Compression series 3 2:25 petrol

Hello chaps,

Quick question if I may. My series runs really well but the valve stem seals are on there way out so I'm thinking about putting on a turners unleaded head. Yesterday I checked compression and got 120 psi (dry) on all cylinders. The landy pulls great and runs really well less for the puff of blue smoke on start up from the leaky valve stems. I know the manual stated that compression should between 160_170psi but should I wait to change piston rings etc.

Many thanks

Rich

Richard Cook said:

Hello chaps,

Quick question if I may. My series runs really well but the valve stem seals are on there way out so I'm thinking about putting on a turners unleaded head. Yesterday I checked compression and got 120 psi (dry) on all cylinders. The landy pulls great and runs really well less for the puff of blue smoke on start up from the leaky valve stems. I know the manual stated that compression should between 160_170psi but should I wait to change piston rings etc.

Many thanks

Rich

Click to expand...

is it burning oil apart from start up or breathing heavy ,if not i wouldnt worry,

Hello James,
No it's fine when running.
Many thanks
Rich

Compresion test should be carried out with engine hot and throttle wide open.......did you do it like that ?

Yes; foot to the floor and cranked over. each cylinder was spot on 120 PSI. Im thinking the cylinder head could be causing the lack of compression also. But i'm completely open to all advice from you all.

many thanks

Gun7354 said:

Yes; foot to the floor and cranked over. each cylinder was spot on 120 PSI. Im thinking the cylinder head could be causing the lack of compression also. But i'm completely open to all advice from you all.

many thanks

Click to expand...

if its running ok and clean just do the stem seals

James many thanks for your advice,
Rich