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Barry · Post by **Barry** » Thu Aug 23, 2007 11:52 am

Under 10 000km,s
Brand new
Tensions spot on
No foreign objects
No siezed cams,etc..etc..

I have my theory as to why it failed..

Opinions??

kevin · Post by **kevin** » Thu Aug 23, 2007 12:11 pm

Ouch! Never seen that. Sheared teeth off before when cam seized on tt motor(bit of silicone stuck in passage). Cant be to much power for belt as Dawie ran the tt at high boost and no probs there. Delamination due to constant heat cycles(bad belt) ?
Out of interest maybe Ben or any other rocket scientists can calculate anyadditional shear from 184kw to 240kw. Might be a factor.

kevin · Post by **kevin** » Thu Aug 23, 2007 12:19 pm

Could it be the way the belt is packed in the boxes and a weekness develops in one of those sharp bends as the outside is stressed far more(develops fine cracks like fuel pipe if bent passed the corect radius). Sorry clutching at straws

Barry · Post by **Barry** » Thu Aug 23, 2007 12:22 pm

kevin wrote:Ouch! Never seen that. Sheared teeth off before when cam seized on tt motor(bit of silicone stuck in passage). Cant be to much power for belt as Dawie ran the tt at high boost and no probs there. De lamination due to constant heat cycles(bad belt) ?
Out of interest maybe Ben or any other rocket scientists can calculate any additional shear from 184kw to 240kw. Might be a factor.

Dont think so Kev.The engine output is not related here..To turn the cams takes so much and no more,does not matter if its 23hp or 500 hp produced.

MD · Post by MD » Thu Aug 23, 2007 1:50 pm

I would be 100% confident in saying it is due to a lack of Tarzan's Grip..

x-rad · Post by **x-rad** » Thu Aug 23, 2007 2:50 pm

poor rubber mix at factory = failure

Barry · Post by **Barry** » Thu Aug 23, 2007 8:19 pm

x-rad wrote:poor rubber mix at factory = failure

Quality control would exclude this theory,Im sure..SPC (Statistical Process control) would pick a bad rubber mix up within 20 or so units.If the QC guy was on the ball,within 5 units as the operator would have noticed something.

Rubber mix is also tested in labs before approved for production.

Tarzan Grip Mike??

Mats · Post by **Mats** » Thu Aug 23, 2007 11:13 pm

The recommended cambelt service life here in Sweden is 6000Km, draw your own conclusions.

Barry · Post by **Barry** » Fri Aug 24, 2007 2:06 am

Mats wrote:The recommended cambelt service life here in Sweden is 6000Km, draw your own conclusions.

Hey Iceman..surely you mean 60 000km`s.....

Mats · Post by **Mats** » Fri Aug 24, 2007 2:51 am

Yes.

Bit scared there for a moment eh?

Jim K · Post by **Jim K** » Fri Aug 24, 2007 5:07 am

"Brand new" doesn't necessarily mean much. It can be new and 20 years old. If the blister pack it was in had a hole, or worse, if the belt was simply inside a carton box it could simply grow old which is an inescapable fact. With belts and other rubber parts as well as head gaskets, you must always try to find some mfg date code, usually expressed as say, 732 (2007, week 32) or 327 or some other easy format. Same as the datecode you look for in tires but you all care about that one!
Stupid question: are all pulleys the newer type or maybe one of them (the crank one) is the old trapezoidal teeth type? It has happened and it victimized the belt...twice!
Jim K.

Barry · Post by **Barry** » Fri Aug 24, 2007 9:04 am

Jim,Pulley`s are all original 24v -164 based.The bottom crank pulley/gear wont fit if its not correct..
I have another engine ready to ship and both these belts were bought from an official Alfa Romeo dealer at the same time.
As a precaution Im removing the second belt and slicing it in half.
I will buy a new one for this engine.

Im surprised no one has asked what my opinion is as to why it failed..
I stated I had an idea at the top..

All my experience says this belt overheated and then started de laminating..
Dont ask me how but that is my honest opinion.
I checked all the pulleys and tensioner/idler bearings today..All are perfect and like new still.No heat discoloration or marks at all..
Even the cam pulleys are still as in new anodized condition...

I still say its excessive heat..

You reckon it may be time ex??..mmmm....

Barry · Post by **Barry** » Fri Aug 24, 2007 9:06 am

Mats wrote:Yes.

Bit scared there for a moment eh?

We need a pooping smiley!

Post by **Zamani** » Fri Aug 24, 2007 9:31 am

Overheated?? How?

Barry · Post by **Barry** » Fri Aug 24, 2007 9:45 am

Zamani wrote:Overheated?? How?

The million dollar question Zman...Unless it just could not handle the heat generated as std.ie: not meeting the heat range criteria..

I was quality manager for a rubber components manufacturer many years ago..We at that time made all the engine mounts,exhaust hanger bushes,suspension rubbers,grommets ,etc.etc. for Alfa Romeo and many other manufacturer..

From my experience the with rubber products I base my opinion on..

Cambelt 24v -opinons~Barry