D14 Leaky Exh Valve

[ChillyB]

#3 cylinder was dead, low compression as detected by putting thumb over plug hole. Push rod was bent and partially unseated from rocker. Exhaust valve was no longer stuck but when I put air on it there was some hissing from the muffler. I pulled the head and all looks OK. Thinking to just lap the exhaust and try again.

Also noticed some valves had seals, others did not. The #3 exhaust seal seems soft, unlike what expected (brittle, cracked, missing). Curiously, nobody sells valve seals for a D14. Should this engine even have valve seals?

 

[Nordic]

I'll tell you what gave me 100% result on one of these 149 engines. I cleaned around the top of the (installed) valve with gas (or ether) and I smeared Ultra Grey Silicone gasket sealer all around the top of the valve. The valve guides should have been replaced but this stopped all oil from running down the valve stem to make the blue puff on start up.

 

[ChillyB]

Cleaning up the head in preparation for
reassembly. Surprised how many head and
manifold bolts enter the coolant cavity
rather than a blind hole. Glad I bothered
to pull the head or I'd not have noticed
this and would have reassembled without
any sealant.

 

[Nordic]

If you want to do yourself a favour, put in new frost plugs on top of the head. I learned this the hard way when I had the head off of my B, 125 engine. Just days after putting the head back on I pulled the dipstick as I was just walking past the tractor and WHAT?? the oil was way up. Thankfully I had never started it with the anti-freeze in the bottom of the oil pan. It turned out one frost plug had a pinhole leak, hardly noticeable to the naked eye. I made up my mind right then and there, if I ever remove another A-C head, new frost plugs go in, just to be sure. They're not much more than $1 each at the auto parts store.