Captain Obvious

Here's some pics of the rack retaining straps that try to show the asymmetry I noticed. I've never ever seen any chatter about it, but it appears to me that these straps have a "front and a back"? The difference is subtle... I've included a sketch I whipped up to exaggerate and highlight the difference: The jury is still out on which way the straps should be installed, but here's what I found. I think the more gradual end goes towards the front of the car, but since I've never been in possession of a rack that hasn't been worked on in the past, I can't be sure: Thoughts from the collective?

Looking at the burrs and shiny spots on the end of the shell... Do you think they already cut down the length of a longer bushing? I also find it interesting that there's a mark on the outside diameter that reflects the location of the lube groove on the inside. I'm guessing that thing was cast bronze and the groove was cast in and not machined in?

I would try loctite red to glue wingnuts to the ends of two of the threaded rods. Makes quick and dirty "long length wing-bolts". Since they are just hand tightened, loctite red might be strong enough. If not something else like solder, braze, or weld if the loctite won't hold. Been a while since I looked at them in detail. but I think the originals are brazed. And for the receiving end, do what you had before... Stud threaded into the carbs and coupler on the other end to accept the newly created wing-bolts. Flat and rubber washers under the wingnuts. Cup washers optional.

As CanTechZ mentioned above, you need to put the air cleaner into the cover section before you slide the cover into place. The trick is that the M8 bolts that clamp everything together are "long wing bolts", not wingnuts onto a threaded shaft. That way, the bolts are not in the way when you slip the cover into place... They are kinda half hanging out of the cover portion. Slip the cover/air cleaner combination into place, and then twist the long wing bolts to hold tight. I thought someone fabricated their own version of those wing bolts? @zKars maybe? Seems like the crafty kind of thing he would do.

So what is the red megaphone thing at the rear corner of the valve cover? Remnants of an alarm system or something? I have no idea what that is:

Translation - "After she left the garage, I sat in the drivers seat, grabbed the steering wheel, and made 'vroom vroom' noises. It was fantastic."

I just took a look at a pair of (Hitachi version) SUs here, and the throttle opening cam starts to push on the throttle linkage at close to the same time the other linkage starts to move the nozzle down. So the answer seems to be... "Pretty much at the same time." Depending on where you have your nozzles set (how many turns down) and how you have the throttle opening linkage arm bent, you might get one a small amount ahead of the other, but not by much. I wasn't there when they designed it, but I suspect they were aiming at "the same time".

I looked through the FSMs a while ago and never found a complete diagram showing whole system including the tach. I whipped one up though using the 72 manual as a starting point. Doesn't show wire colors, but at least shows how things should be connected. Does this help at all? :

I found a razor knife in the cavity down under my windshield cowl panel. WOOOOO!!!!! $$$$$$$$

I'll check the next time I'm looking at a set of round tops. The amount of throttle increase is "adjustable"* but I thought the throttle increase is about the last thing that happens. Memory says (take that for what it's worth ) the nozzle has already started to drop before the idle increase kicks in. * By bending the linkage

I know you said the chain is already tight, but I'm thinking if you loosened the top of the curved (slack side) guide, it might give you enough slack to move the bottom end in and use the other hole.

That's not good. I heard about the flooding. Hope everything recedes and turns out OK. So definitely the first thing would be to check the choke cables to see if they are just too tight. And yes, I would leave a little margin there. In other words... You should be able to move the choke lever a little bit without the nozzles moving at all. I don't know if you need as much safety margin as what Patcon suggested, but if you've got the travel in the choke lever, then even that much doesn't hurt. Here's to hoping it's that simple.

Yeah, most of the linkages on the SU's are a sloppy affair. I wouldn't worry at all about the slop in the fast idle actuator, and I also wouldn't worry at all about the fact that the linkage that connects to the nozzle wiggles around a bunch. Except... When the choke is off, that linkage that connects to the nozzle should always be pulling the nozzle up tight against the underside of the carb. In other words, even though the linkage is sloppy, there should still be some spring pressure pulling that nozzle all the way up "with a snap" when you push the choke off. So, I got two quick thoughts... First thought is that you simply have the choke cables mis-adjusted and pulled to tight. If that's the case, even with the lever pushed all the way to "OFF", the nozzle will still be held down a little bit by the cable. To check that, what happens if you loosen the clamp screw onto the cable and let the lever down further? Does the nozzle come all the way back up then? If that isn't it, my second thought is that maybe one of the return springs on the choke linkage mess is not installed correctly. Take some good pics of the springs on that choke actuation linkage so we can have a look?

I'm not really digging the "bump" in the chain flow in that pic. It doesn't look smooth where the chain where it steps off the tensioner and onto the slack side guide. Could you pull the top of the slack guide out some away from the cam and then push the bottom end in a little? That might make the chain "flow" a little more smoothly from tensioner to the guide?

Haha!!!

Whatever works.

Oh, and forgot to mention... Since you're trying to create a complete path that clears out the entire engine interior, that's why the two vent connections are so far apart. If they were both on the valve cover, you would set up a little circle there. And if they were both on the block, you wouldn't clean out the head area. They put one on the head and one on the block so it pulls through the entire block. On "V" style (and opposed) engines, you can put one vent on each valve cover because they are each joined to each other through the block cavity. But on the inline engines, you need one at the bottom and one at the top.

The top and bottom are not sealed at all. There are huge holes between top and bottom at both the front (where the timing chain lives), and the rear where the valve train oil drains back down into the oil pan. Top and bottom are in no way sealed from eachother. The point of the two vents is that you are supposed to have positive crankcase ventilation (PCV) under all operating conditions. With just one vent hole (located at either top or bottom) you could vent off the blow-by, but you would not be able to completely remove the vapors from the block. By having two vents, you can set up a circulatory path and actually refresh the air inside the crankcase with fresh clean air. This enables you to do more than just vent off the excess... It allows you to evaporate off the water vapor and more thoroughly remove any corrosive blow-by gasses.

Gotcha. So he's assuming you (the purchaser) will do something appropriate with that crankcase vent and NOT leave the vapors in the block. @duffymahoney

Newer cars have MAP sensors, AFM's, TPS sensors, and O2 sensor feedback. Using all of those tools allows them pull out of one block vent through the PCV right into the intake manifold while venting the second block vent back to the air cleaner in front of the AFM. Problem is that on our early (much more crude) EFI cars, we had only one of those input sources (the AFM)*, and we have no feedback system (O2). The whole system operates on "assumption". Assumption that everything is working as designed because the ECU module has no way to know or tell if it isn't. So if you pull from one side of the AFM without balancing it with the replenishment source being pulled from the same side of the AFM, things get out of whack. And there's no feedback source of info to account for it, and no computer to learn from it. * We do have a three position TPS, but that three position switch won't do anything to help with PCV details.

When you say he provides engines without them (the block breather tube) in place... Are you saying that his engines (as delivered) just have the breather hole hanging open with no tube installed, or are you saying that he actually blocks off the hole with a plug of some sort?

I don't know what year they started putting that support bracket in, but I can tell you it was present on my 3/74 small bumper 260.

I've run into the same thing and I was planning to use the green loctite sleeve retainer. Haven't tried it yet, but I have high hopes for that. And I agree that it's weird that the original pipe was in there so firmly, but pretty much shows no retention at all when pushed back in once it was pulled out. As for the PCV and catch can thing... With the EFI, things get a little more complicated. You need to either vent everything upstream of the AFM, or vent everything downstream of the AFM. But don't mix the two. Or vent everything completely separate from the EFI system. In theory, PCV systems change direction depending on the engine RPM and load. So the whole notion of "inlet" and "outlet" is a little troubling for me. At low load (low blow-by), high intake manifold conditions, the flow goes one way. But at high load conditions when the blow-by is higher and the intake manifold vacuum is pretty much non-existent, theory says that the flow direction reverses. I guess the "normal" direction is pulled out the large pipe in the crankcase, through the PCV valve, and into the intake manifold. So if I had an "inlet" and an "outlet", I would connect the inlet to the big pipe on the crankcase and the outlet to the valve cover.

My thoughts (for what they're worth): There are those that say machining the sintered oil impregnated stuff can be problematic. Unless you do it right, you can "smear" some of the material and close off the oil holes. That said, if you're only machining the OD, then that shouldn't matter. Also, SAE 841 is softer than the traditional "bearing bronze (932 or 660 leaded)". It's probably going to be softer than the original bushing, but for the steering rack application, it's probably good enough. As for the second choice from McMaster, I like that it's made from 932, and I like the oil groove. But if you cut 20mm off, you'll be cutting right through the middle of the oil groove. Now since we're using thixotropic grease and not oil... Does it really matter? And as you mentioned... I think a lot of this will all come down to how you like the fit on the ID. Good luck with the lathe work and keep us posted!!

I haven't personally vetted the details in the below, but here's a thread in which some people actually mounted pressure sensors before and after oil filters and measured the differential pressure across filters. https://bobistheoilguy.com/forums/threads/oil-filter-pressure-differential-testing-psid.341925/ I didn't study it thoroughly, but a quick skim seems to support the theory that the delta-P over the filter media on any clean filter is very low and not enough to open the bypass valve. And that delta-P is pretty much unaffected by oil temp and only goes up as the filter becomes dirty.