WMD - 8 May - Rear Suspension work

[QB93Z]

We will be working in the garage here in Westminster, MD on Saturday, May 8th.

Everyone is invited to stop by. We will be working on adjusting the rear ride height on Scott's 1991 ZR-1.

If anyone has any work they would like to do, come on up. We can do some pre-BG trip oil changes.

Call me if you need directions.

Jim
443-244-1347

[Scrrem]

Maybe I'll swing by and attach my new propeller, rudder, and pontoon rigging :mrgreen:
Rich

[Jagdpanzer]

Jim,
Can you help adjust my dive planes for BG conditions?

[secondchance]

Jim,
Can you help adjust my dive planes for BG conditions?

Have you bought a Junkers 87??? does it have dive siren?:mrgreen:

[Jagdpanzer]

Have you bought a Junkers 87??? does it have dive siren?:mrgreen:

Yun,
You must be refering to dive brakes
http://www.kmp.ca/images/stuka3.jpg
Which I'm affraid won't be be of much use in the wet BG conditions.

However, diving planes like these may be a better choice.
http://www.history.navy.mil/photos/images/h69000/h69039.jpg

[secondchance]

Are you talikng about adjusting front/rear attitude or do you actually have some sort of winglets?

[VetteMed]

Are you talikng about adjusting front/rear attitude or do you actually have some sort of winglets?

I think the dive thing was a joke based on the flooding in BG :sign10:

[secondchance]

I think the dive thing was a joke based on the flooding in BG :sign10:

Duh... It's been a long day and will take another 4...

[QB93Z]

I think Bow Planes would be a great idea Phil. I think that they can attach to the snow plow mounts I put on last winter.

Jim

[QB93Z]

TRAFFIC ADVISORY -- -- -- -- TRAFFIC ADVISORY

If you are coming to Westminster for the 8 May WMD, do not try to drive on Main Street.

Westminster will be having an annual Flower and Jazz Festival downtown and Main Street will be closed.

If you are coming into town on Rt-27, turn left on W Green St (one block before Main St). When W Green St ends at New Windsor RD, turn right and immediately turn right again into the alley by my garage.

If you are coming from the east on RT-140, take RT-140 all the way around Westminster and turn left onto RT-31 South (flashing red left turn signal). Turn left at Uniontown Rd (second light). Turn right onto New Windsor Rd (the first stop sign), then take the first left into my alley.

Call me if you get lost, and we will send out a ZR-1 Search Party.

Jim
443-244-1347

[HIZNHRZ]

Jim and Yun, a serious thank you helping to think through the latest set of actions, each helping to improve the listing of my Z?s back end from passengers side to drivers side. At it?s worst point last year, the passengers side was an inch and a half higher than the drivers side. We have improved the situation to where the delta is now less than 1/2". The average ZR-1 is has a 1/4" or less difference between the height of the drivers and passenger sides.

Prior to yesterday and at separate times the stock rear leaf spring bolts and castle nuts were replaced and adjusted with longer bolts. These are the parts that are sold as the rear end lowering kit. While using the bolts to lower the car, the ride height problem also improved about a half of an inch.

The rear leaf spring was then removed and inspected. It looked just as one would expect the leaf spring of a low mileage ZR-1 to look. Because you can?t always see a defect, we rotated the leaf spring 180 degrees when we put it back in. No difference in ride height was noted.

Yesterdays objective was to first inspect the position of the bat wing relative to the ground. Not surprisingly, the left side was still higher. We then measure several chassis point to ground and verified the same difference between the passenger and drivers side. There appears to be little that can be done to adjust out the height difference. What we did, however, was loosen the front and rear C-beam bolts and jack up the back end of the car. We artificially corrected the listing problem by jacking up the drivers side inch and a half higher than the passenger side. We then tightened the C-beam bolts, lowered the car, drove it and re-measured ride height. There was a 5/8? improvement verifying Yun?s theory that the C-beam was in tension. We tried the same approach by loosening, jacking up, and retightening the bolts that hold the bat wing to the frame. No further improvement was noted.

At this point the car is 3/8" to a 1/2" off level. While this is a little more than the average Z it is a whole lot better than it was. Thanks again guys.

I'll post some pictures when I get a chance.

[QB93Z]

It was an interesting day. I learned a few things about the C4 suspension. There is no doubt that the body list (leaning to one side) is determined by the differential housing batwing position. There is no "adjustment point" for the body height. The batwing is rigidly attached to the transmission/engine by the c-beam. The engine is mounted to the frame at the motor mounts.

We attempted to change the body tilt by taking all of the slack/movement in the c-beam connections in the same direction. In the pic you can see the wood block on the driver's side of the frame with the c-beam bolts loosened. Then we tightened the bolts and revoved the jack.

http://i407.photobucket.com/albums/pp152/QB93Z/2010%20May%20WMD%20-%20Rear%20Suspension/DSC03270.jpg

We were able have an effect on the side to side height difference but we couldn't get all of the tilt out.

Jim

[Scrrem]

Sorry I missed, but got my shed completed today, start emptying the garage today, so time was well spent.

OK, from what I am reading in your post Jim, does that mean that possibly the frame is twisted since the batwing is catty-wompas?
Rich

[QB93Z]

It has got to be a feeling of accomplishment to get the shed finished and start clearing out the garage. Next the lift.

I do not think the frame is twisted. I suspect that the remaining 1/2" may be in suspension components, either front or rear.

Jim

[secondchance]

Jim and Yun, a serious thank you helping to think through the latest set of actions, each helping to improve the listing of my Z?s back end from passengers side to drivers side. At it?s worst point last year, the passengers side was an inch and a half higher than the drivers side. We have improved the situation to where the delta is now less than 1/2". The average ZR-1 is has a 1/4" or less difference between the height of the drivers and passenger sides.

Prior to yesterday and at separate times the stock rear leaf spring bolts and castle nuts were replaced and adjusted with longer bolts. These are the parts that are sold as the rear end lowering kit. While using the bolts to lower the car, the ride height problem also improved about a half of an inch.

The rear leaf spring was then removed and inspected. It looked just as one would expect the leaf spring of a low mileage ZR-1 to look. Because you can?t always see a defect, we rotated the leaf spring 180 degrees when we put it back in. No difference in ride height was noted.

Yesterdays objective was to first inspect the position of the bat wing relative to the ground. Not surprisingly, the left side was still higher. We then measure several chassis point to ground and verified the same difference between the passenger and drivers side. There appears to be little that can be done to adjust out the height difference. What we did, however, was loosen the front and rear C-beam bolts and jack up the back end of the car. We artificially corrected the listing problem by jacking up the drivers side inch and a half higher than the passenger side. We then tightened the C-beam bolts, lowered the car, drove it and re-measured ride height. There was a 5/8? improvement verifying Yun?s theory that the C-beam was in tension. We tried the same approach by loosening, jacking up, and retightening the bolts that hold the bat wing to the frame. No further improvement was noted.

At this point the car is 3/8" to a 1/2" off level. While this is a little more than the average Z it is a whole lot better than it was. Thanks again guys.

I'll post some pictures when I get a chance.

No need to thank me Scott.
So many, including Jim, David and so forth, have been generous with their help in solving mysteries and helping me get my car back to where it is now.
I feel I owe the same to all ZR-1 brothers (and sisters if they are out there).