The CAM-Z: autocrossing a Z28

The current plan is

KYB AGX adjustable shocks and struts (I'd love koni yellows, but that are $$$. I use the AGX's on my Grand Prix and I've been very happy with them.

UMI adjustable upper strut mounts

UMI wonder bar

IROC springs or Moog reproductions

Big bars front and rear, unsure on size and brand

Maybe tubular LCA's, or poly mounts and a rebuild of stockers.

UMI adjustable panhard bar

Jeep stering shaft

This list will change based upon price, availibility and impassioned arguments that I am stupid.

Junkyard a 36mm hollow front bar and leave the rear alone to start.

I agree with slowcamaro on the front bar. As long as your at the junkyard grab the 24mm rear bar. This is the combination GM used on the tuned sport supension package for Z28s and Trans Am. I am using them on my Firebird and it greatly improved the handling.

Junkyards are pretty empty 'round here, but I'll keep an eye out.

Guess I'd better crawl under and see what I have on there now. It is a Z28, even if it is an early one. It might already have something good.

Shouldnt be hard to find a 36mm hollow bar on the used market, most later ws6 birds got them. rear bar should be stiff enough especially with fresh springs. 

Also if youre talking about changing the front LCA's poly isnt the best option. Go global west delalums.

AClockworkGarage said:

 

I fired her up yesterday. she started after 3 agonizing chugs. like a dead battery.... battery shows just under 13 volts sitting, just over 15 when running.

15 volts is too high.  Typical for a GM car just after starting would be about 13.8-14.2 volts.  I'm thinking your unregulated regulator is cooking your battery.

If you go with a big bar in the rear such as a 24mm and have subframe connectors the right rear tire is going to want to come off the ground in right turns especially with today's tires. I suggest stiff springs instead of a big bar in the rear so that you don't wind up with a smoky right rear like I have on my IROC with the Performance suspension. You do need a bar though, so something smaller is best. Also, at minimum G92 IROC spring rates in the front because your left front has a major impact on what the right rear is doing. The G92 IROC springs are not enough to keep my right rear down with 275 Nittos.

I managed to find a set of SSM subframe connectors on CL. Talked the guy down to $120 for the pair. Have to meet up with him sometome this week to pick them up.

Not sure if they'll make a huge difference considering the cage, but they can't hurt and they'll make a good jack point at the very least.

They do even with a cage. It takes away the snap loose tendency these cars have. Watch old Player's Challenge races on Youtube to see snap loose in action with cages especially on the street courses. There's one where two cars go snap loose while battling and spin seemingly choreographically.

It took a week to arrange the sale but I picked them up today. A NOS st of SSM subframe connectors.

As you can see she's tucked in for the winter, but she'll be back next year for another season of Autocross, and hopefully a few NHA hillclimb events.

Sponsor Wanted.

Weather was ok yesterday and I had a hostage. I mean assistant. Willfull assistant.

Got some better voltage reads on the battery.

12.2 when sitting, 14.4 when running and 10 something when cranking.

Over the course of multiple starts it varied between slow painful cranking and firing up without complaint. Very confused.

Starter maybe? I dunno.

Once i got it running I threw the timing gun on it again. Maybe it's the mallory box, maybe I'm a moron, maybe both but I cannot get this thing to work. the timing mark just wanders around drunkenly.

The motor had a slight miss when I started, and a severe bog when going WOT. The timing light was pretty worthless, So I went by ear. Rotating the distributor clockwise until the engine smoothed out. Quick trottle blips no longer produced a bog. Success, I had guessed my way to victory.

A quick blast up and down the moutian told me, you've solved your problem at the cost of a lot of power. The car was noticeably slower.

Grumble.

Double Grumble.

I'm thinking about yanking all the Mallory stuff and just putting in an HEI setup.

In reply to AClockworkGarage :

Your troubles sound very similar to the ones I had. I know nothing about the Mallory setup, but if it uses a hall-effect sensor somewhere to determine RPM check that. 

Do you know how old the timing chain is?

Also, does it crank better with the coil disconnected? 

I know nothing about the internals of this engine. PO told me the longblock was stock. So the timing chain is probably 34 years old.

Excessive wear in the timing set causes timing to jump a lot, especially during rapid speed changes. They rarely stretch/wear more than 3-5° slop at the cam before they break, but that's still 10° at the crank. 

My friends shop truck jumped 18° with a timing light before he tore it down. LOL

It could probably use a timing chain, but if I'm going to that, I might as well swap the cam...

And If I'm gonna do that, I might as well Swap the motor...

And If I'm gonna do that I might as well go LS...

And if I'm gonna do that...

This is how it starts.

I'm more the type to patch them until they pop, then go nuclear.

It tends to happen when you're cheap and have a lot of free time. 

You may be right on that Timing chain tho. The original has nylon coated gears which can crack and introduce slop.

No biggie, a new double roller is 50ish. But I have to pull the timing cover, which means i have to replace the oil pan gasket. awhich means the motor has to come outbat least a little.

I might as well find a used Vortec truck motor, throw a cam in it and swap.

If you LS swap a 3rd gen in an apartment parking lot over a PNW winter you will be my hero.   

The more i think about it the more feasable it seems. I could afford it, but it would mean stock suspension for another season.

In reply to AClockworkGarage :

From my experience with a 3rd gen, unless this motor was a a headache I just couldn't deal with anymore, I'd do the suspension first.

SEADave said:

If you LS swap a 3rd gen in an apartment parking lot over a PNW winter you will be my hero.   

Sometimes I forget that building a car in an apartment parking lot is unusual. That's just what poor people do. Then I see all the attention team parking lot build gets at the challenge and think, you merely adopted the parking lot, I was born into it.

You raise me $5k or so and I'll LS swap this beast in my parking lot.

Start a gofundme.

In reply to AClockworkGarage :

Throw a new $69 HEI  billet distributor from Speedway and get rid of Mallory stuff.  It will simplify your life.

Check the distributor bushings as well if your timing jumps around.  There should be no slop when wiggling the shaft with the dizzy out of the car.  Make sure end play is within spec as well.

You can yank the cover out with the pan on, but you bend the crap out of the retaining groove on the back. 

If you trim the bent parts off with a grinder/tin snips you can even get them back in. 

*Note, this doesn't work with the newer motors with the flat lip seals. 

Not that it's the right way to do it, but the easy way to put it together is without the front lip seal, then fill the whole gap with "The Right Stuff" sealer. I use the mini caulking gun dispenser as it's more controllable.

I've done it half a dozen times or so with no more than a little seeping.