Captain Obvious

For me, that Memphis ZCON was the start of faces to a screen, but it has continued since then. I've hopped into a car with a Z guy I had never met before... In the middle of traffic. And after verifying that neither of us was carrying and axe, we went on a pub crawl. I've met for pancakes in Princeton with Z people I had never met before. I've met for project show-and-tell and food north of Toronto with Z people I had never met before. In Orlando, when you've seen enough of the Great Mouse and the other tourist attractions... I've met up with Z people there. I've even been invited to a meal at the parent's house of a Z guy who used to live close to me but now lives completely at the other end of the country. When traveling on completely non-Z related events, I've made stop-offs to see some friends and make new ones. I've met for coffee (and hopefully provide a short respite from the rigors and boredom of work travel) with Z people who find themselves in the area for a layover. I'm wondering if it's just the food and drink.....

Right. I should have mentioned that. But once they have seated, things should, or at least "COULD" be good. And something else I didn't mention... When you're tightening the bolts. the torque should shoot up real quick like. You shouldn't need to use the bolts to jack the towers down onto the head. It should go from nearly zero torque to turn the bolt head to significant torque in a very small amount of rotation. That's the sign that you had every thing clean, had no burrs, have the towers aligned on the dowels and seated properly with the plastic mallet tapping. if you find that you have to use a wrench and turn the bolt a significant amount* before the torque shoots up, you should stop... Take it apart again and find out why. * More than a half turn maybe?

And one more pic just to round out the collection... I'm always mentioning that the center linkage for the round-tops is longer than the linkage for the flat tops. Here's the two side-by-side so you can see the difference(s). I tried to line up the right ends for the pic:

And just so the flat-top guys don't feel out in the cold... Here's a pair of linkages for between the two flat-top carbs. Same scenario as above. One has had the throttle opener arm removed, but the washer is still present: It looks like it was done with a hacksaw or cutting disk. Again, I (probably) did this some time ago, but don't remember the details. Whoever did it was clever enough to place the saw slit on the underside where it wouldn't be noticeable when installed. I like to think I'm that clever. Here's a pic:

I took some pics. Here's are a pair of linkages for between the two round-top carbs. (Obviously) the top one has the throttle opener pivot, and the bottom one has had it removed: Shot from the end showing the throttle opener arm: And here you can see the file marks from where the pivot was removed from the other linkage. I (think I) did this, but it's been so long that the details have faded. In any event, here's the linkage with the pivot and brazed washer mechanically removed:

First thing I would do is make sure the mating surfaces (bottoms of the towers and mounting pads on the head) are clean enough to eat off. And I would (under magnification) make sure there were no burrs or "upset" metal anywhere on any of the mating surfaces. One might wonder how burrs might get kicked up? Well in the case of the head on my car, my PO used a screwdriver between the towers and the head to pry some of the more stubborn the caps off. That screwdriver wedging caused burrs that prevented the towers from sitting properly after that. So if you (or a PO) did anything like that, you need to look into it. As for the percussive finesse... I would put all the caps in place, lightly tap them with a plastic mallet to seat them, put the bolts in and snug them up to a low torque. Maybe a third of the final torque. Then put the (well oiled) cam in place and see how it spins. If it spins free, then tighten up the towers to 2/3 spec and see how it spins. If it still spins free, tighten the towers to spec and see how it spins. If it still spins free at full torque, congrats... You're done. Let's start there and see what happens. If it DOESN"T spin free, then you need to start the percussive adjustments. But I'm going to start off hopeful and see what happens?

Cool. So are you going to drive around for a while with that attached? I still haven't looked closely at the wiring diagram to see how things are really connected. I will do that when I get a chance.

What he said. I went to ZCON Memphis as well, and during that trip a whole bunch of us jelled into a collection of good friends. More than just a bunch of people who owned similar cars, but people who honestly like each other and like spending time together. I really hope I have a vaccine in time to go to ZCON later this year. I've got people I want to see. And the cars are nice too.

I think you should google that. "Hummer" "Forum"

CanTechZ, The linkage between the two carbs on your Canadian car looks the same as the one they used for Europe. And as mentioned above, the US version is different. Not without a torch. The linkage is brazed together. Best bet (and something I have done in the past) is to remove it mechanically with saws and files. And speaking of such things... @Dadsun , I wish I had known you weren't going to run the throttle opener when I sent those other parts. I think I've got said 240 linkage piece here with that part of the linkage removed. I'll see if I can find it and snap a pic.

Interesting. I don't think we ever got that damper device in the US. We got the throttle opener system instead. And the linkages are clearly different between the two systems. I wonder which worked better.

Haha!! Actually it was an accidental hit. I was joking that maybe you were printing something more green. On your printing press in the basement.

Excellent. I noticed pretty much the same thing. Except in my case, after I replaced my wheel bearings, I could hear the diff whine.

He didn't say he was a banker. He said he was in the "world of banking and manufacturing". I'm guessing he was "manufacturing" something that went into a bank.... They demand loyalty in the printing industry, right?

But without a zip-tie, that linkage piece will still be in there flopping around and buzzing with engine RPM. Even if there is a screw in it.

Yes, like the top picture:

So it seems that I guessed right and the oversized rings came off the same fixture and were just left longer than the standard rings? Cool. That's a good piece of info right there. Might not be the case for all manufacturers, but at least the one you bought was made that way. So what brand did you buy? And glad to see the math worked out on the overlap as they came out of the box. And as for the oil ring expander... I really have a hard time believing they were making different expander ring versions for STD and .010 oversized. That wavy ring is so compressible. I'm no expert, but I bet it's the exact same ring they put in the STD set. About the only thing they could do would be to remove two complete sections so the tips aligned. You couldn't remove just one section, you'd have to remove two. If you removed two sections that it would even wrap completely around?

Seconded. Nice work. So I once went through all the gyrations to never put force through the bearing balls to put everything together. Then I discovered that I had way overgreased the cavity and had to take it apart again anyway to pull most of the grease out. And there just isn't any way to take that thing apart without putting force through the balls. In the end, I decided that they had designed it such that there was a mild press fit to get things together and it was designed such that the amount of force required to press the stub into place isn't enough to damage the bearings. So I just started doing it the way the manual says to do it. You know... The easy way.

And if you do decide to move forward with the oversized rings and get to the ring grinding portion of the show... Just remember that details are important. You want nice clean parallel edges. You want square corners but you don't want burrs or knife edges. You need to remove the burrs, but you don't want to break the corners any more than that. It sounds easy. "File or grind the tips until you get the desired gap." But execution isn't as easy as the description. Plenty of info on the web to learn from. An admission from me... I've never done it. I have a ring grinder here (thanks @240260280), but after testing and measurement, I found that my ring gaps worked out fine without grinding. So I wasn't looking forward to doing it, and thankfully, I didn't have to.

I'm imagining the L25 means he put a 260 crank in his 240 motor and then had the block sleeved to run slightly undersized pistons he had custom made.

Make sure you clean all the carbon off the valve stems and guides before you run your wiggle test. I've seen situations where the built up coating of carbon was helping take up the gap. I could definitely feel a difference between dirty and clean.

Really hard to diagnose sounds like that over video. I would expect pinging at idle to coincide with the compression cycles, and the noise I hear is an intermittent buzzy kind of thing that is not at the same interval as the compressions. If I had to guess over the internets, I would look at your driven accessories first. Water pump, alternator... That sort of stuff. In any event, glad to hear you're doing better than you were. Those old needles really looked terrible and I'm glad the SM's have helped. So have you been out on the road yet? Idling is one thing... Engine under a real load is another. What oil are you running in the dampers?

Considering how much you have to compress the rings to get them into the bore, I would guess* that compressing them .010 more wouldn't even be noticeable. How much would the expansion force change with an additional .010 compression? I mean... five thousandths more compression per side really isn't much at all. Makes me wonder... Do the ring manufacturers have different fixtures for each ring size, or are they just grinding off more of the tips for the oversized rings? Maybe at the extremes there are different castings, but each raw casting can be machined into a couple different size categories or something? That's a common manufacturing technique. Bottom line... In a pinch, I'd be willing to try the same thing you're doing. *Strictly a guess since I've never done it

I just checked the 83 manual and the torque numbers are the same. 181-239 ft-lb That said... I bet @Dave WM uses the old style nut. I think he hates change even more than I do.

As for the fitment, the only change I can come up with is that you don't need to stake those ZX nuts after installation. The prevailing torque distorted threads do that for you. As for the torque, I'm no expert, but I would just torque them to the same torque as the original spec for the Z. You would lose a tiny bit of the torque number due to the friction of the distorted threads, but I bet it's such a small percentage of the total that it wouldn't be significant. I've got a ZX manual around here somewhere. When I get a chance, I'll dig up the torque spec they used in there.