Jon:... my eye was drawn to the photos of your engine. In particular the rear shows a crankcase vent tube. This was used on engines prior to 1967. ..... I'm wondering if the head may have been changed out for an earlier one at sometime.
I'm glad you guys brought that up! A friend of mine and myself were talking about that vent tube one day, trying to guess what it's for. Early British engines had a tube connecting the valve cover to one of the carburetors (without a PCV device), plus a tube that extends out of the block and down the side below the oil pan. It's cut off at an angle, that in theory would create a low pressure in the tube, helping to vent the crankcase. The vent in the back of the Alfa block just makes a mess! It had the entire bottom of the engine and transmission soaked. The car is a EURO spec, originally delivered in Germany; The cam cover hose doesn't have a PCV device. If you guys are pretty confidant that the rear vent hose can be capped off I'll do that.Thank you Jay, again thoughts and fingers not in sync. The PCV was on USA models. Having two vents is not going to harm. The rear vents to the atmosphere so you can expect amounts of engine vapor to keep the chassis underside rust protected as well as oil drips on garage floor or driveway. I would think a block off plate would help significantly.
well it's been a month since i dropped off the head at the machine shop and i still don't have a quote from them for the work they say needs to be done . i may have to drop by this week and press some flesh. anyway this question from Jay is eating my stomach lining away: I've always heard that you shouldn't do a valve job without replacing the rings too; i was just hoping that since the cylinder tops showed absolutely no wear ridge, and that it's apparent someone has been in this engine before, i could get away without replacing the rings. i did a board search this morning on the subject and of course came up with a whole spectrum of opinions. the one question i have that i couldn't find an answer to is: can the pistons simply be removed, the rings changed (and gap checked of course), and the cylinders honed without removing the sleeves and changing the seals etc? most people in previous posts go into this big long dissertation about pulling the sleeves and reinstalling the pistons through the bottom without the rods attached (until the sleeve is back in the block), at which point the rod is replaced with some hose clamp/ fishing wire trick. am i reading that wrong? is that process only for doing the rings while the engine is still in the car? sorry for all the questions... this is my first sleeved engine and it's very complicated compared to regular old cast iron engines.Even a piece of heavy-wall PVC pipe will work (with the large washer at the base). There isn't a lot of force involved.
Is markgberry not removing his pistons & liners? With the engine torn down this far, replacing the rings and re-honing the liners would be an obvious job "while he's in there". Otherwise, the fresh valve job may increase compression enough to cause oil leakage past the old rings.
On the other hand, scope creep isn't always a good thing.
You could do that, sure. After all, folks with cast-iron blocks have to hone their cylinders "in place". The only issue is that if your crankshaft is still installed, you are going to get honing debris on the rod journals and around the main bearings.can the pistons simply be removed, the rings changed (and gap checked of course), and the cylinders honed without removing the sleeves