In most of the world, a washer is just a means to evenly distribute the load when tightening a bolt. They are pretty generic. On a Porsche, there are a surprising number of washers that have unique part numbers. When elbow deep and you see this in the parts book you often say to yourself …
Cleaned out the third piece of brass bits today. Discovered that the distributor drive gear had jumped enough that the shim had come out of place and was sitting in the bottom of the case. Good that I found that. If it weren’t for dumb luck, I don’t think I would have any with this …
I suspect this will be the final installment in the trials and tribulations for this head and associated cc’ing, clearance checking, deck height measuring, and compression calculating. Not only am I exhausted from doing this four times, I think we’re at the limit of what can be accomplished with this head. Our deck height is …
Inspecting my heads today I noticed that the valves, which had been stamped long ago, no longer match the number next to the chamber the head. The machinist is telling me they are confident they’re in the right spot. Got me a little worried.
With the heads reworked a second time, I’m back to the single 1.0 mm cylinder base gasket and more measuring for deck height and compression ratio. Compression is low for this big bore kit. Deck height is high at average of 1.91. Looks like we’re back to removing the cylinders to try a different gasket …
Doing things the first time, it’s not always obvious why things are the way they are. When it comes to Porsche engines, there certainly seems a reason for everything. Case and point, the head bolts It would appear at first glance that I can use any of the head bolts in any position to secure …
After a trip through the mail, our heads returned home. They got very similar measurements of the head angles as I did. They also mentioned that my original machinist may have surfaced the head, but did not adjust for decking off the top. Which I believe would explain my issue with getting 1 – 1.5 …
I had removed the pistons from the engine, thinking my machinist might be reworking them. Having abandoned that idea, the pistons were put back on the connecting rods today. Ring gaps reset. I’m back to the single 1mm copper cylinder base gasket.
After a lot of consternation, I shipped the head off to a well known Porsche machine shop for a second machinist opinion if you will. Unlike my original machinist, they indicated they wouldn’t consider machining the pistons. They did think they could improve the head squish angle. They might get into the valve seat, but …
The results of measuring my heads, clearances, and compression has given me a lot of anxiety. In consulting with my machinist, his advice has been to use thick shims to avoid interference and run with it. Uncomfortable with some conflicting info and not knowing how to proceed, I used a metal contour gauge to try …
