Broken Elephant Foot Valve Adjuster

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dps650rider

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Went to adjust the valves the other day and when I went to loosen the lock nut on one of them it snapped right off with very little effort. Wow, good thing that didn't happen when I was riding! Has anybody else ever had this happen on anything? I did some searching on the web and found a few stories like this on other engines.

Of course this meant taking the cylinder head cover off to replace it. The adjusters I used (CB Performance) came in a pack of 8 so I replaced all 4. Seriously considered going back to the stock units but the elephant foot ones are so much better, and they has seen plenty of adjustments in 41,000 miles I figured it was save to use them again. Besides that I don't know if I have 4 good stock ones because they have lots of mile on them.

So I wondered, I never use a torque wrench to do this but this time I did. Wow, 20 foot pounds is tight. I doubt I ever tightened them this much with a box wrench. Out of curiosity I looked up the spec on a Porsche (that's what the adjusters were made for) and it was 20 foot pounds too.
 
No, I haven't. I've been the mode of preparing and collecting parts and such for a complete overhaul. A challenge out here in the sticks. Things like those elephants foot adjusters, and Kedo adjusters get my attention. So, being a cautious type, I just order the stuff to see whut's goin' on there...
 
Had another one break today adjusting the valves... most of the day spend removing them and putting stock ones back in.

Going to take a look at ones made by Porche, probably won't do anything until the season is over.
 
TwoMany, Do you have any of the OEM Porche adjusters on hand? I want to get a measurement from the bottom of the foot to the start of the threads to see if thread engagement is really a problem with these.
 
Looks like a 4mm difference in thread ends.
CB-Empi-Lengths.jpg


Dangit, I like those brittle CB adjusters.
Don't have the equipment, don't know the steel composition, but wonder if tempering them at 260°C - 280°C for a few hours might make them usable.
Tempering.jpg


Updated the elephants foot comparison thread:

http://www.xs650.com/threads/elephants-foot-valve-adjuster-comparison-porsche-vw-mikes.32559/
 
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I've installed the EMPI screws in 4 or 5 motors over the last 10 years or so. None have broken yet to my knowledge. In fact, that motor we tore down over the weekend has them and they were still fine. I do like the looks of the CB ones, in particular the longer thread length at the bottom. I even bought some and was going to use them next build. I may still do so. I had to wait for them to be re-stocked when I got them. Hopefully this means a new production run and maybe some changes to the hardness treatment.
 
If you do use the CB's you may want to consider torquing them to less than spec. I think that is why I had the second failure in such a short period of time. When I initially installed them I torqued them to specs which I found was tighter than I had been tightening them with just a standard box wrench.

I originally bought the CB units because of the thread length, but I am now thinking that it doesn't make any difference in thread engagement after coning the rocker arms. I will try and check this tomorrow using another set of rocker arms that I have that are coned. If I find that it doesn't make any difference I am definitely going with the OEM Porche units. Maybe they will also wear better than the CB's.

BTW, I took a ride with the stock adjusters and the increase in noise is very significant, probably more so with the cam I have because of the .010 and .012 clearance specs.
 
I work in the scrap metal industry and could get access to a Niton or x-ray gun. I can try to get them to shoot my CB adjusters to see the composition of the steel if that would help in determination of their hardness. This is all above my intelligence level but would be happy to contribute if I can. I think the only issue may be if the are coated with anything, then it may not provide accurate steel composition readings.
 
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Willis, that would be interesting, but don't knock yourself out on this. The manufacturer *might* address this, maybe not, who knows.

This closeup of a fractured CB adjuster's crimp ring shows very fine granularity, possibly indicating MIM (Metal Injection Molding), which may not respond to traditional heat treatment.
CB-Adj01a.jpg
 
ok.. here is what we got when we shot with the Niton XLT 898 x-ray gun. I had some old stock adjusters shot too so we could evaluate a base level. We had a hard time getting good readings though. This is presumably because the pieces are so small, so we had to shoot them each quite a few times to get good readings. Hope this helps on some level.

OEM - registers as a 4130 composite
97.77 Fe (Iron)
.52 Mn (Manganese)
.84 Cr (Chomium)
.31 Zn (Zinc)
.23 Mo (Molybdenum)
** other alloys registered minimally under .05%

CB Perf. - registers 8620 composite
96.13 Fe
.78 Mn
.62 Cr
.22 Mo
1.27 Ti (Titanium)
 
I've never used a torque wrench on the adjuster lock nuts, just made them what felt right (and tight enough) to me. You said that 20 ft/lb spec was very tight, tighter than you were making them without a torque wrench. Maybe it's too much for these aftermarket screws and that's why they're snapping off? Maybe it only applies to factory screws?
 
That's what the gun read it as. Here is the definition i saw on the web:

General Characteristics
Alloy steel 8620 is a case-hardening steel containing nickel, chromium and molybdenum as alloying elements. The alloy shows good strength and toughness properties, and has a higher core strength than grades 8615 and 8617.

Applications
This alloy may be used in the production of medium-strength parts such as forged camshafts, fasteners and gears.
 
Strange, you reading hi Ti, no Ni, has me confused.
Any idea of carbon?

Edit: I could understand the titanium if they were TiN plated, but I don't see any on mine...
 

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