Set up for rear trailing arm shims? Options

[morehills]

When taking my trailing arms out I noticed that I had three shims on the passenger side and only two on the driver's. Is that normal? I think I remember how they were set up for reinstall, but is there any general wisdom on how to configure them when I put the suspension back in. I'll have the rear aligned by my shop when they reinstall the engine, so maybe this is not very important. Thanks, John

[gnomefabtech]

Those shims are how you set rear camber. All these cars are a bit bent, so they are not the same side to side. I have nearly 10mm on one side and none on the other. Totally normal.

[brant]

You have to do a 4 wheel alignment whe the car is finished ( motor weight)
And likely will have to change both sides to match the alignment specs needed.

Not every shop knows how to align a 914
And ideally you would take the specifications into the shop with you for performance and modern tires. The factory specs will not give you the extra performance. Take extra shims with you to the shop or they will give you what they can get and not what you want

[morehills]

Thanks. I have an excellent shop. So I'm sure they can get alignment right. But it's a good thought to get some extra shims so they have all the goods they need to dial it in.

[mlindner]

And buy some extra shims to take to speed things up.

[brant]

I’m sure I’m not the only one here with a to go bag for alignments

[flxzcat]

Stupid question, but are the shims only for adjusting the camber?

[mgp4591]

I’m sure I’m not the only one here with a to go bag for alignments

I call dibs on Brant to help me with my alignment! (IMG:style_emoticons/default/beerchug.gif)

[Dave_Darling]

Stupid question, but are the shims only for adjusting the camber?

Yes, that is what they are for. The only thing they do is move the outer trailing arm pivot mount downwards, away from the bottom of the chassis. That causes the top of the tire to tilt outward, giving you more positive camber.

Fewer/thinner shims means more negative camber, thicker/more shims means more positive camber.

--DD

[Olympic 914]

When you change shims, do you also possibly change the rear toe adjustment ?

Also, it's a good idea to put a driver's weight equivalent in the seat when making adjustments. It could change the camber.

[technicalninja]

those shims adjust camber BUT...

Toe is adjusted via the slots that the trailing arm outer mount has in it.

Merely loosing these bolts WILL alter the toe.

These bolts HAVE to be removed to change the shims...

Process is to check camber on rear and decide if you need to change shims.

I bought extra shims from this member, I like stainless...

http://www.914world.com/bbs2/index.php?sho...=372781&hl=

Make your camber adjustment, recheck that puppy and then comes the HARD part.

You have to rotate the trailing arms via the slotted mounting holes to adjust toe.

You make an adjustment, recheck toe, and make further adjustments until you get toe correct.
Toe needs to be adjusted PER SIDE, not against each other.

A dedicated alignment machine will make this easier BUT it can be done on the ground using a variety of methods. Stringing the car up will work fine.

Tangerine Racing makes special outer mounts for exactly this purpose.

https://tangerineracing.com/shop/ols/produc...ng-arm-brackets

Those screws make setting toe easier. They work better one direction, if you go too far you should back up past "perfect" and come up on the toe setting with minor adjustments.

And I go a bit farther on loading. Static "rest" height is often higher than actual "in motion" height. This can be more pronounced on lighter cars (914 qualifies as light).

On a streetcar, I'm prone to full tank of gas, 100lbs in each seat, 100 lbs in front and rear trunk.

Track car is different, actual driver and equipment, 1/2 tank of fuel and nothing else.

Aero track car is even harder to determine average ride height. I'd probably load that critter up pretty heavy on the alignment machine.

[brant]

These help keep things the way they should be

[technicalninja]

Forgot an IMPORTANT step...

"Jouncing" the car between measurements.

If you make ANY adjustment the suspension pieces have non-normal loading on them.

You will see good alignment techs bouncing the car between adjustments on a rack.

This helps bigtime but I believe rolling the car forward and jabbing the brakes hard enough to "jounce" the car is better. This is a PIA on a rack.

It is NEVER a bad idea to take a spirited drive after you're done and recheck your alignment stats.

Edit: Brant, your shit is BAD-ASSED!

Ninja approved! (IMG:style_emoticons/default/ninja.gif)

If you've got a set up like Brant, you DO NOT need my suggestions...

Brant's set up ALSO provides triangulation on the mount. It's STRONGER!

[bkrantz]

And since a 914 is a pretty light car, if you tend to drive solo--and you are a, um, big person--you should have the alignment done with equivalent weight in the driver seat.