[alfa] Re: Chains versus things that snap without warning

[George Graves <gmgraves@xxxxxxxxxxx>]

On Sep 22, 2004, at 4:58 PM, alfa-digest wrote:

> ------------------------------
>
> Date: Wed, 22 Sep 2004 17:41:48 +0100
> From: "Tim Hancock" <timhancock@domain.elided>
> Subject: [alfa] Chains versus things that snap without warning
>
> <Chains are good for about 70,000 miles before they should be replaced,
> and on some cars, the belt life approaches that pretty favorably. In
> those cases, using the belt is a good decision.>
>
> Can't run with that one I'm afraid, there are innumerable 164TS whose 
> chains
> are still merrily thrashing around without any problems at 150,000 
> plus miles.
That's a nice anecdotal story, but it really doesn't mean very much. 
Now, I'm not too sure I know what a 164TS really is, but I'm going to 
guess that it's either a two-liter, Twin-Spark 4-cylinder 164, or a 164 
Diesel. Either way, these were never sold in North America and I have 
no knowledge of them. OTOH, I know a guy with a 1985 VW with a belt cam 
drive whose current belt has almost 130, 000 miles on it. That's great, 
but it in no way alters the fact that VW recommends that  the belt be 
changed at 60,000 miles. Likewise just because it is possible to get a 
164TS chain to last upwards of 150K doesn't mean that Alfa recommends 
that you keep it that long.




> In a clinical world perhaps the owners should have religiously had 
> their
> engines overhauled at 90,000 (to pluck a distance out of the ether). 
> The
> record I have come across personally for an 8 valve TS engine having 
> had no
> work whatsoever (normal servicing aside) carried out on it is about 
> 280,000
> miles. Later TS engines with rubber bands are a load of old rubbish by
> comparison and break with appalling regularity. Progress?...don't make 
> me
> laugh!
I'll try to avoid saying anything funny, then. But I agree with you 
that chains are probably a better solution, it's just that in some 
cars, like the Alfa  12-valve V-6, it's no big deal (except that you 
have to be careful not to let the motor turn backwards - even a few 
degrees) because the water pumps have to be changed on a similar 
schedule as the belts, so it's a no brainer. I have never heard of a 
GTV-6 belt breaking, but I have seen them skip time. A tooth or two 
doesn't seem to hurt anything (except the running of the car), but more 
than that and US$5000 rebuilds ensue.

> Just in case anyone suspects me of cynicism (One of the few things we 
> Brits
> are quite good at), My take on why belts came in is 1) They are cheap 
> for car
> manufacturers to build 2) They require regular replacement which makes
> business for workshops 3) They break regularly with no warning which 
> gives
> workshops even more business..or means you have to buy a new car as 
> the cost
> of a rebuild is more than the value of the car (see Alfa 164 V6 and 
> many
> others). All other so called advantages are just marketing boys flim 
> flam with
> no substance.
You are probably at least partially correct. I do know this. Overhead 
Cam engines were the domain of exotic cars such as Jags, Aston-Martins, 
Maseratis, Ferraris and Alfa Romeos before the glass-fibre reinforced 
Gilmer belt cam on the scene. After that OHC and even DOHC engines 
became commonplace. So, yeah, it's definitely a cost thing. On most 
cars, as I said before, it's not really a big deal, but on some cars, 
such as Ferrari V-8s, it was a very BAD choice.


> A rubber/composite item working in an oil dominated dirt laden 
> environment is
> just plain crackers. Timing chains thrive on oil, and indeed operate 
> with
> plenty of clean oil flying around in a filtered environment. What is 
> more, if
> a timing chain or tensioner is getting to the end of the road for 
> whatever
> reason, it normally announces this by getting noiser/ rattlier and 
> giving all
> concerned plenty of notice. Timing belts are the masters of high speed 
> engine
> Hara Kiri with no warning. Which do you prefer? Timing chains do wear 
> out
> eventually, but they do not degrade in the same insidious silent way 
> that the
> belt does.
Replace them on the manufacturers maintenance schedule, and you 
shouldn't have any trouble. I've owned a number of cars with timing 
belts, and have yet to have one actually give me any trouble. And 
remember, a broken belt is not even a problem on a non-interference 
engine, just an inconvenience.

> A few chain systems are poor designs. The Lada engine had an awful 
> timing
> chain system, but they rarely destroyed the engine no matter how 
> rattly they
> became. The Nissan Micra has a single row chain that does 
> break...design
> fault...its too weeny for the job.
>
> The simple fact that belts require regular replacement introduces the 
> further
> risk of incompetent fitters, and if you think every timing belt is 
> fitted
> properly then you are kidding yourself. Some garages in the UK will 
> not do MOT
> tests on diesel engines unless there is documentary evidence of a 
> recent belt
> change. So many have failed on test resulting in writs flying about 
> that the
> Test centres have had enough. No manufacturer I know of has judged the
> replacement interval of belts accurately. They simply don't have a 
> clue how
> long they last, hence most manufacturers have had to HALF the original
> expected life in the light of the number of breakages in real time 
> use. As far
> as I am concerned their credibility is shot to pieces on this issue.
>
> FWD/RWD? Anyone who watched John Handley (It might have been John 
> Rhodes..or
> it might have been both of them come to that!) drive a 1000cc Mini 
> round the
> OUTSIDE of Graham Hill in a 3.8 Litre Mk 2 Jag going round Tatts 
> corner at
> Aintree in 1962 does not need much convincing that there is perhaps 
> something
> in this FWD thing. You might not like FWD, but that is a different 
> matter. In
> engineering terms it works, and in general provides a safer driving 
> experience
> for day to day drivers, reducing the risks of being put in an oversteer
> situation, a situation which many drivers could not cope with...my 
> mother
> in-law being a prime example!
The only thing really wrong with FWD is that with the front wheels 
doing the accelerating, the steering, the driving and the lion's share 
of the braking, it's hard on tires, From a physics standpoint, when one 
accelerates off the line, the moment of inertia transfers rearward. 
This favors a RWD car by putting the moment of inertia over the driving 
wheels where in a FWD setup it takes the force OFF of the driving 
wheels. If you want confirmation of this watch the Alfas vs the BMWs 
come off the line in the European Saloon Race Championships. The BMWs 
(with less power) get off the line better and get a jump on the Alfas 
due to the fact that they're RWD. Of course, the Alfas usually win 
anyway (hey, they're Italian), but you can see what I'm talking about.

Also, FWD cars are fairly limited in the amount of horsepower they can 
carry. One reason why Alfa Romeo is going to AWD in most of it's 
current platforms is because the GTA engine is stuck at 250 HP. They 
can't really compete with BMW on an HP basis in the showroom. The next 
generation of Alfas will be back to RWD, especially for their more 
sporting options for this very reason.



> End of rant
>
> Tim Hancock   Boston UK
>
> 164TS
> 164Super
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