The diff swap from Hell. Going from 3.70's to 3.00's which will be a touch friendlier on the highway. 3-4 hour job, right? And that's with the car up on jackstands and crawling around on the floor. Had to pull the backing plates cuz the E-brake cables go through the 4- bar housing brackets. Had to pull the E-brake cables to do that and disassembly of the brakes etc was required to get them out. The housing had to come out cuz scraping the old gasket - which had merged with the powder coating - couldn't be done under the car. Not too bad considering 11 bolts/nuts to yank the housing. Tailpipe hangars had to be removed to let the housing down far enough - sure am glad I bought a trans jack a while back - to miss the additional crossmember at the back of the frame just behind the axle housing. (It holds up the tailpipe hangars - 1 1/2" OD DOM tubing.) E-brake cables had to be cut about an inch shorter to go back into the Gennie Shifter E-brake block. (They'd splayed out a bit.) Figured I was in Fat City driveshaft-wise cuz the new diff had a 1" longer companion flange and I had a spare driveshaft (painted red)1" shorter than the one (bare) in the car. When I fired the car a few years back, it had a 2.73 diff. Way too high. Installed the 3.70 and found the red driveshaft 1" short since the 3.70's companion flange was 1" shorter than the 2.73. Kinda ticked me off cuz the red driveshaft was built with new tubing, eletronically balanced etc. When the Central California speed shop built the new (bare metal) driveshaft for me, we swiped the front yoke off the red driveshaft. Gettin' confused yet? So with the new roadster having a 1" shorter wheelbase and another Buick engine mounted the same place longitudinally I figured I had er made with the red driveshaft. Turns out it was 1" too long for the Detroit Locker that was in the new roadster. (The 32 has a 106" wheelbase and the 31 on 32 rails roadster has a 105" wheelbase.) Surprise, the red driveshaft won't go in the 32's T-400. I find I have a one year series of slightly smaller yokeT-400 and the other car takes the common as heck bigger yoke . . . and I have two of those. Off to the driveline shop, where along with a couple of the right size cups (1 1/16" to 1 1/8") for the rear U-joint that I had in stock I learned a lot of interesting stuff. Swapped the new U-joint with bigger cups onto the rear and put the smaller front yoke on the red driveshaft and it fits fine. So yesterday I bought a longer bolt for the Gennie Shifter E-brake cable block to U-bracket and that should take care of that. Looks like 2-3 more hours of buttoning things up and a speedo gear swap will have the 32 up and running. I hope the new 3.25 diff for the new roadster goes easier. Probably will since the body will be off for plumbing etc. and I'll install that diff then. Nobody said it would be easy, but Geez.... ~~~~~~~~~~~~~~~~~~~ A few days later, the latest with the diff swap: Got the E-brake hooked up, although the 'e' clip retainer on the pin was tough to get in so I substituted a longer pin with cotter pin. (Gennie Shifter gives you a connector kit when you buy the cables and they toss in a narrow U-bracket and short pin for the Vega style hand lever and a wider U-bracket and long pin for the Model A style lever.) Still gotta get a shorter pin in, cuz there's a possibility it will rub on a bolt nearby. So, figuring the trans was drained down low enough I pulled the speedo gear carrier so I could go from a 45 to a 36 and have the speedometer show the correct speed with the 3.0 diff. You guessed it, when I popped the little carrier out, about a quart of ATF went into the sleeve of my sweatshirt and filled it up. What the hell, finished the speedo carrier/gear swap and gave up for the day. Funny part about all this is, I'm a patient and careful worker and not above stopping the job and thinking about it for a day or so. Always other things I can do. Two more little jobs - adjust brakes and bolt up the tailpipe carriers - and I think I'll call it done. Simple Green and cold water got most of the oil out of the sweatshirt. Probably do it again today and if it's clean enough toss it into the washing machine. I was stupid enough once't to wash a batch of red rags in the washing machine and like to never got the machine clean. Darned near got caught by Sweetie. Like someone said once upon a time, "Stupid is as stupid does." ~~~~~~~~~~~~~~~~~~ Some days later.... Got the rear wheels on. Adjusted the rear brakes. Then found the E-brake handle tops out without locking up the brakes. It's close to lockup, but not quite. Adjusted the cable adjusters at the front of the outer cable. Gennie Shifter made this thing too darn narrow far as I'm concerned. No wrench access due to the adjusters are too close together. Mix that in with a somewhat tight area and the adjusters are somewhat useless. Ok, I can loosen the two 10-24 allen setscrews in the cable termination block and slide the cable forward - except I don't want to do that since I'd have to use some Vise-Grips to pull it forward and since the cables are nice and round, not splayed I want to keep them that way. Couple of ways I can go here. Shorter bolt in the termination block (the bolt goes from E-brake handle lower pivot U-bracket to termination block) except you can't hardly get the pin in when it's under a bit of tension even though the hande is released. Drill the threads out of the termination block and use an even longer bolt from there to the U-bracket and adjust it with a nylock. As things stand you can't adjust the tension with the present bolt since the narrow U-bracket requires a 1/4-28 bolt with two opposing flats ground down to almost 1/4" so it will go into the narrow U-bracket. Probably the easiest way out right now is to use the wider U-bracket which I'm guessing is for the Gennie Shifter Model A style handle - mine is the smaller'n a Vega style handle. With that I can use a long bolt, be able to get a wrench on the - doesn't have to be ground down - bolt head, spin the adjustment up to proper and lock it down with a standard nut. Anyhoo, once the E-brake is squared away, the job is done. And you may be thinking, with all the BS that went on, how does the diff work? Pretty good is the report. The speedo is on the money as well. Going from the 3.70 to the 3.00 - which is about 20% change - hasn't affected in town performance to any degree. The trans shifts throught the gears more noticeably. Before, with the 3.70s and light throttle applications you couldn't hear the car shift and it sounded like one gear. On the highway, running 70 mph, the car is @ 2400 rpm. Right at the peak of the torque curve it seems. Before, 70 mph was 3000 rpm. I don't expect the in-town mileage that ran 10-12 mpg to change, but the highway mileage may go up. From 16-17 mpg to - I hope - 18-20 mpg. Vacuum readings at highway speeds haven't gone down too much, but I'll have to check on them next highway run. I thought the 3.00 diff would be a little higher than I wanted, especially so in remembering the 2.73 the car used to have when first started up. That didn't last long and I popped the 3.70's in for improved performance. It is nice to be spinning down the highway at a lower rpm, the engine is quieter and the car runs as smooth as it ever did. In the end, the diff swap was worth all the trouble. Now I just gotta clean up the mess and put the tools away. Sometimes I think hot rods is a funny hobby. A lot of stuff on these little and mostly open cars are easy to work on and I go to great pains to make things accessible and easy to work on, but sometimes things gotta go where they go and we have to live with it. The best part was, the 3.00 diff which looked good, felt tight and turned over quietly with no binding runs quiet and looks to be a good one. Sometimes you gotta work hard for what you want and sometimes just making what should be a bolt-in swap can require some re-engineering along the way. And like the old saying, if hot rods were easy, everybody would have one.... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A previous tech article on E-brake ergonomics with a few pics that may help to illustrate. http://www.jalopyjournal.com/forum/showthread.php?t=297037
Good description. Every time I think I'm getting a good handle on this hot rod stuff, along comes a job that shows me who's really in charge....
yep some times just have to work stuff out! its worth it when yer happy in the end! glad it made ya happy!!!
I am dazzled and amazed. Ran a 3.00 gear in my hiboy for a long time; you will like it. With a 30 inch tire, gives about 30 mph per thousand rpm.
Took almost as long to read that then it did to get your gears swapped! I hate chaning R&P, but damn it's always worth it in the end.
I'm liking it so far. Car is a little quieter, but the wind noise (roadster mit top) seems louder. Runs right at 2400 rpm at 70 - with a 75 per speed limit on the local freeway. I have a 2400 rpm stall converter in the car and thought it would give a few probs heat-wise, but it's running like it did before. Light throttle settings at cruise seem to lock up ok at lower rpms so not a prob there. I made a gas mileage run down the hill - 12 miles down and then back up the steep grade - to Laughlin just for the hell of it. 90 mile round trip including about 20 miles in town at 25-35 mph. Got 15 mpg which bodes well for level ground running. Probably give that a shot next week after the rain storms are gone. That trip usually returns 13-14 mpg. The level ground trip returned 16, almost 17 mpg running 70-80 per with the 3.70's last December and as noted I'm hoping to kick the mileage up about 2 mpg. The mpg gain is nice, but my main interest was in getting the engine down to reasonable rpms in highway driving. 3300 rpm @ 80 is a little high imo. A lot of guys have suggested I simply go to an overdrive and truth to tell I wouldn't mind one, but the car still has lots of performance (462" & 2400#) with the 3.00 diff and 30" tall tires. Since I already have a built T-400 I didn't want to change. I'll be thinking a little harder about an OD in the 31. It has the same power train the 32 does with an additional 40 HP. Gearing on it is 3.25 with 28" tall tires. Which figures out to be about 5% higher than the 3.70 30" tall tires the 32 had. The 31 should come in at 2200# as compared to the 32's 2400#. The 3.70's and 30" tires worked out great in Sunny California. Most times speeds were 65 mph and down. Out here, speeds on the 75 per freeways seem to hover 75 - 80 mph. Gotta keep up with traffic....
C9 so what kind of mileage are you getting now that you've had it running a while? I'm switching from a 3.31 stock rear to a 3.0 ford 8" and of course now I'm re-doing the brake system from the pedal onward...I can't wait though for the taller gears , keep the noise down a bit! oh FWIW I don't expect to get any mileage increase on mine, but you never know
Please don't take this the wrong way , cause I feel what you are saying ..... But dammit man buy a digital camera ! A picture is worth a thousand words .... And they help your memory .
no offense, but i'm so glad to hear that i'm not the only one that has to fight with the seemingly simple stuff. nothing ever goes easy or as planned, for me, haha!
I haven't had a chance to take the car on a long run. Rain, snow, cold, high winds, flu, other stuff. It does seem to be doing better on mileage, but that's subjective stuff with the key word being "seem." A mix of in-town and a little bit of highway mileage. Still pleased with the performance. Right now, trying to get some narrow slot mags polished up for the 32. And . . . collecting parts for the 31 on 32 rails roadster. New starter - cotton pickin' work of art for a rebuilt HD stocker. New flex plate and looking for a converter. Probably a B&M Hole Shot with 2200-2400 rpm stall. I have a 2400 stall B&M Hole Shot in the 32. It flash stalls at 2800 rpm due to the torquey 462" Buick engine. Still working good after 49,000 miles and 15 years. One thing I am looking at doing is firing up the 31's engine as is. I pulled a head and there is no ridge to speak of, more of a pattern than actual wear. I bought the engine out of a big storage shed - that didn't appear to leak in rainstorms - about 7 years back and it looked like it was taken out of a wrecked car several years prior. A 75 model with the good block and very low compression, poor flowing heads with 7.9/1 CR. I like the 9.0/1 CR engine in the 32, but eventually the 31's engine will get a big cam, dual quads etc. Got that stuff on hand as well. 10.0/1 CR is the aim here. And 9.5/1 CR wouldn't hurt my feelings. My pal is forever getting a donor car with good SBC engine, a little cleaning and painting along with a rumpty cam and aftermarket intake and 4-bbl. I've always done the bore and rebuild bit, but if the engine in the 31 runs good, I may run it as is until I get pistons, rings and some different heads. Finding a donor car would be nice, but every time I see a big ol GM car, they turn out to be Chevy's. Should be 70* F weather here next weekend and I'm hoping we'll be through with the chilly stuff for a while. Geez, Laughlin River Run, Harleys, skimpily dressed wimmin, Bloody Mary's for breakfast, beer for lunch . . . we shouldn't have any probs fitting in with all the RUBs. (Rural Urban Bikers.) The bike vendors carry things that work on hot rods so it should be a fun day. Route 66 Fun Run first part of May so I suppose I'll have to wash the 32. Somewhere in there is Viva Las Vegas. (And HF & BassPro is right down the road from VLV.) As well as the Rock A Billy reunion at the Vegas drag strip - if it's still going this year.
Not the same. A 700R changes a 3.7 to 2.59 in OD. In order to have a 3.08 final with a 700R you would have to be running a 4.4 gear
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