rebuild carrera tensioners?

haycait911 · haycait911's Garage

I can compress the tensioner on the left side with my finger. the right side I cannot budge by hand.
which is the normal situation?
first, has the left tensioner failed?
I was getting intermittent LH noise, emanating from the chain housing, especiallly when hot.
has anyone rebuilt these things? and does pp have the kit, I can't find it on their site.

spuggy · 06-10-2007, 03:12 AM

They don't last for ever, and some of the original upgrades fitted in the 80's have to be getting pretty old now...

The ones in my '78 930 motor were replaced "while we were in there" @ 90,000 (spun #6 bigend).

They had looked fine when the PO treated it to a pro top-end rebuild @ 65,000, and were re-fitted then.

Only the left hand one didn't look usable this time around, but we figured hey, they've probably been in there 20+ years, replace them both.

redtdi96 · 06-10-2007, 03:41 AM

I'd replace both with OEMs (either pressure or non pressure fed).
Just too big a risk here not to do both as a failure could kill engine quick

baloo · baloo's Garage

Have you gotten any response back re. anyone trying rebuilding the tensioners-- versus buying new ones?

haycait911 · haycait911's Garage

haven't heard back from anyone who's actually rebuilt them, or where to get kits. that would still be my first option. I need to get this engine running properly before I can properly assess it. I don't want to spend more than necessary to do that. anyone?

Eagledriver · 06-10-2007, 05:51 PM

I don't have one in front of me but I'd try to take the bad one apart and see what has failed. The easiest replacement would probably be to buy a used one from a dismantler like Partsheaven in Hayward CA.
I've never heard of a rebuild kit for these.

-Andy

haycait911 · haycait911's Garage

can anyone tell me if I should be able to compress the tensioner with a finger. one side is rock solid, the other I can easily compress. which is correct? tensioners are still in place in the car. Don.

88-diamondblue · 06-10-2007, 06:52 PM

On mine I had to use a vice to compress the tensioners. Even in the vice it took a lot of force to compress them. My guess is the one that you can do by hand is toast. Replace it!

scottc · 06-10-2007, 08:14 PM

You should have to use a vice to VERRRRY SLOOOOOWLY compress the the tensioners (to avoid damage) so they can bleed off the oil in the damper chamber. If you can compress with your fingers you may have a broken spring as well as shot seals. I have rebuilt several sets of tensioners as per the instructions in the factory manual. I have never had a failure since rebuilding BUT I have always fitted them with the little safety collars to prevent total collapse.

They are not hard to rebuild and the bleeding technique is straightforward. The oil seems to act primarily as a damper.

I think I have always gotten the kits from Stoddard and they were pretty cheap: like $20 each.

Good luck, Scott

haycait911 · haycait911's Garage

Scott, are you talking about the standard or oil-fed tensioners?

scottc · 06-10-2007, 08:42 PM

haycait911:

Sorry I was not more clear. I am talking about the standard tensioners used up until the oil fed Carrera tensioners were fitted in 1984.

Scott

hcoles · 06-12-2007, 04:40 AM

IMHO - I suggest putting in oil feds with Jerry Woods travel plugs. As mentioned when the oil feds are bled they are hard to compress and do it very slowly or you can break them. You can't even move them by hand. You will see oil slowly coming out of the weep slot at the top.... there should be threads out there on all of this.

69BahamaYellow · 08-23-2007, 12:29 PM

I have rebuilt these things successfully, and here are some tips for everyone's benefit:
1) Good tensioners are rock solid, and can not be compressed by hand; not even with a good pair of vice grips. If they can, the internal ball check valve is bad. If they can be compressed slightly with little resistance then get solid, they have air in them, and you need to bleed them.
2) Bleeding a rebuilt tensioner is tough, and requires 3 hands to do it easily; follow the procedure in the Haynes manual and you will see why. I found the only way to get every bit of the air out is to perform the bleeding proceedure with the tensioner submerged in a can of oil. Quite difficult and messy, but this was the only way I could get them to feel rock solid after I pulled the installation pin. Otherwise, they were spongy in the first 1mm or so of travel, after installation, (indicating there was still air in them).

Hope this helps.
69BahamaYellow

MattAlpha · MattAlpha's Garage

Any chance you have a few pictures of the process?

I find the Haynes manual lacks in a lot of areas, especially pictures.
Thanks,
Matt

TargaT · 08-23-2007, 07:43 PM

I rebuilt mine and they were rock solid when I installed them. They both failed shortly after, not sure why. Luckily I had safety collars. The rebuild process was pretty finicky. I don't think I'd do it again.

Joe

69BahamaYellow · 08-29-2007, 02:39 PM

Here is a picture of a tool I fabricated to assist in the re-assembly process. This tool allows me to assemble everything while the tensioner is submerged in a can of oil and compress the piston rod using a small wire to open the ball bleeder valve (through the hole in the piston rod). I think the key is to never compress the piston rod into the tensioner unless you are relieving the pressure through the bleeder ball valve. I see lots of posts where C-clamps or vice grips have been used to compress these things for installation. I suspect this damages the bleeder ball valve and eventually causes them to fail. I would like to know if Targa T used the vice grip method to install his tensioners, which later failed. I'm not saying this is the only reason these things fail; obviously, the factory saw fit to update them to the pressure fed types for good reason. I can tell you that mine have ran for about 60K miles since rebuild with no signs of problems, but I also run the disks that Targa T mentions that prevent a total collapse if the tensioners fail.

69BahamaYellow

hcoles · 08-29-2007, 02:45 PM

good points.. I compressed mine using very large channel locks and pressed slowly...
where is the picture? I like the idea of the wire to open the check valve...

69BahamaYellow · 06:48 PM

Sorry the picture didn't come across the first time. The screw on top presses the top nail into the piston rod through the top of the tensioner. The nail on the side holds the top of the tensioner just above the tensioner housing so you can insert a wire into the small hole in the top of the piston rod. This will hold the bleeder ball valve open while the piston rod is pressed to the bottom of the tensioner. Then remove the wire and press down the top of the tensioner. No damage and no air trapped in them.

69BahamaYellow