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[Beartooth]

[Beartooth]

Has it been a year and a half? Yikes! The bad news, unsurprisingly, is not much has changed. The good news is, it's been an enjoyable runabout and back-road blaster, and the shop is complete enough that it's parked inside now (usually, depending on other projects and finish work on the shop). The work on the shop definitely falls in the "eat your vegetables first" kind of thing: it's getting there, but I've still got a couple weeks of work before it's sorted. Then I stumbled across a Jaaaag that was too good a deal to pass up. It's an '85 XJ-S, and it's basically rust-free with no signs of accidents and able to move under its own power, but it needs a lot of mechanical attention. Given the prices I'm seeing, my reward for fixing it up will probably be enjoying it for a while until I can find a good long-term home for it. It's one of those cars that's one clueless owner/mechanic away from the wrecker, and that'd be a real shame for such a car. Hard to believe a near-perfect example is worth maybe $20k and a typical driver would do well to hit $5k; it's just so much more car than that, to my eye.



Anyway, on to the 931. I drove it on and off through last summer, but later on, the fan motor decided to eat itself. It might have kept going quite a while if I'd just kept oiling it, but that's way too much of a hassle. It started making noises, then sounded like it was binding up, so I just unplugged it and avoided driving it in stop-and-go traffic (there were a couple times when it first failed where I had to shut it off coasting to a light, then hope I got moving enough to cool it down between lights).

Since I couldn't immediately find the Toyota fan people talk about, I decided to go back to the 12" universal fan I had sitting around. The first time I tried to mount it, I tried to do so with the mounting bolts aligned with the holes on the radiator, but immediately found that the air box wouldn't fit that way. Speaking of the air filter assembly, my winter storage "present" was a mouse chewed up a shop towel, built a nest, and left a litter in there... Could be worse: I don't see any signs of the wiring having been hit. Anyway, I had some 1-1/4"x3/16 steel stock, so I cut some brackets and counter-sunk some screw holes for the top so the fan could drop low enough (the top of the fan basically aligns with the top of the radiator now - not counting the eyelets). Hopefully the pictures give a good idea. The bottom was much easier, since the flange of the fan sits below the bottom of the radiator. I painted the brackets just so they wouldn't rust and scrounged some hardware. Nothing pretty, but it's probably something I'll revisit when I get around to rebuilding the engine. Also, I stuck some strips of foam to the bracket where it meets the radiator to keep it from rubbing or vibrating. Probably unnecessary, but who knows. Still to be done is to wire in a relay. Right now it's just wired to the original fan plug, and it feels a lot weaker than when I hot-wired it to a battery. I suspect it's one of several places where the factory wiring is robbing voltage, and any 924 would benefit from a relay wired directly to the battery.







That might be it for a while. After I got the fan in, I drove into town - the first time I've taken it more than a dozen miles from home this year - and filled up with gas with some Techron and Sta-bil. Happily, it's still firing right up (maybe with a little extra cranking the first time I started it this spring). Going off the odometer (180 miles; the gauge is another "need to fix"), I didn't expect it to take much to fill, but it took over 11 gallons! No leaks and nothing weird I've noticed, so hopefully that's just because of occasional runs to warm it up and the cooler weather (last fill was in November). Anyway, I'm holding onto the original shroud and will probably put the Toyota fan in it, or an aftermarket 11" fan. Ideally, I'd drop in an aftermarket fan with a PWM controller, but I think what I've got will work for now (with a relay/wiring upgrade, of course).
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1980 931 diamond in the rough

[Beartooth]

I installed the relay yesterday, and it's a big difference. I used a pretty standard relay (weather sealed though), mounted just under the coolant expansion tank using one of those mounting bolts. I pulled the power supply off the alternator and used the ground just behind the left headlight. I just wired the positive side of the trigger circuit with the supply wire, then ran the negative side to the thermostatic switch on the radiator (obviously grounding the other side of the switch). So far it works just as you'd expect, and as I indicated, it makes a big difference. Before, you couldn't hear the fan at all over the engine; now you can, and it makes a pretty healthy sound with the engine off. This is just an uneducated guess, but it's probably pulling 20-30% harder. It has no issues keeping cool in traffic so far; It'll be interesting to see what it looks like when it gets hotter, but I think it'll cool better than the original setup now, even without the shroud. Degraded wiring might be partly to blame, but I suspect most cars would stand to benefit from a relay in place of the original wiring.
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1980 931 diamond in the rough

[Raize]

I hate how Porsche used tiny wires with a ton of voltage drop for everything.

[Beartooth]

Yeah, I'm surprised at how much wimpier the fan sounded before. I'm wondering how much of a difference relays would make on the headlights; it's tempting to keep adding relays, but it might be wiser to hold off until I rebuild the engine and install a whole relay subpanel to cover the fan, headlights, maybe fuel pump, and I'm sure I could think of more. I suppose they were saving money with the thinner wire, but it seems like a big trade-off to me. I suppose the Germans weren't known for being fanatics about the electricals, but you'd think a premium car would have a bit more premium wiring.
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1980 931 diamond in the rough

[924RACR]

[Beartooth]

Yeah, I thought of the VW connection, but dismissed it because it was never sold as a VW and would have wiring specific to it. But I suppose there is a good chance the wiring is a vestige and was actually designed and specified by VW. It definitely seems marginal - the volt gauge drops .5 volts when I turn on the headlights, and it took me a couple tries to find a circuit with enough power for the wideband (it'd just keep flashing the warm-up code, I think it wasn't able to get hot enough for the initial calibration). But on the other hand, other than needing a new turn signal switch, fuel pump relay, and some contacts cleaned, it's worked pretty well considering the age and neglect.

I've never had a 6V car, and it seems like ancient history, but then you realize that when the 924 was designed, 6V systems were only 10-15 years in the past. Obviously, I'm about to tread on English soil (figuratively; I've done it, literally, a couple times in the last three years), but so far at least, I haven't found any major gremlins in the XJ-S. I've got a fair way to go on it though...
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1980 931 diamond in the rough

[Beartooth]

Another "long time, no post!" I just drove the car for the most part last summer, and with the mild winter we've been having, I've been using it a couple times a week. Big contrast there, to last January at least: I had to plow out my driveway with a skid-steer a couple times last winter - but at least snowmobiling was good! So it ended up sitting most of last winter. Anyway, a lot of the reason I haven't driven it in winter is the heater is pretty terrible. I haven't been able to get much heat to the floor, hardly any air flow, and the air isn't very hot. I suspect the heater core needs to be either replaced or cleaned out like the radiator.

I decided to see what I could do about that today. The floor-vent lever has never felt quite right, and sure enough, I discovered that the air flap is sticking - it moves ok in the "vent" half of travel, but wouldn't go all the way to "floor" until I manually moved it. I think something in the heater box - maybe the heater core itself - is a little out of place, and that's what the door is contacting. I've put it all the way to "floor," and I'll see if that works better. The next problem is, the fan motor likes to squeal. Dried out bearings, I suspect, so I took the cap off the inlet, and noticed the "toilet lid" wasn't opening. I could lift it, but the flow/fan control had little effect on it. A quick look turned up the problem.



Yet another reason it'll all have to come apart at some point, but that'll be down the road. I got the idea to drill a hole and use a zip-tie as a quick fix, and it worked.





While that was open, I did my best to oil the bearings. The top one I'm pretty sure I got pretty good; all I could do is squirt some towards the center of the windings and hope some of it made its way down to the lower bearing. We'll see if all this helps.
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1980 931 diamond in the rough

[Beartooth]

Well, the heat is better now... I think the heater core is in better shape than I thought, it's just the lack of airflow meant it couldn't go anywhere. The strange thing is, now I'm getting nothing but cold air out of the vents - fortunately, blocked off if I flip the little "defrost" controls up. Before, I was getting some heat from the vents, but probably now I'm just getting a bunch of air flow bypassing the heater core where it was mostly air circulating inside the cabin with the "toilet lid" closed. Another thing I'm noticing now that I've got good airflow is the heat is blasting my right foot - I must be missing a piece of duct or baffle of some kind. So the bad news is, the air box has a bunch of leaks and possibly other issues that won't be resolved until I can pull it all apart. The good news is, now I'm getting good enough heat that I can handle some colder weather (it was 35-40F when I got home yesterday; I'm sure when it gets significantly colder than that, all the leaky weather seals will overwhelm the heat output). The fan is another issue: when I drove it back and forth, then into town in the morning and afternoon, it squealed constantly. On the way home last evening, in the I position (one notch from full fan), it was quiet enough that I couldn't hear it over the road noise.

One other thing I've run into - the only thing that's caused some reliability problems - is the fuse for the fuel pump. Sometime last summer or fall, out of the blue, it wouldn't start. The cause was the fuse and/or contacts - I cleaned both, and it worked fine for a while. Then a couple months ago, I accidentally brushed some wiring with my foot and it died on me. I had a great time pushing it across a busy street! This time one end of the fuse had actually melted a little. I put another fuse in and it started up just fine. It's partly VW electrics, but also the fact that you can only get aluminum fuses anymore. It's not a question of if, but when those fail unless you clean them regularly. It would be nice, and probably a big step up for reliability, to wire in a completely new fuel pump circuit and relay. That'll probably happen at some point, especially if I get a Microsquirt to run the frequency valve.
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1980 931 diamond in the rough

[924RACR]

If you get a Microsquirt - use it to run the whole damn thing!!!

That said - yeah, I actually cut the wires for the fuel pump fuse out of my stock fuse block and wired in a modern AGC blade style fuse holder, because of the corrosion problem. It definitely helped, wasn't that bad a job.

You'll find that once you remove the heater unit, there's a bunch of degraded foam that seals the joints etc; you'll want a very soft closed-cell foam strip to replace it all, probably can find some from McMaster Carr.

The heat blasting out at your feet will be from the lower door (controlled by the lower slider), which indeed will seal with that foam - but should be easy to verify that the slider and door are working with it in situ. Having it closed with no foam won't stop the heat, but should cut it down and help more make it to the topside and defrost. Worst case, cover it up with duct tape or the like for now, till you can fix it completely... note also there's a matching port on the passenger side you'll probably also want to cover.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[Beartooth]

If I go with the Microsquirt, I'm thinking I'll convert to an EDIS-4 setup, and if I remember right, that also has an output to a fuel pump relay, so it's also an opportunity to upgrade the fuel pump wiring. I think I remember reading about your wiring modifications; I might do something similar.

I'll have to experiment with something to adjust the airflow to the foot, but it's not terrible. I kind of figured there's a bunch of foam and such that's degraded. I'll tackle that some day. Surprisingly, last time I drove it the fan didn't make any noise to speak of. Since it seemed to go away in the I position, I just left it there and didn't touch it all day today. I'm not sure if that's the oil finally getting where it needs to be, or if there's something else going on; it's definitely nice to be getting decent heat and no noise though - the little things!
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1980 931 diamond in the rough

[924RACR]

Actually, the EDIS setup IMO isn't the most efficient/simplest route - not to mention then you're stuffing a bunch of Ford electronics in there, and I have nothing but loathing for Ford's quality.

But maybe that's just because I've been in the industry too long... LOL

EDIS requires a bunch of extra components (and thus cost); instead, a good Bosch 4-tower coil as used in many VWs is able to be run directly by the Microsquirt (also I think part of why Ciprian uses it in his EFI kit), and so is simpler and cheaper, as well as higher-quality Bosch product.

The Microsquirt setup uses a new, separate fuel pump relay, as well as a new overall ignition relay; indeed, you're basically creating all new wiring if you're not half-assing it, excepting a single ignition signal lead from the original ignition switch. You add in a new fuse board, relays, and even power leads from the battery to get all new wiring, in parallel to anything you wish to keep from original.

The wiring design is pretty straightforward IMO, it's right in the Microsquirt manual.

Or save yourself the trouble and buy Ciprian's kit, for those who don't look forward to doing wiring...

I'd bet the oil is finally getting where it needs to be, on the heater fan; I'd be inclined to go back in there and give it another shot, just for good measure.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[Beartooth]

Oh, sorry - I was just thinking ignition because I'm planning on keeping K-jet and thought I'd discussed that with you, but come to think of it, it was someone else (maybe @Fasteddie313). I know there are a lot of good arguments for EFI, but I love K and KE-jet - I think there's a lot of potential that people just gave up on when manufacturers and the aftermarket went all-in on EFI. I've also toyed with the idea of converting it to KE-jet. Part of the interest is because of my two KE-jet M117 Mercedes. I plan to experiment with porting, cams, and intake mods to pick up some NA HP, hopefully sooner rather than later. Some day I'd like to build a turbo M117 and go hunting LSes - but I'd need a car to drop it into... So I'm fairly committed to K/KE-jet. That might mean a lot of frustration - I might be "that guy" trying to squeeze blood from a turnip - but I've gotta try.

Anyway, I'm kind of a Ford man (I have an old Fairlane, a '97 F250 turbo diesel, and a '94 Explorer). There's plenty to criticize, but EDIS is one of their hits. It's a powerful and reliable system - the plugs that were in my Explorer must have been in there 100k miles or more: they were so worn that the gap measured .080, give or take, but it started and ran fine! The parts for it would be dirt cheap from a wrecker, plus there's lots of aftermarket support if I want/need it. That said, I see the VW coil you're talking about is about $75; any idea what the output is like? Microsquirt can also run the quad-coil setup that superseded the wasted spark. That coil is more pricey and takes up a couple outputs I might want for something else, but might be worth it. Oh, but it would require a cam position sensor too... I'll have to do some more reading on that one.

I tested the cold weather capability a little more the other day, and it started at about 10F. The heat was ok - that's about the point where it struggles to keep up, and of course it takes a while to get the chill out of a cold car. The fan's been working, but still making some noise (only loud enough to notice sitting still or moving slow). I'll probably try putting more oil in it, but I won't be surprised if it still just eats itself like the fan motor did.
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1980 931 diamond in the rough

[924RACR]

CIS will never be as good as EFI with full fuel and spark control, as is available now. The driveability and efficiency blows the old stuff out of the water - even old L-Jet.

It's about modern processing capability and controls strategy. The world I live in, professionally - modern electronics controls for automotive, for Bosch. You can't even compare them. You are definitely trying to squeeze blood from a freeze-dried turnip.

Also explains my disdain for Ford stuff... glad I never have to work on Ford products, and pity my colleagues who do...

Yes, the MS can run the quad coil, but as you correctly noted you'd need a cam sensor, and that's a huge amount of squeeze, to have to fit, for no real performance benefit. Batch fire and wasted spark is easy, still efficient, and works beautifully.

I find no issues with the output of the VW coil; I've now used it on both my 924 EFI conversions (one street 931, one full race NA 924).

Agreed, at 10F the heater doesn't seem to be able to do much more than take the edge off the heat... German expectations for HVAC vs. American, don't ya know... with a more powerful blower fan, that'd help, since the Turbo does put out a wonderful amount of heat very quickly in my experience... but we haven't found a slam-dunk answer yet.

Munk's, the shop we work with locally here a bit, swapped in a 996 deck lid fan they had kicking around into a 931 (which we just EFI'd with Ciprian's kit) which ate it's blower fan - locked up solid. I checked it out, and was surprised to find it wasn't really any more air volume than the original fan in my 931! As good as, but not better as I'd expect from a new tech fan.

So there's still room for improvement out there... still on my list of wanted upgrades, someday...
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype