[Stevew]

Hello all!

Several weeks back I received a promo (bribe?) in the mail from Fiat to test drive an Abarth. Was in Reno today anyway and scheduled a visit to the dealership.

Kenny, the salesman, was remarkably well informed and although local streets did not provide much of an opportunity to exercise the 5 speed, I had a wonderful time doing brief sprints and listening to the marvelous exhaust note.

When we came back to the lot, Kenny popped the hood and we talked about the 4cyl, turbocharged, direct injection engine. I asked about the timing belt and here's where I got a big surprise. Change interval on the belt is, wait for it, 150k (!). Why so long? It only has to operate the one and only camshaft - on the exhaust side. Intake valves are handled by Fiat's Multiair system which controls valve timing, lift and duration with electronically controlled solenoids (I gotta get out of the house more!).

Here's a video Kenny sent me this afternoon. A worthwhile 5 minutes for the two other folks on the BB who are unfamiliar with this amazing technology:

All the best.

 

[bianchi1]

Italians always have great tech. going for them..

 

[NMMilano]

I admit that's a high interval but I don't think it has as much to do with how many cams it's turning as with improvements in belt technology. Other cars with out Multiair now have intervals above 100k, when I started changing belts in the early eighties the interval was often 30k.

 

[Greg Gordon]

The new Fiat 1.4T is a great engine. Its single cam actually operates both intake and exhaust valves through a pushrod system. Think of the GTV6 single cam in reverse. The Multi air system is between the pushrod and valve and limits lift and duration under most condtions. It's a brilliant system that works very well.

The belt interval is due to simply using a high quality belt, it's thick and has a tensioner that actually works.

 

[Stevew]

On second thought.

Greg,

Excellent observation!

I went back and watched the video more closely and indeed one cam operates both intake and exhaust cams, with the hydraulic system performing it's magic only on the intakes. The narrator talks about "full lift" just as the exhaust is opening, which might make less observant viewers (guilty!) believe the system works on both cycles. I gotta pay more attention.

I'll take a bow for this observation, however. Watch as the piston reciprocates and you'll notice MultiAir is so advanced, the pistons don't even need rings :laugh:.

BTW, Dodge Dart (for one) also uses this engine.

And finally, I'm pleased to report all the machines in my signature line use chains to operate their cams. :laugh:

All the best.

 

[Greg Gordon]

Steve, I do prefer chains! Sometimes the older ways are just better.