2016 CMC Rules

[Daniel Allford]

I am growing tired of welding up K members.
aftermarket tubular members which accept stock arms are under $500
Dan Allford #82

[ShadowBolt]

I am growing tired of welding up K members.
aftermarket tubular members which accept stock arms are under $500
Dan Allford #82

How about going to a harder tire instead? I'm afraid all we do with tubular K-members is move the issued somewhere else.

JJ

[AllZWay]

These weren't issues prior to CMC2. Neither were rear ends, transmissions, among other things.

[BryanL]

These weren't issues prior to CMC2. Neither were rear ends, transmissions, among other things.

I disagree. I don't think the changes to CMC2 have any effect on K members. Guys were welding them up back in original CMC trim, too. Plenty of AI Camaro's like Patterson running the stock k-member without cracking. I have had one crack but my car is still running 45 less rwhp than stock. Of course when I go over a curb coming into rattlesnake I don't think the 30 extra hp is what cracks a k member. I don't think the power has any impact on our rearends either and don't see that we have any more problems with diffs than before. Transmissions may be correct but that seems to only be the T5 but again driver input is going to be the biggest factor with it.

I didn't even think there was a road racing k member available anymore? Only weak drag units.

Now I'm all for going to a harder tire.

[AllZWay]

I disagree. I don't think the changes to CMC2 have any effect on K members. Guys were welding them up back in original CMC trim, too. Plenty of AI Camaro's like Patterson running the stock k-member without cracking. I have had one crack but my car is still running 45 less rwhp than stock. Of course when I go over a curb coming into rattlesnake I don't think the 30 extra hp is what cracks a k member. I don't think the power has any impact on our rearends either and don't see that we have any more problems with diffs than before. Transmissions may be correct but that seems to only be the T5 but again driver input is going to be the biggest factor with it.

I didn't even think there was a road racing k member available anymore? Only weak drag units.

Now I'm all for going to a harder tire.

I never tore any of these up until CMC2...then went through several rears and two transmissions. Still haven't torn up a k-member though.

[Suck fumes]

Maybe you guys should buy a mustang. Ford builds k members that don't crack....just sayin haha (kidding)

We need to switch to nittos! They last a long time and have good grip.

[dtanker65]

I disagree. I don't think the changes to CMC2 have any effect on K members. Guys were welding them up back in original CMC trim, too. Plenty of AI Camaro's like Patterson running the stock k-member without cracking. I have had one crack but my car is still running 45 less rwhp than stock. Of course when I go over a curb coming into rattlesnake I don't think the 30 extra hp is what cracks a k member. I don't think the power has any impact on our rearends either and don't see that we have any more problems with diffs than before. Transmissions may be correct but that seems to only be the T5 but again driver input is going to be the biggest factor with it.

I didn't even think there was a road racing k member available anymore? Only weak drag units.

Now I'm all for going to a harder tire.

Where are they cracking?

[BryanL]

Where are they cracking?

Not sure on all of them of course but I had experience with it cracking at where the factory weld was done. The factory weld isn't the best from what I'm told-chalk up another win for the Mustang.

Procter-if you would use the clutch that wouldn't happen. I know the AI guys have had some diff problems but didn't know of yours. Was yours the trans or the clutch? Or did the clutch cause the trans to get hurt? I think I remember you lost reverse for awhile? How many miles were on that trans and how many on the track? I'm just a big fan of the T56 if it's original or was put together correctly. The T56 to me is the strongest piece in the drivetrain at our power levels.

[AllZWay]

The first was just the reverse... stock 165k... not really a racing issue.

The second was the gear rings that made it shift bad. It was repaired. The third I haven't ever torn it apart.. won't shift 2-3.

[dtanker65]

[QUOTE=BryanL;73519]Not sure on all of them of course but I had experience with it cracking at where the factory weld was done. The factory weld isn't the best from what I'm told-chalk up another win for the Mustang.

I looked at the one on my S197 Mustang and I am thinking that it has to have been heat treated after it was welded out. It is well supported by the inner fender/shock towers too, but if it were to get bent or cracked I doubt it would be repairable. The car maintains alignment remarkably well, in spite of my occasional errors in judgment.

I grafted a 79 Trans Am front sub-frame on to an old truck once, and the factory welds on it were the worst I had ever seen. I re-welded the unit before installing it using a skip welding technique. All of the data I have been able to find regarding modification of production car front chassis members for racing, calls for skip welding reinforcement to maintain as much of the original temper as possible. Welding up a beefy repair in one spot creates a soft area in the part that will yield causing alignment issues or failure to the adjacent areas. I wish I knew more about the K member on the LS1 car.

Were me, I think I would gather as much information as I could about the common failure points in the K member, find a good K member, and Tig weld gussets in the problem areas being very careful to control the heat affected zone.

On second thought my 69 Mach 1 had some of the worst welding I have ever seen. During resto I found holes blown through it and giant mig globs with wire stubs sticking out. All covered up with factory seam sealant. I am guessing the welders at Ford bought a lot of beer for the pooky shooters to keep their jobs :-)