Namerow

Carburetors have their charm, but after reading through this Nissan, 'how-to-make-it-run-sort-of-ok' document, it's easy to see why the industry embraced electronically-controlled fuel injection when it was finally ready for prime time. Of course, if there were no emissions control requirements and no CAFE rules and we all lived in San Diego, carburetors would probably still rule.

At this point, I believe that the key questions to be resolved are: Is there are retired cooling system engineer in the audience? Was the Manifold Thermostat actually installed on pre-72 Z's? (no speculation - we need a clear picture of the engine compartment of a guaranteed-original 70 or 71) If the Manifold Thermostat is removed to make the manifold heat circuit operate full-time, what are the coolant flow characteristics through this circuit (i.e. hi v. lo vs. no volume; front-to-rear vs. rear-to-front flow direction)... - under cold-engine conditions? - under hot-engine operating conditions? For Z's equipped with the Manifold Thermostat, does removing this thermostat (assuming that it's suspect) cause negative issues somewhere else in the cooling system?

The Manifold heat thermostat functions so that it's open when the engine is cold and closed when the engine is warmed up. If your Manifold thermostat is stuck (mine was), it's almost certainly going to be stuck in the 'open' position, which means two things: Your manifolds and carbs are probably being treated to heated coolant all the time (including when you're sitting at stop lights in 33-degree weather with a hot engine) Removing the Manifold thermostat from the circuit won't make any difference, because the thermostat was already stuck in the 'open' position. Removing the Manifold thermostat from the circuit and then blocking the circuit with a plug may not be a good solution either. There are concerns (although not confirmed) that this might create undesirable side-effects in the operation of the regular sections of the engine cooling system. I suggest that you remove the Manifold thermostat and check it to see if it is, indeed, stuck 'open'. Use the test procedure from the FSM (see my other thread for details). If this test shows that your Manifold thermostat is stuck in the 'open' position, you can probably get it working again by soaking it overnight in a jar of 'C-L-R' (chemical used for 'de-liming' electric kettles and other home appliances). You can also try carefully heating it (actually, over-heating it) with a small butane torch to see if you can get it to close. Again, see my other thread for more details.

@ Zed Head and Stanley... You're right, I'm wrong. I was tricked by a my too-quick look at a different coolant diagram that appears right at the beginning of the '72 FSM's Cooling System section (see Fig. CO-1, below). While re-visiting my notes, I found a nice flow diagram (copyright credit to Bill Wilhelm) that Blue posted some time ago - also re-posted below. It provides some additional insights. All in all, though, Fig. EC-23, is certainly the definitive one when it comes to figuring out how the Manifold Heating circuit works. Specifically, until the main (rad) thermostat opens, the Manifold warming circuit is active. Coolant enters and exits the main thermostat through the base of the main thermostat's housing. Intersting that Fig. EC-23 was included in the Emission Control section rather than the Cooling or Fuel sections. Maybe the tech writers at Nissan just treated the Emission Controls section of the FSM as the dumping ground for, 'little gizmos that nobody understands'. I think the point still stands that if the Manifold Thermostat is stuck open (or removed), then the manifolds and carbs are going to be seeing some degree of heating even after the engine has reached normal operating temperature. That is, unless pressure differentials change when the main (rad) thermostat opens, so that the flow through the manifold heating circuit is reduced or stopped. The only way to tell would be try a different version of Stanley's aborted experiment by replacing the rear transfer pipe with some kind of clear tubing. @ CanTechZ... I have two rear transfer pipes (Item #26 in the parts diagram). One is known to be from my old, one-owner '72 Z. The other I recently pulled off my current '70 Z. They're identical (although the '70 has gone through several hands, so I can't guarantee that all the parts are original). I take your point, though, about how the diagram implies that the Manifold Thermostat (Item 38) is a substitute for a plain Connector (Item 20). I wonder if the early design for the manifold heating circuit tried to get by without using a thermostat (see my comments re system pressure differential, above), only to experience some kind of unforeseen problems that made it necessary to add the t-stat ($). I certainly agree with the comment that auto manufacturers resist adding anything that they can't charge premium money for... like, say, racing stripes, alloy wheels, sunroofs, chrome side trim strips, rear hatch louvres, etc. Oh, sorry -- it was the dealers who added those, wasn't it.

Great photo, zCars. Now we have a full understanding of what lurks inside the little cylinder. Not sure if I'd be willing to try that if I only had one thermostat at my disposal. Some further thoughts, and then I'm going to return to my plating project . 1. I did not, unfortunately, use the 'scientific method' when I was fooling around with my thermostat this morning, so I can't really say for certain that re-setting the adjustment screw was what solved the problem. Other possibilities: The heat from my butane torch might have 'excited' the wax in the actuator pellet much more than dousing it in boiling water, to the extent that expanded with enough force to break the output shaft (the one with the 'foot valve' and e-clip on the end) free of whatever crud was making it bind. All I can say is that the main housing was too hot to hold after I got done with my de-soldering exercise. Tapping on the end of that shaft with my pin punch might have also contributed to breaking it free. There may never have been a problem with my thermostat in the first place. Yesterday, I had it immersed in only about 2 cups of boiling water. That may not have been a big enough heat sink. Today, I switched to a big pot of boiling water on top of the stove. The valve was closed tight in about 30 seconds or so. Steel cap on aluminum housing. That sounds like a recipe for disaster in a cooling system component. My unit is aluminum cap / aluminum casing. To CanTechZ's point, I'm not so sure that it wasn't on the Series 1. The wording in the 72 FSM is a little cryptic, in my opinion. Also, the Parts Manual doesn't show any start date for this part -- just an end date. That implies that the manifold thermostat was part of the design from the get-go. Given that the thermostat operates in 'closed' condition under normal engine operating temps, its absence in this secondary coolant path would lead to manifold heating under hot engine temps. That seems wrong. The no-thermostat solution to this would be to block off the circuit -- which would beg the question of why the circuit is there in the first place. Do you see it otherwise? Maybe Carl Beck or 27th can comment. 2. It occurs to me that the thermostat's adjustment screw may not be so much for ensuring that the valve closes fully, but rather, how much time it takes for the valve to close. Of course, it may affect both. zCars' new photo shows about 3/16" of exposed thread on the stem of the adjustment screw. Mine started off with about 1/8" of exposed thread, so comparable. My car was made for the USA/Canada market and I suspect zCar's was too. More exposed thread on the adjustment screw implies longer travel (valve starts off further away from its seat), thus longer time before the valve meets the seat. Makes sense for moderate-to-cold climates. I wonder if Nissan dealerships in tropical climates got a field service bulletin suggesting that they trim the valve for less travel/faster close? (jalex, are you listening?). If so, I've now got mine adjusted for 'tropical' conditions. Maybe I need to try the boiling water test again, with the screw set back to where it was in the first place! ... (pause) Yep. Confirmed. I went back to the shop and backed the screw out about an 1/8" and then put the torch on it like previously to get things 'warm'. Valve closes nicely. Conclusion: It now looks like the the C-L-R dip followed by the combination of thermal shock (torch) and impact (hammer and punch) is what did the trick. Turning the adjustment screw in and out might have helped, but I can't say for sure. I'm leaving my adjustment screw back at the 'factory' setting. I'll put a single wrap of teflon pipe-thread tape on the housing/cap threads, tighten things down, and then declare it, 'Job done'. Small part. Long story!

Re Zup's last post: Thanks for the link to the HybridZ posting. The possibility of water pump cavitation might support my fears that this silly little valve is more important than it may seem at first glance. Not sure if the cavitation issue has ever been verified in actual practice, but it seems plausible. Anyway, I hope that my discoveries over the last 24 hours will provide a new option for Z owners who don't have their valve installed but still have it tucked away in their spares bin. Maybe zCars will have his two about-to-be-restored manifold thermostats up for sale on eBay soon!

Hah! Gentlemen, we have closure! My manifold heat thermostat now performs perfectly. Here's what I did (after the four-hour soak in C-L-R, of course): The little adjustment screw and locknut that appeared to be seized together forever were, in fact, soldered together. If you look closely at my #3 photo above, you'll see what appears to be a shiny-silver, crowned nut. It was only when I put my micro-torch to it and saw things starting to melt that I realized the truth. I broke the nut free from the (brass/copper) top plate first using a 4mm box-end wrench and then backed it off about one full turn. Then I tackled breaking the adjustment screw free from the lock nut. I rigged things up in my bench wise so that both thermostat housing and box-end wrench were anchored and could turn and so that the wrench couldn't lift off the nut when I tried to turn the screw (sorry, no pix -- not enough hands). That left one hand free for the torch and the other for the screwdriver. You need to find a screwdriver whose blade fits tightly in the slot on the end of the adjustment screw. Otherwise, you'll round out the slot and it'll be 'game over'. Heat with the torch until the solder melts enough for the screw to turn within the nut. Then turn the screw in until you use up the available adjustment. Now, put the torch way and turn the re-locked screw-and-nut with the box-end wrench until the nut snugs up against the housing's top plate. With a small-dia. pin punch, push Item #6 ('Supporting Plate') down against its spring a few times, just to make sure it's moving freely. Now test in a big pot of boiling water, using the test method mapped out in the FSM (see Zed Head's posting, above). Do NOT accidentally suck boiling water up the hose into your mouth! Assuming that your 'hot' test is successful, now dunk the assembly in cold water and verify that the valve re-opens. Re-solder the screw/locknut pait to each other and to the housing's top plate. Have a beer to celebrate your now-ready-for-action, 40-year-old, NLA-anywhere, 'Manifold Heating Thermostat / Switch' ! p.s. I am now taking orders in my new retirement business of fixing Nissan manifold heat control valves. May I take your order, please? WARNING: This is a fiddly little job. If you lack patience or have had a couple of beers to get prepared, you will likely end up with: 1) a broken valve, 2) burned fingers, 3) scald marks, 4) all of these. Also: Don't forget to do the boiling water test before you start. No point wasting time on a job that doesn't need doing.

More... OK, I think I've figured out how the adjuster works. I now see that there are two springs inside the assembly. The inner one (small diameter) serves the obvious function of resisting the valve shaft's motion relative to the pellet. The outer spring (large diameter) sits just inside the bore of the housing and supports Item 6 ('Supporting Case'). The pellet and attached shaft with valve are mounted to Item 6 (hence the name, Supporting Case). When the adjusting screw is turned, it moves Item 6 down towards the valve seat, thereby reducing the pellet and valve closer to the valve seat. Looking down into the main housing through the 'outlet' port, I can now make out the actual valve. It looks like it's sitting about 3/16" - 1/4" off the seat. That seems like a long way, so maybe turning in the adjuster screw would help achieve full seating of the valve (I've got about 1/8" of adjuster thread length available). Time to get out the micro-torch and my miniature socket wrench set! p.s. re Zup's photos and notes, that '73 valve looks like it's identical to the '72 unit that I've got. The PO just unscrewed the top cap and inserted a 90-degree pipe elbow between the two parts. The thread used on the manifold thermostat's main housing and cap is not a pipe thread (instead, it looks like a fine thread of ~ 19mm dia), so who knows how that pipe fitting was attached (hard to believe that the PO invested in a 19mm tap-and-die set). I bet there's a lot of pipe-sealing compound in there!

Update - Sunday AM Well, I'm afraid that the C-L-R 'de-liming' didn't work . I soaked the T-stat main assembly for about 4 hours. The bubbling action was strong and constant... so much so that it began to occur to me that the stuff might be dissolving something other than just mineral deposits (like brass, maybe). Anyway, I pulled the valve out of the C-L-R and repeated the 'blow test' (per the FSM-recommended procedure). Used boiling water fresh from the kettle (showed as 195 degrees F, although immersing the valve probably dropped it to 180 - 185). I sucked up the water into the valve -- to ensure that the pellet was actually seeing the hot water -- and then waited for over three minutes to see if the valve would close. No joy. After this, I removed the hose that I'd connected to the valve and then clamped the valve housing in my bench vise so that the outlet port (i.e. hose end) was facing up. With my inspection light, I could clearly see the tip of the tip of the pellet shaft, c/w the little E-clip on the end. Using a small pin punch, I tried lightly tapping on the end of the shaft to see if it would show signs of movement. Nothing. Then I tried pushing down as hard as I could on the pin punch to see if I could move the shaft back against the internal spring. Still nothing. So I'm at an impasse here. Non-functioning part that's locked in the undesirable position (i.e. always open, meaning that hot coolant will always be flowing through the intake manifold passages, even when the engine is up to temperature). Don't know if it's seized, out of adjustment, dead, or all three. As you can see from the third picture, the little lock nut and adjuster stem are tiny and both appear to be made of brass (i.e. fragile). They also look like they're firmly attached to one another, so I'm reluctant to put a wrench on the nut to see if it will turn. I'm even more reluctant to put a screwdriver in that itty-bitty slot to see if the 'adjuster' will turn. Also, I'm not even sure how the adjustment works (I think that turning the screw may just move the whole pellet/shaft/valve downwards towards the valve seat). I suppose that I could heat the assembly carefully with a butane micro-torch (that would certainly get the actuator pellet's attention!), although I'm worried that I might weaken or destroy the valve (presumably made of neoprene) in the process. (sigh) It's an interesting state of affairs. Putting the valve on the engine in it's current state will be no better than just leaving it off -- and either of these approaches is non-desirable, because -- as note previously -- the result is hot coolant flowing through the intake manifold all the time. If I simply block off the valve or its connector hose, it would seem to be a recipe for crud building up inside this part of the coolant circuit (and maybe even trapped air that could get into the main circuit and cause problems somewhere else). I wonder if there's another car of similar vintage that used an inline coolant control valve like this? If so, there might be an alternative solution. If I knew that there was another part out there that I could conveniently purchase, I'd pry my Nissan valve apart to see exactly where the problem is. Suggestions, anyone?

Chris: PM sent

Very cool. Thanks, guys. An update from my end: The labelling for Fig. EC-20 is, indeed, reversed re Items 7 & 8. The 'case cover' is simply threaded onto the main casing, so it's easy to get off (big hex-nut fitting). After the cover is off, though, there's a brass cap (from which a central shaft with the adjusting nut protrudes) that looks like it's a press-fit into the main casing... so I'm probably never going to get to inspect the innards without destroying something. I've got my thermostat soaking in CLR now. There was a lot of 'action' right off the bat, so my suspicion about mineral build-up might be correct. We'll have to wait to see, though, whether it frees up the workings. Interesting that the designers decided to add an adjustment facility for such a simple device. That may explain, too, why there's a threaded cover rather than just making the device completely sealed. Maybe they knew something we don't ! Don't know if anyone else spotted this, but the intended flow direction for the coolant is the reverse of what I would have expected. According to the FSM diagram (unless this is another labeling error), when the T-valve is open, the coolant is flowing out of the rear bypass tube, through the T-valve, then into the manifolds, and finally exiting into the main thermostat casing at the front of the engine. I always thought the flow direction was the opposite (i.e. from front to back, and then around the rear of the engine into the Y-fitting). I guess I'll have to go back and look at those coolant flow diagrams that someone came up with in the midst of that long debate over whether or not it's safe to bypass the cabin heat coolant circuit. I'll report back tomorrow on whether or not the CLR soak worked.

I have one (1) 'Intake Manifold Thermostat' in my parts bin (PN 14100-E8850). As you probably know, this valve is NLA from Nissan and appears to be NLA from all the Z specialty suppliers too. Its job is to control the flow of coolant through the intake manifold heating cavities (which also duct out to the carb bodies for 1972-73 models). I expect that it's arranged to work the opposite of the regular coolant thermostat: i.e. it operates open when cold, then closes off flow once the coolant heats up). According to the Parts Manual, they were fitted to the Z engines right up until July 1973. I want to fit my parts bin unit to my '70 (which arrived with the manifold thermostat missing), but only if it's working properly. I just tried a dunk test in boiling water and it wouldn't close, so I assume that it's jammed in the neutral/open position because of the usual chalky crud that can build up in a poorly-maintained cooling system (my unit hasn't been installed in an operating vehicle since 1980, so it hasn't been 'exercised' for a l-o-o-n-g time) Does anyone have any experience with fixing these little thermostatic valves? I can't find any mention of it in either the Z FSM or the L24 Engine FSM -- not even a note on a diagram to indicate that it even exists. Q1: I'm thinking of soaking it in CLR, on the assumption that it's mineral deposits from tap water that are causing the problem. Has anyone tried this? Q2: What's the correct temp. at which it should start to close? And how long should it take for it to cycle from fully open to fully closed? Q3: Do I have the operating logic correct? (i.e. normally open, then closed when hot). Is it designed to fully close, or just partially close? Q4: There's a tiny phillips-head screw with an equally tiny lock nut on the tip of the internal centre shaft. Has anyone tried to take one apart to assist in cleaning up the moving parts? Q5: Does anyone know of a source for these (either NOS or used)? Any guidance welcomed.

Hi Chris: Just thinking out loud here... Eyeballing it, I see fab based on welding it up from five separate pieces: left, centre, right, full-width apron, and the little reinforcement gusset between the apron and the 'left' piece. Creating the curved flange on the 'left' piece looks like the biggest challenge, but one of those Eastwood shrinker/stretcher tools would get it done. With cutting, forming and welding, it looks like maybe 5 - 10 hours of work. Let's be optimistic and call it 5 hours and value your time at, say, US$50/hr (includes shop overhead cost), so that's $250. Add in materials and consumables at another $50 and you're now sitting at $300 per piece. Add a profit margin, too, so it looks like an 'advertised price' of $350 would be about right. Forget about stamping this from one piece -- there are some pretty big draws involved here. At this point in time re access to large-scale 3D printing equipment, I'd say forget about that, too. Nevertheless, I'll check with my university contacts later this month to get a second opinion. It's a fast-developing technology and you never know what lies around the corner.

"Everything is original including the pain." I like that.

IIRC, the Reverse Switch is an 'interruptor' type and doesn't care about the quality of its local 'ground'. The switch is normally 'open'. When you engage Reverse, the switch contacts close so that power can flow through the switch and back to the main harness. The switch has a rubber dustboot to protect the 'in' and 'out' terminals from water and crud. On the units I've looked at, the boot had perished and the terminals were pretty dirty. I'd look at that first. The dustboot may be destined for the trash bin. Clean up the contacts and the wire-end terminals, re-install, and then figure out some way to seals things off. Alternatively, just buy a new switch (which may come with a brand-new rubber dustboot). I don't think you're going to find much difference from one switch manufacturer to another, but I would suggest you pick a known brand just to be safe.

Eastwood Internal Frame Coating http://www.eastwood.com/internal-frame-coating-w-spray-nozzle.html Tough phenolic resin penetrates, converts and encapsulates the rust on the internal surface Zinc phosphate seals it to prevent future corrosion 24"-long tube with conical nozzle reaches in to spray coating in a radial pattern for complete coverage Aerosol covers 10 sq. ft., qt. covers 50 sq. ft. Fully cures in 24 hours US $18.00 per can. For your small-ish job, one can should be enough. The features of this product that make it attractive are: 1. Zinc phosphate content helps to neutralize whatever rust might already be there, while the resin base seals off the surfaces from exposure to air and water 2. The applicator is a long, skinny tube with a special, multi-directional spray tip on the end -- perfect for what you want to do. I found that the tube had an undesirable curvature that made the tip scrape against one wall of the structure, so I heated it with my heat gun and then flat-rolled on my workbench using a spare piece of flat 1é2`plywood. The tube straightened out very nicely and held its new shape. 3. Cures to a dry surface (unlike wax-type cavity sealers), so won't trap dirt Practice the application first, so that you can execute an nice steady 'pull' for even, run-free coverage. Be careful not to snag the tip of the spray wand on a lip inside the A-pillar, since you will then be holding a 'live' spray can, pointed at your pretty yellow paint. In face, some judicious masking around the top of the A-pillar might be a good idea for just this reason. I wish my Z looked as nice as yours. Keep us posted on your build.

I like your theory, Zed Head. The outermost studs, at 8mm, are probably just a bit too small to withstand the bending cycles. The factory's field fix (re-tap for a 9mm stud) suggests that they were thinking along these lines too (note that the 9mm replacement stud would have reduced the longitudinal clearance for the stud within the manifold mounting hole -- which suggests that it's not an issue of actual stud/manifold contact). This kind of fatigue failure is based on number of cycles (assuming that the bending load falls slightly short of causing instant fracture), so a lot of L24's may have the original front and rear studs still intact but well on their way. It may be that the rear stud is found sheared off more frequently than the front one because the rear stud also mounts not only the engine slinger plate but also the coolant rear transfer pipe. It's the latter item that probably got messed with the most (during attempts to replace perished coolant hoses), leading to the 'uh-oh' moment when just a bit of wrench force on the nut snaps off the already-weakened stud. Interesting that Nissan never up-sized these studs from 8mm to 9mm over the full 240-260-280 production series. Maybe the engines had to get up over the typical ownership period (say, 60 to 70 thousand miles) before the studs saw enough thermal-load cycles to start breaking off.

Thanks, guys. Some very useful thoughts (and reminders) have surfaced here. I agree (sigh) that the manifolds are going to need to come off. Bore scope or not, trying to accurately mark and center-punch the top of a sheared-off, rusty 8mm stud that's sitting at the bottom of a .5" x .5" hole sounds like a high-odds proposition. And I'm still not sure how one would align the drill so as to end up with a pilot hole that runs true down the centre of that itty-bitty stud. The left-hand drill bit technique sounds tempting, but not tempting enough. The root issue here is galvanic corrosion between the threaded surfaces of a steel stud and an aluminum head. I'm not convinced that drill-generated heat and bite is going to be enough to overcome that -- although I'm intrigued by the notion that the resulting hole might relieve the 'pressure' between the stud threads and the head. I think I'll experiment with another alloy casting I've got lying around that also has a snapped-off stud. Note that I've never had the engine running since I bought the car, so I don't know whether there's observable leakage at the back of the manifold or not. A small voice in my head says, 'Listen to Sweatybetty' and just leave it alone. But then Zed Head's came along and spoiled that with his comments about potential damage to the head. I've looked at a number of Youtube videos that deal with removing broken studs. My sense is that the weld-a-nut-to-the-top-of-the-stud strategy is the right one. The views of the localized heat generated in the stud by the MIG is pretty compelling... According to the video narrator, the technique becomes a little more challenging when the stud size gets down in the range of 1/4" dia. -- which, of course, is exactly what I'm dealing with on the Z. I suppose that if the welded-nut approach doesn't work, it should still be possible to use the drill-out strategy as a fallback. The extreme heat cycles created by the MIG would certainly assist chances for success with the reverse-drill. BTW, the Nissan-sanctioned explanation that the end studs break off because the manifold expands as it gets up to operating temperature is interesting. The hole in the manifold flange for the stud measures 0.56 diameter, while the max diameter of the 8mm stud is 0.33" (8.34mm). If the hole is centred over the stud when the manifold is dropped in place (maybe a bad assumption), that would allow about 0.1" of radial clearance before wall of the manifold hole comes into contact with stud. That suggests that the exhaust manifold must be expanding lengthwise to the tune of 0.08" - 0.12" at each end (or by up to 0.24" from front to rear!). That seems hard to believe. Maybe it's more a question of manifold fore-aft misalignment during assembly?

If you are able to resist the voices... This one looks like it has a mix of Series 1 and Series 2 features. If it's got the chrome 'button' style coat hooks on the B pillars, I'd like those. If you need anything from a 72, I have a small store of spare parts that might produce the basis for a parts swap. Don't forget to check to see if the aluminum door sill plates are still there. If they're the 'Datsun' logo type and in restorable condition, you might be able to sell them for a fair chunk of change. Love the 'forced entry' technique used by someone to get the rear hatch open!

This topic came up here about two months ago. In fact, I even commented at the time (without much optimism). However, now I have to deal with the reality of my own situation and I'm looking for 'been there / done that' tips from anyone who's managed to accomplish the task successfully without pulling the head and manifold. Issue: the rear-most manifold stud on my L24 engine has been snapped off (not by me!) flush with the face of the cylinder head. The exhaust manifold is still in place, and I'd prefer to leave it there if I can. That means drilling out the stud with a hand drill and working within the confines of the hole in the manifold flange (which is about 0.56" dia. and 0.60" deep). The consensus seems to be that this particular stud was undersized in the first place, meaning that there's not much point in worrying about preserving the original M8 x 1.25 thread. Next size up would be M10 x 1.25. Max OD of the existing M8 x 1.25 internal thread appears to be 8.34mm (dimension was taken from a thread chart) Recommended ID for the pilot hole for an M10 x 1.25 tap is 8.8mm (which is only .003" different from 11/32", so that's the drill I'd plan on using) That nominally leaves 0.016" difference between max ID. of old of 8mm thread vs. OD of the new pilot hole. It suggests that the pilot hole would need to be centered accurate to within 8 thou of true center for a 'clean' pilot hole. Not much room for centering error when starting the drill, then. Fortunately, though, the thread pitch won't change from old to new, so that (perhaps) provides some forgiveness for starting the pilot hole a bit off centre. There's still, of course, the matter of aligning the drill 'tilt' so that the pilot hole runs parallel to the the centreline of the existing hole. If I've done my trigonometry right, a 5 degree error in drill tilt will generate about 0.09" (one-and-a-half sixteenths) in top-to-bottom misalignment for a 1"-deep hole. Cut that down to just 2.5 degrees of drill tilt error and you've still got 0.04" of misalignment at the bottom of the 1" pilot hole. Acceptable for an exhaust stud hole, I suppose, but only just. Now it gets interesting. The L engine is, of course, not mounted vertically so using my hand drill's bubble-float aligner won't work (and that would only assist with alignment in the vertical plane anyway). So how to gauge the right 'tip' angle for the drill, up-and-down and side-to-side? In addition, there's the matter of centre-punching the top of a sheared-off 8mm stud while looking down through a 0.6" dia x 0.6" deep hole in the exhaust manifold flange (while leaning over the fender of the car). And BTW, that hole in the manifold flange isn't likely to be centred all that accurately relative to the stud. Which leads to my question: Has anyone accomplished this job successfully with engine and exhaust manifold still in place? If so, what tips can you offer for: a) centering the drill bit's starting point on the stud, and; aligning the drill so that the pilot hole runs true? Or is this just a bad idea?

Agree that the cover bag for the S30 windshield wiper motor would be a nice addition to your product line. The shape is simple, so I don't think it wouldn't be terribly complicated to fabricate. I'd make my own, but I don't know how to seam/seal the edges.

sorry - double-post

As an FYI to anyone reading this thread, Motorsport Auto now offers a rebuild kit for the S30's brake proportioning valve...

Very nice. I enjoy seeing what you've been able to accomplish in this project, especially because you're working in a relatively small garage space (and I think we all know that you can never have a garage space that's too big). Can you share some tips on buying parts off the internet from Japan-based vendors? For example: Do you direct-shop from vendors' websites, or are you searching through eBay-type auction listings? Do you speak/read Japanese, or are you using an online translator? How are you able to understand, and then select/negotiate, the shipping arrangements? Or do you work through a broker in Japan?

This seller is also offering a number of other S30 parts, including: 280 crank280 cylinder head (complete)S30 NOS inner rear quarter panels (both sides - B-pillar + front half of wheel arch)S30 NOS roof rear frame (includes hinge pockets for hatch)No frame rails, though.