Derek Kiefer's 69 Malibu build

[Derek69SS]

Another day, another broken part... Finished 3rd overall raw of 65 drivers (4th in PAX) at the Corvettes of Minnesota autocross yesterday, running all day on only 3 shocks.

An unknown bind occurring at full compression snapped the shaft on my LF coilover on my first run, so I made 6 of my 7 runs, and drove 60 miles home with the shock doing absolutely nothing on that corner. Damage to the shock body occurred from running with it flopping around inside the spring... I didn't realize it was broke, thought it was just a blown shock. Only decently fast way around a right-hander was to be real smooth with the brake, settling it down on the bumpstop before turn-in, and trail braking to keep it on the bumpstop through the middle of the corner.

Last week I took FTD of 58 drivers at a local autocross in Chippewa Falls, WI.

I am now at about 90 runs on last year's Yokohama's, and there's not much left in them.

[andrewb70]

Wow...is this with the QA1 kit with the conical spring set-up?



Andrew

[Derek69SS]

No, this is Alston Varishock with Speedtech Chicane upper mounts.

There is a spot on the frame where the spring was rubbing inside the pocket on full compression. When I checked my clearances, I did not remove the bumpstops, so I think it interfered only when the bumpstops were compressed. I can't remember if I re-checked clearances after changing lower arms either... I did the Chicane mounts in 2019 and replaced the SPC lowers with the beefy new version in 2020. Spring making contact with the frame was putting side load on the shaft. I am NOT blaming the parts for this failure.

[Blown353]

Good catch. It doesn't take much side load at all to tear up a shock shaft.

Amazing it didn't try to spit the spring off the spring seats doing 6 runs and then driving it home with a broken coilover shaft, but I guess unless you have enough rebound travel to unload the spring it would stay in place.

Had a similar thing happen on a friend's 70 Chevelle with hybrid style coilovers that sits pretty low, the top of the coilover body would contact the little tab which is part of the spring perch inside the frame at full compression. Didn't break the shock shaft on his, but did tear up the coilover body and end cap real bad and trashed the coilover. Since the bottom of the coilover body was attached to the lower control arm and because it was a hybrid coilover the upper part of the spring sits in the frame, he didn't notice anything was wrong until it was up on the rack one day and I noticed the top of the shock body was all beat up from hitting the frame and starting to leak pretty badly.

Switched to Global West coilover specific lower arms which dropped the lower mount 1.25" compared to his previous arms, that put the coilover body further away from the frame at full compression and now there's plenty of clearance.

When I do the upper mount coilover conversion on my frame I'll pay extra close attention to clearance through the entire travel range.

Also, I didn't see you mention it, but how's the tire clearance up front with the 295s? Any rubbing, or did you modify the inner fenders?

[Derek69SS]

Also, I didn't see you mention it, but how's the tire clearance up front with the 295s? Any rubbing, or did you modify the inner fenders?

It's really tight, stock inner fenders... 10.5" wheels with 6" backspace.

There were some minor rub marks before, but now lots of rub marks inside the inner fenders after running an event with no compression damping on one side. The big thing is I had it all dialed in on 275/35 and changed to 295/35 which is quite a bit taller.

I'm going back to 275s now due to the 295s being 3 months out for delivery.

[Derek69SS]

This little project escalated quickly.

Thanks to Justin Nall at Vector Force Industries for hooking me up with these Viking Crusader triple-adjustable coilovers and some 850# springs.

I got a little carried away with making room to be sure nothing would bind, which opened up the possibility to move the coilover mount further outboard on the A-arm, which will make for a significant improvement in the motion ratio.

I still have the other side to do, but should go pretty quick compared to figuring out the first one.

[Derek69SS]

I got my first few really professional looking action-photos with the car's new look at an autocross this weekend with Minnesota Autosports Club at the MN State Fairgrounds.









Saturday's fastest run:


Sunday's fastest run:


There were 109 drivers both days. I finished 11th overall raw on Saturday, and 13th on Sunday... 12th in PAX both days, and won CAMT both days.

[JFStAmour]

First time seeing this thread. Great story, great car, and great driving!

[Steve68]

Great Story and Pictures, with lessons for all on the backside,

I have a friend from here in Orlando with a 72' with a lot of the same parts and mods you have, he was on LS1tech conversion page, won the autocross at Chevelbration, beating some big name driver and Car builder and parts manufacture, havent heard from him in a while, motors broke,

Again great posts and Pics

[andrewb70]

It is great to see the progress that you have made and are still making!

Andrew

[Derek69SS]

Thanks everyone for the compliments.
On Father's Day I decided to hit another little local autocross, and talked my wife into driving as well. We ended our day early with a tire puncture on the right-front. I didn't want to de-bead the tire, or wear out the battery on my portable compressor (that I needed to use a couple times on the way home), so we called it quits after our morning runs.

After 118 runs and 1250 street miles on Yokohama A052s, the last 8 being 2-driver 95deg day and forgot my sprayer, the rear tires started to delaminate... this was to be my last event on these tires anyway.





Last night I mounted up new 275/35 Nankang CR-S, as the 295/35 Yoks are unavailable until late summer/fall.
I was planning to buy 2 sets of tires this year, but supply chain screwed up that plan.

[chevelletiger]

This little project escalated quickly.

Thanks to Justin Nall at Vector Force Industries for hooking me up with these Viking Crusader triple-adjustable coilovers and some 850# springs.

I got a little carried away with making room to be sure nothing would bind, which opened up the possibility to move the coilover mount further outboard on the A-arm, which will make for a significant improvement in the motion ratio.

I still have the other side to do, but should go pretty quick compared to figuring out the first one.

How much farther out is the hole spacing on the lca you redrilled?
I'm looking to do this to my speedtech arms since there off as I had to finish weld the tabs for my splined swaybar.
Thanks.
Phil

[Derek69SS]

They're about 1.5" further outboard

[chevelletiger]

They're about 1.5" further outboard

I know the stock motion ratio is about 1.8 from conversations with Tony G,of ABC Performance.

What would it be moved out 1.5?
Thanks!
Phil.
Just as a note,I did some measurements on my speedtech lowers,and I get a motion ratio of .683,if I move mine out 1.5 from what speedtech designed for there motion ratio.

I called them and they said they would call me back with some numbers.

I don't know what stock is because I don't have an original LCA

[Derek69SS]

I was hoping that I could get this finished up before UMI's King of the Mountain, but decided to delete the license plate recess, so that added enough work that it doesn't look like I'll be done before then. The fancy "chrome" paint needs to go on a base finish that has fully cured for a week, so I am already running out of time for that. Steel bumpers will go back on for KOTM, but the fiberglass ones should be completed before SCCA Nationals.

Factory bumpers are 21lbs each, and the fiberglass are 6lbs each, so I am only taking 30 lbs off the car, but at the extreme ends, reducing the polar-moment.

I'm trying some "chrome" paint, which I have never used before, and hoping both the finish and the bumpers themselves hold up to running over cones... adding a splitter would help protect the front bumper though.

The rear bumper fit really well, front was not very good. Both have big seams where the molds came together that required body work.









I cut out the recessed area for the license plate, used foil tape as a backer, and put the first layer of fiberglass on from the back side.

[andrewb70]

If the chrome paint doesn't work out I've seen some very realistic looking chrome vinyl wrap.

Andrew

[Derek69SS]

If the chrome paint doesn't work out I've seen some very realistic looking chrome vinyl wrap.

Yeah, that's plan B if the paint doesn't work out.
I wanted to try this stuff anyway.

I'm most skeptical of its durability. You paint the part with gloss black, let it fully cure, and then spray the chrome over it without scuffing. Experience tells me that will eventually lead to peeling, but I figure it's worth a try.

I will probably go back to steel bumpers in a few years when I race prep my Corvette, and retire this car to "just" street duty... I'm getting real close to scratching off everything on the list that I've ever wanted to do with it, and not willing to cage it for the next-level stuff I want to move up to.

[Derek69SS]

One more goal accomplished with this car; I qualified for the shootout at UMI's "King of the Mountain 4.0" !

That was an awesome experience, and the UMI team puts on an amazing event.
I coned out in the first round, but being part of the show, getting to do parade laps and then throw down a run on a crazy fast course in front of a couple thousand people was incredible!

[Derek69SS]

Here's a drone video of my shootout run, with audio from my in-car added to it.
This was my one and only run on the course, and I got sloppy in several places, hit one cone, and wiggled another.

Sure wish I could have had a 2nd run at the course to clean it up!

[andrewb70]

The drone video is awesome.