Early turbo chain tensioners?

[blue72s]

Hi

My stock 2.4S (numbers matching) has early turbo chain tensioners p.n. 930-105-049-00, which were fitted in 1981 at 58,000 miles according to the service history of the car (I bought this car last year).

Are these type of chain tensioners OK, should I leave them alone or replace them with the later ones p.n. 930-105-053.00? The mileage is now 77,000 miles, engine never been rebuilt before and still running well.

Why were the early chain tensioners superceded, and when did it take place?

Thanks in advance.

[Flat6pac]

I think the change is the thickness of the top boss on the tensioner. Around 1982 Porsche went to a thicker idler chain wheel and required a tensioner with a narrower top hole.
The 2.4 would use either but if you use the later number for the 82/82 you will need spacer
930.105.513.00 to use with the narrow top tensioner.
Either one is sufficient but I would highly recommend putting a set of guards on the shaft incase of failure.
Bruce

[Henry Schmidt]

Originally Posted by Flat6pac

I think the change is the thickness of the top boss on the tensioner. Around 1982 Porsche went to a thicker idler chain wheel and required a tensioner with a narrower top hole.
The 2.4 would use either but if you use the later number for the 82/82 you will need spacer
930.105.513.00 to use with the narrow top tensioner.
Either one is sufficient but I would highly recommend putting a set of guards on the shaft incase of failure.
Bruce

All of the information above is accurate but I would add one caveat. Install wider idler arms to prevent failure. The later turbo tensioner housing is thinner to accommodate wide arms, because Porsche engineers discovered that the major cause of hydraulic tensioner failure is binding in the idler arm.

Our host offers factory arms in their catalog but if they are not available or within your budget Supertec has a solution.