Alfa Romeo Forums banner
21 - 40 of 72 Posts

·
Moderator
2015 Chevy (Holden) SS, 1989 Milano (Shankle Sport), 1991 164S
Joined
·
17,334 Posts
My own feeling is that if you still have the original tensioner, perhaps you should use that.

I know of those who have "fixed" the original so that it does not readjust once set and have had luck with it, so I don't know, but I've used the original as is for 198k miles so far. Don't plan on changing if I can help it. But then again, who knows?
 
  • Like
Reactions: nickguy

·
Administrator
Joined
·
15,258 Posts
I agree with Del. No way would I use the tensioner again, at least without modifying the way the set tension is locked. It must never, ever, and I mean ever be possible for it to slip.

Pete
 

·
Moderator
2015 Chevy (Holden) SS, 1989 Milano (Shankle Sport), 1991 164S
Joined
·
17,334 Posts
I think that developing a better way to establish the proper tension should be incorporated, if the tensioner part itself is otherwise not at fault, although we don't know that yet. Twisting the belt doesn't seem particularly accurate for such a critical use.

This is not like putting some amount of adequate tension into the serp belt.
 
  • Like
Reactions: nickguy

·
Premium Member
Joined
·
118 Posts
Discussion Starter · #26 ·
Think I will call Centerline and see if I can get some feedback. The main reason I got it was that the car previously had a spring tensioner which broke a spring and that kind of disturbed me. Was not able to source a hydraulic one so it seemed like the best solution.
 

·
Premium Member
Joined
·
118 Posts
Discussion Starter · #27 ·
I've looked at the design of the tensioner. Did it slip on the (curved) slot? Otherwise looks like a good design to me

Pete
Think the belt slipped at the crank because the offset of the cams was the same.
 

·
Registered
Joined
·
2,369 Posts
A very interesting and perplexing read. Since Nick keeps repeating that he heard something, it seems likely that the "something" might have been pulled into the path of the crank pulley, derailing the belt for a split second (are you missing a 10mm socket?) It seems unlikely that Nick's initial tensioning was the cause of the mishap because generally a loose belt will cause a slip on the back cam, not both, and usually on startup, which was not the case here. Since there was some trauma involved, I'd carefully inspect the Centerline-Zat tensioner for alignment before reusing it. Reinstalling everything, and rotating the engine several times (without any snags) will put to rest the idea that the key in the crank pulley sheared.
 

·
Moderator
2015 Chevy (Holden) SS, 1989 Milano (Shankle Sport), 1991 164S
Joined
·
17,334 Posts
Good comment.

I'm still not really convinced that setting the belt tension as they say, ie, give it about a 90 deg twist, is the best way to do it. Maybe it works, maybe it doesn't. Their method is based on the fact that there is no method built into these tensioners to measure the tension actually achieved and whether or not it is sufficient.

I wonder, can a Gates belt tension tool be used to measure the tension in a factory supplied tensioner properly set, and then the Centerline version when it is adjusted with just their "twist of the belt"? Surely, Centerline ran such a test?

I do agree that the cause is probably a foreign object momentarily getting between the crank pulley and the belt, with perhaps the belt not as tensioned as it should have been (thus no apparent damage to the belt). That area is sure close to the ground and all sorts of crud being tossed around by the right front tire.
 

·
Registered
Joined
·
2,369 Posts
I have never tried a Gates cricket tool on a timing belt but I think Fred Di Matteo's advice from one of his posts (prior to ALFABB) is appropriate: "strum it to make it sing” (context: installing a fresh belt on a 12v engine with hydraulic de-tensioner). This may not mean the same to everyone, but as a former musician let me explain: when the tension is low the frequency is almost imperceptible, like a thud (unmusical), say 20 to 80 beats per second); now tighten it until it strums in the range of the human voice, that's "strum it to make it sing".
 

·
Moderator
2015 Chevy (Holden) SS, 1989 Milano (Shankle Sport), 1991 164S
Joined
·
17,334 Posts
I like that, and have heard mechanics say the same thing with belts in general. Not exactly accurate unless one might have frequency analyzer, but that would be an interesting test as well.

In general the important criteria is that the belt tension should be at a minimum safe tension or above (within reason). What that minimum safe tension is, we do not know, except by having skipping? Not comforting.
 

·
Moderator
2015 Chevy (Holden) SS, 1989 Milano (Shankle Sport), 1991 164S
Joined
·
17,334 Posts
Different design, different requirements, ie, really big teeth instead of very small ones, no skipping unless outrageous and totally obvious looseness, or a broken chain. I have always preferred chains, while realizing they do require a design for lubrication, and requiring only simple tensioners, if at all, depending on application.

Doesn't the later versions of the V6 use a chain in the system?
 

·
Registered
Joined
·
2,369 Posts
I have a a somewhat flippant answer for Pete. Listen to the musical score for the initial factory scene of Mafioso, a film shot in 1962 by Alberto Lattuada, music composed by Piero Piccioni. That's the sound of the timing chain, more or less. I think this is a Fiat factory.
www.dailymotion.com/video/x551uld?start=60
 

·
Administrator
Joined
·
15,258 Posts
So from the above 2 posts I believe the answer is 'if the chain is quiet, it is tensioned correctly' ... which of course is not really correct.

Del, the later versions of the Alfa badged v6 were designed by Holden and yes use chains. It is a pity Busso did not use chains for his v6 because Alfa Romeo's implementation of timing belts is always fairly poor (although Alfa Suds do not have issues, but ALL Busso v6 engines have issues with their timing belts, apparently), but they seem to do timing chains okay
Pete
 

·
Registered
Joined
·
2,369 Posts
"So from the above 2 posts I believe the answer is 'if the chain is quiet,"

Quite the contrary! Did you listen to the loud explosive percussive music of Piccioni?
 

·
Administrator
Joined
·
15,258 Posts
"So from the above 2 posts I believe the answer is 'if the chain is quiet,"

Quite the contrary! Did you listen to the loud explosive percussive music of Piccioni?
I did, and sorry I don't understand your point. Car engine timing chains are not untensioned and noisy like that
Pete
 

·
Premium Member
Joined
·
118 Posts
Discussion Starter · #39 ·
Today's update. Secured the liners and rotated the engine. All the bores are perfect. So looks like all the rings are working/ present. Dial indicator on cylinder 1 shows that the clocking of the crank pulley is spot on so no slippage or woodruf key breakage.
Have not pulled the crank pulley, Not seeing a valid reason and the oil seal seems fine. There are some scratches on the surface of the cogs but no significant damage that I can see.
 

·
Moderator
2015 Chevy (Holden) SS, 1989 Milano (Shankle Sport), 1991 164S
Joined
·
17,334 Posts
Still seems to indicate that you were unlucky in having a foreign object, probably something fairly flat, get in between the belt and the pulley for a second, perhaps with a belt slightly looser than it should have been.

I have trouble feeling good about adjusting that tensioner. Proper test information sure would have been nice to see. Or, is the adjustment by guess. Something to worry about?
 
21 - 40 of 72 Posts
Top