sound increases in volume and quietens of its own accord. I'm told its not the tappets, that it is a tapping cam follower? Now if it is a loose tapping cam follower, what damage is it doing? and is a relatively inexperienced mechanic (me) going to be able to fix it?

I don't know how 'relatively inexperienced' you are, but have you tried setting valve clearances yet? If so, did it make a difference?

[houlio]

No i havent had a look at the valves yet, i will have poke this week.

Thanks

[//j17]

In Triumph SC engine is a good ol' pushrod engine - cam follower sits on cam, push-rod sits inside cam follower and is pressed down by rocker arm. If you rocker clearencies are too great there will be a 'slap' where the rocker arm makes/break contact with the end of the push-rod. Check the clearencies COLD using the 'rule of 9'. Get the car on flat ground, put it in 4th with handbreak off. It's then quite easy to move the car and turn the engine. With #1 (valve nearest front of engine) fully open (down) adjust #8 (furthest from front of engine) - 1+8=9. When that's done roll forward to the next valve (which will be #3 - 9-3=6, so adjust #6).

For a standard cam the clearencies are 0.010in (.25mm).

Another noise that can be similar is a 'loose' crank pully. With the engine off/out of gear/handbreak on try grabbing the fan belt down by the crank pully and push/pulling it. Watch the pull it's self (not the belt) and if you see a little play then that's probably your issue. It's not unknown for the woodruf key that locates the pully on the crank (or the locating slots in either pully ot crank) to wear. When this gets really bad your car starts to sound like a old, badly maintained diesel tractor.