Project GR350 Update: That's not gone well.

"Paul, Man of Mustangs" (stangmanpaul) 11/06/2013 at 00:35 • Filed to: projectgr350

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Um, there's supposed to be distance between the Watts link bellcrank and the crossbrace. We'll have to cut the Watts/Coilover cradle out (this is why we only tacked it in), and make a new one. The Mustang's frame rails diverge a bit, so this was apparently a 1/4" too narrow or something, or my frame rails are a quarter inch too wide. Also, apparently my coilover brackets are backwards. It might be ok, as long as the coilover clears everything.

Lastly, I don't have pics of it because I wasn't thinking, the axle is too wide. I should have listened, but now the edge of the tread is even with the outside of the fender lip. There are three solutions at the moment: Flare/roll the fenders. Because my fenders are probably 50% bondo by weight, that might not be a good idea.

Use late-model Mustang wheels. We have some in the shop with tires, but they're for a 2009 Mustang, and they're the, IMO, ugly split 5 spokes from 2005. I'll also need spacers in the front because of the massive offset, and we'll likely still need to roll the front fenders. 235 section tires don't fit particularly well under 65 Mustang sheet metal in the front.

Put narrower axle shafts in the housing. This is the preferable option, in part because it requires ditching those shitty OE Ford calipers and putting in some Wilwoods. Sure, it's a pricier option, but then I get to keep my wheels, not roll the fenders to the point of shattering bondo, AND I get an awesome set of brakes, to boot! I think it's a worthwhile upgrade.

Also, don't these control arms look awesome!? They should be in the top hole for a street car, but we're just trying to get things to fit at the moment, not drive.

Edit: Forgot to mention that I did have to cut a hole in my trunk to clear the Watts cradle. It also gave me an opportunity to rid myself of some rust:

wabbastang > Paul, Man of Mustangs 11/22/2013 at 11:10

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So as of about 10 minutes ago I've been following your build on oppo... I couldn't find any pics to see what you've done for a watts link setup, if it started life as an SN95 griggs conversion (i assume so) or what. Every griggs watts link I have ever seen has been in my shop because some part of the rear bracing was broken. If that's the path you are on, spend some time and reinforce it or replace the rear brace system entirely with something decent. More often than not it's that LH drop-down bracket snapping off right at the bolt hole, or the whole damn arm bends/breaks off. It's neat.

Paul, Man of Mustangs > wabbastang 11/22/2013 at 20:40

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Usually, it's due to poor installation or hitting a curb going sideways. The arm is designed to bend or break first in an impact so that the center section and tower survive. Everything is designed with crash worthiness and repair in mind. Watts towers generally aren't meant to fail because of how hard they are to repair. But those complaints either haven't made it back to Griggs, or they were poor installation. For instance, the snapping at the bolt hole is usually because people don't actually torque it down to 60 ft-lbs.

wabbastang > Paul, Man of Mustangs 11/23/2013 at 20:33

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I don't think they are meant to do anything and not saying they can't work, just seen a lot of failures using them as-is. That lower bolt doesn't break, the lower bracket does.. I'm sure they have heard plenty about it but if you ask, you'll be reminded that everything they make is perfect so you must be doing something wrong :P

Paul, Man of Mustangs > wabbastang 11/24/2013 at 12:25

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If the bolt is not torqued, the bracket breaks because the bolt wobbles in the hole, wearing it out. And the tower has to be welded all around to get full contact with the frame. Otherwise stress risers occur at the ends of the welds. Also, you need to think about what you would rather have fail: a replaceable arm, or your frame rail or your axle housing. I'd rather have the arm fail, personally.

wabbastang > Paul, Man of Mustangs 11/25/2013 at 01:53

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All I'm doing is sharing some experiences with a manufactured part that's been proven to need some attention to be reliable- it's coming from seeing dozens of them break, not in theory or from forum trolling, but as a result of a lot of experience with these setups both installing and fixing them. Probably in the hundreds of cars, from everyone who manufactures them on street and track cars. Consequently I've seen lot of failures, enough to establish a pattern of where and why and also of how to avoid it. A number of manufacturers have experienced issues like this over the years and redesigned parts as a result, Lakewood is a good example, and Griggs is not. The suspension is not something to be designing (or excusing, if that can be a post-tense verb for a moment) a *failure* point into, it should be capable of far withstanding any force acting on it any NEVER break or separate. If you are picking what the best thing to break first is in the parts that locate your axle, then you should think about doing something different.

Paul, Man of Mustangs > wabbastang 11/25/2013 at 22:17

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I should say that I am a designer for Griggs. We recently had a customer pinball a GT500 on a bridge, and he is only replacing control arms, rather than the K-member and straightening the frame. Also, look to the Mashouf wreck at Laguna Seca where a Griggs car slammed into a wall head-on at 130 mph, and the driver came away with only broken thumbs. Cars are designed with crumple zones, no? No different with suspensions. In a road-race suspension, the links should only be strong enough to withstand normal racing loads. If a car crashes into it hard, something is going to give. A wheel, a suspension link, or the frame. I choose wheels and links for failure points because they are easily replaceable. So, if the suspension NEVER EVER BREAKS, then it's gonna be the frame that breaks, and then you junk the car. Or you can just swap in a new control arm. Your choice.

wabbastang > Paul, Man of Mustangs 11/26/2013 at 23:01

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I think if you are in fact actually engineering the suspension system as a "real" suspension engineer then fine, take these things into account; I digress from the standpoint of making suggestions to the average Joe who shouldn't be making excuses to where he's going to "design" failure points (aka "I couldn't figure out a good way to ...."). Along those lines I'll be honest as well and say I have a rather large performance/race shop, the kind with 40-50 cars on the books, not the buddy down the road who works on the neighbor's car. I've seen endless junk from UPR and the like snap from hitting a pothole, and the fuseable link theory just doesn't cut it there. I'm biased against Griggs to some degree due to a combination of some really hokey shit that just plain doesn't work (and I hope/assume it's not you behind those specific things as you're obviously an enthusiast also, insults my last intention), along with a huge lack of support on their part to recognize issues and adapt. If you're in the industry we've seen a number of faulty suspension products lately, and good redesign and good product support stands out when it happens. In my experience if you take a problem to Griggs and say "hey guys, why doesn't the front joint on your S197 torque arm make any sense?" and are told to screw, it's not confidence inspiring. Maybe I've seen a run of bad luck and should give it another shot, like I said things evolve, but it's just been my experience.

wabbastang > Paul, Man of Mustangs 11/26/2013 at 23:02

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And will follow up the rant by making it clear I see this as more of an opportunity to give Griggs a shot and understand some things more than anything.

Paul, Man of Mustangs > wabbastang 11/27/2013 at 01:51

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I've only been here for just over a year, so I'm still learning the ropes to some extent. Stuff is getting redesigned, though. It's tough to do when there's only 5 guys, 3 of whom are full time. It's my job, though, to do the redesigning. So feel free to let me know what problems you're having, and I'll listen. I can't guarantee that anything will happen, but I'll try to help you out. There was a good deal of downsizing, so there's more responsibility on fewer people, making support more difficult. The S197 torque arm front joint is like that mostly due to a lack of room. There's not much room to work with the driveshaft joint, so we had to make due. I'd really prefer to do it our standard way, but it just doesn't fit in the tunnel with the exhaust and driveshaft without serious modification.