Autolusso adjustable cam pulleys & Tensioner
1 - 13 of 13 Posts
Joined
·
4,517 Posts
Adjustable pulleys make it very easier to adjust the cam timing set amounts either direction to gain horsepower from different timing or while fitting non standard performance derived cams
now while the standard pulleys are fully adjustable as they have no key way it would be a major pain in the arse to keep re timing a car with dial gauges etc while doing a rolling road tuning session etc. also useful if once installed your adding other modifications at a later date etc..
dont add performance but allow you to extract performance lost by getting camshaft timing correct for the parts you have installed for performance
Joined
·
391 Posts
Joined
·
46,806 Posts
I've just finished replacing the cambelt, tensioner & idlers on a GTA today, the tensioner has only been on the car 14 months. Something in the backing plate has gone allowing the spring to half come out and the pulley wheel slide back in towards the engine, making the belt rub. So a non-schitt tensioner sounds pretty appealing!
Joined
·
391 Posts
One of the Alfa GT register in the eastern states (Australia) had a cambelt go bang in only a few months after replaceing, this could be the cause they could not find.
Allan
Joined
·
140 Posts
The tensioner looks very good. Keep us informed as to when they will be available.
Joined
·
2,613 Posts
Hi Dan i might be wrong but that sounds like my GTA haha
Tensioner only been fitted 10months! (only 8 of those it was actually driven)
To say i am not happy about a tensioner failing would be an understatement after soo little time fitted. I will say that i will never fit one of those tensioners ever again. (pictures may follow!)
It should put my mind at rest that an OE part is now fitted
Joined
·
2,613 Posts
Without conducting alot of engine testing this would be very hard to judge indeed.
I work for Gates Power Transmission who originally designed the cam drive system for these engines.
Thousands of motored and fired engine testing is conducted which is then finally proved in actual vehicle testing.
An automatic tensioner works by having an adjustable rate spring with its own damping characterisitcs and its own adjusting and working arm. These design points are quite critical.
Unfortunately if these parts are copied poorly they can lead to failure.
The automatic tensioner helps keep the tension in an operating window.
However a fixed tensioner, which this appears to be works in a completely different way. The fact that it can only be tensioned for installation. Then is left. It does look like it will take up all the tolerance of stack up etc with the adjuster. But it will not control the dynamics in the same way e.g. thermal expansion of the engine will cause the engine to grow, the automatic tensioner can take this into account, but a fixed tensioner cannot! This will cause a rise in system tension, but also the tension levels will fluctuate alot more than standard system.
Fixed tensioners tend to be used more on motorsport applications where timing intervals are alot shorter and maybe checked more often.
Joined
·
1,059 Posts
Good response, thanks for sharing.
Joined
·
1,038 Posts
Whilst the idea of a more robust tensioner sounds appealing, I don't think that a fixed tensioner (which the photos in the OP appear to show) is a viable solution. If it was, surely Fiat would have done this themselves, as it would be even cheaper than the piece of junk they did in fact use.
A fixed tensioner does no tallow for the considerable expansion that occurs with an all-aluminium engine like this, and will likely result in excessive belt noise, increased wear and reduced belt life.
I've been down this road before; 20 years ago with the old 12V Busso and it's infamous hydraulic tensioner. A fixed tensioner was not considered suitable for road cars then, and I doubt it will be for the 24V now. Fiat's solution to the 12V problem was to use a dynamic mechanical tensioner (similar in principle to the 24V), as well as changing the profile of the belt teeth and pulleys.
The tensioner design used on the 164 24V was better in my opinion, but they could be tricky to set, and of course were more expensive to manufacture.
A fixed tensioner does no tallow for the considerable expansion that occurs with an all-aluminium engine like this, and will likely result in excessive belt noise, increased wear and reduced belt life.
I've been down this road before; 20 years ago with the old 12V Busso and it's infamous hydraulic tensioner. A fixed tensioner was not considered suitable for road cars then, and I doubt it will be for the 24V now. Fiat's solution to the 12V problem was to use a dynamic mechanical tensioner (similar in principle to the 24V), as well as changing the profile of the belt teeth and pulleys.
The tensioner design used on the 164 24V was better in my opinion, but they could be tricky to set, and of course were more expensive to manufacture.
1 - 13 of 13 Posts
Join the discussion
Join now to ask and comment!