August 9, 2009
Got the Cylinder head finished & ready to mount
Head was basically intact, but dirty, and some rust on the ferrous parts. Chambers were carboned up. Seats were a bit recessed, but no signs of cracks.
Springs were out of spec. Left picture shows one compared to a new spring. Valve stems showed wear on the tips, which would make it hard to get good rocker clearance setting. The tips can be ground flat, but the stems also miked almost 0.005 under spec in some places. I decided that all new valves, springs, and guides were necessary.
It's best to heat up the head before driving guides out. It makes them come out a lot easier, plus you don't drag out as much of the soft aluminum. I heated it with a propane torch to about 200 degF as measured with a non-contact thermometer.
The tool on the right fits into the bottom of the guide while a deep-well socket on the press ram pushed the head down.
Old parts on the left, new on the right. Cleaned up the intake and exhaust ports while the guides were out. I was able to open up the ports quite a bit in places, too.
Pressing in the new guides. Again, heat the head but also freeze the guides and they'll go in pretty easily. The head is bolted to the plywood fixture which holds the head at an angle such that the guides are vertical. The little cleat on the front edge of the bottom of the fixture is a boo-boo fix. I was under the impression that the angle between the valves was 90 degrees. It's not. The cleat tilts the fixture back about 6 more degrees.
Flat surfaces seal better, so I wanted to make sure that not only the head gasket surface, but also the rocker box seating surfaces were flat.
I used a process the Brits call "linishing", and we Americans call "rubbing on a flat, abrasive-covered surface". The surface is that of a granite surface plate with 220-grit wet/dry paper glued to it. I used WD-40 as a lubricant, but about anything works, even water.
I put some machinist's layout bluing on the surface to gage the progress.
Ditto for the flip side.
I sent the head out to have the seats cut to shape and to be concentric with the new guides, then lapped the new valves to the seats. Did a cosmetic clean up the surfaces that show, then installed the valves. This puppy is ready to install on the engine.
Had an extra picture...
Questions or comments: elhollin1@yahoo.com