Chain tensioner kits???

[LDunville]

Pelican has two chain tensioner kits, their standard kit for $1208 and their "Peace of Mind" kit for $1624.

I have a 1968 911S with about 100k miles and my receipts say a tensioner kiy was installed in 1974.

Do I still need to install a tensioner kit, and if so which one?

Thanks

[RSTarga]

If I was you I'd use collared turbo tensioners with new ramps and upgraded sprocket supports. Just as safe and quite a bit less.

[Soterik]

Larry, please call me regarding tensioner kit (availability and pricing) in the morning.... west coast time, 206 three two one- 2960, that's IF you want to go with tensioner upgrade, otherwise I agree with David (RSTarga).

Eric

[Grady Clay]

There are two different types of “tensioner kits”:
Most common for early cars are the tensioner rebuild kits.
This is an inexpensive set of parts (springs, balls, O-rings, etc.) to recondition existing chain tensioners.

The ‘other’ are tensioner ‘update’ kits to install the later (external oil fed) Carrera tensioners.
These include new tensioners, oil plumbing, chain covers and more (hence the $1k+ price).

There are pros & cons to each approach.

The pressure-fed Carrera tensioners can be in a ‘failure mode’ (occasional ‘rattling’) and refill with pressure-fed oil.
The downside is people tend to continue driving like this and eventually something breaks.
If you have a Carrera tensioner update and it occasionally fails, there are rebuild kits for this tensioner also.

My personal choice (agreeing with David above) is the (no external plumbing) ‘Turbo’ tensioner (narrow support) rebuilt with new parts and with the Jerry Woods travel-limiting mod.
This tensioner uses the wider 2-bearing idler arm ( R & L ) – a significant improvement in its own right.
This maintains the original appearance of early engines with the later ‘improvements’.

The engines should ALWAYS have fresh chain ramps of the latest (plastic) versions.
If you don’t KNOW what chain ramps you have and age, replacement should be your highest priority.
Many 911 engines have succumbed to a broken original-type (hard rubber) chain ramp causing the engine to ‘jump’ cam timing and more bad things happen.

Our (’68-’77) magnesium chain housings can have the large chain tensioner / idler arm support pin become loose in the housing or at least crack the epoxy on the back side (toward the cylinder head).
Always inspect for this condition.

There was a period where ‘solid’ ‘mechanical’ chain tensioners were in fashion.
These were a solid block of aluminum with an adjusting screw and locknut.
These provided no compliance for engine expansion and could result is excessive wear to chains, sprockets and even jackshaft bearings.
If you find these, take them out of service. They are useful for setting cam timing.

The ‘while-you-are-there’ issues are stretched chains, worn or damaged sprockets and as always – checking/resetting cam timing.
If you unscrew the cam nuts (requiring re-timing of the camshafts), it is an easy ‘next step’ to replace the gasket between the chain housing and the crankcase.

Best,
Grady

[Cliff]

Great discourse on chain tensioners;much has been clarified, thank you....Cliff