Lucille pulls another one on me....

[gggGary]

What plastic doesn't harden after 40 years and hundreds if not thousands of heat cycles?
I have a 10 year old MC windshield new in the box the plastic mounts are literally crumbling. can break chunks off with thumb pressure.

Wintergreen oil on guides?????

 

[mrtwowheel]

Pete, curious, how would you compare that rubber to windshield wiper material? Dense, but denser than tire rubber?

Scott

 

[MaxPete]

What plastic doesn't harden after 40 years and hundreds if not thousands of heat cycles?
I have a 10 year old MC windshield new in the box the plastic mounts are literally crumbling. can break chunks off with thumb pressure.

Wintergreen oil on guides?????

True Gary - but as noted, I have never seen an NOS part let alone a really new production part. The used loaner I have from Lakeview and the pieces of Lucille's guide are both very hard shiny plastic.

Pete, curious, how would you compare that rubber to windshield wiper material? Dense, but denser than tire rubber?

Scott

Hmmm...I'd say that the material on the MikesXS guide is more like tire rubber. It is dark (not reflective) and reasonably "sticky" as you run your fingers over it - but it also appears to be very robust. As I said, digging in a fingernail can be done but the mark disappears immediately.

 

[gggGary]

One more failure mode for your list and I think a way too common issue.
Overtightening, I wonder how many thousands have tightened till the plunger stopped moving and reinstalled the cap?
On those years without a locknut a bit of grit in the cap threads can cause an overtightening episode.

 

[MaxPete]

One more failure mode for your list and I think a way too common issue.
Overtightening, I wonder how many thousands have tightened till the plunger stopped moving and reinstalled the cap?
On those years without a locknut a bit of grit in the cap threads can cause an overtightening episode.

Yup - if some is good, then more must be better and too much will therefore be just right!

It always amazes me when I read about people criticizing OEM engineers on vehicle forums (fora?) - these people ain't stupid and while they don't always get it right, they are always trying hard to do so. Also, they have far more time, expertise and physical resources to do things than most shade-tree mechanics and so, ignore service intervals at your peril.

 

[gggGary]

While I'm here..... I did sand down the edges of my chain.... followed by multiple cycles of soaking in the Stoddard tank and blowing clean with shop air. I'm confident it's clean.

This is one of those differing opinions things. Any time I've cleaned an assembly no matter HOW fastidious I was, if I later further disassembled, I found dirt had migrated in. I'm against any form of abrasive blasting crankcases for that reason. Would I run a motor with a sanded cam chain? Sure but I wouldn't DO it. there.
I always cringed when I saw spark plug abrasive blasters used in aviation..........

 

[Jim]

Actually Gary....... never was a fan of just abrasives for plugs either.... After blasting plugs, I always followed the above.... numerous cycles of stoddard wash and shop air.
And differing opinions are a good thing....

 

[Mailman]

Ok guys, I have here an unused Mikes XS guide, my original XS2 (5000miles, probably hasn’t run since the early 80’s) , and a NOS unused. All photos are from L to R Mikes / XS2 / NOS. These are just my casual observations. All are identical in size shape and dimensions, with one exception. My original guide is mounted on a flat bar instead of a channel. My original, the metal is very smooth in appearance, the other two feel like rough castings. My original LOOKS absolutely perfect with hardly any marks on it, but feels like hard plastic. Mikes feels like hard rubber and the NOS falls somewhere in between, you can dent it with a fingernail but it’s definately harder feeling than Mikes. Here are the phot comparisons.

 

[mrtwowheel]

I've seen the manufacturing of many OEM internal engine and transmission parts. When these parts are precision ground, believe me, they are NOT meticulously cleaned afterwards. Usually the only cleaning is from the coolant used while grinding. No way would most of these parts pass a white glove test. That white glove would be covered with metal dust and abrasive.

Scott

 

[MaxPete]

Indeed - although the recent upgrades to Ford's engine plants in Windsor have included very substantial investments in equipment to clean the sand out of the engine castings.

 

[xjwmx]

I've thought this might be a good way to make a front guide. Shape and cut a channel into some teflon stock with a milling machine, and hold it on with pop rivets in four places. The rivets could be deeper if there was a raised central area like an SR500 guide. Recovering a used-up oem guide is what I'm talking about.

 

[MaxPete]

Ok guys, I have here an unused Mikes XS guide, my original XS2 (5000miles, probably hasn’t run since the early 80’s) , and a NOS unused. All photos are from L to R Mikes / XS2 / NOS. These are just my casual observations. All are identical in size shape and dimensions, with one exception. My original guide is mounted on a flat bar instead of a channel. My original, the metal is very smooth in appearance, the other two feel like rough castings. My original LOOKS absolutely perfect with hardly any marks on it, but feels like hard plastic. Mikes feels like hard rubber and the NOS falls somewhere in between, you can dent it with a fingernail but it’s definately harder feeling than Mikes. Here are the phot comparisons.
View attachment 124176 View attachment 124177 View attachment 124178 View attachment 124179 View attachment 124180

Thanks Bob - very interesting information. Perhaps the OEM guides were originally softer and more "dentable" much like the MikesXS guides are now - but the OEM stuff has hardened and become embrittled over time.

 

[MaxPete]

I've thought this might be a good way to make a front guide. Shape and cut a channel into some teflon stock with a milling machine, and hold it on with pop rivets in four places. The rivets could be deeper if there was a raised central area like an SR500 guide.

Yup - but I'm not sure that Teflon is quite the right stuff either. This fall - when / if my job calms down, I am going to drop in on a few industrial buddies in engine design depts. and have a chat about materials and glue etc.

Pete

 

[xjwmx]

There was a guy I haven't seen here in a long time, Purplezinger, who was retired from a place that actually made chain guides like we're talking about. In the middle of a thread he offered to make some up and it was like nobody even saw it. Met him once, smart guy and good mechanic.

 

[MaxPete]

Hmmmm - wish he was still around!

 

[Jim]

.........an SR500 guide. Recovering a used-up oem guide is what I'm talking about.

You mean like this?

 

[MaxPete]

Yup - ZACKLEY!!

 

[robinc]

but I'm thinin' the OEM guides rubber is more the consistency of Mikes guide than plastic.

Yes, I agree Jim. The consistency of the rubber on the OEM and Mikes guides is very similar. The OEM might be slightly harder, not plastic, but hard to tell with a fingernail test. However, I think the rubber feels thicker on the Mikes guide which may trick one to think it's softer.

While I'm here..... I did sand down the edges of my chain.... followed by multiple cycles of soaking in the Stoddard tank and blowing clean with shop air.

Likewise did the same, but in spite of doing this perhaps I didn't get mine clean enough and that was the source of my flakes?

 

[Jim]

........I didn't get mine clean enough and that was the source of my flakes?

Flakes from the chain would have been magnetic (steel).... yours were aluminum.

 

[robinc]

Ah, yes, good point. Man you don't miss anything do ya?