Hydraulic camchain tensioner - is it sick ?

trond · trond's Garage

I have a question on hydraulic cam chain tensioners; one of them may be compressed by hand, the other not at all. When I installed them 3 years ago I remember pumping them by hand to fill with oil. None of them got any firmer and because they were identical I assumed thats how they were supposed to be. 3 years and 15000 miles later one feels the same, while the other barely moves at all, I had to very very slowly compress it in the vice. Something is definitely not right here and I might have been luckier than I deserve

Flat6pac · 01-31-2012, 11:02 AM

The oil fed tensioners, Carrera, have to be bled off in a vise. The earlier ones could be compressed with a long screwdriver against the idler wheel support when installing.
Bruce

trond · trond's Garage

yes.

And one is firm as it should be (has to be compressed in vice, slowly). The problem is with the other one that compresses by hand easily. It was new, and I have used it for 15' miles without any apparent issues or noise.

I'll just have to get a new one.

Flat6pac · 01-31-2012, 05:32 PM

With a failing Carrera tensioner there is usually chain noise about 2000 RPM.
Bruce

67R69S · 02-02-2012, 05:40 AM

Is it possible to rebuild the pressure fed tensioners? I know there is a kit for the regular tensioners.

rgmrgm · 02-02-2012, 06:13 AM

i had chain noise on an engine i had just put together. one of the tensioners was very difficult to compress. i had several of the oil fed tensioners on hand and all but that one could be compressed by hand. i replaced the stiff one and no more chain noise

hcoles · 02-02-2012, 07:16 AM

Quote:

Originally Posted by rgmrgm

i had chain noise on an engine i had just put together. one of the tensioners was very difficult to compress. i had several of the oil fed tensioners on hand and all but that one could be compressed by hand. i replaced the stiff one and no more chain noise

Not sure if this helps but all the tensioners I've handled, which is not many, were very difficult to compress... I had to use a clamp or vice and squeeze very slowly. This seems to me to be the desired behavior.

trond · trond's Garage

There seems to be some confusion on how the hydraulic tensioners work, and there seem to be a lot of defect ones. The two check valves are supposed to trap oil inside the tensioners even after disconnecting the oil line, making the tensioner 'pump up' and get stiff. It will compress slowly in a vice because oil slowly leaks out through a calibrated passage.

Tensioners that work as bicycle pump, or a pogo stick even after filling with oil or usage in the engine and can be compressed by hand are not good.