924Board.org

[Beartooth]

Thanks Mclaren! Let me know if you have any questions on that; I'm hardly an expert painter, but I might be able to point you in the right direction. I've finally got tires mounted and they're ready to go on the car.

A couple weeks ago, I dropped off the radiator to be gone through, thinking it could be boiled out and good to go, but I wanted to make sure. The bill came out to $180. That seemed excessive at first brush, but it turns out it was partially blocked and they had to tear it down completely and rod out the core. Better to pay the money now than chase overheating problems later, and given that there doesn't seem to be much for replacement options, it's not worth trying to push it. I again have to shake my head at what I can imagine the servicing this car saw was. The radiator was a mess, obviously, but I'm finding some scale on almost everything. I'm going to have to flush and use some kind of scale remover, but at least with it being summer, I don't have to worry about leaving just water in it.

Continuing on the cooling system, I've got just about every hose I need; I'm just short of the two elaborately-molded heater hoses that connect to the heater core. One is available, but at something like $55. The other I think I have a solution for using a couple off-the-shelf Gates hoses for other applications and a splice. I think there are three hoses that only the original piece will work for; the rest can be replaced with pieces from Gates (and maybe others) with a little work. I'll probably create a thread with all the part numbers for that at some point. I ended up putting the two heater core hoses back on. I wonder if they were replaced at some point: they look to be in really good shape (much better than most of the other hoses), and the hose clamps on them weren't OE, so somebody had been in there. Lastly, it looked like my heater control valve was seeping, so I went looking for an alternative since the OE control valve is another expensive piece. I thought maybe an early Rabbit control valve would work, but didn't want to chance the Chinese URO and Febi replacements, so I found an Everco all-metal replacement (no longer in production, but I found a NOS piece on ebay). Well, come to find out they work in opposite directions: if I'd hooked it up as is, I would be getting heat with the "cool" setting and cold with the "heat." I also had the coolant flow direction mixed up in my mind initially, but fortunately I figured that one out. Anyway, I adapted it by cutting off the piece that the cable mounts to off and welding it onto the other side. Other than having to run the cable retainer backward, it fits nicely, and I can't see why it wouldn't work. In the end, it's probably more work than it's worth to save $35 or so, but I'm pretty happen with how it came out.







Finally, I tackled a job that's probably not totally necessary, but I it should only help. My manifold to wastegate pipe had obviously cracked at some point and been re-welded (by someone with less skill than me, apparently), and I know I've read it's a common issue because of having a fixed pipe subject to lots of thermal transients, plus a wastegate that's mounted in such a way that it likely adds stress to it (mine came with a broken mount plate, as I indicated earlier). So I bought a stainless flex pipe and went to work attaching it. The pipe is 40mm, so too big for a 1.5" (38mm) flex joint, but significantly smaller than a 1.75." I ended up buying a 1.75" flex joint, then used some 1.75" tubing (which is close to 40mm ID) cut into a couple rings, and welded that up. I think in hindsight, it would have been wiser to have the pipe expanded to 1.75" (if possible). Like I mentioned, I'm no great welder, and this was probably the toughest job I've ever attempted. I didn't want to make the problem worse by guessing on the alignment, so I bolted the pipe up with the flex joint and tacked it in place. I had to do that under the car, on jackstands, and I may not have had the best setup in terms of gas and wire (I welded it with stainless wire and a argon/CO2, 98% argon, gas); it took quite a few attempts and dropped several flaming balls of molten metal before it was adequately tacked. Once I got it out, things got a little better, but I went through several cycles of welding, leak-checking, grinding down again, and more welding before I was satisfied. Then it was such an ugly mess of welded globs that I ended up grinding and sanding it down. I've found what little stainless I've done to be more temperamental, but this one still surprised me. The good news is, it fits nicely, and hopefully means no more cracking wastegate pipe. With that done, I installed the rest of the exhaust system.



Earlier, I welded in a bung for a wideband O2 sensor; I think I found a good spot to put it on top of the pipe at about 1 o'clock, sticking into the torque tube tunnel. It seems to have good enough clearance, it's near the ideal mounting point (on top of the pipe), and of course keeps it clear of anything I might run over (nothing new for this car, but hopefully those days are over!). Finally, while I was futzing with the no-name universal 10x14" muffler that works but doesn't fit that well, I had to wonder what a better choice would be. It looks like Borla has something closer to the stock size; anybody try one like this? https://www.summitracing.com/parts/bor-40659 Definitely a "down the road" thing, but the boy racer in me wants to try it!
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1980 931 diamond in the rough

[Beartooth]

It lives. I finally get it all back together, and after just a little tweaking, it fired right up. I finished the cooling system work, put that all back together, then pieced the intake and fuel injection back together. Lots of little details there; things I either didn't put back together quite the way they came apart, or that needed tweaking, or both. I massaged the WUR, something that took far longer than it should have. I flushed the cooling system, then put some fairly permeable fabric in the line from the thermostat to the radiator (hard to explain, but I cut about a 6" circle of it, then pushed the center into the hose and pushed it onto the metal pipe so it'd be held and could catch anything going into it). It did collect some gunk; nothing crazy. I also changed the oil - it smelled pretty fuel-contaminated and looked pretty black despite only having been run in there an hour or so and not really driven. I used some engine flush stuff to hopefully clean that out.

Anyway, it's a night and day difference compared to how it ran before. I'm pretty well convinced that the frequency valve was either blocked or not operating, and that's why it wouldn't want to rev up at all. I could get it to idle and rev a bit, but I think it would just go stupid lean as soon as you tried to get anything out of it. Now, and I've only opened it up for a handful of short bursts, it takes off normally and really wants to pull once the turbo comes in. I've only driven twenty miles so, and there's plenty of shake-down left, but it goes nicely so far.

The one big problem I have is there are some concerning noises. There's a hard-to-describe noise that seems to be coming from the top of the engine - maybe something related to the turbo and normal? Then there's a squealing noise - seems to be more in the lower gears, and maybe kind of goes away. Finally, it's making a significant squealing noise when the starter is engaged. I'll have to see if I can post a video.

The best news is that, other than the terrible shifter condition (I can make it work, but it's finicky), the transmission seems quite sound. I'm treating it fairly gently, and so far it seems happy with that - you just have to be careful of trying to get 1st if you're not fully stopped. So, mostly good news for now, and I'm finally able to enjoy the car a bit!
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1980 931 diamond in the rough

[Beartooth]

Well, first the bad news: apparently it was my turn to be an idiot. At some point, I put the starter in, threaded the bolts in, connected all the wiring, and left it as such. I mentioned a noise when I was starting it, and that's why. It made contact with the flywheel and ground out of the nose of the starter as you can see. I tightened the starter down the other day, and that actually locked it up; I had to take the starter off and bump-start it. I took it to a starter/generator shop who looked it over, but weren't able to dig into it right away. They said it'll probably work for the time being, and it does, but makes kind of a grinding sound with the starter engaged now, so I'll have to get on their calendar. Incidentally, somebody forgot to tighten the compressor scroll bolts too, and I lost one of those...



Anyway, I tinkered on that stuff today, and also decided to back out the turbo bolts and see how that was going. The first came right out, I smeared a bunch more anti-seize on it and put it back in. The second broke free, then bound up. I ended up working it back and forth with some penetrating oil (and managed to gouge a chunk out of my finger when I pinched it between the end of the bar and the extension). It finally came out, and I found a piece of thread (about a third of a single thread) turn off. I'm not sure what caused that; I have another bolt, so I just put that on with more anti-seize and finished it off, but it is a concern. I'd read that chromoly bolts work about as well as anything, but I might have to re-think this. I wonder if using Ti bolts had something to do with keeping the bolts from seizing up.

Well, the good news is that I survived my first trip to town today. Other than the starter woes, it's been starting right up, running pretty smoothly, and not doing anything to concern me. I'm not sure what oil pressure is supposed to be, I'm hanging out at around 4 bar going down the road; it drops to around 1 bar idling, but I'm not sure how much I trust that gauge. I put the cheapest oil I had sitting around in it (Rotella 15W-40) because I plan on changing it again soon. Like I mentioned, the old oil smelled pretty fuel-contaminated. After I've put a few-hundred miles on it, I'll plan to change it out for synthetic.

It is a lot of fun to drive, and the turbo definitely adds to that. I may have something off, because a couple times when I've gotten into it it's started breaking up around 5000 RPM. I can't say it's spark knock, but I definitely don't want to take a chance on it. I'm about finished setting up an Innovate SSI-4, and I plan to use that to make sure I'm not losing fuel pressure on the top end (and I plan to ditch my Mickey Mouse pre-filter setup once I've run a tank through). Of course, the fuel gauge doesn't work, so running it down to near empty could be a game of chicken. I still haven't done anything about the shift linkage, and so shifting is kind of a game of blind man's bluff, but I'm figuring it out. I do fear the second gear synchro is weak: I've gotten a little bit of a grind a couple times, even with fairly conservative gear changes. But I can live with that; it'll be interesting to see if changing the gearbox oil helps. One thing that's both nice and a little impressive is that I don't see any drips anywhere. I replaced leaking front crankshaft seals and the axle shaft seals, in addition to pretty much everything involved with the turbo, but even so, it's pretty gratifying not to have a ton of leaks to chase down. Well, onward and upward, I hope! Next will most likely be shocks and control arm bushings. Those are all shot; I'm probably doing well to have nothing more than some vibration in the steering wheel and the sloppy reactions of blown-out shocks.
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1980 931 diamond in the rough

[Beartooth]

Man, it's been a month... I'm making progress, but definitely two steps forward, one step back. I'm at around 500 miles I've put on the car so far. It's functional, but with a lot left to do, and something's still not right in the fuel injection.

As soon as I got it on the road, the odometer quit. It appears somebody went into it already - I think to replace the plastic drive gear on the odometer shaft. The issue I had was the metal gear came free and was spinning on the shaft. I used a vice grip to knurl the shaft, and also calibrated the odometer as best I could by spinning it with a drill and timing the trip odometer. It seems to have worked: I used 60 MPH as a benchmark, and now it reads low below that, and high in the higher speeds. I also cut off the stop peg at 85 MPH so I'd get some indication above that - not that I'd exceed that...

Next I went through the control arm bushings. I bought a set of Prothane bushings and installed them, along with grease zirks. I also used my dremel to grind some channels for the grease. Honestly, I'd have gone with OE bushings - I don't think poly is better for what I'm doing - but the OE bushings are expensive, and the other options seem to be China junk and not worth my time. Anyway, it wasn't a bad job. The biggest issue I ran into was that I used a cut-off wheel to cut through the inner sleeve of the rear bushing, and I couldn't avoid nicking the shaft on the control arm. I just filled it in with some JB weld; hopefully it holds up - if not, replacements aren't that expensive. Also, one of the control arms was bent slightly, but I managed to get it pretty close to straight again. Also, the ball joints, although original, seemed like-new tight, and the boots were in good shape too, so I just took them off, cleaned out as much of the old grease as I could, and put some new grease on.





On the topic of suspension. I installed new shocks and struts inserts. The rears were dead simple. The fronts weren't that bad - half the job was painting the struts just because. Kind of a bummer that I bought new boot and bump stop kits before realizing the Bilsteins come with new boots and don't use a bump stop... Anyway, the shocks and strut inserts were all factory items: Konis with what appear to be 1979 date stamps. Man, am I having to make up for years of lost love on this car!

Finally, and hitting on where I seem to be having ongoing issues, I eliminated my Mickey Mouse fuel filter setup. When I drained the tank and pulled the pickup, I found a bunch of rusty flakes had settled in the sump. I removed a good cup of all that, and I have no idea how much more there might be. I bought a sock-type tank filter, and adapted it to just the threaded metal piece that the original tank pump attached to. I did that with some 7/16 fuel line, a brass 1/2 PEX 90 elbow (which I cut down a bit) and some spring clamps. I was a little concerned as to whether it would spin freely enough in the limited space it had, but it actually worked out ok: I tightened down the metal piece that screws into the tank without it first, and marked the bottom, then aligned the sock filter with that so it'd sit at the bottom. It only makes a pint or two difference though. The filter I used was the Delphi FS0176. There may be others that will work, but you are limited by what will fit through that hole. I'm also not sure not sure how this compares to the 928/944 fuel strainer, but at $15 for the filter, $5 for the elbow, a few dollars for the fuel line, and a few dollars more for the clamps it's at least worth a try.





Anyway, the problem I'm having is I seem to be suffering from intermittent lean-out. It was so bad yesterday that, driving into town, I could only maintain 50 MPH or so, and it was indicating close to 20:1 AFR. I figured it had something to do with being low on fuel (it had 5 gallons of gas in it when I left home) and the pump having to strain. I filled it up before returning, and it seemed to get better, but it didn't seem like the problem was gone. Today when I drove it, it started off lean and feeling sluggish - showing around 17:1 AFR - then just straightened out and seemed to run well until I got where I was going. On the way back, I didn't have any major issues, but it did seem a couple times like there was a step change where it'd be pretty lean, then richen up (going from 17ish to mid 14s). I've only dared to hold my foot down a couple seconds when it's doing this, up to around 4000 RPM, and it doesn't seem to be enriching much, so I have to back right out. No pinging or surging, or I wouldn't have even pushed it that far. What's really frustrating is that when I first got it going, I could tell it was enriching it the way you'd expect under boost: it'd drop down around 12:1 or even lower if you held your foot in and pushed it past 4000 or so.

There's a possibility I've damaged the fuel pump already by making it suck through that filter (not tiny, but only 3/8" in/out), or that the new filter is already partially blocked by rusty sediment again. Or maybe the frequency valve is cutting out. Or maybe (if I'm lucky) the main fuel filter is partially blocked already. Whatever the case, it seems it's time to unleash my secret weapon. I've wired up an Innovate SSI-4 (four-channel multi-function sensor interface), and all I need to do is hook it up to the duty cycle diagnostic connector, coil, and get the fuel pressure sender in place. That should allow me to check for and/or eliminate fuel pressure issues and see if the lambda control is doing something funky. Once I get the fuel supply issues sorted, my plan is to move the fuel pressure sensor to the WUR circuit so I can see what the control pressure is doing. The one channel I forgot to mention is a MAP sensor (just need to T into the line to the distributor/WUR). I don't want to get too optimistic, but I'm hoping that proves to be a great diagnostic and tuning tool. Stay tuned!
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1980 931 diamond in the rough

[Fifty50Plus]

One suggestion is to turn the flat fuel filter upside down in the tank in case it's getting clogged with more rust sitting on the bottom.
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1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car

[Beartooth]

Yeah, that might have been a better idea, in hindsight. I had one tank fill along with some Techron before I put the new filter in, and I'm hoping that washed most of the rust down. Good chance there'll be more though. I also replaced the main fuel filter today and cut apart the old one. It had some fine rust in the filter media, but was hardly packed full. That said, it was an off-brand filter from a local store, and maybe not that great a piece - could maybe be causing a restriction.

On the filter topic, I've spent hours trying to find a good breakdown on fuel filters and not come up with a solid answer on what the correct filter is. I put in a Hengst H127WK, which fits perfectly except that it comes with one male and one female adapter fitting; mine uses a female fitting on both ends, so I just had to swap out the male one. That cross-references to the Bosch 0 450 905 907, Mahle KL21, and Mann WK726. The 924.org parts breakdown lists a filter for early 931s that seems to be a smaller diameter, but the part number for the later filter (Bosch 61967) is one I can't find listed anywhere. Anyway, I think what it boils down to is two different case diameters and possibly different fittings. The one I'm using is 125mm long (NOT including the fittings) by 74mm diameter. Hope that's helpful to someone some day. I have to wonder if the "correct" filter is NLA, but with the only difference being the need to swap the one fitting to make it work.
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1980 931 diamond in the rough

[barnwerks]

A tank outlet screen assembly from a 944 is a direct fit and will provide the external pump a sufficient volume of fuel to prevent cavitation.

[Beartooth]

Yup, I'm aware of the 928/944 fuel strainer, and that may be better, but I don't know and have no way to compare. I think the sock filter I'm using is a bit finer filter, and probably a better filter overall, but that's mostly based on the fact that it's what most OEMs are using now. The 944/928 strainer is an easier, direct fit, obviously. It's also around $100, vs. $15 (plus another $15 for the bits to attach it), and that's really most of the reason I decided to experiment with it.

Anyway, it was a bad day for team Porsche, but not disastrous. I drove to the nearest town to mail something, then pulled it into the garage to (finally) check the valve clearances and swap some fasteners on the turbo. I'd run across some washboard, and thought it'd popped the hood. Turns out it broke the pin that latches the hood... Then I noticed some fuzz around the timing belt cover, and it turns out the timing belt is chewed up - after only 400 miles or so. The only cause I can think of is there were some loose bolts on the crankshaft pulley that I tightened up a couple weeks ago. It was one of those things where I'd just snugged the bolts down, but forgot to torque them. If it was loose, maybe the belt was able to move forward on the sprocket and that started chewing it - I'm not sure. Obviously, I'm not going to risk driving it, and fortunately, timing belts are cheap. Before I ran it, I'd bought and installed the Continental kit with a new belt and pulley. The crank pulley had a couple nicks in it that I smoothed off a bit, but they didn't look like anything that'd cause issues. I think I'll try a Gates belt if I can find one in town, then keep an eye on it.
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1980 931 diamond in the rough

[safe]

[Beartooth]

Yeah, I agree it's a lot, and definitely a problem unless I'm lucky enough that most of it washed down on the first full tank I ran through it. I'm half-planning on dropping the tank this winter, but before I commit, I think I'll drain it and see if I'm still getting a pile of build-up like that. It might make more sense to clean it out until it stops (provided it stop after a handful of drain-and-clean cycles), although you do have the problem of whatever rusty sediment makes it past the strainer peculating through the system until it clears up.

That brings up one advantage of the sock filter: it's rated at 31 microns. I'd have to guess the plastic mesh type strainer is much courser. Hopefully the sock doesn't get obstructed easily; at least it's cheap if I have to replace it. I hear you can clean the plastic screen types, so there is that. That said, in a case like mine I definitely want as much filtration in the tank as I can get to keep that junk from traveling upstream.
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1980 931 diamond in the rough

[Fifty50Plus]

FWIW....
I opened up the tank on my racecar earlier this year because my engine would quit after 3-4 laps on track. I found that the fuel pump relay had failed and replaced it. It happened again the same weekend. I then thought it was a bad fuel pump so I replaced it when I got home. It happened again at the next event blowing the fuse on the relay so I packed it up and went home to ponder more. I drained the tank and found the same quantity as you of rust in the bottom of the tank. I had one of those 944 screen filters in the tank which seemed to be working because I pulled the fuel filter in line before the fuel distributor. That filter was very clean, no particles, no blockage. HMMMM... Tested both fuel pumps and they were good. So I cleaned out the rust in the tank and replaced the 944 screen filter. I went back to the track and it happened again 4 laps or so and the latest new relay blew.
I wen home and I installed a complete new electrical system for the fuel pump. Red wire from B+ to a 15 amp fuse, up to a switch on the dash, back to the positive side of the fuel pump, a new ground to the negative side of the fuel pump and voila: the car has run flawlessly for the last 5 races. I suspect that the factory wiring harness is the real culprit blowing the fuel pump relay.
The rust in the tank wasn't a factor since the 944 in-tank filter had been living in that environment for quite a while (6 years since I built the car).
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1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car

[Beartooth]

That's good info, Fifty! Was that running an original replacement pump, or a higher-performance (and higher amp draw) pump? I've heard of people running the Bosch 61944, and I was kind of tempted until I considered it's rated for easily twice the power I could ever hope to get out of mine (and almost four times the factory output). I'd heard of voltage drop issues, so I checked that with the circuit jumped, and it was less than a volt different from the battery. I should check it again with the engine running though; could be the relay is weak. I've also thought about eliminating the original relay setup. It would be really nice to have a setup that runs the pump a couple seconds as soon as the key is turned on, incorporates a RPM limiter, and maybe an inertia switch - plus obviously providing more current capacity and bypassing 40+year-old wiring. Anyway, it's gotta be frustrating losing time on the track, plus the time and money to replace things that didn't need replacing! In addition to getting the electronic fuel pressure gauge set up (will run through the SSI-4), I'll definitely look into the wiring more deeply.
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1980 931 diamond in the rough

[Fifty50Plus]

Both pumps were whatever Autohaus AZ sells. I don't think a higher flow pump is needed since much fuel is being returned to the tank. Further, when I disconnect the fuel input line to the fuel distributor after the filter and turn on the pump massive amounts of fuel flow out. We have to be able to provide a fuel sample at impound and this is how I do it.
I eliminated the WUR last year and replaced it with an adjustable fuel pressure regulator (set at about 46 lbs) since I had had some blockage either at the frequency valve or return line to the tank. All good now. Headed back to the track on Thursday for multiple libations and racing on the weekend.
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1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car

[Beartooth]

Well, I continue the trend of two steps forward, one step back - much better than the reverse, so I'm not complaining! I'm up over 500 miles on the car, and it's generally running better and better as I go. The biggest thing I notice is that the lambda control seems to really hunt at times, which is kind of annoying. I finally got the SSI-4 working, and it's hard to tell if there's some electronic noise influencing it, but the duty cycle I'm seeing is never static, and when it's in the "hunting" mode, it swings around 20% (often 60-80%).

I think the original oxygen sensor is actually still working (I haven't checked it out in any way); would the next step be to disconnect it and see if I'm still getting the hunting behavior? Additionally, when I get into it, I initially feel a more noticeable surging sensation that goes away once I get some boost going. All this is mirrored on the AFR too: usually lots of swinging at cruise and light throttle (maybe 14.5-15.5, not that the gauge is necessarily keeping up). I also had a couple drives last week where it didn't seem to want to enrich at all; foot down halfway or all the way, it wouldn't drop below 14-ish and I'd quickly back out. But the last couple times I drove it, the AFRs would push down and hold when I held my foot in, usually terminating just under 11:1.

I'd say just a little richer than I'd want, but I'm not in any hurry to make any adjustments, and if/when I do, it'll be done delicately. I'm not sure if the motor has ever been touched, but it's not blowing smoke and has used maybe a quart of oil; about all I could ask for, and I don't want to ruin that! Anyway, I changed out the plugs for one range colder just for a little more margin, and as an excuse to take a look. They look pretty good, I'd say. They all looked on the lean side, but that's not totally surprising given what I've seen in the AFRs. They all look pretty similar, but #4 is maybe a bit lighter (the lighter of the two in the picture), and smelled a bit like burnt oil where the others didn't? Just something I noticed... Given how similar they looked, it would seem the fuel distributor is pretty well in sync, and the injectors can't be in too bad a shape. Oh, and the plugs I'm running now are Bosch WR5DS; I've seen some recommendations for colder, but given I'm two steps colder than factory, I think I'm ok anyway, and the WR5s were the coldest I could find easily.



The next thing I tackled was the timing belt (again). I'm not sure how well it comes across in the pictures, but most of the teeth on the old one look half-squished. I think what happened is that I massively over-tensioned it. I followed the Haynes manual, which says to tighten it until you can just twist the long end 90 degrees. I could go to the tipping point on the tensioner and still twist it past 90, and I'm hardly a gorilla! So I replaced it (obviously), with a Gates vs Continental belt (not that I think it was the belt's fault - I've just always had good luck with Gates, and it's what O'Reilly's had) and tensioned it by frequency to the best of my ability. Before, it seemed to make a hard-to-describe sound, like a mix of thrumming and howling, that I think was from the timing belt. I think I still hear a hint of it, but nothing like before. While I was at that, I checked and adjusted the valve lash, but I probably could have left it. I tightened up two or three lifters, but they were all pretty close.





Oh, and one more failure to throw on the pile (not at all my fault, this one) is the radiator fan. I got home the other day, went inside, and thought I heard a dying cat or something. It was the fan, barely running and making noise intermittently. I guess I'll have to go in and re-grease or replace the bearings. I dug out a generic pancake fan I had sitting around and was able to get it in place temporarily. I'm wondering now if I should re-do the fan wiring: I tested the "new" fan straight to the battery, and it seemed to blow a lot harder than after I mounted it and wired it into the original fan plug. Might be partly the radiator affecting the flow, but I don't think that's all.

Lastly, I guess I blew it: I'd been dreaming of taking it up the Beartooth Pass near me (an amazing drive if you're ever in Montana between Billings and Yellowstone Park). I thought it was still open Tuesday (the website showed it open when I'd last checked), and so after wrestling with the radiator fan and changing the oil (going with Mobil 1 5W-40 FS for the cooler months), I hurried up there... only to find it closed. And on a string of beautiful, warm weather! It may be socked in now (Wednesday brought in cool, wet weather), but I guarantee it was perfect top to bottom at the time. Who makes these decisions?! At least it was a pretty drive up as far as I could get, just not that exciting with the more sweeping corners lower down - would have required "take me to jail" speed. A little disappointing, but I guess there's next year...




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1980 931 diamond in the rough

[Cedric]

Progress, slowly but steady. The euro 931s I've measured at euro boost levels are sitting at afr11 at full load. It couldn't be that much higher without triggering the knock light.

Regarding the cam belt, nowdays i use a frequency analyser app and set it at ca85-87hz. We had a discussion on the subject here a few years ago, and it seemed like others were in that area aswell. Its so easy to overtighten it, the twist belt method isnt very good.
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1980 924 Turbo
www.instagram.com/garagecedric/