Captain Obvious

So here's a question for today. If you look closely at this water jacket hole... Up by the timing chain and cylinder one, on the left side of the engine. It's threaded. The paper towel wad is stuffed into the head bolt hole, and the other hole just goes down into the water jacket. There's a corresponding hole in the gasket and the head. but question is... Why is it threaded? : I tried to measure the thread size and didn't come up with anything standard. It's a very loose fit on M10-1.5, but it's not big enough to be M12. So it's either a badly corroded out M10, or it's something unusual. Any ideas?

Yeah, I was planning to measure the projection once I got further along with the head reassembly. Based on the valve lift number you posted from the FSM, it's close either way. But with a closed clearance of approx. .380, I guess it's easier to believe that all my valves stopped in a position where there was no collision. Still thinking about that five mile drive home with only half the cam spinning!!

LOL. Well we have both been under your dash, so yes... We're even. Thanks again for checking so I didn't have to!

Yup!! There it is! Thanks much for the confirmation! So what you're saying is that I've got people who do that for me? Haha!!!

I also took some quick and dirty measurements on the distances between pistons and valves... The valves, when closed, are about .185 below the head bottom surface: And the dish depth on the pistons are about .115. Don't have a pic of that measurement, but it was like this with the caliper in the center of the piston: So... The bottom line is there is about .300 clearance plus the head gasket thickness between a closed valve and piston when the piston is at TDC. That distance may have saved me a whole lot of crunching. Also, assuming that valve opening distance is greater than .380-ish, I believe this confirms that the stock motor IS an interference design?

So I've started addressing the block. Cleaning things up in preparation for the head reinstall. I've got a hodge-podge of pistons in there. I've got four of these: One of these: And at cylinder #1, I've got one of these: No real surprises there, I guess. I know my PO had been in there, so I was kinda expecting some stuff like that. I did notice that the cylinder 1 marked "STD" does stick up out of the block by about fifteen thousandths at TDC, but the one marked 34 at position 6 sits flush. So I've got some mismatching on compressed volume there, but not enough that I'm going to do anything about it right now. I can't rotate the engine right now because I've got the timing chain wedged, but I suspect all of the pistons except the "STD" one do not protrude above the block deck at TDC. So anyone see anything "project stopping horribly wrong" with that combination of pistons? Is there any rhyme or reason to the "34" or "45" markings?

Well with the valves lapped into place, I know both the valve faces and the seats are consistent now. So even if the valves rotate, they should be fine. In fact, some cars, they try to rotate the valves on purpose. Is that not the case on the Z?

So what is it about those jets that makes them so magnificent? I've not looked into them at all.

My guess would be a bracket that helps hold the passenger side finisher panel in place right above the passengers knees. Bolts to the bottom lip of the dash right below the glove box and the plastic finisher panel clips into it. That finisher panel is then screwed into place with a screw on each end for the final lock. I did not crawl inside my car to verify...

I'm waiting for new ones to arrive. I ordered new dowels for the head to the block, and also a complete set for all the cam towers. Under closer scrutiny, my cam tower alignment dowels were pretty badly abused. Even the ones that I thought were OK (because they fit into the holes) only fit because my PO had already filed off the pliers he used to man-handle them out of position. Forget it.... I ordered all ten. And I figured that since I was already paying for shipping, I got two new dowels for the block. The status of the head at this point is all the valves are in. All the seats are clean and the valves all seal. All the springs are oriented the correct way. Didn't forget any of the hardened washers. Didn't forget any of the valve stem seals. The valve cover holes that I plugged with the aluminum inserts have been drilled and tapped. The head is sitting on the bench in a holding pattern now waiting for the tower dowels to arrive. Once they get here, I can put the towers on and get the cam installed. About the only new item of interest is that I found burrs kicked up on the inside corners of a couple of the valve retainer wedges. The tips of the burrs were shiny with the implication being that the burrs were contacting the valve stem at the bottom of the locking groove that the retainers lock into. So... Basically, some of the valve retainers were not seating in that groove completely because the burrs were in the way. The burrs look like they were caused when the retainers were forcibly pushed into place when the valve spring really wasn't compressed enough. Hit the retainer on the hilt with a hammer and screwdriver and it'll snap into the groove. But it may take a corner out on the way! With my valve contraption, I was able to compress the spring to the point where the retainers fell into place. No forcing required. I look back at some unexplained weird engine behavior over the past couple years and I think it's all coming together. Things like... I set the valves. Then check them again in a couple hundred miles and they're off far enough that I readjust. Then check again in a couple hundred more and they're off the other way. I think stuff like the cam towers not being seated properly and burrs on the retainer wedges are the reason for the instability. And since some of the head bolts go through the cam towers, it couldn't have been doing good things for my head bolt clamping pressure either. Which probably explains my slow minor coolant loss. I think it's all related.

OK, so here's the plan then... I'm hoping that I'm doing such a thorough job with the head that it'll never ever ever have to be pulled off that block again. The threads in the block should be able to hold one more torqueing! I've sorted through my head bolts. Four of the originals were rusty and didn't make the cut. I've substituted four others from the spares group into the batch that I will re-use. Thanks for the input guys.

Fantastic!

Send me a print and we'll talk.

Thanks for the input guys. I haven't figured out what I'm going to do with a head gasket yet, but I'm looking into it. I've got two of the later ZX gaskets on order and I may end up using one of those, but haven't finished the investigation yet. Todays question.... Would I be completely shunned from the collective if I re-used head bolts? I've got three sets of used bolts here and I'm sure I can put together one set that looks great from the three sets that I have. What say ye? I'm planning to cut the heads off a couple of the old rusty long ones to use as guide pins to get the head lined up easier during the re-install procedure, but even with that, I've got enough remaining to make a good looking set.

So today's question... Back to the head gasket. The original head gasket for my 77 listed on the parts fishe is 11044-N4200. I believe I have traced the superseding history as shown below: 11044-N4200 - 09/1974 - 04/1980 11044-N4210 - 05/1980 - 02/1981 11044-N4220 - 05/1980 - 02/1981 (don't know why there are two of them. Might be turbo) 11044-N4221 - Supersedes all of the above Then when they went to the F54 block, they changed the head gasket: 11044-P7900 - 80-82 GL (turbo) 11044-P7910 - 81-83 GL and non GL (everything 83 turbo and non turbo) 11044-P7911 - Supersedes all of the above And I believe the latest part number for the F54 gasket is 11044-P9600 So the question is... Can I used the same head gasket that was intended for the F54 block on my N42 block instead?

Thanks Dave! I think that's just how mine behave. Maybe just a tiny bit looser. I think my new ones behave like the original OE seal you started with. But they are clearly gripping the stem. And BTW... I did a little measuring of some valve stems, and they are purposely ground a thousandth or so smaller up at the top end where the retainers install. Maybe the first half inch or so along their length? That would be why your valves drop easier once you get them to that point. The stem is actually a little smaller at that point along their length. So it makes perfect sense that as you push the valve down through the seal, you'll reach a point where you get to that narrower part of the stem and it won't grip as tight.

Thanks guys. I did a few more valves, and I think I've got a non-problem. There is significant interference between the seal and the valve stem, but the stem is so smooth and with a little Mobil-1 on there, the seal just can't get a grip. jonathanrussell, what I have here behaves exactly as you described. I messed around a little bit with a valve and seal loose from the head, and I think it's OK. The seal is scraping the stem, but with the oil on there, it's really slippy. I'm moving ahead. Thanks again guys!

Yeah, that's what first struck me as odd. The brand new ones didn't feel any tighter than the old ones I pulled out. OK... So probably a little step backwards today. Just when I thought I had a day of nothing but progress!

Crap. Well maybe I'll check one more valve to see if it's my imagination. If it's not imagination, I guess I'll stop with the reassembly and get a different brand of seals on order. Dave, Checking the ID of the seal is pretty much impossible since it's bendable rubber. Can't get an accurate measurement. IMHO, the best way would be to place them on a gradually tapered dowel rod and see where they stop and then measure the diameter of the rod there. I don't think a direct measurement with calipers or something like that would work. And yes, I used a little drop of motor oil on the seals.

Well you know that if you don't find the root cause, it will absolutely happen again. Intermittent problems suck. Did you replace all the electrical connectors in the engine compartment? If the connector to the EFI temperature sensor isn't making great connection, it'll run very rich.

LOL. So today I officially turned a corner and started on the reassembly. Here's the first two valves back in the head. Woot!! : Everything went great. But this process does bring up a question for today... I'm using the Sealer Power valve seals. ST-2034: The seals went on great using the little condom that came in the box, but after installation, they don't seam very tight against the valve stem. I'm no engine rebuild expert, but in my limited experience the other valve seals I've messed with on other cars seemed to have a tighter grip on the valve stem. Anyone have any input about this? Just for a point of reference... The weight of the valve itself is enough to pull the valve down even with the seal installed. My previous experience with other seals is that the grip of the seal on the stem would keep the valve in place against gravity. Of course, it would slide if you pushed it, but gravity alone wasn't enough. Have I got an old dead box of seals, or is that normal?

Yeah man. Never seize.

Nice. It's already running well enough to get to Nashville? You've got a year to finish the tune!!

Would it be easier to tack weld an 1/8 inch spacer to the head flange where the washer makes contact? You running carbs or EFI? How thick is your intake manifold flange?

Clogged filter somewhere? Do you still have a fuel pressure gauge installed? Oh, and if Dave is right and you ran it out of gas, you shouldn't ever tell us that. You should make up some story about how your fuel filter clogged with sediment from the bad gas you got last time because they were filling the tanks at the station while you were putting gas in your gas can. Yadda, yadda, yadda, Or something like that.