Sunday, April 27, 2014

Sway bars

Fitted the new Hotchkis sway bars. The front is a 1.25" hollow bar

and the rear is an adjustable type with 3 settings. Nice bits of gear!

Thursday, April 24, 2014

Diff build

My shiny new freshly built diff! Follow along and I'll go through how I built it up.

You need a few specific tools to build a diff properly, some you can make yourself, some you have to buy. Here is one of the tools I made, a spanner for holding the pinion flange while installing and removing it (which you have to do a lot!). I made two different ends, for the two common Mopar universal joint sizes.

One of the most vital tools you need and want is an impact wrench. Beats the hell out of doing things with a socket! You'd be at it forever...   Here I'm installing the pinion gear in the housing, along with the pinion flange. I used a kit that allows you to shim the pinion gear to adjust the bearing preload, instead of the usual collapsible spacer (or crush sleeve as its known).

You use the appropriate shims to get the correct bearing preload, which is 20 inch pounds for new bearings. This little inch pound beam-type torque wrench is used to check the turning torque (it bends as you turn it around, allowing you to check the resistance on the little scale).

I pressed the carrier bearings onto the Auburn Sure-Grip limited slip differential and bolted on the new 3.55:1 ring gear.

Once your pinion bearing preload is set and you've estimated your pinion depth shim (by checking the shim that was on the old pinion gear in the case) and placed the appropriate shim under the bearing (I used a dummy bearing to set this up, where by I bought another identical bearing and ground out the inside diameter so that it slips on the pinion gear as opposed to having to be pressed on and off, which greatly speeds things up and prevents damage to the bearing and the shims), you can install the carrier and ring gear into the housing. The spanner shown is another tool I made. It's for adjusting the gear backlash and carrier bearing preload.

Gear backlash has to be between 0.006" and 0.010" and is checked with a dial indicator.

Once the backlash and carrier bearing preload is set you can check the pinion depth by testing the wear pattern on the ring gear with special non-drying ferric oxide paint. This photo shows my final pattern with 0.030" pinion depth shim and 0.008" back lash. Perfect!

And that's it! Here is the finished diff and some of the tools and bits and pieces that I used. I'm looking forward to seeing how the limited slip and 3.55:1 gears change the feel of the car, no more peg legged 2.76:1 geared diff! Huge thanks to Cass aka Dr Diff for his help and advice (and the new parts)!

Tuesday, April 15, 2014

Drums redux

As part of the second shakedown test-run I'm building up a new diff with 3.55:1 gears and rebuilding the rear drums. Here are the parts after a thorough wire wheeling. Years of abuse and road grime leave these parts caked with greasy dirty mess.

Freshly sand blasted, solvent washed, prepped, and painted and good as new! I drove the old pinion bearing races out of the diff center and new ones back in after the paint job.

Here are the parts of the drums before a soak in white vinegar or a sand blast, depending on the part.

And those same bits after being cleaned up and painted or restored.

The freshly rebuilt drums with new Firm Feel race shoes. The drums will only be temporary until I decide if I'm sticking with the 15" wheels or going to 18"s. But it was a good exercise to rebuild them, and don't they look great!

Monday, April 7, 2014

Shakedown II work

While the cuda is in a running state, and before I pull it apart and finish the body and paint, I decided it would be a good time to mockup and test the modified steering, braking, and suspension setups that weren't on the car for the initial shakedown. So I've been working lately on getting those things ready for another little shakedown run. This image isn't really showing any of that, instead it just shows a rough cardboard rear spoiler mockup, but it makes for a nice first image! The final spoiler will be made out of alloy with the little braces and bits riveted together. I really like the little led brake light and empty tail lights, looks rad!

This is the new hydroboost unit and its accompanying master cylinder. This unit uses power steering pressure to boost the brakes, as opposed to engine vacuum. These things are a hit on the pro touring scene and give you good power and better reliability apparently, and also let you run a big cam without worrying about lack of brake boosting at idle or low rpm. I am thinking of replacing the hydraulic lifter cam in the motor with a big solid cam...

As I'm running hydroboost and a steering quickener I thought it would be a good idea to have a power steering fluid cooler in the mix to make everything happier when it's being thrashed. I made this alloy bracket to mount the cooler in the engine bay.

Here's the cooler in place roughly where the battery used to go. It's plumbed into the return line from the steering box, with a Y junction just after it and before the reservoir tank, with the other inlet on the Y taking the return line from the hydroboost unit. The cooler will have fresh air ducted to it from a NACA duct in the hood.

This shot shows the whole setup, with the KRC pump, hydroboost unit, cooler, and braided stainless high pressure lines. I love the no-nonsense industrial/racecar look!

I've also added a Moroso air-oil separator into the PCV vacuum line to catch excess oily mess before it goes into the intake manifold.

And I've added this nice little alloy radiator overflow tank.

 All together I think the engine bay is looking fantastic. I love it!

The new Mcleod Racing clutch I've got has a different pressure plate finger ratio from stock, so I needed a pedal stop to limit the travel of the clutch pedal. The factory ratio is 6:1 and the new plate is 4.8:1 I believe, so it's a wicked short pedal throw.

The stop bolted in place. Feels nice and solid and you can really stomp on the pedal, without fear of bending the pressure plate fingers or damaging the Z bar clutch linkage. The 10mm nut I had previously welded onto the firewall for just such a purpose came in very handy for mounting the stop!

Here's one of the new 11.75" 'cop' rotors with 3" long Moroso wheel studs. I have Firm Feel race pads for the factory calipers and the rear drums and that along with the hydroboost, adjustable proportioning valve, line locker, and cooling ducting, are the extent of the brake modifications I'm doing at this stage on the car. I'm unsure as to whether I'm sticking with 15" wheels and tires or going to 18" so I don't want to go all out and stuff the baddest brakes I can into the 15" wheels only to have to replace it all if I go to 18"s. I want to keep the 15"s as they match the tough old school look I'm going for on the car, but they are heavy and won't handle as well as modern 18" setups, so if they end up being too much of a limiting factor then I'll go to 18". And then of course fit the biggest brakes I can inside them. So the setup above is just the bare minimum for now, and should give good performance on the street, while lacking a bit on the track.

I'm running the rear brakes for this second shakedown run, and have temporarily plumbed the line and the line locker inside the back seat area. There's an illuminated rocker switch controlling the line locker, which is just there for testing purposes and not for doing wicked mean skids honest!

I've also installed the modified column with the 1.5:1 Coleman Racing steering quickener grafted in. I can't wait to see how this feels! The Hotchkis E-Max has a similar setup and apparently has "magical steering", so it should feel pretty good! The factory steering is slow and way too over assisted with no road feel at all, and rack and pinion conversions have too many drawbacks, so a setup like the above gives heavier faster steering with more road feel. Just the ticket!

While I love the factory pistol grip Hurst shifter and will be running one with custom carved wooden grips in the finished car, I also have a soft spot for the classic Hurst white ball. So I bought one and made a quick custom handle for it, just for this shakedown run. Looks rad in the stripped black and gray interior!