Joel’s SL-C Build Thread

[Joel K]

Continuing with the brake install, next up is mounting the parking brake calipers on the rear uprights. I have the RCR supplied optional Parking brake kit. The calipers look great with the SL-C logo and billet aluminum construction. Unfortunately, a number of builders have not been able to get them to grab well and replaced them with other options.

Since I already paid for them I figured let me give it a try and see if they will work out. The end design will probably incorporate a linear actuator vs. the supplied ratcheted handle. But before I get to the linear actuator install I focused on mounting the calipers

Video of the caliper install...

One issue I noticed is that the supplied brackets do not place the brake caliper close enough to the outside perimeter of the rotor. Just eye-balling it, a better location would be to bring the caliper about 1/4” closer to the rotor center. That would increase the contact patch of the brake pads. At this point I’m wondering if this is the reason some other builders have reported that these calipers don’t grab well enough. Here is a pic which shows the excess pad gap...

I milled down the bottom of the bracket to see if I could get the calipers better located. After trimming .2” off the bottom of the bracket, the pad coverage looked much better. I wound up using this as a template for the actual bracket...

Also, I was not looking forward to drilling two holes through the side of each upright to secure the brackets. The ideal bolt is 10mm and that leaves about 2.5 mm of material on each side of the upright so the drilling needs to be dead on. If I got it wrong and drilled through the upright webbing that would be really disappointing so decided to use a different approach.

I noticed some pics of PB caliper mount brackets in Rob Mesa’s and Kurt Hoffman’s build threads. These eliminate the need to drill into the side of the uprights. Rob’s mount to the inside face of the upright and Kurt’s mount to the outside face. Rob has version 1 of the uprights and Kurt has the latest. My uprights are different than either so got the cardboard and plywood out and started mocking up some brackets.

Here is a pic of the three designs I narrowed it down to...

Design #1 Rob Mesa Style - secures the bracket with the wheel hub bolts.
Design #2 Kurt Hoffman Style - bolts to the two threaded holes on the upright used by the GT-R, and are unused on the SL-C.
Design #3 was a hybrid approach, using one of the GT-R holes and the closest wheel hub bolt.

I think all three designs would work and decided to go with design #1 which is similar to many after market brake bracket kits which leverage the wheel hub bolts. I like the fact that this eliminates the need to drill holes in the side of the uprights and I can easily swap to another parking brake solution if this doesn’t work out.

Next step was to mock up a wood version of the bracket. This was a good excuse to purchase a set of transfer punches from Harbor Freight. Should have bought these in the beginning of the build. Saves you a bunch of time and adds accuracy to making brackets.

I used a transfer punch to locate the holes for the hub bolts and also the caliper mounting holes. Notice how much the stock bracket was trimmed to position the caliper closer to the rotor...

Here is a pic of the finished aluminum brackets. Milled the hub bolt hole areas of the bracket down 1/8” to keep the cap bolt heads away from interfering with the screws that thread through the stub axles...

Pic of the bracket mounted on the upright. This bracket places the caliper slightly higher than where most builders have mounted them and puts the caliper at the 3 o’clock position on the rotor...

Pic of mounted bracket with the cap bolts in place...

Pic of the caliper mounted on the aluminum bracket. Fabricated .89” thick spacers to replace the washer stacks...

Pic from above...

Caliper is nicely placed on the side of the rotor at the 3 o’clock position...

With the complete pad coverage on the rotor the calipers seem to grab quite well so fingers crossed they do the job and work out.

Moving on to securing the stub axles and main caliper install.

 

[Joel K]

Minor update, but for the sake of completeness I’ll document installing the stub axles. I haven’t seen this documented in too much detail so figure this might help others.

My kit is a 2018 and was shipped with the C4 bearing hubs. Ideally I’d like to have the upgrade with the beefier C6 X-tracker or C7 hubs, but figure since this is exclusively a street car I can start off with the C4 setup and upgrade at a later time.

With C4 hubs, be aware that you should absolutely not put the car on the ground before you torque up the rear wheel bearing hubs and stub axles. The bearings will fail instantly if the car is rolled without the stub axles installed and torqued.

On my kit the front bearings are Timken and the rears are WBI-513020. WBI recommends to torque the rear bearing to 250 ft-lbs. The GM stock C4 rear bearing recommended torque value is 166 ft-lbs. To add to my confusion I’ve seen GT40s threads on the topic recommending values as low as 120 ft-lbs.

I emailed RCR and they recommended to follow the hub manufacturer spec. I also called WBI and they confirmed 250 ft-lbs is the correct value for their C4 hubs. So, let’s get started...

Tools needed for the job...
28” Pry bar
Anti-seize
36mm Deep Axle Nut Socket
250 ft-lbs 24” torque wrench
A couple throw away open top lug nuts

Short video on the install...

First step - applied anti-seize to the splines on the stub axles...

Instructions from WBI...

Never tighten the bearing hubs with an impact wrench...

To hold the axle in place I inserted a pry bar on the studs. Placed some throw away lug nuts on the wheel studs so they were not damaged. Also decided to apply the parking brake by using a clamp. The logic behind applying the parking brake was to reduce the pressure applied to each wheel stud by the pry bar...

Just a theory, but did not want to put all that force on two studs and then have a problem removing/reinstalling the rotor. When I put the longer studs in the bearing hubs it took extra care to get them to align with the rotor holes so did not want to have to revisit that.

Tightened the axle nut with a standard ratchet then got out the heavy artillery, a Teckton 24” 250 ft-lbs torque wrench. With the 24” torque wrench applying 250 ft-lbs wasn’t too hard and the pry rod barely flexed...

Next step is the caliper install.

 

[Joel K]

Back on post #205 I documented my first approach on mounting the cooling tubes. For the side mounts I came up with the concept of using dual P clamps to securely mount the cooling tubes to the chassis pan. This was a good approach and initial design, however it did not account for mounting the heater and AC hoses.

I reviewed the many SL-C build threads and the different approaches to mounting the heater and AC hoses. The most elegant use hard lines instead of the supplied rubber hoses. After drooling over those designs I realized I’d just stick with using the rubber hoses included in the kit and the other rubber hoses I already purchased.

So the two approaches I focused on were the following:

1)Secure the hoses to the side frame rails with p-clamps or billet AC/Heater hose clamps.
2)Just not secure them at all and let them lay in the side body area.

Since I plan to make close out panels between the interior tub and side frame rails I was unsure whether to also mount the heater and AC hoses there. Just too much going on in the same real estate. Also, those clamps would not be accessible without removing the body in the case I needed to remove the hoses for some reason.

And as far as just leaving the hoses to lay in the side body area I was concerned they could flap around and make noise or squeak when rubbing together. It would make them easily serviceable, but if they wound up making noise it would be difficult to address after the car was finished.

So I came up with a third design option. Here is a basic drawing of the new design...

The new design incorporates a few features:

1)Brackets mount only from the bottom of the chassis pan.
2)Each bracket holds the cooling tube, two AC hoses, and two heater hoses.
3)Keeps all lines separated to avoid rubber hoses squeaking/tapping against each other.
4)Makes removal/install of cooling tubes, heater hoses, and AC hoses possible without removing the body. Not necessarily easy, but possible.

Here is a detailed video on the fabrication...

First step was to cut up the 5/8”x3”x24” aluminum bar into the top and bottom bracket pieces and square up with the mill. Bottoms are 1.25” tall and tops are 3.75” tall. This leaves .5” for insulation around the cooling tubes...

Now drilled holes where the material will be removed from the top of the brackets. I like to drill a hole with a larger bit so it makes a rounded edge with a bigger diameter than the 1/4” end mill. Also drilled the 8mm mounting holes in the bottom bracket halves and 6.7mm holes in the top bracket halves...

Now trim the top of the brackets leaving only a mounting point for the P-clamps. Also tapped the M8 holes and drill 5mm holes for attaching the P-clamps...

Here is a pic how the p-clamps attach the hoses on the brackets...

After that, secured the brackets together with M8 screws and use a 1 5/8” hole saw to drill out the clamps to hold 1.5” cooling tubes. Here is a pic of the brackets completed without the 3/32” silicone rubber strips installed...

Drilled holes for the cooling tube brackets leaving a 1/4” gap between chassis and bracket on the passenger side and 5/16” on the driver side. The gaps will provide room for brake lines, heat barrier, and sound deadening...

Passenger side Hoses installed. Used multiple P-clamps to secure the heater and AC hoses to the top of the bracket. This will provide enough separation to avoid any squeaking and keep them quiet...

Pic from the front, will probably install a hose separator or stand-off to secure where they collect to keep them from knocking together...

Driver side hoses installed. You see the vacuum and radiator bleed line hoses. Will add another stand-off with hose clamps near the front corner...

Now that these are done, time to line up the remaining unwelded cooling tube sections, mark them and send them off to the welder.

 

[Kurt Hoffman]

I was so proud of how my hose routings looked, then you had to go and one up me Joel! Now I’m depressed. Oh well, no one will ever see them.

All kidding aside, nice work. Those brackets were an excellent idea and turned out very nice. Your catching up. I’ve hit a snag with my windshield install I need to figure out and have a lot of business travel keeping me away from home and the SLC.

Keep up the great progress. You need to get ahead of me again so I can copy your great ideas.

 

[Hector]

Wow!! Joel you took building brackets to a new level . Amazing work , truly truly impressive , I feel like a total slacker just attaching the hoses to the frame with clamps LOL!! The spacing for insulation purposes is also very wise . I was able to get the parking brake caliper fully engaged, except mine is not centered. Fingers crossed that the caliper size and clamping pressure are big enough at least to hold the car on a mild slope .

 

[Joel K]

I was so proud of how my hose routings looked, then you had to go and one up me Joel! Now I’m depressed. Oh well, no one will ever see them.

All kidding aside, nice work. Those brackets were an excellent idea and turned out very nice. Your catching up. I’ve hit a snag with my windshield install I need to figure out and have a lot of business travel keeping me away from home and the SLC.

Keep up the great progress. You need to get ahead of me again so I can copy your great ideas.

Thanks so much Kurt, sharing all of our ideas and progress is a lot of fun. I’m actually switching roles in June which will eliminate most of my travel schedule so looking forward to continuing the progress.

 

[Joel K]

Wow!! Joel you took building brackets to a new level . Amazing work , truly truly impressive , I feel like a total slacker just attaching the hoses to the frame with clamps LOL!! The spacing for insulation purposes is also very wise . I was able to get the parking brake caliper fully engaged, except mine is not centered. Fingers crossed that the caliper size and clamping pressure are big enough at least to hold the car on a mild slope .

Thanks Hector. I am really giving my Harbor Freight mini mill a real workout. I enjoy milling so much that I think I come up with ideas just to use it! LOL. Anyway, thanks again for the feedback.

 

[Hector]

Thanks Hector. I am really giving my Harbor Freight mini mill a real workout. I enjoy milling so much that I think I come up with ideas just to use it! LOL. Anyway, thanks again for the feedback.

I have a tiny desktop cnc milling machine , plan to use it to make interior pieces such as machined labels on the aluminum knobs , need to figure out how to program it . That mini milling machine is nice!! I wish I had enough room for one

 

[Joel K]

I have a tiny desktop cnc milling machine , plan to use it to make interior pieces such as machined labels on the aluminum knobs , need to figure out how to program it . That mini milling machine is nice!! I wish I had enough room for one

CNC is really cool. I think I may get into 3D printing for the interior. Right now I have no knowledge of CAD or 3D printing, but impressed with what the other builders are doing with them.

 

[Joel K]

Time to finish up the brake work with the caliper Install. I have not settled on a color for the car yet so holding off on changing the color of the calipers. Also, I think the dark gray calipers look good with the gunmetal wheels so I may just leave them as is.

Here is a video of the install...

First thing I did was apply anti-seize on the face of the hubs, this prevents the rotors from rusting and adhering to the wheel bearing hubs. The car will always be garage kept and will be rarely driven in the rain so more than likely that will not be a problem, but the anti-seize can’t hurt...

Next step is to install the banjo fittings on the calipers.

RCR supplied two long neck straight and two 45 degree banjo fittings. The straight banjos were oriented pointing in toward the chassis on the front calipers. The rears were positioned up and forward of the toe bracket spacer.

Here is a pic of the rear line orientation. I may put a brake line clip on the toe rod, but not sure that is necessary...

The rear line from behind, plenty of length for adding some negative camber and toe in...

I replaced the front banjos with short ones from Earl’s to minimize the rotation of the line when the uprights turn. To me it just seemed like a better choice....

Also used longer banjo bolts. These are made by Earl’s, part #425977517ERL...

Applied a very light coat of anti-seize and torqued the banjo bolts to 20 ft-lbs. I tried to torque to 30 ft-lbs but the banjo kept rotating. I noticed at 20 ft-lbs the crush washers actually crushed pretty well so for now I’ll leave at 20 ft-lbs.

Next step was to install the calipers. I applied a small amount of anti-seize and torqued the front bolts to 95 ft-lbs and the rears to 75 ft-lbs.

Before I installed the front pads I applied some brake grease to the pad ends and pins. Permatex Ultra Disc Brake Caliper Lube is a highly recommended brand so I used that...

Pic of the front brake pads, they are unidirectional and the arrow points in the direction of wheel rotation. They also have these attachments known as roller skate wheels which are supposed to keep the brake pads quiet and reduce vibration...

Pic of the installed pads before I tapped the pins in to secure them. Make sure the pin ends are seated in the outside holes in the caliper before you tap them in. I used a counter punch and hammer which worked well...

On the rear pads, brake grease was also applied to the anti-squeak shims. Brembo includes the grease for the rear pads...

Installed the pads and retaining clips to finish the job. Pics of the Gunmetal wheels with the stock caliper finish. This combo I think would go with any body color. Installed Gorilla Open top steel lug nuts, really nice. The stock lug nuts would not clear the longer studs.

Front wheel and caliper. These are the 19” front wheels and you can see there is more than enough room for the roller skate wheel attachments on the brake pads...

Rear wheel and caliper. These are the 20” rims...

Next up is to get more cooling tube sections welded and place the body on for the second time.

 

[JohnP]

Hey Joel,

Please check out our brushless fans from Delta PAG. They're really very impressive and full digital controls and variable speed. They move a tone of air and also a lot thinner and lighter. Check them out at let me know what you think deltapag.com

Take a look at a customer review:

All the best,
John

 

[Joel K]

Starting to think about the final engine installation. One small item on the list is to re-clock the alternator to get the charging post away from the frame.

Early on in the build I purchased the alternator from GM that goes with a stock LT4 engine. Turns out since it is a PWM controlled alternator it is more complicated to wire it up and get it to work at the correct voltage.

Anyway. This post will focus on re-clocking the alternator and the tools necessary for the job. I’ll cover the wiring and controlling the alternator in a future post.

Pic showing the original location of the charging post at the 9 o’clock position…

You can see the charging post is too close to the frame and to avoid a short I wanted to move it to roughy the 6 o’clock position…

I tracked down that a company named Litens makes the factory GM decoupler for many late model GM alternators. They have a YouTube video showing how to remove their various decouplers…

Here is a video link to re-clocking my alternator…

Purchased a 10mm nut diver from Rock Auto and the 17mm hex tool from eBay.

1)10mm Nut driver pulley removal tool - Gates 91024-4
2)Alternator Decoupler Pulley Tool - H17 x H19 - Gates 910243

1st step was to remove the decoupler dust cover. Unfortunately this is designed as a throw away part and you have to pretty much destroy it in order to remove it. Poked a hole in the center and pried it off. Litens does sell replacement caps, for the low price of $20 you can get a new one.

Then used the pulley tool to remove the decoupler by turning the 10mm hex end of the alternator shaft clockwise while holding the decoupler steady with the H17-H19 tool. Pic of the alternator without the decoupler dust cover…

Next step was to remove the rear plastic cover and the 4 long screws which hold the front and rear aluminum alternator housing ends together. After gently tapping the front alternator housing cover with a rubber mallet it loosened up and I was able to rotate and re-clock it. You can see the charging post is now pointing down…

Reassembled the alternator housing and reinstalled on the engine. You can see the charging post is now at the 6 o’clock position which should work out well.

Pic from the side.

 

[Steven Lobel]

Awesome work. You know 99/100 would put a nut on the post and cut it short. You did the correct way.

 

[Joel K]

Awesome work. You know 99/100 would put a nut on the post and cut it short. You did the correct way.

Thanks Steve, appreciate the feedback. Part of the fun is learning. Now I know more about decouplers and 3 wire alternators than I ever thought I would need to know.

 

[Joel K]

Time to revisit the body fitment. This post will focus on the fore-and-aft placement of the body.

The first fitment was just to confirm if the front clam would clear the mocked up radiator and shroud which was shifted forward to clear the power brake booster. In the first fitting I left the body where it was mounting by RCR. Although the car was not delivered as a roller they did attach the tub and body to the chassis primarily to fabricate and install the side impact bars.

This is the first time I’ve seen the body on the car with wheels. Just loving the look of the SLC…

This is the second fitting. The following lists what I wanted to accomplish by fitting the body again at this point in the build:

1)Now that the chassis is square and the ride height is set I wanted to see how well the wheels can be centered in the body.
2)The final placement of the dashboard is determined by centering the body over the wheels.
3)The steering column placement and angle is determined by the dashboard placement. I wanted the steering wheel centered as best as possible in front of the driver binnacle. This gives me a chance to fine tune what angle and where the steering column mounts.
4)The angle and placement of the steering column determines placement of the driver’s seat.
5)The driver’s seat angle and placement determines pedal assembly placement.
6)See if the body clears the AC and heater hose bulkhead fittings
7)Confirm the front clam still clears the radiator which has been moved forward 1” in order to clear the brake booster.
8)Lastly, I can now position the intercooler brackets and attach them to the chassis.

Here is a link to the video covering the process…

The general approach was to place the body on the chassis without the tub installed. If the body lined up well then install the tub and see if the fit could be duplicated.

So without the tub installed, I centered the body over the front wheels. When I did this, the right rear wheel would need to be moved forward about 1/2” in order to center. The left rear wheel would need to be moved forward about 3/8”.

When looking at the rear suspension, the washer setup looks like it could move the rear wheels forward by about 1/4”. Any more than that would require removing all the washers including the safety washers which sit in front of the rear control arms.

Another approach would be to leave the safety washer in place and also turn the rear heims out which rotates and moves the hub forward. I did not want to do this because I was concerned the tires would stick out too far from the body.

So by moving the body rearward 1/4”(where RCR mounted it fore-and-aft) puts the rear wheel adjustment within range. That leaves the front wheels too far forward by 1/4” which then requires them to be pulled back.

As a point of reference, the cup holders are .25” from the rear chassis cross member.

Ride height is simulated with the anti-droop rods installed. Currently set at 4.25” in the front and 4.75” in the rear. Probably go to 4.5” in the rear when I set up the car for real.

With the chassis squared up, here is how the wheels lined up. All measurements are from the rim and the fender edge. Pretty happy all these changes can all be accomplished by adjusting the suspension.

Right side…

Left front…

Left rear…

To correct the right rear and move it forward .2” I removed two washers in front of the heim joints both top and bottom. Still have 1 washer and safety washer left top and bottom if more adjustment needs.

Updated right rear control arm setup…

Updated right rear results…

To correct the position on the front wheels I turned the rear fork heim joint on the upper control arm in two turns and removed one washer behind each heim joint. This moves the front wheels back about 1/8”. These adjustments also increase the caster although I don’t know how much at this point. The front wheels still need to move back another 1/8” so planning on turning the front fork heim joint on the lower control arm out which will move the wheel the rest of the way and probably reduce the caster a bit and hopefully the caster setting is within range.

Updated front control arm setup…

Updated front results…

Also checked the fitment for the AC hoses and radiator. Happy to report that both fit nicely with a little clearance. I will put a washer on the inside bulkheads for the #8 AC line and one of the heater hoses just to provide a little more clearance.

Pic of the AC and heater hoses with the body on. Just fits…

Lastly, a few comments regarding the tub placement. For some reason the tub appears to have been mounted too far right about 1/2”. There is little to no room for error with regard to placing the seat between the center console and the side impact bars. So having to move the tub to the left 1/2” to center the body creates an additional challenge of mounting the driver seat. I’ll cover the details in a future thread.

 

[Kurt Hoffman]

Nice work Joel. Your results are making me feel much better about the similar adjustments that I need to make once I get back out into my shop.

 

[Howard Jones]

Have you checked out your suspension alinement setting after setting the body in your proposed position? Also, the windscreen fit is a very important factor before setting on the center section's final position.

By the way, whitch HF mill did you buy? I am getting closer to buying some machine equipment myself. Could you post a picture of your mill setup ?

 

[Joel K]

Have you checked out your suspension alinement setting after setting the body in your proposed position? Also, the windscreen fit is a very important factor before setting on the center section's final position.

By the way, whitch HF mill did you buy? I am getting closer to buying some machine equipment myself. Could you post a picture of your mill setup ?

hey Howard. The suspension was squared up, zero toe, zero camber. There Is a margin of error in there and my guess is +-1/8”. Based on the changes I made I think the right rear is now .2” forward of the left.

The main reason to put the body on was to see how thing’s aligned and make some changes. Also, just wanted to see my margin of error for mounting the seats and intercooler brackets. When I mount them I’ll leave +- .5” so if the body needs to shift forward or backward I won’t have to move them.

I may find once I have it aligned add some toe and camber things may need to change a bit more but based on what I have read to start with zero toe and camber is the recommended approach.

Here are some pics of my mill setup. All in all I have been very satisfied with the Mill from HB. I bought it to make 1/4 scale RC car parts never anticipating I’d be building a component car. LOL. Certainly a light weight machine that is best for aluminum, but I have machined some mild steel parts. You just have to know the machines limitations and work around them.

All the parts I have made for the build I used this machine and replacement parts are readily available from littlemachineshop.com. I added an automated sherline rotary table which works great and a 3” vice. I absolutely enjoy milling and making parts. Also have a hold down clamp set which is a must. Have had this machine for 5 years and has been trouble free. And I’ve abused it for sure. Happy to discuss.


Here are some pics. Excuse the mess, never cleaned up after fabbing up the cooling tube brackets..

 

[Howard Jones]

That is a nice little mill. I can see that it would be limited as far as how big things can get but for the most part, it's the little stuff you need to make most often.

So I completely agree with the zero toe and camber starting point. From here any final suspension setting changes will give you more clearance. However, there's still caster. The default setup as I understand it is equal numbers of washers in front and behind the rod ends both top and bottom A-arms. I did it that way and when I measured the caster I found that I had just about 6 degrees upfront. I liked how that drove so I have never changed it. At the rear I never measure it but again I like the way the car feels so it's remained that way for years. Just be aware that too little caster will make the car darty and looking to drive itself whereas too much will make it hard to steer. But if you are between about 5 1/2 and 7 degrees it will work pretty well. I would not recommend too much out of that range. Less than 4 and more than 8 wouldn't work IMHO.

I would just measure caster before you finalize body placement. Once it's on...............well you know what I mean. AND don't forget to finalize the windshield fit before placing the body for good.

 

[Joel K]

That is a nice little mill. I can see that it would be limited as far as how big things can get but for the most part, it's the little stuff you need to make most often.

So I completely agree with the zero toe and camber starting point. From here any final suspension setting changes will give you more clearance. However, there's still caster. The default setup as I understand it is equal numbers of washers in front and behind the rod ends both top and bottom A-arms. I did it that way and when I measured the caster I found that I had just about 6 degrees upfront. I liked how that drove so I have never changed it. At the rear I never measure it but again I like the way the car feels so it's remained that way for years. Just be aware that too little caster will make the car darty and looking to drive itself whereas too much will make it hard to steer. But if you are between about 5 1/2 and 7 degrees it will work pretty well. I would not recommend too much out of that range. Less than 4 and more than 8 wouldn't work IMHO.

I would just measure caster before you finalize body placement. Once it's on...............well you know what I mean. AND don't forget to finalize the windshield fit before placing the body for good.

Thanks Howard, always appreciate you keeping an eye on the builds and providing advice. Totally agree with the above, definitely not rushing to mount the body and understand you don’t mount the body until the windshield is fitted.

Once I make the next adjustment to the front lower forks I‘ll take a caster measurement and if it is in range I think I’m in pretty good shape.