Jump to content
hornetball

WHAT . . . DID . . . I . . . DO?!?

Recommended Posts

39 minutes ago, RCman said:

I saw your car up there Sunday looks really nice

Wonder if I can get it together for Driver's Edge in a couple of weeks?

Link to post

Deep into the suspension.

Pretty much finished with the front.  I removed the old VBP  fabricated arm/fiberglass leaf setup that isn't legal for vintage racing and installed stock stamped control arms with the 550# "F41" springs and Billies.

Old:

IMG_0432.thumb.JPG.84407a4dbdc65f89e96265d9c973d14e.JPG

 

New:

IMG_0431.thumb.JPG.c52dbfece210a53186eacd7a9544fadc.JPG

 

Control arms were fitted with Made in USA Moog ball joints and grease nipples for the poly bushings.  The way the poly bushings work on these arms is metal-on-metal, so frequent greasing should work perfectly.

IMG_0433.thumb.JPG.fc0cff937a2dd97d3e857669377cdd78.JPG

This is what the old ball joints looked like:

IMG_0439.thumb.JPG.9c506eb3849f9110aa41dde9759adcb3.JPG

Moving onto the rear and driveline, I got it all torn down and have discovered the last of the car's secrets.  Again, I'll be installing the 330# "F41" 7-leaf rear spring with Billies to replace the VBP fiberglass components.  I'm also installing new diff bushings, trailing arm bushings and one U-joint.  Not together yet (waiting for parts), but I can provide some more carnage pics:

Trailing arm bushings:

IMG_0435.thumb.JPG.4cbfe86a981380eec80dea95f1550107.JPG

Trailing arm bump stop perch (it's OK, I enjoy a welding project):

IMG_0437.thumb.JPG.429a8dadcc90c8f7b90de7e8801e3d30.JPG

This is the differential cross-member.  "FWD" in triplicate?!?

IMG_0438.thumb.JPG.e0a1995c1b48abaddb558607e772c4d3.JPG

Full VBP kit for sale cheap -- lightly used ?

IMG_0440.thumb.JPG.04b467153e9f8b7fc1072fe10918e16e.JPG

Link to post

Pressed in new diff bushings and re-installed the diff.  You can see how bad the old bushings were:

IMG_0441.thumb.JPG.b986c025eb2effe2a1fe7ebbb30b7af7.JPG

 

Diff cross-member with new bushings.

IMG_0446.thumb.JPG.ff2fb8a10e0c2e4b940ea3c9c4669eec.JPG

 

The recommendation is to allow the weight of the car to press the cross-member into place with a bit of driving before final torque.  This is to avoid stripping the threads in the frame.  I heli-coiled the threads on the driver side as someone hadn't followed that recommendation in the past.  You can see that I still have a bit of space at the top of the bushing.

IMG_0447.thumb.JPG.f0da5b50caed70727f5f21020b0f8d16.JPG

 

Trailing arms were removed, bushings replaced, brake shields cut out and bump stop landing repaired.  They look nice with a bit of paint.

IMG_0442.thumb.JPG.61ad9ed748e6347aad9f19dd2982eb09.JPG

IMG_0448.thumb.JPG.33853e48866df96b8f62278ff3a1a584.JPG

 

I drilled holes for the cotter pins that retain the trailing arm shims.  The factory started doing this in 1965, but my 1964 didn't have the holes.  When I took things apart, I noticed that I was missing shims on the drivers side.

IMG_0449.thumb.JPG.51921c00bad055dac2fe9a4ecfc46c55.JPG

 

Trailing arms installed.  Putting these in wasn't as bad as I expected.  Nice when something goes easier.

IMG_0450.thumb.JPG.e49bdcf6d870746ee476689d00b05544.JPG

 

Rest of rear suspension assembled:

IMG_0451.thumb.JPG.35b742e6885ae5203c7cbff0e660007a.JPG

 

One more Easter Egg.  Once I got the spring installed, I noticed the driver's side lower shock mount was rotating.  Inspecting further . . . stripped threads.  Parts on order.

IMG_0452.thumb.JPG.b24492a8823707c7a9745e493c0c10c7.JPG

Link to post

I bought a set of PACO Motorsports hubstands to do the setup.  Nice thing about these is I can do caster, camber and toe (including thrust line).  They are drilled so I can use them on the Vette, Miata and Formula Ford.  All I need now is a set of scales for the cars with coilovers.

IMG_0454.thumb.JPG.8dc9676f22b7cc45620a9fb2dcdc64dc.JPG

IMG_0455.thumb.JPG.61a1e2ee7e27a2ba0b6fb68364af7987.JPG

They come with these cool spring-tensioned wires for doing toe/thrust.  These end up being parallel strings if the car has the same track front and rear.  Otherwise, what you are after is a symmetrical trapezoid (equal left and right).  This Corvette had equal tracks and based upon the measurements and shims used, I have a straight frame.  ?IMG_0458.thumb.JPG.fcbc330a1535b0018d7c7c5badda3500.JPG

IMG_0457.thumb.JPG.91265463442abd2e7d788bccd297a0cf.JPG

Using these with a two-post was a breeze.  Measurements stayed consistent no matter how many times I lifted/lowered.  Would buy again.  My camber setup was -1.5F/-1.0R (bias-ply setup).  Caster was 2.5.  Zero toe front and rear.  Ride height 1.5" lower than stock.  If I want to go lower, I need to pull the front springs and cut them -- a project for another time.  Went for a drive on these settings.  On a smooth road the car tracks really well.  It does tend to wander on bumps -- but the caster is a compromise between tracking and manual steering effort.

Also installed a "Spreader Bar" which is a C2/C3 Corvette thing to help stabilize the upper control arms (like a strut bar).  They are mentioned in the Chevrolet Performance book, but I wonder how effective they are?

IMG_0463.thumb.JPG.f6fd91b6eaa66c8da62445af1f94f0ac.JPG

 

This is the harness bar that G-Speed welded in for me.  I painted it today.

IMG_0460.thumb.JPG.7b47c5ad23c6734ff7bc143af59bc57d.JPG

IMG_0461.thumb.JPG.0766528cb2e5140296176eb992be47df.JPG

Getting close . . . .

Link to post

Just an anecdote--    bias tires tend to wander no matter what your alignment settings.  I ran both bias and radial Hoosiers on my RX7, and the bias were very difficult to keep the car pointed straight.  it would wander all over the track on back straight (between 6&7) at TWS- which was where I used to tighten my belts and check gauges.   no can do on the belts because I had to keep both hands on the wheel while straddling the crack all the way down that straight!

With the radials, I could straddle it no problem and the only issues were when I was actually riding over a crack in the pavement. but much more controllable than the bias, which would go whichever way they wanted.

turn-in on the bias going into T1 was also fun.   come off the banking, nail the brakes (pray they work!), simultaneous turn-in & gas, and guess which way the front end was going to point.  You drive with the back end all the way to T2 exit.  With the radials, you still rotate with the gas, but you knew when you turned in exactly where it was going to point once it took a set.

I loved driving the bias because you HAD TO PAY ATTENTION.  never know which way the car was gonna go!

Link to post
3 minutes ago, Matt93SE said:

I loved driving the bias because you HAD TO PAY ATTENTION.  never know which way the car was gonna go!

And . . . all that extra fun costs less too!

Link to post

Harnesses and roll bar padding IN!

IMG_0464.thumb.JPG.8f11aa6f23e6edac7b75f296e42de1a2.JPG

IMG_0465.thumb.JPG.33179bbacb116a98fed6f64ec4b1879d.JPG

The harnesses are Racequip model 855015.  They are enduro-style 6-points (pull-down adjuster at the buckle) with 2" laps and HANS shoulders.  The adjusters seem high quality and they are easily tightened.  Plus, they are red and pretty like the car!

IMG_0469.thumb.JPG.cf920f02325754fc8a33a5e5867f3855.JPG

 

Link to post
On 4/8/2021 at 8:09 PM, El_Tortuga said:

Dayum Rick, its go time!!!

Darn right!

 

Car did well its first time out.  You have to manhandle it, but it's neutral and rotates well.  It was warm today (90F), so a good test for the cooling systems.  Water temps were great (205F) as was oil pressure (always ~50psi, even in the turns).  Oil temp ran a bit high (280F), so I'll need to address that with some oil cooler ducting.  Braking is high effort, which makes modulating difficult.  Man oh man, does this thing eat gas, tires and brake pads!

I'm going to go put it on the lift and give everything a good once over.  All in all, a successful first time out.  Time for a cigar!

<UPDATE> Car checked out good on the lift.  Managed to flat spot one of my fronts.  I've got a feeling that I'll be buying a lot more front than rear tires for this car.  TDE tomorrow . . . .

Link to post

I took it out first session Saturday with TDE.  It hung with the Miatas in the turns!  I was really surprised.  One of the Miata guys reported that it tripods (lifts a front tire) in Little Bend.  That must be a cool sight.  The car is running a big front sway and no rear sway -- which is how I got it and apparently is a preferred setup for small block cars.

Unfortunately, one of the valve cover breathers fell apart (glue failure), so I hung it up.  Have some teething issues to work through, but so far so good.

Link to post

If that's the only failure you had, then great first start!!

Last time I was at MSRC was maybe 10 years ago with a Z Club event.   several Porsches were there as well, and the old 911s really love to do that.  Wish I had video at the time, but I remember rolling thru rattlesnake and wagon wheel behind one car, and there was a front wheel several inches off the ground the whole time except for the L-R transitions in the middle of rattlesnake.  I had a friend riding shotgun and he was dumbfounded.  mostly that I was keeping up with him in my lowly 240sx street car. LOL

 

Link to post
On 4/9/2021 at 5:16 PM, hornetball said:

Darn right!

Car did well its first time out.  You have to manhandle it, but it's neutral and rotates well.  It was warm today (90F), so a good test for the cooling systems.  Water temps were great (205F) as was oil pressure (always ~50psi, even in the turns).  Oil temp ran a bit high (280F), so I'll need to address that with some oil cooler ducting.  Braking is high effort, which makes modulating difficult.  Man oh man, does this thing eat gas, tires and brake pads!

I'm going to go put it on the lift and give everything a good once over.  All in all, a successful first time out.  Time for a cigar!

<UPDATE> Car checked out good on the lift.  Managed to flat spot one of my fronts.  I've got a feeling that I'll be buying a lot more front than rear tires for this car.  TDE tomorrow . . . .

THAT SOUNDS SOOOO GOOOOODDDDD....

Link to post

Addressed some of my teething issues.

Added a remote breather kit from Kevko Racing to clean up the breathing mess.  This will also let me drain the catch tank periodically to keep an eye on blowby.  So far, I haven't had to add any oil to the engine with more than an hour of track time and plenty of street driving time.

IMG_0474.thumb.JPG.2dbdec6d6f0f43b95642a67d0745294c.JPG

IMG_0475.thumb.JPG.84546f2901a8a043a810cee5d0d674f1.JPG

 

I made oil cooler ducting from aluminum angle and bulb seal to address the high oil temperatures I saw:

IMG_0476.thumb.JPG.4860426c83c6b62347b474488dc299a2.JPG

 

I got black flagged for fuel venting when I overfilled the tank and got a siphon going.  To address that, I fabricated a new vent line that goes way up in the air to prevent braking and cornering from creating a siphon.  At $8/gallon, I don't need to be spilling fuel.  The car uses enough as it is.

IMG_0477.thumb.JPG.8c4db543b835d59742b6e10d9915d5d0.JPG

 

After coming off-track at the TDE event Saturday morning, I was a bit freaked out to see that my coolant had changed color.  I didn't know if it was rust or if I had a HG issue.  Fortunately, just rust so I drained the cooling system and am running Evapo-Rust brand Thermocure for a while to clean up the cooling passages.

ECR this weekend.  Let's see how the brakes handle the back straight!

Link to post

Do you have any sort of check valve in that vent tube?  The check valve will do better than the tall vent.   My RX7 vent tube runs straight out the top of the cell and off to the side, but it has a check valve at the tank and another check valve thingy in the end of the vent tube.   I've filled the cell to overflowing to use fuel for ballast weight some times, and nobody has ever mentioned anything to me about fuel leakage.

Link to post

It has ATL's standard rollover valve at the tank fitting.  It works on gravity though, so as long as the car is upright, the vent is open.

Link to post

ECR!  Brake Fade!  Not a surprise really.  I was using cheap pads and fluid because I'm still a Miata guy at heart -- trying to see what I could get away with.  Time to get the good stuff.  I've got Cobalt XR-1s and Castrol SRF on the way.

Other than that, no real issues.  Minor stuff:

1.  That annoying flat spot causing plenty of vibration;

2.  Throttle pedal tends to flop backwards off the throttle lever.  So sometimes I have a hard time picking up the throttle after braking.  Need to secure that.

Car ran all sessions.  Front tires are now gone, but rears still have plenty of life.  Finally added a quart of oil prior to the last session.  Car was consistently doing 2:13s on Sunday morning even though I was braking way early.  Looking at CVAR Group 1 times, looks like the car will be competitive (to the extent vintage racing is a competition).

Here's a few laps from the warm afternoon session before I had to back off to cool the brakes.  Had a passenger and full tank, so max weight.

 

Link to post
2 hours ago, hornetball said:

ECR!  Brake Fade!  Not a surprise really.  I was using cheap pads and fluid because I'm still a Miata guy at heart -- trying to see what I could get away with.  Time to get the good stuff.  I've got Cobalt XR-1s and Castrol SRF on the way.

Other than that, no real issues.  Minor stuff:

1.  That annoying flat spot causing plenty of vibration;

2.  Throttle pedal tends to flop backwards off the throttle lever.  So sometimes I have a hard time picking up the throttle after braking.  Need to secure that.

Car ran all sessions.  Front tires are now gone, but rears still have plenty of life.  Finally added a quart of oil prior to the last session.  Car was consistently doing 2:13s on Sunday morning even though I was braking way early.  Looking at CVAR Group 1 times, looks like the car will be competitive (to the extent vintage racing is a competition).

Here's a few laps from the warm afternoon session before I had to back off to cool the brakes.  Had a passenger and full tank, so max weight.

 

Umm. To quote Eminem, camera shakes like "a donkey with Parkinsons". Fix that and we are looking forward to more of that brake ALL the way in and big power out 'Murica! goodness.

Link to post

Continuing to refine . . .

Trimmed the front springs to adjust ride height and rake (no coilovers allowed in vintage racing -- you have to do it the old fashioned way with a cut-off wheel):

IMG_0499.thumb.JPG.cfb723b754d94a791bbf5baf5a4ea1e7.JPG

 

Replaced the front sway bar.  The car came with an Addco 1 1/8" bar.  The ends of the Addco were angled too much and ate bushings.  It was also too much bar (car pushed).  I replaced it with a Van Steel 1" bar.  In the photos, Addco is on top and Van Steel on the bottom.

IMG_0497.thumb.JPG.9cdb4a341d30c7794c24665a5662d702.JPG

IMG_0498.thumb.JPG.f71f9c124dfd1092522f58024b6f4a7d.JPG

 

Worked some more on oil cooling.  I still wasn't where I wanted to be after the ducting, so I sprung for a higher quality oil cooler (more $) with a more efficient core.  Here you can see the original B&M "SuperCooler" (top) vs. the Earl's "UltraCooler" (bottom).  I fabbed brackets to mount in the original, post-radiator location and was able to re-use the hoses.

IMG_0493.thumb.JPG.91d531d18f3da00da0e70aeb7d496632.JPG

 

Core details (B&M "SuperCooler" top and Earl's "UltraCooler" bottom):

IMG_0494.thumb.JPG.05af42ed5603301c2379d22db1d150df.JPG

IMG_0495.thumb.JPG.c5f43ee34040ed57ec3a69e6adbf8f46.JPG

 

Time to enjoy a sunset with a cigar and Bud Light Lime:

IMG_0496.thumb.JPG.cc1171486eed17ddb4d334b4fb077595.JPG

 

Off to MSR-C:

 

So, how'd I do?  Well, the suspension changes were a big success.  Car is neutral and no longer eats end link bushings.  My corner speeds are within 5mph of the Red Miata and should increase as I gain confidence/familiarity.

Oil cooling still isn't where I want it.  The improved core cooler only gave me another 10F of cooling.  Honestly, I'm really impressed with the cooling/$ ratio of the B&M SuperCooler.  That's also the cooler I've used for years in the Red Miata.  At this point, I need to swap the location of the oil cooler and cooling fan and put the oil cooler up front.  I've taken the "A" part of the heat transfer equation as far as I can.  I now have to increase "Delta T."

Here's another strange one.  The car is tossing front hub dust caps on track.  I may drill 1/16" holes in the caps to relieve pressure build-up from brake heat.  Anyone else experience this?

The journey continues . . . .

Link to post

My RX7 had issues popping bearing caps off as well.  It also oozed bearing grease out the axle stub seals and flung it onto the back side of the brake rotor, or blew the seal off completely.  As you've mentioned, the trick was to drill a tiny hole in the center of the dust cap to vent the pressure. I also used RTV to glue the stub shaft seal and the cap in place, and the problems have almost completely gone away.  no more grease leakage or loss of cap on track, but I still occasionally have to shove the seal back on the back of the hub assembly.

I'm going to chalk that up to 1970s spindle design and metallurgy allowing the small stub shaft to flex under hard cornering loads and the deflection causes the seal to bind and pull out.

Just a thought.  I suspect your car is beefier, but the bearings on a 1st gen RX7 are tiny.  (they are a known wear item on the Rx7-- I repack them every 3 races and replace once a season)

Link to post

Standard C2 spindles are small.  Designed for narrow bias ply tires.  They carried over into the C3 in 1968, but with wider radials being OEM fit to the C3, Chevy quickly upsized the spindles.  1969 to 1982 are a beefier design.  Fortunately, this car already has the 1969+ spindles.  Another deduction at NCRS judging 🤣.  Even the upgraded spindles seem too small for these Hoosier TDRs though.  I experience some pad kickback.

Getting the drill out now . . . .

Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...