Black Jack: Dyno action... maybe

Still no resolution on the vibration. I was really hoping motor mounts would clear it up. They were dry rotting. So, again, it was good maintenance, but not the cause of the vibration. For the hell of it, I swapped the plugs out, and the old ones looked ok. Definitely a colder heat range than optimal on the street, but they weren't fouled, and again no change in vibration.

I noticed the timing is a bit jumpy when the spout is in. i.e. I'll set the gun to 40*, free revving, the timing comes on up, but a once every second or so, it pops to a different timing. Seems a bit erratic. However, with the spout out, it's totally smooth and stays at 10*. And, the vibration is still there, regardless. It sounds perfectly fine. High load, low rpm (maybe 1600-ish) WOT in 6th gear is perfectly smooth. Tried bypassing the MSD, too. I'm not totally satisfied with the timing jumping like that with the spout in, but that really doesn't seem to have anything to do with the vibration.

I test drove it and decided that if it was gonna let go, then so be it. Feels strong. Can powershift and turn the tires over. I can bounce the car off the limiter for 10+ seconds in 2nd gear. So, I really don't understand what's doing this. My best guess is maybe it is flywheel or clutch imbalance related since I installed them in January about 7k miles ago, but I just don't understand why it got worse recently.

I called my local machinist. I'm gonna bite the bullet start the 306 build. I have a spare OEM block with rotating assembly on the garage floor, some good top end parts, and I've been jonesing to get into it for a coupme years. The machinist thinks he can get to work on it in October.

That's fine by me. I'll keep trying to work through it, but as long as it doesn't get any worse, I'll take my chances to run Larry at foxtoberfest, this year. If it blows, so be it.

Edit:
I thought a pilot bearing might explain things, but after rethinking it, I'd expect to detect differences when in vs out of gear. Oh well... Will keep noodling.

I went back through the EEC tests today and, once everything was set up correctly and fully warmed up, the results were pretty clean.

81/82 and 44/94 are Thermactor/smog-pump related. All of that equipment is gone, so those are expected and irrelevant.

I also got the cylinder balance/contribution test working after forcing the transmission strategy to neutral because of the T56 swap. For anyone who has to do this witgout a T5, you have to use the quarterhorse to set the TRLOAD scalar to 0, which forces the computer to see 'neutral'. Anyways, it came back 9, so the EEC did not identify a weak cylinder. I ran that test 3 times, twice back to back, and then another time after playing with the idle tune for an hour. I guess that rules out ignition and injectors.

The only code I still have any interest in is the 95/96 secondary fuel-pump circuit fault. I have a FP Guage on the A-pillar & fuel pressure is not doing anything wrong. Plus, the Walbro 255 LPH pump sounds normal, so I still need to determine whether that is just related to the pump-monitor circuit/wiring or whether there is actually anything worth chasing.

As for the vibration, I had been seriously considering pulling the transmission, clutch and flywheel and tearing into that next.

I've decided I'm not doing it... I really think it's one of those or maybe the tid bit of grinding I did on the crank around the pilot bearing was enough to throw things off, but I'm already gonna do most of the work when I swap motors, anyways.

I'm moving ahead with building the other motor. When that engine is ready, everything has to come apart anyway, so I'm giving myself permission to quit obsessing over this in the meantime.

Worst case, if there really is something wrong in the current engine and I hurt it, I'm probably risking something like $2,500 in used-engine resale value. I'm willing to accept that rather than tear the car apart twice chasing a vibration I still haven't conclusively identified.

So until the new motor is ready, I'm going to act like the vibration doesn't exist and drive it like I stole it.

If it gets dramatically worse, breaks, or finally gives me an unmistakable clue, then I'll know what it was. Otherwise, I'm going to enjoy the car. So, I invite all of ya to come to foxtoberfest and watch the fireworks!

I finally got curious enough to rough out what I actually have into Black Jack.

This is not a receipt-level audit, because that would be almost impossible at this point. Too many parts came from trades, spares, Marketplace deals, stuff I bought and resold, stuff moved between cars, and things I had sitting around. I had ChatGPT help me work through this thread and rough out the big pieces, while trying to back out the obvious offsets and sold parts.

A couple of rules I used:
- I did not count the T56 itself because I already had it, but did count the accessories I had to purchase to install it (bellhousing, clutch fork, 26-spline disk, etc).
- I did not count normal maintenance stuff like oil, gas, track entries, etc.
- I did not count accident/deer-strike replacement parts as “build cost.”
- I did not count general tools or spare parts that sit on the shelf, and are not really dedicated to this car, but are there "in case" or possibly for the other cars.
- I did try to back out the major stuff I sold, traded, or moved elsewhere.

The funny part is that the car started pretty cheaply the second time around. I bought it back for $3,800, sold off the T5/aluminum driveshaft/shifter/bellhousing stuff for $1,200, and later had the rear-end bump insurance claim paid me $3.3k I also backed out, which offset a surprising amount of the basis in the car after I fixed it. So, the initial cost minus just those things means Black Jack's baseline is -$1.2k! lol

So after all the mods, my best guess is that Black Jack is somewhere around a low-to-mid $20k car in actual net money tied up in it. If I look at it more like “what would this stuff cost to replicate,” it’s more like mid-to-upper $20k.

That sounds like a lot until I remember what is actually on the car now:

T56 swap, 5-lug/Cobra brakes w/ 93 Cobra booster/MC setup, Koni DAs, B-springs, MM plates, Team Z uppers & lakewood lowers, reinforced & welded torque boxes, Stifflers loop, 31-spline welded up rear with Truetrac/3.73s, GT40X/GT40 tubular/E-cam combo, QuarterHorse, ZEX kit, MSD 6+, Mark VIII/DCC fan setup & upgraded alternator, Corbeau seats, 3 sets of wheels & tires: Bullitts/CrossClimates, RE-71RS on Cobra Rs autocross setup, and the 25th Anniversary replica wheel setup with Michelin PS4S fronts and Nitto drag radials out back.

And that still leaves out the stupid number of small repair/upgrade items that add up over time. After it became my primary daily, my autocrosser, my test-n-tune car, the intent to keep it frugal went out the window, but the juice has been worth the squeeze, so far. And... when I think about what most spend on their daily driver, the average new car being over $50k, I don't feel bad at all. I'd say it's better to buy than build, but again, how often does a fuel injected, T56, 5 lugged, Cobra Braked car with A/C, heat, power steering and a comfy street suspension come up? Then, I'd still probably have to do a lot of the small things.

It also reminded me how much the car has changed character. When I bought it back, it was basically a cheap, rough, fun Fox with some good bones. At this point it’s become exactly what I wanted it to be: a car I can drive, beat on, autocross, take to the track, park, get dinged without having a nervous breakdown, and keep improving without treating it like a show car.

The other lesson is that “what you spent” and “what it’s worth” are two totally different things. I still don’t think Black Jack is some high-dollar car. It’s not worth anywhere near what it would cost to duplicate. Feels like maybe $15k if I'm lucky. But for what I actually have in it, especially after all the offsets and parts I already owned, I’m pretty happy with where I am with it, today.

Ps. I think I lied on staying away from disassembling to look for vibration causes. Hope to get into it again next weekend. The vibration seems to be from the backend, like maybe a pilot bearing. Would race as is, but if I can repair before it gets worse, I prolly should. Still planning on starting the other motor build.

Ya know, the average new car today is over $50k. And not counting financing, maintenance, repair, gas, and other operating costs, they lose ~1/2 their value in 5 years.

If I've sunk even 25k into it and can sell for maybe 15k, that's right in line, and probably cheaper when considering no financing & liability only insurance, and cheap repairs in the long run.

It's no economy car, but I chose that financial trade off for the daily fun of driving a fox, and yeah... staying stock would help the value proposition, but as a deliberate selection for a daily driver, it's still really not a bad car to drive today, at all.

On Monday, Father Time is going on the dyno. If all goes well, I'll have a race tune, a 93 pump tune, and then if time allows, I'll put Black Jack on.

The goal would be a simple NA baseline, WOT timing adjustment, and then setting the timing retard from 6* using the MSD Digital 6+ box to whatever seems right on the 150 shot. Was super disappointed in the 100 shot, having picked up only 65rwhp. But I couldn't play with timing that day because the clutch was already slipping.

Before I do, I'm also gonna put a fresh WBO2 in Black Jack, or the new Zeitronix dual wideband gauge, which is coming soon, either way. I've done it all and lost another Bosch sensor, and I've determined that the Innovate MTX-L itself is the problem.