Ok, I am finally down to one very small oil leak. In the process I found out that CV joints need occasional care, more often than my efforts(so, who knew grease drys out after 4+ yrs), so add CV joints to your list of items to ck someday.
Mark
One more thing to check
Ok, I am finally down to one very small oil leak. In the process I found out that CV joints need occasional care, more often than my efforts(so, who knew grease drys out after 4+ yrs), so add CV joints to your list of items to ck someday.
Mark
1990 Van Diemen, the Racing Machine, CM AutoX, 2016 Frontier
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
Thank Mark! one more thing to check.
Ben
More importantly, check those 3/8 nuts after every serious session. Jens tried red Loctite and I still find one or another a little loose pretty regularly. The bolt heads can be safety-wired but you just have to keep checking the nuts.
Caldwell D9B - Sold
Crossle' 30/32/45 Mongrel - Sold
RF94 Monoshock - here goes nothin'
Use jet nuts, not nylon nuts or loctiteOriginally Posted by TimH
Hello Mark,Ok, I am finally down to one very small oil leak. In the process I found out that CV joints need occasional care, more often than my efforts(so, who knew grease drys out after 4+ yrs), so add CV joints to your list of items to ck someday.
Mark
I had this issue as well.
Buy a set of these and install them. http://www2.cip1.com/ProductDetails....01%2D329%2DSET
The CV joint boot metal is dead soft mild steel so it can be formed to make the part. The bolts and nuts bear on a very small area and the area around the holes get thin and the bolts lose tension. Buy the jet nuts as recommended above. Install the washers, torque to 18-20 lbs/ft. The chance of them coming loose is much smaller with the washers and jet nuts.
Dan
“Racing makes heroin addiction look like a vague wish for something salty.” -Peter Egan
I'm using jetnuts with regular washers. Dan's fancy VW washers are an interesting idea and worth a try.
Caldwell D9B - Sold
Crossle' 30/32/45 Mongrel - Sold
RF94 Monoshock - here goes nothin'
Thanks Tim, they aren't my idea, they are original OEM from VW. I grew up in SoCal. I recalled them from my friends' VWs and dune buggies.
Dan
“Racing makes heroin addiction look like a vague wish for something salty.” -Peter Egan
CV plates
I suggest using the VW original CV joint plates as they fit better (better design) and have a bit of heat treating and won't bell when torquing the nut.
No longer made by VW but try the samba.com. and you might some new old stock.
Also make sure you are not bottoming the bolt threads..... Use only AN Jet nuts and torque to 26 ' #.
Shown is the OE piece and the imposter.
Thanks Jerry! Even though they are imposters, they do work for the torque our FF Kents make. I have never had one come loose in my Zink or the Crossle. I can understand the additional torque on the bolts if the car is powered by a Lotus Twincam.
Will we see you at the Charity Challenge at Sonoma?
Regards,
Dan
“Racing makes heroin addiction look like a vague wish for something salty.” -Peter Egan
This issue is raised at least once a year - with the attendant "fixes" from the masses. Most seem to think AN washers with jetnuts and Loctite red are the answer. Then they are surprised when the nuts loosen after a few sessions. Steve Johnson answered this many, many years ago.
The problem is not the nuts, or the bolts. It is the washers. All you have to do is order hardened steel washers, and use them under BOTH the bolt and the nut. Yes, I understand that means pulling the side plates of the gearbox and removing the drive yoke to replace the washers under the bolts (unless your setup has the nuts on the inside). Might as well replace the bearings while you are at it. - as well as installing new proper length AN bolts.
Your problem is that the AN washers are too soft and will crush. That leads to a lessening of the torque and eventually the assembly loosens. So, then you crank down on it again, further crushing the washers and repeating the process. (What's the definition of insanity?)
As Steve said, a properly designed assembly, properly assembled, will not loosen. If it loosens you have a problem, either with the assembly, or the assembler.
And, those VW locking tabs are made with soft metal, so they will also crush.
Charlie Warner
fatto gatto racing
'Cause there's bugger-all down here on earth!
CV plates
so even with hardened washers, won't the CV boot flange still compress/crush under the hardened washers, causing the same issue?
or is the increased surface area of the hardened washer, enough to resolve the issue?
we torque ours every session and always find a few slightly loose.
fletch
March 79V
The hardened washers are the same diameter as standard AN washers (unless you source hardened USS washers). 35 ft/lbs of torque should not compress the boot flange as it should be hard against the cv joint. If you have to re-tighten yours every session then the something is wrong. Remember, the nuts are only usable 3 times (assuming a jet nut). If a nylock nut then toss whenever they are removed.
Charlie Warner
fatto gatto racing
'Cause there's bugger-all down here on earth!
The bolted joint is one of the most ubiquitous devices in engineering and also the least understood by most of us laymen.
The higher the cyclic shear loads, (consider the loads are reversing for additional safety factor), the higher the fastener tension (stretch) required above the loads. The boot flange is very soft vs the bolt head. The minimum yield on CR1010 steel (boot flanges) is only 35,000psi.
A Super Vee powered car will require higher fastener tension, likely higher yield fasteners and hardened washers, more than an FF. If the tension is not adequate, well above the cyclic loads, the bolt will eventually fatigue and fail. The washers must spread the tension load across the joint. The washers will likely need to be relieved on one side to clear the side of the boot flange body and avoid bending the bolt shank under the head. If 12pt fasteners are used, hardened washers with ID bevels are required because the shoulder under the bolt head is radiused. NAS bolts are radiused under the head too. 12pt fasteners may not fit between the gearbox output shaft and the side plates of a MK box.
Don't bother with nyloc nuts or loctite of if the cv joint is near a brake rotor or exhaust. The nylon will melt. Loctite melts and becomes a lubricant between the threads.
Carroll Smith's Nuts bolts fasteners and plumbing is a good resource for us laymen. If you are unsure, consult a mechanical engineer familiar with our cars and requirements. I have probably left out something important, so please feel free to comment, add or disagree.
Regards,
Dan
Last edited by DanW; 09.26.17 at 1:27 AM.
“Racing makes heroin addiction look like a vague wish for something salty.” -Peter Egan
Hmmmm.....
It could be calculated with a little effort and knowledge of the material properties, but I wonder how the addition of the aluminum spacers I often see on CV's would affect the joint integrity?
CV bolts
so on our F/SV, we do use the 12pt NAS bolts with special radius washers under the bolt head, along with AN jet nuts (set up with nuts to the inside).
like i mentioned, we torque them (29 ft-lbs) after every session and there is always 1 or 2 that are slightly loose.
maybe we need to increase the torque value to 35 ft-lbs as charles mentions?
i replace the bolts and nuts every 20 hours.
since we started checking the torque every time, we have not had any fail.
with all that said, it would be nice if they stayed torqued!
regards,
fletch
March 79V
Are the washers hardened? That is the critical point being made here. If not, increasing torque will do nothing but crush them further.
With the proper assembly, assembled properly, they will be good all year.
Charlie Warner
fatto gatto racing
'Cause there's bugger-all down here on earth!
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