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

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TURNA

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Jul 24, 2009
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Is there a posi unit in the rear?
 

454GrandPrix

Master Mechanic
Jul 27, 2016
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There is, though it obviously doesn't work very well. I'm sure it's just worn out. But no worries--I am in the process of ordering a new TrueTrac differential (along with a Strange Engineering c-clip eliminator kit, new 31-spline axles, and 3.55 gears). That should do me.
 
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TURNA

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Jul 24, 2009
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Did you put the additive in with the oil?
 

TURNA

Rocket Powered Basset Hound
Jul 24, 2009
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Socialist NY
What rear is in it now?
 

TURNA

Rocket Powered Basset Hound
Jul 24, 2009
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Socialist NY
Sorry I meant what rear as in 7.5, 8.5. Ford 9
 

454GrandPrix

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(As with many others on this forum, I may need to dump Photobucket and find a new place to host my photos. I decided to try imgur for the following three pictures. So far, so good. Now I need to upload all the rest of them, then go back and insert the appropriate links into this entire thread.)

I've been wanting to install a c-clip eliminator ever since I installed the Ford 8.8 axle in my Grand Prix. I finally acquired the Strange Engineering kit, which also includes an upgrade to 31-spline axles from my stock 28-spline shafts. That means I'll need to swap in a new carrier, so I picked up a Detroit TrueTrac unit with a helical-geared limited slip. Finally, some two-tire hoonage is in my near future! To cap it all off, why not toss in a gearing change? I found someone selling a take-out 3.55 ring & pinion for pocket change, so I'll ditch my 3.08 setup at the same time.

My friend Mike and I tore into the axle Monday evening in his driveway. That evening, we only had time to remove all the stock hardware until the sun set and it began to rain. (Sorry--no photos that day.) Tuesday afternoon was round two, wherein I began by using a hacksaw to cut off the protruding ends of the axle tubes. It wasn't until the passenger one was completely off and the driver one was 3/4 removed that Mike told me to step aside so he could finish the job with his cutoff wheel.

bT9qOqa.jpg


4iI2r2B.jpg


I had insisted on using the hacksaw because I thought the added precision was desirable. I was wrong. After both cuts were complete, Mike used a grinding wheel to smooth off the end of each tube and they both looked fantastic. Oh, well.

Next, axle prep. Strange Engineering "graciously" allows us to press a few things onto each axle shaft, which complicates the install if you don't have a shop press. Lucky for us--and the reason I'm not doing this operation at home--a couple days ago Mike was given a shop press. We immediately schlepped it to his house in my Suburban, knowing it would be used for this job. However, he was only given the press itself. All those other little tools and pieces that come in handy to help you actually press pieces together? We didn't get any of those.

So we improvised:

ynsWIH7.jpg


A random socket, a chisel, an old wheel spacer, a couple brake rotors, some random pieces of steel... anything we could find lying around his place was fair game. It looked comically redneck, but we didn't care. It worked.

With the axles ready to go in, we had to call it a night. Next up: the differential. Stay tuned.
 
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MrSony

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Nov 15, 2014
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Ouch! I'm glad your engine survived. In my case, I made sure to build oil pressure before I first tried to fire the engine.
/QUOTE]
The engine later exploded. RIP 1976 Buick 350. 1976-2003, 2016-2017. :p
 
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454GrandPrix

Master Mechanic
Jul 27, 2016
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IMPORTANT NOTE: I do not suggest anybody recreate our press setup shown in my last post. As it turns out, brake rotors aren't as sturdy as you might think. When you apply lots of force such as shown in our photo, they can crack. Ask me how I know.

It's been a couple weeks since I tore into my rear axle. Pressing everything on to the new shafts seemed easy enough, though it turns out that when the brake rotor broke it prevented us from getting that axle shaft perfect. I didn't know it at the time. As Mike and I were about to focus our attention on setting up the gears and differential, my other friend Matt (who I had wanted to assist with this operation all along) suddenly had a free schedule. With that, I pieced together my car just enough so I could tow strap it across town to Matt's shop. This meant installing the new axle shafts with no differential in the case. My brake drums still had the 4x4.25 lug pattern, so we had to leave those out, too. Instead, I would just bolt the rear wheels directly to the axles themselves.

But what wheels would we use? I wanted to use my matching Z28 wheels, but I could not--they require shank-style lug nuts, and the ones I had been using were 7/16 and thus would not match the 1/2" studs on the Strange axles. The Ford OEM studs were 1/2", but the lug nuts I used for the Mustang wheels had conical seats. In desperation, Mike and I started going through his entire wheel collection to see if he had anything on hand in this bolt pattern that took conical lug nuts. Turns out, he did have something: a set of 19" wheels off a late-model Camaro. He laughed, because without even asking he already knew I was mortified at the thought of putting these wheels on my car, even if only for a few minutes... but I had no choice, so I bolted 'em on for the trip.

At Matt's house, we had to get creative to push my car up his driveway and into his shop. This was easy thanks to his son's stock Wrangler and an old scrap tire to use as a bumper. Just as we were beginning to push, it dawned on Matt that we were using an LJ to push an LJ. He thought that was hilarious.

Despite being the single most embarrassing photo of my car ever taken, I will still share it here so you all can have a laugh:
Kyc7Q3m.jpg


Into his shop it went. Matt did a fantastic job installing the diff and setting up the gears, just like I knew he would. When it all went back together, there was a surprise problem: the passenger side axle moved in and out just a bit. The other side was rock solid. I called Strange for ideas. "It sounds like the pieces are not quite fully pressed onto the shaft on that side," they told me. (sigh) This is the side where the brake rotor broke, and I guess it kept us from perfecting the job. So Matt removed that shaft, put it on his own press, and tweaked it a bit tighter. After a second reassembly, it was perfect. We bled the brakes and I was good to go.

I love having a matched set of wheels again:
SXGCijg.jpg


That brings us to yesterday, which was my shakedown drive. Remember how I used to say this car was a bit tail happy? I was wrong--that was nothing. If any of you out there want a good limited slip diff for your muscle car, I give a hearty endorsement for the Detroit TrueTrac. So far it has turned both tires every time, even when one tire is in loose gravel and the other is on dry pavement. Combined with my shorter gearing, suddenly this car is much more of a handful at full throttle. I quickly realized I ought to avoid WOT anywhere below 60 MPH if there are other vehicles in adjacent lanes, as I don't want this thing to get out of hand and get me into trouble. As it now sits, this car is ridiculously overpowered and is a menace to polite society. In other words, it is exactly what I had always hoped it would be. :)

Hoonage videos are forthcoming, as soon as I can find time to have a friend shoot some.
 
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