Carrera Chain Tensioner Priming

[CarreraWSJT]

I am near the end of a 3.2 top end rebuild. I compressed the chain tensioners in a vice, some oil came out and I installed the pin. I released the pin in an oil bath and the piston immediately extended. I pumped the piston many times but it does not seem to have picked up any oil. The piston can now be compressed by hand. How do I ensure that the tensioner is actually primed?

Regards,
Bill

[CarreraWSJT]

That should read "vise" not "vice".

[burgermeister]

No expert here, but I've never done anything other than compress it and put a drill bit in it to keep it compressed for installation. They are connected to oil pressure, so they ought to be self priming within a few seconds of startup.

[Walt Fricke]

Me, too.

The spring inside the tensioner is what produces the tension. The oil inside is part of the shock absorber (read oscillation damper) functiion. Not too necessary at low RPMs, and it doesn't take long at all for oil to fill this small chamber - which is already pretty full - low by only what you squeezed out. The pressure fed part is useful just to keep the tensioner always full, adding a little bit of oil as the chain bounces up so its resistance to the chain bouncing back down is at its max. The tensioner isn't like a hydraulic ram, with fluid pressure forcing its plunger out.

For the older tensioners, there was a protocol for filling them, perhaps because they relied on oil splash falling onto the cup shaped tops to percolate in and fill and refill them. All in the past.

And think about it: once you compress the tensioner prior to installing it, there is no room inside for more oil, so nothing one could do there.

Once it is installed and expands after the pin is pulled, how would you add more oil? I suppose you could fabricate an oil line, hooked up to some source of oil under pressure, and attach it to the oil inlet. And put in more oil. But you won't find, I wager, any pictures or descriptions of any such contraption.

But I understand the confusion. Descriptions of procedures often continue to include holdovers from the past which aren't really useful any more, even if possible. Consider the advice to bleed the rear brakes first. Can't possibly mean anything nowadays with tandem MCs. But I digress.

[Walt Fricke]

p.s. - there is an "edit" button at the bottom of each contribution any of us make here. So you can fix your own vicious mistakes without reposting. Which is good, because we all know what happens when we reread our stuff: mistakes pop out when before they were hidden from our eyes.

[trond]

I found submerging in oil and pumping does not work. At least it didn't work for me. I called the dealership and were advised to use a old fashioned oil pump, the type with a thumb lever and some hoses and pump it up. I found this to work well, with less mess and no doubt the tensioner is oil filled and that it actually works (which in my opinion is well worth checking)

[Steam Driver]

Forgive the late post on this but I was looking up information on same.

I was amused by your reply. You called a dealership and actually got some useful information on the older cars? All you get from computerized parts changers around here is a blank stare when you take in or ask about anything other than a water wagon!

Anyway I think the “priming” with the pump oiler after installation is great and it works. As far as it goes. But has anyone ever considered that in an engine being newly-assembled, or one that is just being converted to the Carrera tensioners, that even if the tensioner itself is filled after extension there are a lot of new oil lines going to them that are initially full air! All of that will be pushed into the tensioner and temporarily push that pre-primed oil out until the lines and tensioner are filled with oil.

So IMHO the whole pre-priming debate is moot. I did it, but I think once the engine is cranked the tensioners will briefly full of air again!