Cv prep already?

[Loganhawkins418]

what’s up guys! We have an Idaho Dunes trip coming up next month so I figured I’d get started on the prep (after pulling the back up ls2 out and putting the fresh 418” ls3 back in with new turbos and some other goodies)

But anyways, cv stars have some minor and some pretty bad pitting. Two of them have two seasons on them and two have one season, one star is still in good shape. Just wanted to get some opinions on the cause of this pitting…

Axles are strapped at 24 degrees

Cv’s were prepped pre season with certified premalube black Xtreme grease (the stuff that Alper recommends)

Cv’s are empi 934’s from Kartek, I believe they’re the stage two chromoly ones.

First season on them was running a twin turbo 418” ls3 that made just shy of 800whp on low boost. Second season was one trip on the big motor, lost oil pressure so I pulled it to rebuild and swapped in a stock stroke ls2 (rod and piston motor, ported heads big cam etc, with the twins installed, 600-800hp playing with the boost levels all season from 5-15psi)

New motor is making about 780 on 7psi, 1150 on 15 but I likely won’t turn it up that high, car weighs 2800lbs

So, are they just cheap china cv’s, not enough grease or not quality enough grease, to much angle, to much power for the cheap cv’s?

Of course I know they’re bottom of the barrel cv’s but they’re holding up pretty well so far and I know many people swear by the empi’s for 934’s

Thoughts?

 

[J Alper]

pittings is where the metal gets so hot it can stick to the CV,
If you broke the CV, I would say you need a stronger CV, with pitting, it needs better grease, or grease them more often, or angle is over limit,

 

[Loganhawkins418]

pittings is where the metal gets so hot it can stick to the CV,
If you broke the CV, I would say you need a stronger CV, with pitting, it needs better grease, or grease them more often, or angle is over limit,

I always thought the pitting was from shock load but that makes sense! I’ll likely just replace the stars for now and maybe upgrade to some higher quality cv’s later.

 

[Grease Monkey]

@parker@gearone

 

[parker@gearone]

The EMPI CVs are made from a material similar to 1045, which is decent for light-duty or casual use, but nowhere near the durability of the higher-end stuff. The better CV joints are made from 4000 series alloy steels—big difference in strength and longevity.


One thing that goes a lot further than people think is deburring the edges of the CV stars. It helps prevent cracking and pitting, especially when you’re running high angles or big power. A little attention there makes a big difference.


Also—if your car is strapped at 24 degrees—is that metal-on-metal through the bypass, or are you on a limit strap at that angle? I always recommend strapping metal-on-metal at 23–24°, and then limit strapping it around 22–23°. That way you’re not blowing through your limit straps or shocking the CVs at full droop.


CV grease plays a huge role—probably the biggest one. I’m not super familiar with the grease @Alper uses, but I know he and others run it with success. Personally, I’m a big believer that keeping clean grease in the CV joint is more important than what grease you use, but obviously the two go hand in hand. Just make sure it’s staying in the joint all season—CV pitting & failures often start from lack of lubrication.


There are a lot of tricks we use to make these CVs live—we’ve learned a lot over time. They’re expensive, yeah, but there’s real value in the good ones. We’ve run a ton of test miles with Kevin & Connor from Kevin McMullen Racing, and honestly, no one drives harder than Connor.

With all that said, the EMPI joints have there place & we sell quite a few. Nobody knows a shoe string sand rail budget better than me, with that said going with Kartek GKN, Pro am, fortin, gear one, or any other higher end CV joint is probably a good investment if you plan on keeping your car and driving hard.

 

[Rockwood]

Based on the knurling on the corners, it looks like you’re exceeding limit on those.

How are you measuring angle? Like @parker@gearone says, metal to metal, or on the strap is a bit of a difference, and you want to confirm they rotate easily by hand at full droop plus a little.

 

[J Alper]

@parker@gearone Is super passionate about the industry, his cvs are top notch, can not go wrong with his products, If you are thinking about replacing the starts or the CVs i would hit him up,

 

[Loganhawkins418]

Thanks for all the input! I have the limit straps set with the axles at 23-24*. I just ordered some empi stars from kartek to replace these ones to get me through this Idaho trip, I’ll go to the gear one cv’s on the next round! I’ll also tighten up my angles to 22*. I always ran 22 when I had 930’s but last cv service with the 934’s they were at 23 and 23.5 if I remember right (I know they weren’t over 24) so I figured I’d just leave them there since I see people running even more angle than that. Angles are checked with a digital angle gauge that’s zero’d out on the chassis when checking them.