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View Poll Results: belt or chain?
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cambelt
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3 |
18.75% |
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timing chain
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13 |
81.25% |
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03-07-2009
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Status:
-
AO Platinum Member
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Join Date: Dec 2008
Location: Italy
County: Modena
Posts: 13,738
Member car: 24V Quad Cam Monster
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timing chain or cambelt
which do you think is best / you'd prefer alfa's to have
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03-07-2009
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Status:
Wishing I had a
garage
AO Silver Member
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Join Date: Nov 2002
Location: United Kingdom
County: Kent
Posts: 4,703
Member car: 156 2.4 JTD, GTV 2.0TS
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You must be really bored this evening
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03-07-2009
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Status:
Wants his car back
Club Member
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Club Member Number: 800
Join Date: Feb 2009
Location: Ireland
County: -
Posts: 900
Member car: '98 156 V6, GSXR 600
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Timing chain. My old DOHC sierra had one, it meant I could buy a secondhand waterpump (ran off the aux belt) for £10 and fit it myself. How many Alfa owners can say that?
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03-07-2009
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Status:
-
AO Platinum Member
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Join Date: Dec 2008
Location: Italy
County: Modena
Posts: 13,738
Member car: 24V Quad Cam Monster
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Originally Posted by Mitch166
You must be really bored this evening 
yep
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03-07-2009
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Status:
-
Club Member
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Club Member Number: 714
Join Date: Dec 2005
Location: United Kingdom
County: Oxfordshire
Posts: 18,913
Member car: GTV 3.0 V6
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Cambelt.
Quieter, more efficient, more accurate control of timing (don't get longer as they age), cheaper to make, require no lubrication.
And generally much much easier to change.
In an ideal world all cars would have gear driven cams though.
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03-07-2009
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Status:
-
AO Silver Member
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Join Date: Apr 2008
Location: Rochester Kent
Posts: 1,830
Member car: 1997 GTV 2.0 TS
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Originally Posted by symonh
Cambelt.
Quieter, more efficient, more accurate control of timing (don't get longer as they age), cheaper to make, require no lubrication.
And generally much much easier to change.
In an ideal world all cars would have gear driven cams though. 
Desmodromic valve gear would be great in cars. I am sure that eventually the gears would wear out, but it would take a long time, and they are engineering works of art.
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04-07-2009
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Status:
-
Club Member
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Club Member Number: 714
Join Date: Dec 2005
Location: United Kingdom
County: Oxfordshire
Posts: 18,913
Member car: GTV 3.0 V6
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Originally Posted by andyalfagtv
Desmodromic valve gear would be great in cars. I am sure that eventually the gears would wear out, but it would take a long time, and they are engineering works of art.
I think it is great too, however how would you engineer in variable valve timing?
Then there is the wear/clearance issues you mentioned.
When I suggested gear driven cams I was thinking of just replacing the belt/chain with them and keeping the cams and springs. It has been done on OHV engines like the Ford Essex V6. So after all of these years why couldn't someone come up with a solution for OHC engines?
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04-07-2009
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Status:
-
AO Silver Member
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Join Date: May 2006
Location: United Kingdom
County: Hampshire
Posts: 2,826
Member car: 147GTA
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Belt every time for the reasons symonh says. My Alfa engine's water pump is driven by the aux belt - thought they all were. Changing the water pump for £10: in my dreams.
Desmo valve gear isn't dependant upon the method by which the cams are driven. It refers to the mechanical arrangement for closing the valves (thus not relying on hefty springs). The old Ducatis used hairpin valve springs to hold them closed lightly.
Using bevel gears to drive the cam like the Desmo Ducatis has its own set of problems. Also expensive, like the Inter Norton and K series Velocette and others decades before them.
P.S. Cam belts do at least keep people in employment. Oh, and chains break too, ask plenty of GM 2.2 litre engine owners (Z22 engine I think it's called) - we aren't talking new valves here but new c/head. Ask me how I know.
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07-07-2009
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Status:
Being Stalked by the
looks of it
Club Member
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Club Member Number: 1132
Join Date: Sep 2008
Location: United Kingdom
County: Lancashire
Posts: 2,641
Member car: 156 2.0 Twin Spark
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Interesting.
The Essex V6 had fibre timing wheels which were given to disintegrating and taking the engine with them. My old Primera had a chain and at 140,000 miles+ made no noise whatsoever. The chain on my Mini rattled like a biscuit tin full of nuts and bolts and 50,000 miles. I've had 2 DOHC Sierras and they were OK too but they can let go without warning at around the 100k mark. There is also an issue with them in that if the oil is changed and you start the engine without building the pressure first, the chain can slip a tooth or two as the tensioner works on oil pressure.
When it comes to belts, a change for my Alfa is approx £250. By the time I've bought the parts and the kit, doing it for myself hardly saves anything. The job on our Volvo was £175 but only needs doing at 60k (but that includes a reasonable safety margin). The old Mondeo Zetec we had had an 100,000 mile timing belt interval and they don't have a reputation for going early either. changing the belt on a CVH powered Ford took about an hour tops.
I think the answer is that I really don't give a toss which it has as long as it's engineered properly. I'm not entirely convinced that the TS one is to be honest.
__________________
Jobs list:
Door Seal
Air filter - done!
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Thermostat - under consideration
The car in front is a Toyota. And it appears to be pulling away!
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07-07-2009
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Status:
-
AO Member
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Join Date: Mar 2007
Location: Norfolk UK
Posts: 809
Member car: 147 1.6 TS Lusso
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Originally Posted by keithyboy
changing the belt on a CVH powered Ford took about an hour tops.
Both of the Fiestas I had, had the 1.4 CVH engine.
Changed both of the belts myself, with a little help from the haynes manual.
Took a little longer than an hour, not much more if I recall, I have a reasonable amount of mechanical "Nouse", but I'm no mechanic.
Easy little number on the CVH.
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09-07-2009
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Status:
-
AO Gold Member
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Join Date: Feb 2002
Location: The land that Time forgot
Posts: 8,058
Member car: Skinny 155v6 ICBM
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Aye! It doesn't matter which, as long as it's reliable.
I'd have gear driven cams though, if I was designing an engine myself.
Ralf S.
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09-07-2009
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Status:
Pothole :(
AO Gold Member
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Join Date: Jul 2007
Location: United Kingdom
County: Surrey
Posts: 10,369
Member car: Alfa 156 2.4 JTD + Q2!!!!
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+1 for the CVH the cambelt (on my sierra) was nicely positioned at the front of the car with lots of space to work ... don't remember any scraped knuckles from those days
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