Hydraulic chain tensioners: [I]exactly[/I] when did Porsche design them?

[Forza]

I know that Porsche started fitting hydraulic chain tensioners as standard equipment on 1984 model year 3.2 Carreras, but were they offered as an option or available unofficially (similar to 3.1 SCs, for example) at any time before then? When were these tensioners first designed and in any way implemented by Porsche?

[Grady Clay]

John,

The pressure-fed chain tensioners appeared with the ’84 Carrera. Any on 911SCs were retrofitted. I suppose some late ’83 Factory ‘Specials’ and tuners had them. I don’t remember if we had them before the ‘84s came out but we easily could have.

All 911s from ’63 have hydraulic chain tensioners. They just weren’t pressure fed until the ’84 model. Prior to ’68, they relied on ‘splash’ oil in an exposed reservoir. From ’68, they were ‘sealed’ and there were several versions.

The chain tensioners and chain ramps have been the bane of an otherwise almost perfect engine for the 911.

Best,
Grady

[911pcars]

Just to piggy back on Grady's historical text, the wide bearing idler wheel assy. was introduced in '81. Many people theorize the narrow bearing idler assemblies shortened the service life of the self-contained tensioners. Please correct me if I'm wrong.

Sherwood

[jkarolyi]

Porsche had these available way back in 1979. Ironically, the rare 3.1 liter ROW 911SC you mentioned came with factory hydraulic tensioners! Very interesting and obscure Porsche history with this engine...wonder why it took Porsche five years to install them on all their 911s:

911 Sc 3,1

[Forza]

Originally Posted by jkarolyi

Porsche had these available way back in 1979. Ironically, the rare 3.1 liter ROW 911SC you mentioned came with factory hydraulic tensioners! Very interesting and obscure Porsche history with this engine...wonder why it took Porsche five years to install them on all their 911s:

911 Sc 3,1

Same reason it took so long for Motronic to show up: the 911SC, like the 356SC before it, was initially planned as the last of its type, which arguably limited further development to some degree. Anyway, I remember hearing and reading about the early availability of pressure-fed hydraulic tensioners at different times, but I couldn't remember where. Thanks!

[Bill Verburg]

Porsche has a history of offering experimental parts that often appear as regular production items in subsequent years

examples are the modified trailing arms offered on some '73 2.7RS and later were standard on '75 930, 993 exhaust which first appeared on 964 3.8RS, ssk on the '83 SC/RS etc.

nevertheless the first regular production line use of the pressure fed tensioners was on the MY '84 3.2 Carreras

[DanielDudley]

Leffingwell says in his book ''Porsche 911, Perfection by Design'' that not implementing the tensioner upgrade was part of the planned phase out of the 911, that is to say no upgrades were really being considered by Ernst Furhmann, who was strongly advocating the 928 and 944 variants.

It was Peter Schutz that authorised the tensioner upgrade and created the white 4WD convertible show car that preceeded the Carrera and the 959.