BUILD THREAD my 1980 Grand Prix w/BBC 454 build thread

[454GrandPrix]

For your entertainment, I took a photo of the car's current stance. Remember: this is 37-year-old stock V6 springs and shocks up front, but brand new (and taller) wagon springs out back.

Yesterday morning I told you all about Thursday's stupidly short test drive--all 50 feet of it. I got home from work Friday afternoon with enough time to test my theory on the clunking noise. I put only the rear end on jack stands, then started the car. It only took a second to crawl underneath and verify that, yes, the noise was the driveshaft's front u-joint hitting the stock brace. I shut down the engine and, four bolts later, the brace was off the car. I started it back up and--voila!--no more driveshaft clunking. You know what that meant: time for a real test drive.

For multiple reasons, I didn't want to go crazy. I took one slow lap around the neighborhood. I only got up to about 20 MPH, just enough for the trans to shift into second gear. I was barely applying throttle, which was probably a good thing because I could feel the transmission slipping... so I came around and pulled back into the driveway. I left the engine running, popped the hood, and removed the trans dipstick.

"Umm, how much fluid do you need to add if the dipstick is completely dry?"

I went looking through my garage for some Dexron-III (I swear I had some left over) but I couldn't find any. I decided it might not be wise to drive the GP any significant distance with the fluid so low, so I shut it down and hopped in the Suburban for an O'Reilly's run. Back home, after adding three quarts it seemed to finally show up on the dipstick.... though it is difficult to be sure when there is fluid on the inner wall of the fill tube. Would this be enough to stop the slipping? There's only one way to find out.

Another lap around the neighborhood and the trans now seems much more responsive. Decided I wanted to get a little more aggressive on the throttle, so I went over to a more major road (which has extremely wide shoulders and little traffic, but is still limited to 25 MPH ) and dipped into it oh so slightly. Revving up to 3500 in first gear, this trans shifts very firmly--much more so than the Suburban. I didn't dare hit 35 MPH since this road is a favorite hangout for speed patrol, and I didn't try any sort of tire spinning antics for the same reason. Still, so far things feel pretty fantastic.

When I'm in neutral or park, the engine idles around 1050 rpm. If I'm in gear and I'm holding the car still with the brake, the engine drops way down to 500-550 rpm. It sounds like it is dying, but I think it's actually the car's way of saying it doesn't like sitting still. It would probably sounds pretty wicked if it weren't for the damn exhaust leak at the cylinder head.


The next three things I must do to the car are:
- fix that exhaust leak so I don't asphyxiate myself
- install taller front springs & new shocks
- replace the leaking trans pan gasket (and install a new filter while I'm at it)

My plan is to complete all three tasks this week. To that end, I ordered my new front coil springs & shocks today. While I was at it, I also ordered a LubeLocker gasket for the 4L80E trans pan. Should be fun.

 

[MrSony]

Hell yeah man! Keep an eye on that fluid level in the trans. And that's quite the stinkbug stance you got there. Have you done up the front end, bushing wise yet? Since you're gonna have the front end apart for new springs, I'd go nuts with bushings. Control arm, Sway bar, end links, etc. Maybe balljoints if yours look shoddy. The car is carrying quite a bit more weight than it used to, so I'd be worth it if you haven't already.

 

[Texas82GP]

Congratulations on getting it going. FYI....There is an outfit called JT Raceshop that fabs a floor brace/driveshaft loop that is offset 3" rearward, relative to the stock one.
http://jtraceshop.com/G-body_120103.html

 

[Bar50]

I have only had luck with felcoid? Black pan gaskets on the 4L80. Obviously the cork ones seem to seep all the time. I even have a solid plastic one with a rubber strip made one and steel core...would not seal on a steel/tin pan.

 

[454GrandPrix]

Late this afternoon, I decided to spend "just a few minutes" outside working on the car. Took a peek at a few fluid levels; verified that swapping radiator caps seems to have stopped the coolant leak; then decided to find out why my (AutoMeter) tachometer isn't working. Every time I tried testing for continuity between the distributor's tach output and the under-dash tach input wire, I came up empty. I eventually found out why: I had plugged the wrong wire into the tach input. I made the correction, and was happy knowing that all six of my gauges would at last be working.

Then I started the engine and saw the tach come right to life, but my GPS speedometer was now dead.

To properly troubleshoot that, I'd need to remove the cluster from the dash. I didn't want to do that right now, preferring instead to go for a drive, and that's when I realized my TCU interface/programming module displayed road speed on one of its 'live data' screens. That'll do for now, I decided, so I hastily bent up a small bracket and mounted it to my floor shifter. Good enough for now--let's drive!

I bravely (foolishly?) set out for my friend Mike's place in Pleasant Grove. Driving on Pioneer Crossing let me hit 50 MPH, which is where the TCU locks the torque converter. So far, I've been pretty happy with how it (the TCI EZ-TCU) behaves. This controller allows the user to make all sorts of custom alterations to the program, but I decided not to fiddle with it at all--I just went through the setup wizard and let it take over from there.

As I drove through AF on State Street, I passed my favorite O'Reilly Auto. I saw Eric's black '64 El Camino parked there, so I pulled in so he could come outside and see the car. As we chatted and I opened the hood, he noticed evidence of a fuel leak at the small filter next to the carb. It seemed to be a combination (?) of a chunk of old, worn hose plus a clamp that wasn't doing its job. Eric gave me a piece of new scrap fuel line, I scrounged a clamp out of the trunk of the car, and I spent a few minutes on my roadside repair. It was almost like I was having the full Roadkill experience.

Repair completed, I resumed my journey. I made it to Mike's place without incident. I opened the hood to inspect my handiwork, and everything seemed mostly leak-free. Not waiting for any spoken invitation, Mike just climbed in the car for a ride. (I'm detecting a trend here.) He asked me if I had found the gas pedal yet. When I hem-hawed trying to answer, he chided me: "if you have to think about it, you haven't done it yet." I reminded him that I'm trying to be kind to my brand new engine, but he offered no sympathy.

He lives in the middle of a residential area, so I wasn't about to go overboard. Still, a few blocks later I aggressively pulled away from a stop sign and spun the tires for 10 or 12 feet. He was unimpressed, telling me his ElCo would have been more violent. The smack talk has apparently begun! I'm sure there is going to be some sort of impromptu speed contest in our future.

Anyway, the drive back home went fine. I'm guessing the round trip was 30-35 miles or so. Since everything went so well, I am considering driving the car to work tomorrow.

 

[Bar50]

Set up wizard... I see dump truck shifting envy in the 4L80's future.

Make big block guys everywhere proud.

Strike a little fear in the little motor and weak motor crowd.

 

[454GrandPrix]

Well, I made it to work this morning. On time, even.

 

[TURNA]

I would leave the front ride height alone and just put some 265/60/15's on the back to fill in that wheel well.

 

[Bar50]

Maybe if it was not sitting on the bump stops...

 

[454GrandPrix]

Yesterday I removed the left header to address the exhaust leak. At the same time, I pulled the trans pan to repair the leaking gasket. I took both pieces to work, and put the pan in the parts washer. While it was being cleaned, I grabbed another salesman (who was formerly a tech) to look at the header with me. Using our dealership straightedge tool, we analyzed the situation and brainstormed a solution. We used the hydraulic press to tweak the flange in a couple spots, then we used a large hammer for some 'finishing' work. After all that it still wasn't perfect, but Dave was confident it would seal properly.

So I grabbed the now-clean pan and the header and went back home to reinstall them. I refilled the transmission and started the engine. Lo and behold, the driver's bank is now silent! Well, it's as silent as a big block is gonna get, anyway.

As a test drive, I took it and went back to work so I could dump some fluids into our recycling containers. Now that the annoying exhaust tick is gone, I feel the car is much less embarrassing to drive in public. It does get attention at stop lights. While in gear and holding the car completely still with the brakes, the engine drops to 500-550 rpm. Combined with the fact that (at least one) transmission bell housing ear contacts the body, this makes the entire car quiver noticeably at red lights. I gave my co-worker Dave a quick ride, and when I stopped at a light he said, "I think it's angry we're not moving."

This thing is gonna be a lot of fun.