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GKN Lobro CV star

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I have a 930 star that's pitted but the rest of the CV is good. I was told an Empi star is different and GKN stars are not available. Does anybody know where I can get a GKN star? What would happen if I put an empi star in it? 

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Now would be a good time to upgrade to 300m stars

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These are solid stars.

https://www.alpermotorsports.com/index.php?l=product_detail&p=137

@J Alper has all of the necessary components to upgrade 930s

 

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2 hours ago, acefuture said:

These are solid stars.

https://www.alpermotorsports.com/index.php?l=product_detail&p=137

@J Alper has all of the necessary components to upgrade 930s

 

The RCI joints in our group are not lasting much longer. Same problem. Pits in the star. I think when they get race polished it wears the heat treating thin on all of them. IDK. For now I'm building a new buggyworks car from a chassis using my old car for parts. It's getting spendy and I'd like to just toss in a regular star and keep the project moving. Will an empi star fit?

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36 minutes ago, stumpalump said:

The RCI joints in our group are not lasting much longer. Same problem. Pits in the star. I think when they get race polished it wears the heat treating thin on all of them. IDK. For now I'm building a new buggyworks car from a chassis using my old car for parts. It's getting spendy and I'd like to just toss in a regular star and keep the project moving. Will an empi star fit?

I belive a star is a star.  Don't make a dink if it is empi, gkn, or a 250$ 300m from RCV the star is going to pit.  Turn the star around and run them on the back side.  Works for me.   

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A star is a star?  No way.

For longest life, 300M, race prepped and the correct grease is key.

I got 7 years on my first set of CVs and am currently at 4 years on this set.

They still look like this....

 

IMG_2451[1].JPG

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17 hours ago, stumpalump said:

I have a 930 star that's pitted but the rest of the CV is good. I was told an Empi star is different and GKN stars are not available. Does anybody know where I can get a GKN star? What would happen if I put an empi star in it? 

To answer your question, yes you can put an empi star in and it will work just fine. I've seen Empi CVs outlast GKN CVs on the same car before. 

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300M star strapped to 22 inch's of travel.  

thumbnail (3).jpg

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2 hours ago, Blue-Jay said:

To answer your question, yes you can put an empi star in and it will work just fine. I've seen Empi CVs outlast GKN CVs on the same car before. 

As it has been said before - they all are made to the same spec. the Stars all fit each other on 930's but you need to make sure they are properly clearanced The "race prep" on an Empi is the use of smaller balls and a tumble polish to remove stress risers - its pretty effective.  They are pretty hard from tests I have seen, but people report inconsistent heat treat - that is common with most stuff from China the QA sucks. GKN's have better QC, but if you try hard enough you can make anything fail..  I personally thing the RCV stuff is exceptional and QA is consistent, but then again you still kill them. The "race prep" on most other brands than EMPI is opening up and usually hand polishing the the star and the race to remove stress risers and make things slide better.  300M will definitely help in not "splitting" a star from HP and axle shock, but keeping them alive and not pitting (transfer of metal)  or cracking from excessive heat is mostly always grease related IMO ... Grease is the word...  Keep them packed with good grease that can handle heat and not run out, but will not dry and cake, change it often  and make sure its in the CV not the boot. I have seen people pack the boot and feel good about it - that does Nothing except retain heat, which is worse, no magic is going to push boot grease into the star, centrifugal force pushes it out. Its why people like German Auto do CV seals and Alper does Miniboots (they are great) - to keep the grease in and keep the heat out.   If you find grease in your boot when you pull it back - Stop using the grease or change the grease more often - if the grease is in the boot its not in the CV and the CV is overheating and dying.   Heat kills the CV, it removes the Heat treat and the balls wear out, quickly (they get smaller)  and as they wear, where do you think the metal goes? Into the grease and it helps to wear everything else out.   IMO you shopuld measure with a caliper the ball size on every greasing or just order spares from JAlper here on the board and swap them as needed, Heat makes CV stars get pits through metal transfer because they lose their temper, then heat cycling causes them them to break apart the Strs pit way before the Races because the Races are thicker and can by convection as they are open to the air. The stars are trapped and the heat builds up with no where to dissipate except into the grease that is now over heated and running into the boot.... 300M will actually go bad before a standard star when improperly greased or using improper grease because its already more brittle and you just wanted a lot of money because you failed to grease them properly, used poor grease or did not properly re grease after a trip or two.   Severe angle will usually break the cage first and if not the CV will run so hot it loses heat treat and goes away, but running at a severe angle at high speed with less grease will get the CV's red hot and they will fail fast.  You have to grease them - thats the bottom line. Last thing 930 and 934's often need different grease 930's run hotter due to less surface area and need a higher temp grease - although high pressure grease is important too. 934's are often found on heavier and sometimes higher HP cars with bigger tires, that means you need a higher pressure resistant grease, heat not as big an issue... at least thats been my experience...

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4 hours ago, Blue-Jay said:

To answer your question, yes you can put an empi star in and it will work just fine. I've seen Empi CVs outlast GKN CVs on the same car before. 

Thanks. I noticed it said in the fine print it fit GKN or empi when I ordered one. Probably not ideal but I only have one hard season on this set of lightened race prepped CV's and the rest looked normal. Probably as said by fullthrottleguy it was heat and grease related failure. The grease I use is the green high temp lucus with belray antiseize mixed in. I pack the cups and put in a few squirts up under the boot every once in a while but......... Would this be a good time to beat the "best CV grease" horse again?

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6 hours ago, fastcorvairs said:

300M star strapped to 22 inch's of travel.  

thumbnail (3).jpg

I've never seen a 300m star with those grooves. Looks like either an Empi or GKN. How many degrees at 22" of travel. 

I recommend Fortin 300m stars if somebody only wants to buy a star or wants to upgrade. GKN stars last a long time when prepped correctly, use good grease, and are not over angled. Back angle and improper geometry eats CVs, 300m or not. 

I have the same German CVS with 300m cages in my car, now for 6 seasons. 3 still looked new. One started to develop a little dip.I replaced that one with another german star and all the balls this season. Over 600hp and beat the hell out of it. Hauling arse wheelies through the whoops. My angles are correct. They are properly serviced annually. They are properly prepped. 

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2 hours ago, Hondo said:

I've never seen a 300m star with those grooves. Looks like either an Empi or GKN. How many degrees at 22" of travel. 

I recommend Fortin 300m stars if somebody only wants to buy a star or wants to upgrade. GKN stars last a long time when prepped correctly, use good grease, and are not over angled. Back angle and improper geometry eats CVs, 300m or not. 

I have the same German CVS with 300m cages in my car, now for 6 seasons. 3 still looked new. One started to develop a little dip.I replaced that one with another german star and all the balls this season. Over 600hp and beat the hell out of it. Hauling arse wheelies through the whoops. My angles are correct. They are properly serviced annually. They are properly prepped. 

That's 22 degrees of droop not 22 inches of travel. 

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the strongest star on the market is the RCV, star Fullthrottleguy is running a supercharged LS motor on the 930 30 spline, I think we are on like 3 years with them,

it make me sick when people say my stars pitting and only grease them once a year, or put grease on the outside of the joint

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1 hour ago, J Alper said:

the strongest star on the market is the RCV, star Fullthrottleguy is running a supercharged LS motor on the 930 30 spline, I think we are on like 3 years with them,

it make me sick when people say my stars pitting and only grease them once a year, or put grease on the outside of the joint

I think with your Grease fitting equipped CV bodies (Races) even the Laziest of us can keep CV's alive longer...  How many of those have you put out there on people's cars already?

 

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CV's are new to Rock Racers (Ultra4). Common is the larger 30 series CV's in the Independent Front Suspensions. With the larger CV and 35 spline axles, the CV can easily go to 40* and some push them 45*. This is during turning, Articulation is still in the range of 23*. Different in IFS is that you don't ("cannot" ) have plunge or turning is problematic. Problems have always been breakage and not heat (Maybe 5 years experience as rock racing with IFS is new).  I have always held that axle plunge and spline lock creates the heat and also affects suspension valving. 

Some notes:

A 934.5 will work just fine at the IFS Diff, but will not take the rigors of turning in the uprights. A 934.5 will only wheel turn a max of 30* at 18" of articulation (best case geometry, and replaced every event). A series 30 can be wheel turned to 39* with the CV angle at 45* (best case geometry) Outside of tire (40" x 14") on most of these cars are 90"+ with 4"+ backspacing. Most cars run 4000-5000lbs and 600-900hp. Most cars are holding to 18" IFS articulation because of climbing. Rears in the 24" range (double triangulated 4 bars similar to desert trucks with 500lb+ axles) .  

I have GKN series 30 CV's with 33 spline stars and wanted 35 splines. RCV said that theirs would fit...but they didn't. I still have to track this issue down but not on the front burner at this time. Just FYI.  Series 30 are $$$$1,200.

There are a few IRS cars in Ultra 4. Some use portal hubs and 934 CV's. The portals are about 2:1 and I don't think the CV's are doing well either. The rear IRS are a-arms so you would think that plunge would not be an issue from all that is known about IFS. Have a-arm sand cars shown any longer CV life?  Of course that depends on the designers criteria of no plunge...? 

Thee are also a couple unique IRS cars out there that articulate at the middle with no plunge (Joe Thompson UFO, series 30 CV). And a couple more out there in the design/build stage with minimal/no plunge as a criteria. (34.5 and series 30 CV's) Once you have actively designed a IFS, you get the IRS criteria....It is just working with A-Arms or other novel designs. These other novel designs are allowing travel to 24" with good camber, toe and plunge control .

I believe the Class 1 Buggies have moved to series 30, and surprised the sand cars have not with the high HP. May be the weight factor....but 4 seaters???

 

My roots are IRS Sand Jeeps since the mid 70's. But Ultra4 has captured my interest. 4X IFS/IRS for the dunes coming.....slowly as we learn.

When designing you are always worried about unintended consequences, or things you should have known from a different perspective...which is why I am here....relating and thinking. Cool thread. Ben 

 

 

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On ‎5‎/‎4‎/‎2018 at 7:20 PM, fullthrottleguy said:

I think with your Grease fitting equipped CV bodies (Races) even the Laziest of us can keep CV's alive longer...  How many of those have you put out there on people's cars already?

 

it seems we are drilling some every month or every other week, I am sure I have done a couple hundred of them, not really my idea came from Rob Mac's prerunner, he had them on the Rockstar Alumicraft, and was about 7 years ago, that we have been drilling them

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Hey. Is this the cv that gear oil ran through mid season ?  Could have been your issue.

\

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4 hours ago, danbalz said:

Hey. Is this the cv that gear oil ran through mid season ?  Could have been your issue.

\

Come to think of it yes the 091 CV cups have always leaked Red Line heavy shockproof into the CV's. I'm going to have to use a better gear lube if I want my CV's to last....

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15 hours ago, stumpalump said:

Come to think of it yes the 091 CV cups have always leaked Red Line heavy shockproof into the CV's. I'm going to have to use a better gear lube if I want my CV's to last....

Just pack the trans with sweppco, should be good. hahaha

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