While waiting for my silicon bronze TIG rods to arrive i started pulling down the BP head.
Exhaust valves look pretty hammered and carboned up, and I think its probably been running a touch lean:
[img]http://images.plebeians.net/_data/i/upload/2019/05/02/20190502165525-a409cff9-xl.jpg[/img]
All the valves came out easily with the help of this tool:
[img]http://images.plebeians.net/_data/i/upload/2019/05/02/20190502165535-20ae16df-xl.jpg[/img]
Seriously, if you are pulling valves out of heads, get one. Its a lifesaver.
Exhaust valves were pretty gunked up:
[img]http://images.plebeians.net/_data/i/upload/2019/05/02/20190502165545-0a793d70-xl.jpg[/img]
[img]http://images.plebeians.net/_data/i/upload/2019/05/02/20190502165554-3bff63a6-xl.jpg[/img]
With a few mins on the wire wheel they cleaned up fairly ok:
[img]http://images.plebeians.net/i.php?/upload/2019/05/02/20190502165610-cf5ef668-xl.jpg[/img]
Should be good enough to use for now, and i might see if i can source another head for some 1mm OS valves and heavier springs later on.
Need to lap them back into the head, but all my lapping compound has gone hard. So that will have to wait until i can get some more.
Had some sunny-ish weather, so i got out the pressure washer and gave the head and intake a good clean. Played tunes on the intake manifold in honour of MCM:
Started lapping the valves back into the head, decent finish for now, even if it not so shiny as the original:
[img]http://images.plebeians.net/i.php?/upload/2019/05/04/20190504013157-aff5d6aa-xl.jpg[/img]
First time ive lapped valves since building 4Ks, Kents and the Mini engine.
Also noticed some pitting on cylinders 1 & 2 from a touch of low detonation:
[img]http://images.plebeians.net/_data/i/upload/2019/05/04/20190504013229-19a40345-xl.jpg[/img]
and some scratch marks which suggests that this head may have been apart before:
[img]http://images.plebeians.net/i.php?/upload/2019/05/04/20190504013247-5793d750-xl.jpg[/img]
Perhaps from cleaning with a rotary brush or something.
Debating whether to give the combustion area a clean up with a ball polisher like so:
[img]http://i45.photobucket.com/albums/f100/justinbelshe/Dadzuki/DSC02335.jpg[/img]
Still unsure on how it will work for a complex combustion area rather than the simple bowl type that I’ve used it on in the past.
Also the intake on the BP has this massive expansion chamber in the intake:
[img]http://images.plebeians.net/_data/i/upload/2019/05/04/20190504013140-a4cdc3ea-xl.jpg[/img]
Its actuated by a vacuum lever off this cam:
[img]http://images.plebeians.net/_data/i/upload/2019/05/04/20190504013148-f29cd011-xl.jpg[/img]
Debating whether i delete it entirely. Looks like it only has one exposed end where the cam comes through, and i should just be able to remove the butterflies and pull the rod out. Then i can tap a thread in the casting and seal it up that way. Will decide another time i guess.