Skwerl's first hot rod

[skwerl]

Got my new A arms today and immediately pulled one out and compared it to my old arm so I could tell if it was actually bent and where. It was instantly obvious that it failed at the bend in the rear leg. I was running the older original style and Kelly has already stated many times that they upgraded the arms a few years ago due to similar failures. You can see where it bent at the decorative holes in the gusset and the metal on the outside of the holes is slightly bent. The new gussets are a full 1/4" thick instead of 3/16" and there are no holes drilled in them. I think I would probably have to total the car before I bent the new arms.

 

[Timmbo]

What was the purpose of the holes to begin with? Decoration you said? Seems kind of crazy to remove material from a gusset unless the sole purpose was to reduce weight at every opportunity. But nonetheless they figured out why not to do that anymore. Glad it didn't turn out any worse for ya.

 

[BMR Tech]

Yeah, the newer ones are much beefier.

What exactly happened to cause the damage again? I dont remember what you told me.

Timmbo, we originally designed these for maximum weight savings. Typically BMR has been (years ago) primarily a "street/strip" - and more towards "drag" based company. We came to realize early on, that designing parts with maximum weight savings in mind, was not very smart with the S197 A-Arm design.

They are tough pieces to design, build, manufacture and supply - with great success. This is why you have 345 companies making A-Arms for 79-04 Mustangs, and 1-2 "streetable" designs for S197's. Most companies try, and give up.

 

[skwerl]

New arms are installed. Dang, these are so easy. You don't even need to separate the tie rod end from the hub. I started out by adjusting the inner joint to match the old A arms, then I greased all three pivot points. The lower ball joint doesn't have a grease fitting but I used a grease syringe to fill up the rubber dust boot with synthetic grease. The rear joint has a grease fitting which takes about 4-5 pumps when dry, then about 1 pump once or twice per year. The inner joint has been known to squeak on me in the past so this time I pulled it apart and coated the inside with Prothane synthetic grease. Hopefully that helps and does more good than harm.

Bolting the arms in is straight forward. Only 4 bolts hold them in, although they are beefy connections. Both the inner and rear attachment points are adjustable so my alignment guy can adjust both castor and camber without the need for upper c/c plates.

 

[one eyed willy]

You didn't have zerk fittings in the box for the tie rod ends? I just installed a set few months ago and they had holes for fittings but the fittings were in a small bag.

 

[skwerl]

Maybe I better go look again!

edit- Found them! The old ones didn't have grease fittings so I assumed the new ones didn't either. I also found a sticker in the bottom of the box.

 

[AutoXRacer]

Ooh no, my a-arms have holes in them. Eeekkk!!!

 

[skwerl]

Gerald, try not to slam headlong into any curbs. It gets expensive!

Now that the A arms are installed I put a tape measure on the wheels again. The left front is still about 1/4" further back than the right. I'm afraid it might have tweaked the K member ever so slightly but I'm hoping it can be adjusted out when I get the alignment. I'm sure as hell not pulling the K member out at this point.

 

[Timmbo]

Yeah, the newer ones are much beefier.

What exactly happened to cause the damage again? I dont remember what you told me.

Timmbo, we originally designed these for maximum weight savings. Typically BMR has been (years ago) primarily a "street/strip" - and more towards "drag" based company. We came to realize early on, that designing parts with maximum weight savings in mind, was not very smart with the S197 A-Arm design.

They are tough pieces to design, build, manufacture and supply - with great success. This is why you have 345 companies making A-Arms for 79-04 Mustangs, and 1-2 "streetable" designs for S197's. Most companies try, and give up.

Well I can definitely say as much as Brian trusts you guys your OK in my book. I'll be looking to knock some weight off myself since putting this 5.0 stroked iron block in my car. I really admire the way you guys do business. Looking forward to upgrading to your K-member at some point in the future.

 

[BruceH]

Got my new A arms today and immediately pulled one out and compared it to my old arm so I could tell if it was actually bent and where. It was instantly obvious that it failed at the bend in the rear leg. I was running the older original style and Kelly has already stated many times that they upgraded the arms a few years ago due to similar failures. You can see where it bent at the decorative holes in the gusset and the metal on the outside of the holes is slightly bent. The new gussets are a full 1/4" thick instead of 3/16" and there are no holes drilled in them. I think I would probably have to total the car before I bent the new arms.

That's the result of not having 2x edge margin. There should be at least 2x the hole diameter from the center of the hole to the outside edge.

 

[AndrewNagle]

Maybe I better go look again!

edit- Found them! The old ones didn't have grease fittings so I assumed the new ones didn't either. I also found a sticker in the bottom of the box.

sticker is good but their embroidered key fob is better !

 

[Pentalab]

That's the result of not having 2x edge margin. There should be at least 2x the hole diameter from the center of the hole to the outside edge.

The story I got..when working with Aluminum plate was to use 1.5 X hole diameter to edge of plate. But this is from the edge of the hole..to the outside edge of the plate. So it comes out to the exactly the same as your above formulae. I never see any reference to the thickness of the plates in all of this. IE: I don't believe you use the above formula for thinner plates. (I can see why cross drilled rotor plates result in cracks).

The amount of weight bmr... 'saved' with the old gusset design would amount to zip anyway. If you want to save weight, use a stronger alloy to begin with....and that implies heat treated chromoly....like 4130. The trick with that is... you have to cut it, file it, drill it etc, then weld it. the heat treating can only be done after the welding is completed. If you weld heat treated chromoly, you will weaken it substantially. 4130 is typ 70 ksi yield strength when you buy it un-heat treated. Typ 107-120 ksi after heat treatment. That implies heat treating the finished product.

If you have ever tried drilling heat treated chromoly, have fun. It's extremely difficult. DOM is typ 89-91 ksi in it's raw form at your local steel place. Any welding won't affect it's strength. You can't heat treat DOM anyway. DOM is a lot cheaper.

I wonder if steeda, bmr etc, X ray any of the welds ? That would have to be done b4 any heat treatment. IE: X ray welds, repair any welds, then heat treatment.

 

[BruceH]

The story I got..when working with Aluminum plate was to use 1.5 X hole diameter to edge of plate. But this is from the edge of the hole..to the outside edge of the plate. So it comes out to the exactly the same as your above formulae. I never see any reference to the thickness of the plates in all of this. IE: I don't believe you use the above formula for thinner plates. (I can see why cross drilled rotor plates result in cracks).

The amount of weight bmr... 'saved' with the old gusset design would amount to zip anyway. If you want to save weight, use a stronger alloy to begin with....and that implies heat treated chromoly....like 4130. The trick with that is... you have to cut it, file it, drill it etc, then weld it. the heat treating can only be done after the welding is completed. If you weld heat treated chromoly, you will weaken it substantially. 4130 is typ 70 ksi yield strength when you buy it un-heat treated. Typ 107-120 ksi after heat treatment. That implies heat treating the finished product.

If you have ever tried drilling heat treated chromoly, have fun. It's extremely difficult. DOM is typ 89-91 ksi in it's raw form at your local steel place. Any welding won't affect it's strength. You can't heat treat DOM anyway. DOM is a lot cheaper.

I wonder if steeda, bmr etc, X ray any of the welds ? That would have to be done b4 any heat treatment. IE: X ray welds, repair any welds, then heat treatment.

The best way I know of to drill a close tolerance hole in hardened steel is with a carbide bit at very slow rpm.

 

[GallopingFord]

Brian what is the ETA of the new bumper?

 

[skwerl]

Dunno, Cam. When I ordered it Steve said it was 3-4 weeks out and unfortunately Tasca does not email me any tracking info. It shows up when it shows up and I get zero advance notice.

I have the bumper patched together well enough that the damage isn't noticeable unless you get close and look. It will be fine as long as I don't get any close up shots at the track until it's replaced.

 

[BadPiggy]

Brian,

What's the ETA on the Amazon.com cams?

 

[skwerl]

Wednesday, and Justin is going to try to get me in on the dyno Thursday or Friday.

 

[AutoXRacer]

You went with the 127450s right?

I look forward to your results and idle...

 

[Pentalab]

Wednesday, and Justin is going to try to get me in on the dyno Thursday or Friday.

Is this when you achieve 700+ rwhp... and put K Bell / whipple /centri's to bed..all in one shot ?

Jimbo

 

[skwerl]

Yes Gerald, Your input along with several others convinced me that the 127450 was a good choice.

Jimbo, I certainly hope so! If my mysterious engine miss doesn't come back and the stars align then I think we should hit 700hp no problem. And then we have Funday Sunday at the track this weekend (3/2) so I may even be able to make a few passes for the first time in a month!