Technical Fiat 850 Sport timing chain

[ppalma]

Hi,
One silly question regarding the timing chain.

I'm messing around with an engine, and assembled the timing chain this way, with the "self-tensioning links", the little "duck bills", on the outside.
The manual I have shows these links on the outside, whereas the Uno manual shows them on the inside. This is logical, as the engines turn in opposite directions.
However the links on my chain are facing the wrong way. So the question is, which should prevail? And what are these "duck bills" called?

 

[jackwhoo]

Hi,
One silly question regarding the timing chain.
View attachment 209442
I'm messing around with an engine, and assembled the timing chain this way, with the "self-tensioning links", the little "duck bills", on the outside.
The manual I have shows these links on the outside, whereas the Uno manual shows them on the inside. This is logical, as the engines turn in opposite directions.
However the links on my chain are facing the wrong way. So the question is, which should prevail? And what are these "duck bills" called?
View attachment 209443

Looks to me that if the duck bills are on outside of loop chain forms they operate by centrifugal force to tighten chain.
If that's so,
Theoretically it shouldn't really matter which way They face ,as long as they are on outside of loop.

 

[jackwhoo]

I may have misunderstood, sorry

 

[jackwhoo]

What is direction of rotation of you crank in photograph?

What is direction of rotation of crank in diagram.

 

[jackwhoo]

Ok thought about it a bit more , copy what the manual shows.
If assembled "wrong" oil drag could cause a loose chain.

I look forward to hearing from an expert in these chains as I am just guessing.

 

[ppalma]

I may have expressed myself confusingly.
When I say outside or inside I mean away or towards the engine block. The duckbills actually prevent half of the links from bending one way.

 

[jackwhoo]

I may have expressed myself confusingly.
When I say outside or inside I mean away or towards the engine block. The duckbills actually prevent half of the links from bending one way.

In which case you have an excellent question to which I don't have an answer.

How about a new chain that has duck bills on outside with the bills pointing as in manual picture.

Duck bills a great description

 

[jackwhoo]

I see the chains are available with duck bills pointing either way .

Definitely find out for sure before assembling.

Which way was chain when you disassembled?

 

[850 Dave]

I just checked in my original Haynes manual to see if I could help with this mystery. The manual shows a picture identical to figure #117 that you show above. The caption of the illustration in the Haynes manual states "When refitting, the stretchers must always be turned outward as shown". So, it does matter which way the chain goes on, and the 'official' name of the little duckbills is stretchers.

I know that this post is a little dated, but I hope that this information is useful