Haggard-hawk

**Catmaigne** · 08-02-2021, 02:19 AM

Had to brush up on my coding skillz, but I'm ready to test out this HUD speedo in the car. It's an Arduino Nano and Adafruit 7-segment display that reads off the VSS. I'm testing it with a cheap signal generator.

**shownomercy** · 08-02-2021, 08:39 AM

Where are you planning on stashing the display?

**Catmaigne** · 08-02-2021, 04:19 PM

Originally Posted by shownomercy

Where are you planning on stashing the display?

I'm gonna stick it close to the bottom of the windshield most likely.

**Catmaigne** · 08-07-2021, 03:33 PM

A friend cut me a deal on some old parts. They're 1.7 ratio NSA Scorpions, 7/16" ARP studs, guideplates, and a set of stock heads with a Crane 10308-1 kit on it. He went a little ape on the rockers with the belt sander in order to clear the studs, but he ran it that way for years with no issues. I still have to finish grinding the backs by the pushrod cups to clear the stock valvecovers though.

0807211503.jpg

Didn't want to run the Crane kit because I think the pressures might be a little too much for the stock timing chain at 130k, so I picked up a cheap set of Howard's 98212 springs with in intent of pulling the dampers out and running them with the stock retainers/locks.

0805210308.jpg

I installed the springs on one bank, but I took a closer look at the stock retainers and found some ugly stuff. I can't tell if what I'm looking at are stress cracks from years of abuse, or just imperfections from manufacturing. I compared the stock retainers to another set of stock retainers from a pair of 561 heads I had sitting on the shelf. There weren't as many surface imperfections because they appear polished, but I found a hairline crack on one of them upon closer inspection. They're only about .056-58" thick where the spring sits, whereas most aftermarket stuff is .080+.

Figured it was time to stop being a cheapass, so I ordered Comp 742-16 retainers and 601-16 locks. Hopefully the installed height comes out fine and I don't have to shim anything, pull the seals, etc.

0807211506c_2.jpg

0807211507_2.jpg

@joelster I'll be running an autox + track sprint at Pocono on 8/14 if you're interested. This is assuming the valvetrain goes together smoothly, which I'll know monday when the retainers/locks get here.

**shownomercy** · 08-07-2021, 03:43 PM

Pocono raceway as in the one in Long pond PA ya?

Also, oooof on that clearance, is that really required? First time I have read about it

**Catmaigne** · 08-07-2021, 05:09 PM

Originally Posted by shownomercy

Pocono raceway as in the one in Long pond PA ya?

Also, oooof on that clearance, is that really required? First time I have read about it

Yeah, that's the one. Same place I ran the track night and a few other autox events. Always a great time going there because the people are really relaxed (unlike NJMP and their billion rules).

234120984_10158613798199615_2845058441672296074_n.jpg

And I think the Scorpions always require more work because they're pretty fat compared to other rockers. I have the same exact rockers on my Roadmaster and had to do the same thing, although I didn't overdo-it and my handiwork was way cleaner lol.

**Catmaigne** · 08-15-2021, 12:57 PM

So the Comp retainers I ordered lowered the install height to 1.7" which was the opposite of what I wanted. Even +0.050 locks wouldn't push the installed height high enough, so I gave up and installed the Crane duals. I found that using stock locks in the Crane kit pushed the installed height up another 0.025" which dropped the spring pressure a tiny bit.

I also drafted a tune and did some logging to make sure the rockers weren't causing any false knock. Never logged this car before and just assumed it was healthy because I previously raced my friend's LS1 z28 vert and won by a small margin. It always felt kinda sluggish to me though, but I chalked it up to the fact that my other cars have way more power and gear.

Anyway, the datalog showed that the right bank was running consistently lean with BLMs in the low 130's to 140. Swapped out the OEM O2 sensors and saw the same phenomenon. Checked the right bank header primaries with an infrared temp gun and noticed that the cyl #4 temp was considerably lower than the rest. Also ran a cylinder strength test in EEhack that showed cyl #4 as being unusually strong, so I pulled the #4 injector plug with the car running and the idle didn't change one bit. I then tried actuating the #4 injector manually with some alligator clips hooked up to the battery and couldn't get it to click, whereas all the other injectors on the car did. Thing was definitely stuck because I swapped the injector out for another stock one and BAM, it feels like I gained 50whp. No more goofy BLM issues and the car drives better than it ever did, especially under 1.5k. I think I've been running on 7/8 this whole time (deja vu).

Ran the car at an autox/track sprint event at Pocono yesterday and it did great. I only ran about a second slower than my friend's Mustang on RE71R's, even with my crap tires. Really gotta work on my downshifting though as I screw up occasionally and let the clutch loose too quick. I've never experienced axle hop before so that was a first. I might try to figure out a way to reconfigure the pedals so I can attempt to heel/toe downshift, or at least extend the throttle pedal over so I can blip it with the side of my foot during hard braking.

I think I also figured out the secret with these cars is to run the rear tire pressure 5-10psi lower in the rear than the front. Even pressure on all 4's seems to make the back very squirrely.

Next event is a track night at NJMP later in the month, then another at Pocono next month. Might try to cram another event in before the year ends.

**rentedmule** · 08-16-2021, 07:14 AM

Great that you found the dead cylinder and freed up some ponies. The downshift axle hop and tire pressure discussion sound so familiar! I definitely still struggle with the heel-toe DS and get axle hop every now and then. I missed a heel-toe at a track day and tried axle hop at 80 mph once... not fun.

For tire pressures, I run about 30 psi front and 28 rear on my R888's. I was running way to high for a long time and giving up a lot of grip. I could probably back down even more on the rear but it gets hard to control the softer they get.

**Catmaigne** · 08-16-2021, 03:20 PM

Originally Posted by rentedmule

Great that you found the dead cylinder and freed up some ponies. The downshift axle hop and tire pressure discussion sound so familiar! I definitely still struggle with the heel-toe DS and get axle hop every now and then. I missed a heel-toe at a track day and tried axle hop at 80 mph once... not fun.

For tire pressures, I run about 30 psi front and 28 rear on my R888's. I was running way to high for a long time and giving up a lot of grip. I could probably back down even more on the rear but it gets hard to control the softer they get.

I talked to my friend's cousin who has an LS7 4th gen about his heel/toe technique and he told me it's near impossible with the stock pedal setup. Dude is a PCA instructor and a really good driver, so I trust his judgement. He's going to send me a 3d printed pedal extension for the throttle at cost to try out.

Are you running 10.5's or 11+ wide wheels on the car with the 315s? Guessing a 10.5 might need a few more psi than on a wider rim or else it might get too washy. I also have a rod ended panhard and the rear of the car is very unforgiving and tighter than the front, so dropping the pressure on them gave me more margin before it snaps loose. I was running ~33F/27R cold and it seemed to induce a little understeer at the limit.