Yesterday I removed the oil pan and front and rear crank seals from my SHO motor. The engine only has 15000 miles but the seals are still 12 years old. I didn't want to take any chances on leaks so I'm replacing them now while it's easy. The insides of the engine and pan were shiny new. No traces of varnish or sludge. There was a small layer of sludge on the bottom of the oil pan but that's normal. I'm definitely going to take pics of the bottom end of this engine for you guys! It's incredible the amount of design and over-engineering that Yamaha put into this engine. The oil pan isn't stamped steel but thick aluminum with cross webbing everywhere-a very solid piece. Inside the pan is a oil slosh shield and the sump is quite deep. This ensures that the sump stays submersed in oil even under hard braking or cornering. The crank also has a windage tray. This keeps oil from splashing up and hitting the crank, robbing HP.
I'm trying to organize a group buy for the Quaife differentials over at the SHO sites. I think It may be a bust since the diff is so expensive, but I'll wait and see. I may order the gaskets and clutch kit before the Quaife if the group buy takes too long.
I went through the wiring harness on my Topaz and identified all the wires that I needed. Strangely enough, the SHO harness is much simpler to understand. Probably a result of Yamaha's ingenuity. So now the engine bay will await the day I can finally bolt the drivetrain into place permanently.
Since I couldn't do much else with the engine until the new parts arrive, I decided to play around with the rear brakes. I removed the passenger rear side knuckle/brake assembly and compared it to the Taurus's. I was disappointed to see that my original idea of bolting the entire Taurus knuckle onto the Topaz'z strut and cross-members wouldn't work. The 2 cars have totally different ways of attaching the strut to the knuckle. I don't know how I didn't see this before!
But there was no way I was going to let this stop me from having rear discs. So I disassembled the Taurus knuckle and studied it. It's quite simple. A thick plate bracket is used to attach the caliper to the knuckle. The hub and bearings then mount on the spindle over top the bracket. The rotor just sits on the wheel studs and is held on by the wheel and lug nuts. I took the caliper bracket and placed it on the topaz's spindle. The attaching bolt holes were further apart than the ones on the Topaz spindle. So that bracket can't be swapped. So I pressed the Topaz hub out of the drum brake and installed it back on the spindle. I also put the Taurus hub back on it's spindle. The 2 assemblies started to look quite similar. A quick measurement revealed that the distance from the surface of the hub to the caliper bracket mounting surface on the knuckle were exactly the same! What this meant was that all I had to do was fabricate a custom caliper bracket basically identical to the taurus's. Except I would drill the bracket's mounting holes to match the ones on the Topaz knuckle. SO I pulled out some 1/4" plate steel and started tracing the caliper bracket with chalk. I got it about 3/4 cut out when I ran out of acetylene---DAMMIT!! I was really pumped about this mod and seeing it completed.
I had some time left so I started working on the rotor from the Taurus. First, the Topaz hub would not fit inside the hat on the rotor. So I ground about 1/8" off the circumference of the hub and it fit fine. Then I discovered that Ford had played a cruel joke and made the centre bore on the Topaz drum brake slightly bigger than the one on the Taurus rotor. The Topaz hub had a small ridge at the base of the yolk that the centre bore on the brake drum fits around. The Taurus hub didn't have this ridge. So I had 2 choices: either enlarge the centre bore on the rotor or grind the ridge off of the Topaz hub. I chose #1. I tried enlarging the hole with cylinder honing stones and a drill. But the stones had too fine of a grit to make any progress. So I tried an air dremel with a courser grinding stone. I went around and around the hole until it was big enough(about 1/8" bigger) My biggest fear was that I wouldn't grind all the sides equally which would make the hole out-of round. But I think it turned out OK. Once the rotor could fit the yolk on the topaz hub, it was time to drill 3 new holes in the rotor to match the topaz bolt pattern.(one of the original holes could be used since the 2 cars shared the same bolt circles)I center punched the hole locations and drilled them out. The rotor then fit perfectly on the topaz hub!! I had to install the taurus studs into the hub because the topaz studs were slightly different and the rotor wouldn't fit over them.
So now all that is left to do is cut the custom caliper bracket out, drill 4 holes in it to match the 4 bolt holes in the topaz knuckle, drill 2 holes for the caliper to bolt to, and then 3 small holes to attach the dust shield. By this time next week my car will have 10.2" rear disc brakes!!! I'm so pumped about it. I'll be sure to take some pics and post them on my picturetrail site for you guys. If this really works it will be a major break-through for the Tempohiperformance world. Wish me luck.......
Here's what I could come up with as far as cost. For a bolt on kit, I would need to include: modified(used) tempo rear hubs-$60, custom caliper brackets-$40, modified Taurus rotors(new)-$110.
Then you would need to purchase the following parts locally: 2 calipers with pin kits-$160(if you could get them used it would be much cheaper), 2 taurus rear brake lines-$50, brake pads-$35. The taurus dust shields are probably optional but could be purchased cheap from a wrecker.
I still need to figure out a couple things. Like how to attach the e-brake cables to the taurus calipers, modify the pressure retention valve to lower it from 10psi to 2 psi, and re-arrange the brake lines at the master cylinder so the brakes are seperated front to rear as opposed to diagonally as they are now.
So you're looking at about $500 US for the parts for the rear brake conversion. I am not spending near this much as I am using the parts from my parts car. The rotors were in good condition and I hope the calipers are not siezed.
$500 is steep but SHO parts are expensive. I'll update you on the rest of the swap next week. I should have some pics too. Later....
I knew it! I knew it was possible! Nice work duder! Congrats, you've been a pioneer on a number of fronts in our group! Best of luck. I'm really curious to see how having big beefy brakes out back will affect the braking of the car. I wonder if they'll grab more than the fronts and lock up. Eh, an adjustable proportioning valve would cure that. be nice if we didn't need it though!
Thanks HT! I don't intend to leave the front brakes stock though. You're right when you say that having 8.5" rotors out front and 10.2" rotors in the back would make braking unpredictable(and look funny). An adjustable propartioning valve would help but it would simply be reducing the braking capacity of the rear brakes so they don't overpower the fronts. I am going to use every resource available to me to adapt the Taurus front knuckles to my Topaz. If I can do that then I can bolt on any of the upgrades available for the SHO. Anything from the 10.7" stock rotors, to the 11.6" units from the 96+ SHO all the way up to the 13" baer claw system. I'll start working on the front brakes once the rear discs are installed.
One more thing, do you know anyone an the west coast who would be interested in the drivetrain from my Topaz? I've been advertising locally but no luck so far. It includes engine, trans, all belt driven accessories, etc. Only 52,000 km. total cost would be about $1500-$1600 CDN delivered. Thanks!
Congrats on your progress! Keep setting the pace for Tempo high performance! Say, big brakes in the back would really let you powerbrake for as long as you really wanted to, and had money for new tires.
Good luck on the front discs!
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