tensioner inspection / upgrade kit

[grahamkissack]

I am doing a major maintenance and want to check out the condition of my original '80SC tensioners. The car has about 100,000 miles on it. Is there wear or anything I can check for?

If I upgrade to carrera tensioners, is this the kit I get from pelican? Although I've done all my part buying from our host, I can't help but notice I can pick up OEM Carrera tensioners cheaper on Ebay. Thoughts?

Thanks, Graham

[yelcab1]

Yes, that is the kit. Your decision as to where to buy it.

[sundaypunch]

You will want to upgrade regardless of their condition if they are original. From what I've read you should also upgrade the idler arms to the new style w/ bushings ($120+). As for wear, the tensioner seals go bad over time allowing them to collapse. You can look to see if it's pushing the idler arm as far as it should be. I think you can also check to see if it can easily be compressed (it shouldn't be). I'm looking into doing tensioners as well but haven't figured out exactly what route I'm taking. If I understand correctly you basically have two options-

#1- Upgrade to the pressure fed tensioners. The standard for most people. Downside seems to be that there were some failures in the past when a "bad batch" hit the market. I haven't heard of this recently but would be a bit nervous about buying the $350 kit you reference on ebay from an unknown seller.

#2- Add a safety collar to the existing tensioners. This seems to be a viable (and much less expensive) option. It sounds as if the original tensioners can be rebuilt inexpensively and are practically bulletproof when used in conjunction with the new idler arms and safetly collars.

[Early_S_Man]

Graham,

You may already have the double-bushing chain-wheel carriers ... mid-80 production is when they were introduced. If so, I would recommend installing collars and rebuilding your existing tensioners with Pelican's rebuild kits ... about $30 per tensioner!

The double-bushing carriers solved most of the tensioner failure problems ... and the collars will take care of the other 1% possibility!

[Jim Richards]

Warren, are the "double-bushing chain-wheel carriers" the same thing as what I've heard called 930 tensioners?

[Early_S_Man]

Jim,

No, the 930 tensioners were introduced in mid-1980 production along with the double-bushing chain-wheel carriers [AKA idler arms] ...

The chain-wheel carrier is #5 in both diagrams below, and the rebuild kit parts are #11 thru #24:

[GB83SC]

Warren, I am a bit confused on the year for the double bushing chain wheel carriers upgrade. You mentioned by the mid 80's.
I have a very late 83SC, do you think it was done by then?

Also is the tensioner rebuilt easy to do? or are there special tools required.

Thanks in advance.

[Early_S_Man]

George,

Just to be perfectly clear ... the change was made during the middle of production model year 1980 ... and are sometimes referred to as the '80.5' tensioner changes.

No special tools to rebuild the tensioners ... just a bit of care, and a vise to keep everything clamped together while the snap ring #24 is removed and allow 'controlled' disassembly ... as opposed to 'rapid disassembly' ... which would mean a dozen or more flying parts scattered all over the room!

[rogwilson]

I updated to oil fed tensioners on my 1980 sc a few months ago. The previous mechanic put safety collars on the old tensioners and told me not to worry. Problem, the tensioner on the right side failed at about 120,000 miles. No catastrophic damage, but decided to update to be on the safe side now. Therefore I would highly recommend updating for peace of mind.

If you decide to update, you might want to replace the chain rails, since they are often brittle and are relatively inexpensive.

I believe the chain wheel carriers were updated in 1980 as mentioned above. Check your engine manufacture number. I think the old style was used through 640 0450. Engine numbers 640 0451 and above have the updated version (1980 through 1989). Luckily my engine production number was 640 0534.

If you decide to do the update. Wayne's project book gives detailed instruction on the process. Of course, the archives are full of useful information.

good luck

[aigel]

Testing the tenisoners is done by prying on the piston with a large screwdriver and seeing if it holds up firmly to the tension. If it does, you are good to go and test it again in 40k miles.

If you have the wide base idler in place (stock or upgraded) and install the safety collars, there is really no NEED to upgrade to the carrera tensioners.

On the other hand, once you are in there, it is a piece of cake to follow through and do the upgrade. It all depends if you are on a budget or not. Also, if you plan to resell the car any time soon, do the upgrade. All buyers are looking for it and you will actually get your investment back. This happens rarely with an upgrade, but it is true for the chain tensioners. Having the upgrade signalizes to the buyer that you took care of the car. The knowledge that you are just as safe without them - if you know what you are doing - is missing with most buyers.

Note that the wider base idler arms that started in 80 also had a bronze bushing which greatly reduces the chance of it ever binding on the shaft.

Also, if you install the oil fed tensioners, modify them internally to limit travel to make them truly bulletproof. It is the same idea than the safety collars on the old style tensioners. I am not sure if anyone has written about the trick here in PP, but it is something Jerry Woods does. He probably invented it! Wayne mentions it in his rebuild book but doesn't go into detail...

George (with reluctance upgraded to the oil fed jobs recently!)

[aigel]

One word of caution about buying things on ebay...

This isn't a trivial kit. It is quite extensive with GOBS of small bits. I'd be worried I would get some return item with small bits missing. It can really spoil your wrenching weekend if there is any problems. Buy it here, where you get free advice. And if not here, at least at a reputable parts dealer that will be there for you.

George

[Wayne 962]

About 2 years ago, there were a bunch of "defective" chain tensioner kits floating around. When purchasing a kit, you want to make sure that you get a brand new one and not New-Old-Stock. They went out of production for a while in order for them to fix the problem...

-Wayne

[Wayne 962]

Also, our Peace-Of-Mind kit contains the tensioner kit, plus the upgraded idler arms too:

http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_enginR_pg3.htm#item10

-Wayne