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BTW - in order to sort to half sizes, you really need to be able to measure 1/10,000 repeatedly. You also need a very high quality micrometer. Dial gauge thingies will not do. Also, an older Starrett (or other top quality brand) gauge measures more consistently than a new one. I got mine from my dad, who got it from his dad. It's the years of repeatedly turning the barrel that smooths out any variations in the threads, so it gets more consistent with time. Look for one at your local flea markets!

After getting several different measurements for each shim, you will develop a consistent touch in using your micrometer. That's what it will take to sort the shims. Also, you need the same touch in measuring the engine's gaps to choose by half-sizes. A little practice will go a long way.

Robert
 

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My kids think Subaru WRXs and Honda civics are cool. 😣
Sigh. I bet they don't even like all that noise from bare weber intakes at WOT. ;-), or the wind from a top down mussing their hair gel. Keep the windows up to hear their music don't you know.

:laugh2:

Robert
 

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While reading your experiences 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. Also a crankcase vent tube is shown on the forward cam cover. This was the proper installation on your year Spider. Alfa introduced the PCV system which vented back to the air box. I'm wondering if the head may have been changed out for an earlier one at sometime. The block number corresponds to 1600cc. I'm not sure if it makes that much of a difference. Perhaps the rear tube can be plated off and just use the PCV
Others will be able to add info.
Cheers, Jon
 

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... 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.
Jon:

I think you meant to write "I'm wondering if the block may have been changed out for an earlier one at sometime."

Or perhaps: ""I'm wondering if the cam cover may have been changed out for a later one at sometime."

My guess is that Alfa transitioned the vent from the back of the block to the cam cover sometime during the Duetto's production run. Odd that markgberry's engine would have vents at both places, but maybe engines were built that way in the transition.

Either way, I don't see any harm in having two vents.



 

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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.
Cheers, Jon
 

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Discussion Starter #112 (Edited)
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.
Cheers, Jon
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.
Regards
Mark
 

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You will have to have a crankcase vent...either the rear open vent or the front closed vent that exhaust into the intake . There are vent canister/filters available on the aftermarket that you can use. The original PCV was pretty much a brass housing with a screen. Alfa Romeo didn't used separate blocks for European and USA There is a oval blocking plate in place of the vent tube.
The upper diagram is the air box cover and PCV for USA Alfa . The lower is for European delivery Alfa.
Cheers, Jon
 

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The brass housing with a screen is actually a flame arrester.
 

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Discussion Starter #116
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.
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.
mark
 

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can the pistons simply be removed, the rings changed (and gap checked of course), and the cylinders honed without removing the sleeves
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.

My advice would be to either pull liners and hone them outside the block, or else leave things alone. As you say, if there isn't a perceptible wear ridge, the rings and liners may be fairly fresh.
 

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it would be a lot easier if you had a good compression test; that would tell you if the rings are OK.

OTOH, if you can do an engine assembly yourself, I'd just pull the engine and do a complete overhaul - rings, bearings, sleeves, new rod bolts, new crank cap nuts, etc. It really isn't that hard, and you won't have to wonder "what was done previously". Parts are not all that expensive, and your labor would be "free".

And a few long term issues - clutch disc for example, oil pump overhaul (Just send it to Gordon Raymond, a BB member and master of oil pumps and weber carbs). Check crank aluminum plugs, consider drilling the #2 and #4 bearing oil galleries as well.

Then redo the seat cushions and upholstery, and the carpets, and .....

It's always easy to get lost in the "Oh, while I'm there I'll just add...". ;-)

Robert
 
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