Captain Obvious

Yes, it totally makes sense that the date codes on front and rear halves could be different. I would expect them to be "in the same ballpark", but certainly don't have to be identical. I would also consider it completely reasonable to see some cars with a build date early in a year to have calipers with a year code from the previous year. For example, something built in Feb 1971 might have a "0" caliper on it. Something from October-December 1970 maybe?

Thanks Steve. After looking at some calipers and seeing your pics, here's my read: It seems pretty clear that the number in the center is the year. And since the right position can have both letters and numbers there are 36 choices, I'm guessing that is day of the year. Making the left position the month. Some supporting pics. This caliper came from a 78. Date code "1 8 R" : And these came from a mid-1970 build. Codes "3 0 B" and "3 0 Z" : And on my 77, I didn't pull a wheel and take a pic, but I've got a "3 7 K"

Oh, and forgot to say.... It looks like a graceful crash landing recovery so far. Glad to see that!!

Answers to some of your questions that I haven't seen answered already: 2) Yes, it's that easy. (And I'd be interested in the relatively new hoses if you're looking for them to find a new home. Send me PM if you want.) 3) Those things are supposed to hold the throttle open a tiny amount when you are decelerating hard. You probably won't notice if they are working or not. 5) In theory, nothing you are doing should have any impact on the carbs or the tuning. 6) Probably, and probably.

Got it. Here's a pic of the adjustable bushings so I don't have to keep going to the website:

If I were messing with this, I would probably try to find the centerline of the car and go from there. While I'm here, what did you use for your adjustable bushings? Got any pics?

Bummer. Here's hoping that whatever path forward you choose, it goes smoothly and that's the end of the issues.

On your first question - The old valve should operate like the new one. You should be able to blow through it towards the exhaust galley, but not in the other direction towards the air pump. Your old valve is presumably stuck shut. Second question - There should be no link between the operation of that valve and mixture. The pump is supposed to push fresh clean air into the exhaust stream downstream of the cylinder. The cylinder already fired and pushed the spent charge out on the cylinder by the point where the pumped air is injected. Anything injected into the exhaust stream at that point shouldn't affect mixture (or drivability).

Cool. I didn't think they were hardened, but had to bring it up just in case. Nice work.

Bump. Anyone ever figure this out? Anyone have the Rosetta stone for the date code on the Sumitomo calipers?

Assuming the bleed screw isn't hardened, it sounds like a reasonably simple machining operation on a lathe. And even if it isn't fully hardened through, there is the possibility that it's case hardened. And you'll most likely cut through the case when you knock the tip off. Are you sure that the threads are the same as the generic bleed screw? You said a while ago that there was a "normal" one in there, and it was loose?

Haha! It happens!

That connection point is above your left knee. It connects the output from your ignition control module to the EFI harness. If the car starts and runs at all, then that connection should be OK.

Good. Keep an eye on it. Here's to hoping the whole thing was a non-problem and just a couple chips left over from the head shave and gasket scraping.

I would back up a little and ask some questions: Are you double dog sure the oil pan was free of debris after your recent rebuild? Maybe those fragments are chips that have been in there from before the rebuild. Did you have the head cut? Maybe those fragments are chips that weren't properly cleaned off the head after that process. Are you sure the fragments are metal? Maybe chips from an old head gasket being cleaned off the block or head? Or valve cover gasket even. Some of those have a metal core. While you had the oil pan off, did you take a look at the thrust bearing on the center main? How is the oil pressure? How does the engine sound and run? Any reason to believe there's something wrong inside? I'm not yet ready to jump to the conclusion that there's anything seriously wrong.

If it's not to late... Don't pull the housing. If you have concerns about this being the issue, pull the valve cover and look down along the back side of the chain guide and see if the tip of the bolt is pushing against it. I wouldn't mess with the thermostat housing if you don't have to. They're too prone to leaks to mess with unless you really have a compelling reason to do so. And besides........ The chain guide backing plate is steel, not aluminum. If the stuff you found in the pan is non-ferrous, then it's not the metal from the chain guide.

Excellent!!

My understanding is that the reason exhaust valve seals are less of a concern is... The cavity where the valve stem passes through the exhaust port is never under vacuum like the intake port area is. It's less likely you would ever pull oil INTO that area because you just don't have the vacuum differential like the one you see on the intake side.

Here's some pics from an early 260. Maybe these will help?

Remember, he's living on an old hammer farm and apparently they grew in the field out back. The later you pick 'em, the bigger they get.

Chrome.

I suspect you're having the same "gas seems to have gotten less dense over the years" kind of level adjustment issue that has affected several owners.

Obviously. That would be reckless.

Well if you did check the oil that frequently and it really IS disappearing, that's unfortunate. I was just hoping it might have been a non-problem. A quart in 100 miles is really a lot of oil. At that rate, I would have expected you to crop dust a mosquito fogging blue cloud behind you. Especially without a catalytic converter.