Autocross Ranger: V8 Swap, SLA, IRS

JGraham, I might have missed it, but you mentioned using a 6° pinion shim and that's huge; your drive-line angels didn't look that far off, were they?

Looking at your current panhard rod setup, can you take the axle-side bracket and flip it over mounting it on the bottom of the axle flange?

Then all you would need is to lengthen the driver-side mount below the frame rail.

You and me were thinking the same thing about flipping the pan hard bar! The problem is that the mount is asymmetrical. If I find issues with this topside setup I'll remake the axle mount and extend the frame mount like you mentioned.

Yeah the photos don't show the pinion angle well and honestly I never noticed it with it directly in front of me. At ride height it has +1 degree angle with respect to driveshaft. The wedges will put it in the ~5 degree negative range.

In reply to alfadriver:

The quick web searching I did told me the Shelby GT350 Mustang of '65 used radius arms in the rear with leaves. May have not found the best sources though... a picture would have been nice.

You don't really need to care about driveshaft angles (to and extent), you do really want to care about the relationship between the trans yolk and pinion.

You want the yoke and pinion to be parallel under load. If the trans is pointing down 3-5° (typically), on a leaf spring car you would want the pinion pointing up 1-3°, taking into consideration that the pinion will roll up 2-3° under load.

The only time you want to change the driveshaft angels is if they are close to zero, which you were pretty close at 1°.

Nice a v8 mini race truck.

Maybe I missed it but what's done to that galaxy?

I Just realized you guys are in Norfolk. I'm from that area.

In reply to Nessumsar:

Your right. I'll be looking at raising the trans some to account for the positive angle down at the pinion. This will also help the trans and pinion become parallel with one another.

I did get my bushings installed. For whatever reason the front eye bushings were the wrong size so I had to make some out of delrin. The front eye now being delrin should probably be better than a urethane one actually.

In reply to yupididit:

The Galaxie is back in Iowa, where Luke the intern is from. He was just back down in VA this week and visited with me though.

Some photos of the bushing install.

Is the Delrin bushing wider than the leaf? If so you will need some sort of spacer the keep the leaf from sliding side-to-side on the Delrin.

Looks great!

Nessumsar wrote: Is the Delrin bushing wider than the leaf? If so you will need some sort of spacer the keep the leaf from sliding side-to-side on the Delrin. Looks great!

But does it even matter given how much the tires flex?

(sorry, couldn't help myself)

In reply to Nessumsar:

It is wider. I guess it could potentially slide on it. I probably should have put a shoulder on it. I did however have to press the bushing into the eye. I'll redo it (with a shoulder) if it starts walking.

Got the truck back together this weekend and buttoned up a final few items.

Started getting the rear end back together Friday. I first however boxed the chassis rail c notch I had done last year. I've always noticed a lot of flexing in the chassis ever since doing the notch and boxing it back in eliminated any of it.

Back end all put back together. I can tell already this thing is solid now!

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One good thing about a truck is its easy to pull the bed off and get access.

Had to "fix" my numbering from the flare work.

Fabbed up a fuel pressure gauge mount.

...and did the insta- patina treatment with clearcoat over top.

...and a shot of the flares cleared.

So after all this I got to take the truck back out to test and man it pulls out of the hole great now! Zero wheel hop! The whole truck seems so much more planted now that the rear end is solid and tight. It's not nearly as "twitchy" as it once was.

This week I'll scale and align it. Should be ready for this Sunday's autocross event!

So what all did you change? The axle was shimmed to get the pinion angle back to the stock angle, the frame was boxed a bit, anything else?

Cool work with the added metal on the hood.

I shimmed the trans up slightly to get the output and pinion more parallel as suggested. I still have a slight positive pinion/drive shaft angle when power is put down, but I'm not going to worry about it unless I start having cross bearing failures.

I also installed all new bushings and added one leaf back into the spring pack.

Lastly I added alittle more preload into the traction bars.

It can be argued which particular change cured the wheel hop, but I'd imagine everything played a small but significant role.

Yeah, sounds like a lot of little things that all add up to real improvement. Good work. This is a really cool project.

I think you'll want that panhard below the axle centerline or at least the ability to lower it and test.

For sure lowering the panhard on my AE86 was an improvement on an already pretty well sorted autox'er.

In reply to kevlarcorolla:

Your right. It was a goof (being lazy) on my part. I'm going to run it as is right now and make a switch later on in the season. By then I'll be able to tell exactly how much it might affect it.

Thanks again everyone for the support and thoughts!

Got the truck weighted, corner balanced, and aligned.

Weight minus driver, before corner balancing.

I'm pretty happy with the total weight the front/rear balance. 2930 lb, 54/46% I think is pretty good out of a pickup.

w/ driver pre-corner balancing.

I ended up going up 2 rounds on the right front coilover to get a perfect cross balance.

The front end was actually pretty much spot on as is. Right now it's setup with 1.5 degrees of camber and 0 toe.

One question for the leaf spring guys. Is there any thing that can be done to adjust leaf spring preload? I solely used the front coilovers to get the corner balances right. I wish could have added preload to the left rear in conjunction with the front right so I wouldn't be affecting ride height as much. Any thoughts would be great.

Shims under axle is how ive done it. Its an absolute pain in the ass and not an exact science as far as thickness vs weight.

Did you soften or disconnect the sway bar end links? Before and after you scaled the truck. You might have added to the preload.

In reply to Dusterbd13:

Thanks. I may try this. Any known disadvantage to shimming just one side?

Not in my experience, but i ain't a rocket surgeon or good driver.

We made our own shims from 1/8 thick plate cut into rectangles and notched so the could be slid in like an alignment shim.

I use spring sliders instead of shackles and shim under the slider mounts to get the cross weight and ride height where I want it but I don't see any reason why you couldn't shim the axle pads.

With shackles the spring rate changes with travel so you'll be effecting that no mater where you shim but your whole rear suspension is non-linear so that may or may not be an issue.

Note: That non-linear comment is not intended to be a criticism or to imply that I think you should be doing anything different. I totally get why you're modifying the current system rather than designing and fabricating something from scratch. I also think you'll be able to get the truck to handle well with the system you've got. It's just going to be harder to predict the results of an adjustment than it would be with a more linear suspension.

In reply to APEowner:

No offense taken. I appreciate the all the suggestions you've given throughout the build. I almost pulled the trigger on ordering a set of spring sliders last week. I may do it before the end of summer.

I can actually move the shackle mount up and down pretty easily. Do you think this would be a better option than shimming the axle?....or is this a 6 of one, half a dozen of another type situation?

Why not make a set of shackles with jackscrews? With your fab skill that should be a piece of cake!

Or rather, make the upper shackle mounts adjustable with jackscrews?