1979 Pace Car build

[Redtwilight]

Dang... guess I'm lucky. The local 1/8 mile track is only 18 minutes down the road. The next closest is a 40 minute drive. And within 2 1/2 hours I can be at one of 7 different 1/8 mile tracks or at one of 4 different 1/4 mile tracks.
Then there is a world renowned roadcourse within 30 minutes. And countless round tracks within the same 2 1/2hrs.

 

[broncojunkie]

We used to have a decent track 30 minutes away, but someone purchased the land and tore it down. To add insult to injury, they didn't even use the property as planned. I believe they were going to sell off lots or sell as commercial property. Instead, they just ripped everything out, then put it up for sale for some ungodly amount.

I'm finally home and started working on the car some more. Installed water temp and oil pressure gauges today (huge pain) and started trying to line out a problem with my front brakes dragging.

Although I hoped to get some drive time while I'm off, it looks like it'll be short-lived. I spoke to my boss and came to the understanding that they won't be calling me to ride over this time. Got off the boat yesterday and the boss called, literally, before I even made it home. I need a new job. I'm really getting fed up with this. As bad as it is on my hobbies, it's even worse when it comes to being away from my family. It also pays well, but the govt takes a bigger share, so I don't even see much of a difference, other than grey hair and a sore back.

 

[broncojunkie]

Got a little bit done on the car today. Figured out my brake issue. The master cylinder/booster pushrod was too long and just needed adjusted a little to shorten it. I think as the fluid heated up, it would expand and there wasn't enough clearance between the rod and master cylinder. Basically, as the fluid expanded, it was acting as if I was touching the brakes. There should be a slight amount of clearance to allow for expansion.

I also fixed a couple other electrical gremlins. I had been having issues off and on with the fan relay not wanting to kick on and I noticed the right turn signal wasn't working. The negative battery ground was evidently not good enough. I moved it to a better spot on the engine block and everything seems to be working fine.

The plastic t-handle on the hood release broke off today. I think it was just from be old and brittle. The cable itself seems to be in great shape. I haven't really looked at it yet, but I'm presuming I have to replace the entire cable. Any of you guys know if that's the case?

 

[broncojunkie]

Still fighting a backfire issue at higher rpm. Tried backing off on timing and it didn't phase it. Right now, I'm suspecting either a lean fuel condition or something in the ignition system. I did some testing on the ignition system and everything seems to be working fine. The plugs do look like I'm running lean, so I'm addressing that first. Fuel pressure and delivery are good. After some research on proper carb adjustment, I found that the 4.5 power valve is a little too low for my engine. I switched to a 10.5 PV and there was no change. Plugs still showing lean.

Instead of trying to tune the carb by reading plugs, I decided to order a wideband air/fuel ratio gauge. I'm working till Tuesday or Wednesday, but as soon as I get home, I'm hooking it up and seeing what I've got going on fuel wise. My carb (Quick Fuel brawler race series 650 cfm) has a 68 primary jet and 76 secondary jet. The backfire seems to happen even when I'm not in the pedal far enough to open the secondaries, so I'm suspecting I may just need to jet up a couple sizes. I'm hoping that's the case.

I'm still not completely ruling out an ignition problem, but since I'm fairly certain I'm running lean, I'm going to check/fix that and then go from there.

 

[broncojunkie]

Oh, and I did manage to clean up the old draglites and mount the new slicks. These are strictly for the occasional track day, if I ever get it running decent.

 

[broncojunkie]

I should also mention that I purchased some hubcentric spacers and longer studs for the front wheels from Maximum Motorsports. The 15" draglite front runners won't clear the sn95 brakes without them (and, iirc, some light grinding on the caliper brackets). I haven't installed the studs yet, but it's on the list.

 

[broncojunkie]

Got the wideband hooked up and, as expected, it was WAY too lean. Carb came with 68 primary jets, and 76 secondary. I went ahead and installed 76's in the primary and wideband showed pretty much ideal ratio. Took it for a drive, and it was obviously running rich. I only had the wideband hooked up temporarily. My guess is that I was taking readings with no air filter. When I reinstalled the air filter, it changed the amount of air in the mixture. So I installed 72's. By the time I got finished with that, it was raining and has pretty much been raining non stop since then. Not a drop of rain the whole time I was working over, but now that I'm home, we get rain. Figures!

 

[broncojunkie]

I can't believe it's been so long since I've updated this thread. I've worked on it on and off since last August. Nothing I did seemed to fix the problem. Swapping in several different distributors, coils, ignition boxes, plugs, wires, rewiring different things, etc. I found a few issues and fixed them, only to find that the car still has a miss and backfire on deceleration. I came to the realization that there was a problem with the cam. I ordered a new x303 after reading about some quality control issues with Comp cams.

I tore the engine down and found a lot of slop in the timing chain. A closer look and I believe it may not be drilled correctly for the cam alignment pin. It's a parts store brand. The machine shop who built the short block installed it. It looks like a quality double-roller timing set, but I believe it's machined out-of-spec. I went ahead and replaced the cam as well. The original cam looks fine, as do the lifters, cam bearings, push rods, etc. I also recently had the heads off. Valves and pistons look fine.

I have everything back together except for plug wires and coolant. I finished up late last night and I guess I overdid it, because my ankle and back are hurting today. I'm taking it easy. Had to get the wife to round up an old set of crutches just to get out of bed this morning. Sucks getting old. I can't work like a young man anymore, I guess.

 

[broncojunkie]

Started feeling better after a hot dose of ibuprofen. Buttoned up the engine work. Started it up. Had a loose rocker, so I went back through them and got everything adjusted correctly. My 150a breaker for the alternator failed, but I had a replacement. Got that swapped out. Set timing to around 13 degrees btdc. Cleaned up a rough looking contact on the msd rotor. Seems to run smoothly, but still backfiring. I'm at a loss.

 

[broncojunkie]

I'm going to go back and pull some plugs and see if it's running lean. I'm running a 650 carb and it's tuned down to the smallest jets in my kit. Being a 331 stroker with aftermarket heads and fairly aggressive cam, it seems like it should require more fuel. I tuned it using the wideband, but I'm not sure I trust the readings.

 

[broncojunkie]

After some more carb/timing adjustments, she's running a lot better. Still has a stumble and occasional backfire, but I think I can get that figured out. It's driveable as-is. Unfortunately, it'll have to wait another 4 weeks, since I'm back to work. But that'll give me time to come up with a good plan. I still need to set the timing curve, too. I hope to get started on the body work for the 79 cobra soon, so this one needs to get finished. I completed the motor (351w) for the cobra a couple weeks ago, so I need to address the body work.

 

[Redtwilight]

Good to see your still working away at the 4-eyes!

 

[broncojunkie]

I ordered a set of msd wires last night. I still have my suspicion that maybe the Accel wires aren't quite up to the task and could be cross-firing into other cylinders. If nothing else, I'll have some peace of mind. The ignition coil (blaster 2) is putting out one hell of a spark. It stands to reason that the spark could take a different route if everything isn't up to par. By moving my timing light around to each plug wire, I can see that a few of them have an irregular pulse. I just thought it was my timing light, but I'm leaning towards wires now.

 

[broncojunkie]

I finally figured out my misfire/backfire issue. It seemed to run rich no matter how small of a jet I went down to. I ended up driving the car without the air filter and it ran ok. With air filter, pig rich again! The air filter was put in last summer. It can't have 100 miles on it and looks nearly good as new. I'm guessing it was defective or just took a load of dust or pollen. Anyway, a new filter and I was able to tune the carb.

I figured I was overlooking something minor. I just underestimated how minor it was! FWIW, I had driven the car without the air cleaner before. But it wasn't tuned correctly because I was usually test driving with the air cleaner/ filter in place, which was causing a rich condition.

 

[broncojunkie]

Spent some time buttoning up some loose ends today. Cleaned up wiring under the hood, replaced the sealed beam headlights with new housings that accept H4 bulbs (low beam only, but waiting on high-beam bulbs to show up), reinstalled glove box, cleaned inside and out, secured the passenger side lower air dam which was missing fasteners.

Pics to follow

 

[broncojunkie]

 

[broncojunkie]

 

[broncojunkie]

 

[broncojunkie]

I also forgot to update that I did some work to the sunroof. New weatherstripping on the glass and body and cleared 3 out of 4 sunroof drain tubes. One is being stubborn. All 4 were clogged pretty badly. I washed the car today and the sunroof channel drained properly and there were no leaks. Huge win for me, as that was a little worrisome.

 

[broncojunkie]

The past week or so, I managed to knock some things off the list. Finished the led headlight upgrade. The difference is amazing.

I also worked on getting the dash lights working properly. After pulling the gauge cluster, replacing bulbs, even upgrading to led's, they still barely worked. I finally discovered that the electrical contacts on the bulb housings were flattened out and not making good contact with the board. I simply bent them out a bit and reinstalled. They're working great now and the green led's look great.

And no pic, but I also got the giant tach and shift light installed.