• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

How tappets work and why they need adjusting?

Share this page

R

RobWarren

Jedi Hopeful
Offline
BJ8 owner. Engine just nearing rebuild completion.

I know that after 500 miles of breaking-in, the engine head needs to be re-torqued and tappets adjusting, and this led me to think "What do tappets do and why would they need adjusting?"

I've done some basic research on their function as a device for transferring cam motion into valve lift but I'd love to hear this forum's thoughts and expertise on how the tappets work on the AH and why they need adjusting - and how to adjust them!

Photos would be REALLY helpful.
 
When you retorque the head (presumably squishing the head gasket more) you potentially change the operating clearance between the cam/lifter/rocker-arm/valve stem.
 
Randy - you're always lurking with answers - love it mate.

So do the tappets on the Healeys not allow for a change in clearance? Do any tappets for that matter - have I stumbled on a magic new invention?
 
Hydraulic lifters compensate, but solid ones do not.

I'd say you're nearly a hundred years late with that innovation :wink:
 
This quote came from a search on the forum (use advanced search always to get historical posts older than the default 1 week). Use a .012" feeler gauge and the
EOIC formula.

Here's the formula (Exhaust Open Intake Closed:

Adjust intake valve when exhaust just starts to open,

Adjust exhaust valve when intake is closing.(almost closed)

This formula was given to me by a machine shop in JAX Florida when I lived there and overhauled several Healey engines. He was a very experienced machinest and was able to repair any thing I threw at him with Healey engines.
Patrick

Use the bump starter button on the back of the starter electrical connection or put the car in 4th gear and push to get the valves where they need to be as above. It may be necessary to remove the spark plugs.

Clearance is necessary to ensure full opening and closing of the valves, and to avoid excessive clacking of the rockers on the valve stems (too much clearance).
 
The post came from me. I always adjust the lifters with the engine hot. New engines done cold until broken in and then a hot adjust along with head retorque.
Patrick
 
Back
Top