79 T-140 leaks oil bad

[jeff becks]

just bought a 79 T-140E  It leaks oil bad from base of pushrod covers. How hard is this to repair?

[Rex]

Depends on how good or experienced as a mechanic you are.
Couple of hours work for a decent one.

[L.A.B.]

just bought a 79 T-140E  It leaks oil bad from base of pushrod covers. How hard is this to repair?

Firstly, it is important to ensure you have the correct set of pushrod tubes, bands and seals, as various changes were made to the pushrod tubes and seals over the years to try to stop leakage problems, which often results in the wrong combination of tubes and seals being fitted by an unsuspecting owner/mechanic?
A change was made to the pushrod tubes and seals around that period ('79/'80) so you certainly need to check you have all the correct seal parts to match the tubes you have?  

Secondly, getting the right amount of compression on the tube seals is important. Too much or too little seal compression (between the tappet blocks and cylinder head) and the seals will probably leak again after a short time?  

[52t-bird]

Hello,If the leak is from the exhaust tube before you do the pushrod tube oil seals check the leak is not actually coming from the tappet block.I had a 1980 T140 and replaced all the seals only for the leak to continue. It turned out late T140's had a mains pressure oil feed through the barrel base to the exhaust cam followers and this can force its way past the tappet block and leak everywhere! If the tappet block is at fault you will have to remove the barrel take out the tappet block and replace the o-ring.It may be possible to find out from your engine number if you have the pressure fed type tappet block. Hope this helps. Regards David

[L.A.B.]

It may be possible to find out from your engine number if you have the pressure fed type tappet block.

A '79 model would normally be expected to have the pressure-fed exhaust tappet block (as would all pre-EDA30000, 1982-on serial number models)