Heavy tappet tick

[ronnie]

Hi. Minor 1098. Sitting ticking over there's a heavy ticking noise like noisy tappets then it goes silent to a nice tick over. Any ideas !!
Ronnie

[les]

Distributor drive?

[bmcecosse]

There are no 'tappets' in an A series engine - just cam followers in the block running on the camshaft (behind covers unless 1275) - and then the rockers under (surprisingly) the rocker cover. On start up it may take a few seconds for the rockers to get a good oil supply up from the depths. Check the valve gaps (12 thou inlet and better with 15 thou exhaust) to see if they are excessive. While in there - pull some rockers to the side to see if there is excessive rocker shaft wear obvious. Or - just think of it all as the clickety-whirr of a well oiled sewing machine.....and enjoy.

[ronnie]

I would think there is an obvious problem as when I bought the car the engine was very silent on tickover so must be something needing attention

[philthehill]

bmc
Whilst I agree that there are no tappets in the true sense of the word unfortunately BMC in their wisdom choose to call the cam follower a tappet so continued use of the word tappet instead of cam follower will occur.
Also listed as tappets in the BMC parts list.
Phil[frame][/frame]

[bmcecosse]

Hahahahahah -the 918 has proper 'tappets' ! You can of course pull out the cam followers (not on a 1275) and inspect them if you wish - just lift out the push rod first by slackening the adjuster right back and sliding the rocker to the side slightly - perhaps the end ones will need to be taken off the rocker shaft. DO NOT loosen the head nuts or the rocker pillar nuts... This will also let you inspect the wear on the rocker shaft. the rockers themselves rarely wear to any great extent unless they have been run dry. I think there is enough room (maybe rad removed) to slide out the old shaft and fit a new one with out disturbing the head - I've certainly done it on a Mini.