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Discussion Starter #1
Hi,

Suffering from the age old problem of leaking hydraulic cambelt tensioner on my 1990 12V QV. Have previously tried the seal kit that Alfa sell, and that made no difference, still leaking copious amount of oil (or was a two seal kits tried incase the first was faulty... can't remember).

Anyhow, cambelt, etc, due to be done again soon so want to try and put a stop to the rediculous amounts I seem to be spending on oil each year (also bear in mind I do about 500 miles a week in my 164)

Are the mechanical units worth fitting or a risky retro-fit? Any other options/suggestions - preferably tried and tested (other than spending £400 on a new hydraulic tensioner or however much they are)

cheers,

Dex.
 

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I've seen a few variations on this - not least the kit Alfa do to replace the hydraulic unit with the thermo-mechanical one (like the 155 V6 and most US market 12V).

Couple of people I know have fixed type ones installed and haven't had any problems. A number of options out there but it's not a difficult DIY thing to do.

Have a search on the AlfaBB as well - some decent pictures on some of the threads.

FWIW, the thermo-mechanical one on my 155 V6 has done 110k miles and still works fine. The hydraulic one on my 12V V6 in the Strat leaks a very small amount after I re-furbished it. Probably the trickiest part is making sure the O rings on the hollow stud don't get damaged during reassembly - if they do, the thing will p155 oil out!
 

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Mine has (effectively) been running with a mechanical tensioner for a few years now and I've had no trouble. It still has the hydraulic tensioner but it made an irritating rattling noise at idle so I put a tack weld on it! Interestingly (apologies if you already knew it!) I got some useful information from someone on the American 164 board a while back. The hydraulic tensioner is, in fact a "de-tensioner" - i.e as the oil pressure goes up, it SLACKENS the belt! The explanation I was given (which made a lot of sense to me!) was that the biggest loads on the timing belt are at startup and when the engine stalls - these being the biggest accelerations the valve train is likely to see. At higher engine speeds, the tension can be reduced - apparently to prolong belt and bearing tensioner life.

I change mine every 36,000 anyway and have had no trouble with the "solid" tensioner. In fact, as the car is semi-retired now, I change it on a time rather than mileage basis.

A couple of other thoughts:

1. If it is leaking oil, have the crankcase breathers been checked? in particular the can on the back of the block with the small tube leading back to the crank case from the bottom of it? Apparently these are famous for blocking up and can cause all the oil seals to weep a bit - especially if the engine is old and there is a bit more blow-by past the piston rings than there should be.

2. If 2 seal kits haven't fixed the problem, is there a small nick or scratch in one of the mating surfaces - especially the hollow stud that the oil comes up the middle of?
 

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When you say srat is that by any chance a a stratos replica

FWIW, the thermo-mechanical one on my 155 V6 has done 110k miles and still works fine. The hydraulic one on my 12V V6 in the Strat leaks a very small amount after I re-furbished it. Probably the trickiest part is making sure the O rings on the hollow stud don't get damaged during reassembly - if they do, the thing will p155 oil out![/QUOTE]
 

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My 166 12V V6 Turbo have done 188000 km with mechanical tensioner. Changed it with the service intervalls. Works great!
 

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When you say srat is that by any chance a a stratos replica

FWIW, the thermo-mechanical one on my 155 V6 has done 110k miles and still works fine. The hydraulic one on my 12V V6 in the Strat leaks a very small amount after I re-furbished it. Probably the trickiest part is making sure the O rings on the hollow stud don't get damaged during reassembly - if they do, the thing will p155 oil out!
[/QUOTE]


It is. A CAE Corse. It's got a 12V V6 from a 164 I used to run. It's currently running aspirated but I'm in the long-drawn out throws of installing an Eaton blower.
 

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Yep, the seal kits are very very tricky to install. THEY MUST BE FREE OF SCRATCHES AND NIKS. Autodelta did mine back in 1998 and it's still running leak free (a friends Dad uses this engine, different 164, as a daily runner).

As far as using the mechanical tensioner I have no experience but I do know that the yank forums hate them for some reason. I think many a timing belt has slipped and they blame the mech tensioners.
 

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There is a slight leak on the piston shaft on mine. Not surprised really, as the design isn't great in that area. I've seen mods whereby the shaft seal is replaced with a 'proper' spring tensioned lip-seal which helps.

Certainly, the main culprit for leaks is often the O rings on the hollow bolt. Tricky little blighters.

I think the big (potential) problem with the thermo-mechanical type is if they are over-stressed during installation - it's easy to do if you don't follow the instructions and it can break one of the internal springs, which leaves it not working properly. That, and un-sympathetic cold-start thrashings can lead to belt slippage.
 

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It is. A CAE Corse. It's got a 12V V6 from a 164 I used to run. It's currently running aspirated but I'm in the long-drawn out throws of installing an Eaton blower.[/QUOTE]

Ooooo! That looks good! What sort of power output are you hoping for and have you done any other mods to the engine? Brilliant car, the Corse, by the way. I've always liked them. I still have occasional dealings with its designer!
 

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It is. A CAE Corse. It's got a 12V V6 from a 164 I used to run. It's currently running aspirated but I'm in the long-drawn out throws of installing an Eaton blower.[/QUOTE]

whats a CAE corse sounds interesting the picture only shows the engine compatment which on its own looks quick Id like to know more as ive always wanted a hawk seen a few at alfa shows
 

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oops didnt read the other post after your first one chriss (avocet great minds and all that)
sorry everyone
 

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Discussion Starter #14 (Edited)
Mechanical (de-)tensioner now fitted, a straight forward install apparently. Just needed to source a 10mm stud and 8mm plug from a local nuts and bolts place as Alfa UK don't recognise the part numbers mentioned on several US web pages (60897506/60897507). In lieu of the 10mm/8mm stud, used a 10mm and drilled the mounting hole on the tensioner rather than turning the 10mm down to 8mm on the stud - seems to be OK.

Time to see now how much (or little) oil I get through now, as i suspect all the losses were through the tensioner. Certainly the extra cost of this mech tensioner over the hydraulic seal kit is much less than I was spending in oil a year!!

I check the oil vapour canister regularly after it blocked a few years ago and this was correctly draining. I have changed the drain hose and an array of other hoses anyway, as they were past their best and some were getting a bit brittle with surface cracks appearing.

One thing I have noticed is the oil pressure remains stable now at any particular number of revs, where before the gauge pointer was a bit nervous particularly at idle. The gauge show just under 4bar at 3k when up to temperature, and a very steady 1.5 bar at idle (approx 800rpm), and oil pressure now rises and falls immediately in line with the revs where it was a tad irratic before (e.g. some lag on revs rising to the gauge rising).

thanks for your advice.
 
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