Tappet Noise that isn't!

[ians]

If you have what sounds like a tappet setting noise (engine speed related ticking coming from the rocker cover) but it wont go away even when you have double and treble checked the tappet clearance settings then it may well be a worn rocker shaft.

 

This is my second TR3 and the second time I have had this problem. The noise is actually the rocker slapping against the pedestal because it is wobbling on the rocker shaft.

 

I changed my rocker shaft today (less than 90 mins) and the problem has gone away again.

 

I have attached a picture which quite clearly shows serious signs of wear due to rear rocker lubrication failing, the feed hole was blocked with crud. Slightly surprised that it was this one that failed being closest to the supply but there you go. The shaft is very badly worn and the rocker showed signs of uneven wear on the side face that presses against the pedestal.

 

If you do decide to do this make sure you have a suitable punch to remove the Collar Retaining Pin (pn# 500975) you will need two new ones as well as the shaft (pn#111064).

 

Anyone know why Triumph use this DIY maintenance unfriendly method of securing the end cap?

 

 

 

[Andrew Smith]

Ian,

 

I have the same problem - whose rocker shaft did you buy?

 

Cheers

Andrew

[ians]

Mine came from Rimmer but I believe that most of the regular culprits stock them.

 

Take a picture before you disassemble the original. There are two types of rocker and they need to be assembled correctly to align with the valves and pushrods.

 

I know the oil feed is working as I ran the engine briefly before refitting the rocker cover and witnessed oil coming from all of the rockers.

[BlueTR3A-5EKT]

500975 pin is a tapered mills pin.

Bang it in from the top, tap it out from the bottom. Then it can be reused.

If you look closely before taking the hammer to it the pin head diameter may well be visible, top compared to bottom.

 

Peter W

 

PS for what its worth I have a worse condition than your photo shaft that I use as a drift to knock out bearing races.

 

PPS. Could you note the wall thickness of the genuine shaft compared to the repro and report back?

Edited July 26, 2013 by BlueTR3A-5EKT

[Andrew Smith]

Peter,

 

What's your view on the current Moss rocker shaft offering?

 

Cheers

Andrew

[Ashley James]

Ever since I can remember cars have been wearing out rocker shafts prematurely. MGs and Morris Oxfords, TRs, even Bentley R Types. Worst were XPAG engines in T series Midgets. Austin Healeys and Westminsters we always quite quiet, but often they lose oil pressure because they're flooding the rocker covers.

 

IMO you just have to replace them from time to time, but a friend's father used to invert the one on his Morris Oxford and double it's life! They were 25 bob then.

[David James]

Hello Chaps

Help - Another similar problem maybe?

I have what I believe to be a cam follower tapping sound on no. 8 valve which I presumed was the camshaft.

After a trip to France I needed to adjust tappets.

Adjusting the tappet at what I believe is the correct position of the camshaft on rotating the crank the tappet clearance gives a value almost double in another crank position. This only happens on the 4th cylinder exhaust valve.

I can adjust the tappet at its widest point to its correct value but it gives a reading smaller than it should be at the correct setting position.

The engines sounds lovely then but I not prepared to risk running with a smaller than spec'd clearance.

I had thought this was probably due to the camshaft base circle being worn.

I am obviously loathe to remove the camshaft if it might be a problem that was rocker shaft related.

 

What do yous think.

 

Cheers

 

David.

[peejay4A]

Until recently I used the rule of 9 to adjust my valve clearances. I've not been happy with the result so I used the technique outlined in the last part of this piece. http://www.macysgarage.com/myweb6/valve_adjustment.htm

 

In a couple of cases I was able to close up the gaps by 2 or 3 thou and the valve train is noticeably more quiet.

[Ashley James]

The cam base circle never wears, only the tip does that. I'd assume the rocker shaft and remove it to see if there's a step in it and only worry if it's perfect.

[David James]

Thanks chaps

 

I will have a closer look at the rocker shaft although the sound does seem lo come from lower down near the camshaft.

It will be wonderful if was the rocker shaft.

 

Fingers crossed

 

David

[BlueTR3A-5EKT]

And the state of the rocker bushes?

Peter W

[Ashley James]

Don't take it for granted, but often replacing the shaft is enough because it wears the most.

[ians]

 

 

 

PPS. Could you note the wall thickness of the genuine shaft compared to the repro and report back?

 

 

I measured the Rocker Shaft that I removed the OD is 5/8" and the ID is 5/16" which makes the wall thickness 5/32".

 

What I can't tell you is how old this rocker shaft is. I cant tell you what the new one is as its fitted now but I dont remember it being significantly lighter (Ie thinner wall thickness)

 

Ian