<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dogginator &raquo;</TD></TR><TR><TD CLASS="quote">I think that the fatigue endured by the nut would be mainly due to the thermal expansion during heat cycling... So, I think we agree with each other.</TD></TR></TABLE>Yes. Stess in the nut due to acceleration is too small to worry about. Thermal cycling is maybe 10,000 or 50,000 cycles during 200,000 miles. Rockers see cyclic stresses with the valve action, over 10^9 cycles.

 

How about make some nuts out of unobtainium?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dogginator &raquo;</TD></TR><TR><TD CLASS="quote">

This isn't my area of expertise (PhD Chem E), so I'm not doing a very good job of explaining. Plus, someone borrowed my strength of materials book, so I cannot consult that to better my explanation. My base understanding is that ferrous metals have a fatigue limit close to the yield point and aluminum has a fatigue limit well below the yield point. Cold working was a poor choice of words on my part.</TD></TR></TABLE>

Ferrous metals (and titanium, anlong with some other metals) have what is called an 'endurance limit'. The endurance limit is always below the yield strength. However, you can cyclically load the material below this endurance limit an infinite number of times without fatigue failure. Aluminum, however, has no endurance limit. Simply put, there is NO stress below which aluminum can be cyclically loaded an infinite number of times without eventual failure. Aluminum will ALWAYS eventually fail. Aluminum does, however, have what is called a 'fatigue limit'. This is simply the stress that can be applied cyclically to aluminum over a specific LARGE number (not sure what the number is) of cycles before it will fail. I should also note that with a smaller cyclic stress, more loading cycles can be made on the aluminum before failure.

 

Remember the purpose of the lash nut is simply to "load the joint" It is a locknut. It puts the threaded adjuster in tension to eliminate thermal and vibratory movement of the threaded adjuster. With similiar materials the threads on the bolt and in the nut are relatively matched little lever arms and have "similar" deflection. If you go to an aluminum nut, all your deformation (yield) will be in the nut. The aluminum nut will have to be 2X to 3X thicker to produce the same margin of safety in the thread stress.

Personally, I would go with the Ti nuts.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by StorminMatt &raquo;</TD></TR><TR><TD CLASS="quote">

Ferrous metals (and titanium, anlong with some other metals) have what is called an 'endurance limit'. The endurance limit is always below the yield strength. However, you can cyclically load the material below this endurance limit an infinite number of times without fatigue failure. Aluminum, however, has no endurance limit. Simply put, there is NO stress below which aluminum can be cyclically loaded an infinite number of times without eventual failure. Aluminum will ALWAYS eventually fail. Aluminum does, however, have what is called a 'fatigue limit'. This is simply the stress that can be applied cyclically to aluminum over a specific LARGE number (not sure what the number is) of cycles before it will fail. I should also note that with a smaller cyclic stress, more loading cycles can be made on the aluminum before failure.</TD></TR></TABLE>

That is what I thought, though you put it much more eloquently.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BigMoose &raquo;</TD></TR><TR><TD CLASS="quote">Remember the purpose of the lash nut is simply to "load the joint" It is a locknut. It puts the threaded adjuster in tension to eliminate thermal and vibratory movement of the threaded adjuster. With similiar materials the threads on the bolt and in the nut are relatively matched little lever arms and have "similar" deflection. If you go to an aluminum nut, all your deformation (yield) will be in the nut. The aluminum nut will have to be 2X to 3X thicker to produce the same margin of safety in the thread stress.

Personally, I would go with the Ti nuts.</TD></TR></TABLE>

I've seen nut designs that have a thin hex section and a longer threaded section. This increases the thread contact area with only a minimal mass increase. Aluminum's propensity to gall would actually aid it's locking behavior. This would add a safety factor in the event of thread failure.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pootie &raquo;</TD></TR><TR><TD CLASS="quote">How about make some nuts out of unobtainium?</TD></TR></TABLE>

Those would be made by Mugen.

 

I just have to wonder whether LS/B20 people would actually blow a bundle of cash on these nuts (which, for these motors, would serve little to no useful purpose).

 

I think alot of people would spend money on this kind of upgrade. Every little bit helps, at least in the minds of some.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by foot &raquo;</TD></TR><TR><TD CLASS="quote">I think alot of people would spend money on this kind of upgrade. Every little bit helps, at least in the minds of some.</TD></TR></TABLE>



Consider it an insurace policy against something like this:

https://honda-tech.com/zerothread?id=1247701

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by foot &raquo;</TD></TR><TR><TD CLASS="quote">I think alot of people would spend money on this kind of upgrade. Every little bit helps, at least in the minds of some.</TD></TR></TABLE>

But keep in mind that there is a BIG difference between DOHC non-VTEC and other Honda motors. In SOHC and DOHC VTEC motors, the rocker arms are mounted on shafts. And since there is no way to adjust clearance at the shafts, valve clearance is adjusted at the valve tappet. So the locknut basically moves with the valve. But on DOHC non-VTEC motors, the rocker arms are not actually mounted on anything. They ride on ballstuds that ride in sockets mounted in the head. These ballstuds actually have the adjustment threads on them and screw into the rocker arms. And the locknuts lock the ballstuds onto the rockers (just as they lock the tappets on the rockers in SOHC and DOHC VTEC motors). What I am trying to get at here in that on DOHC non-VTEC motors, the locknuts are located where the rocker arms pivot. So any weight savings would be of dubious benefit unless it was REALLY big.

 

I agree that for the DOHC non-VTEC engines, this would make no sense. However, for the B-series DOHC VTEC and the K-series iVTEC, this would be applicable. The cost should not be that high for aluminum nuts. (I'm guessing $5 maximum.)

The K-series may have a different thread than the B-series, as the part numbers are different. Would anyone care to measure theirs?

 

Still intrested... where would I go about getting a set of Titanium locknuts?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LSVTEC 91 Civic &raquo;</TD></TR><TR><TD CLASS="quote">Still intrested... where would I go about getting a set of Titanium locknuts?</TD></TR></TABLE>

That M7x0.75 thread is not common. These (aluminum or titanium) will most likely need to be custom made.

 

would you consider making them for H22s as well?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by iakona &raquo;</TD></TR><TR><TD CLASS="quote">would you consider making them for H22s as well?</TD></TR></TABLE>

They are most likely the same as the DOHC VTEC B-series lash nuts. However, someone needs to measure these nuts as I did for the B18C.