'67 Camaro E/SA redo

[HandOverFist]

Originally Posted by Dave Turner

Rich, other than achieving a static height change, was there a need/goal that required the installation of the 2 aluminum spacers?

Dave - The ride height over the rear tires was the only reason for the lowering blocks. Even with the 1" under split-leafs the car sat too high in the back...it now has the perfect stance.

[HandOverFist]

Thanks Alex for the offer, but there was a sudden turn of events this morning.

When my partner showed up this morning I had the housing ready to pull out. One thing led to another and we were headed to town to pick up his torch and welder. Long story short is the perches are repaired, reinforced and the housing is back under the car ready for battle. Plan on being back at Bowling Green this Saturday to pick up where I left off.

[NHRA 303]

Originally Posted by HandOverFist

Thanks Alex for the offer, but there was a sudden turn of events this morning.

When my partner showed up this morning I had the housing ready to pull out. One thing led to another and we were headed to town to pick up his torch and welder. Long story short is the perches are repaired, reinforced and the housing is back under the car ready for battle. Plan on being back at Bowling Green this Saturday to pick up where I left off.

Had this almost happen to me too about a year ago. I was turning my drive shaft by hand. When it locked up on me. Which made my heart skip a beat. Opened the rear cover. And low and behold. Three teeth stripped off the ring. After only 20 passes. So im looking a little closer at the ring. And realize that its a "street gear" What the hell! This is a full race rear end. 40 spline axles, 5/8 studs, race brakes. The whole nine yards. So i gave them a call. And they just turned it back on me. "Well we really dont know what transpired when i ordered it". Are you kidding me. So anyway, the point to my quote. When i took the rear to have the new "RACE GEARS" installed. I noticed the same distortion happening to my perches. I just staightened them. And boxed them just like you did. Ive put another 50 passes on them without any problems. And i hit it them pretty hard. Im running a D/S 66 chevy II. If i get really motivated next winter. I might replace them with Caltracs. Moser's equipment is slightly cheaper. But they have a few screws loose working there.

[HandOverFist]

Gawd! I really hated seeing those pictures again...

[FireSale]

For your info, this thread motivated me to spend the extra money and put an all Strange Engineering rear end setup under my 68 Mustang.

Dale

[HandOverFist]

I would enjoy seeing that Dale.

[FireSale]

It's about three weeks out. Just got the order completed Friday. I'll send some pics when it's in.

Dale

[bigsixman]

Tough luck Rich with the Moser perches. We have always braced the original 12 bolt GM perches and never had a problem. There is no question in my mind that the Moser perch is an inferior part. That perch should have not crushed, we used to pull the GM ones loose from the tubes until we braced them, but they never crushed.

Smith Racecraft makes a first class perch designed for racing that you can order for a stock height or 1" lowered built into the perch. They are a nice piece that you may want to check out.

[HandOverFist]

Pretty sure we are good to go now...there's a bunch of heavy metal under those perches now hehe. Our buddy Perry Simpkins told us today he has the stock multi-leaf perches under his '69 running mono-leaf springs...they must be stouter. If we had not been able to salvage our brackets I probably would have ordered the Calvert's...they look just right.

[Bill Harris]

Those reinforced perches will probably survive the next world war. However, it might be good to reflect on what happened and try to identify the root cause of the original failure. It is easy to say that the Moser perches are defective/weak/junk/chinese, etc. and that they should know better since they build axles for drag racing and have for many years. But before crucifying them, the posted pictures show that this might well have been a case of mixing incompatible suspension components.

Looking at the end view of the collapsed perch it is apparent that the wedge used to set the pinion angle is too narrow for the perch. The implementation created a pyramidal structure with the spring at the base, a narrower spacer and an even narrower wedge working against an unsupported surface. The compressive force generated by the housing rotation was applied through the unsupported horizontal portion of the perch to the narrow wedge. That force on the horizontal part was more than it could support and it collapsed.

The horizontal portion isn't supposed to take the load, the vertical portions of the perch should be taking the load and transferring it (ultimately) to the spring. The vertical portions of the perch were essentially unsupported in this application as witnessed by their being forced apart and actually torn away from the horizontal part of the perch on one side. The modified perches, as well as the Calvert perches provide additional support to the horizontal portion of the perch, certainly a much more robust design.

As witnessed by many racers, even stock 40 year old perches can withstand the forces generated by drag race launches, although it certainly isn't a good idea. I suspect that if the springs were in direct contact with these perches they would never have failed. That wedge, in that position, was the ultimate culprit. Putting the wedge between the spring and the slightly wider solid spacers might have provided enough support to prevent the failure too, but since the spacers look to be narrower than the perch it would be marginal.

Also, Calvert can supply their springs with different amounts of arc so that the ride height can be set without having to have a bunch of spacers between the perch and spring. He also has wedges which are wider than the usual 2" parts.