the flyin' scotsman

After some time of waiting, contemplating and agonising I transplanted the tensioner with the Porken product, a new tbelt and few other WIAI.

On first start she purred as if nothing had changed............tbelt looks perfect through the vent holes, runs smooth and quiet.

I'll take it easy for a few kms and after that WFO............many thanks to Ken for a great product and Roger for support with other items.


For sale: OEM tensioner, rollers, crank brackect and rollers, arm, many bolts, bracket from water pump, etc etc.....................a/c trades considered.

The_Remora

I am curious to see how these Porkensions things work out. I love the idea of it and need to do the TB rebuild soon. If you guys who have done it don't bust your motors up I may go this route. Interested in how it works out for you.

EC928NC

Congrats Malcolm! Another Porken product installed. I've got over 500 miles on mine and it's still tracking straight and true. I haven't redlined it yet, but I don't drive that way anyway. I have had several spirited romps though....

the flyin' scotsman

Take the '70 design OEM tensioner and roller system and compare it to the PorKen unit - modern techology, more robust components with some weight savings and there's no tension worries, its automatic.

the flyin' scotsman

Thanks Brad........now thats its all installed and I look closely at the OEM design I don't see why we'd have any concerns re tracking.

We're going to a car show this weekend which is a 200km round trip through some winding Rocky Mtn highways .........should be a good brake in run

The_Remora

It does sound like a great improvement over the factory system. The points you make are exactly why I anticipate doing this mod to my own 928. Since some of you guys are already running the Prokensioners in your cars, the next wave of us are intently watching and appreciating your beta-testing.

the flyin' scotsman

Chris.........I notice in your sig that you have a Ducati Monster...........check out the cam drive on your bike!

Many other manufacturers use a similar design in fact PorKens design uses Audi components.

PorKen

Malcom,

What did your, uh, piston extension measure?

The_Remora

I will check out the cam drive on the Ducati, I need to do some work on it soon anyway. Thanks for the tips!

the flyin' scotsman

Ken..........I never thought you'd ask

The 1st measurement was 6.8mm and after the engine went around a few times it measured 6.3mm. I installed a new belt as well I removed the crank roller assembly. I assume that after everything settles the piston finds an operating range dependant on the engine heat expansion. I could not measue it after it was warm with all the covers and accesories in place.

I did measure the belt tension with the Kemp tool and its within range. My next venture will be to recheck the valve timing after a break in period.........is there a timeframe/mileage period you'd recommend?

PorKen

Starting from 6~mm, the belt will likely stretch to 8~mm. When the engine gets hot, it retracts ~3mm. 5mm looks like the sweet spot, ~11.8 is the maximum travel.

What belt did you use? Was it easy to slip over the gears, or was it just enough?

PorKen

Using the Kempf tool, you have to take a quick measurement, as the tensioner retracts when you twist the belt. I also found it to be in the Kempf window between high and mid, depending on how quickly I did the check.

I think the Porsche 1500 miles/2400 KM recheck interval is overkill. I think 1500 KM would be fine.

the flyin' scotsman

I used the ContiTech belt and it was just enough to get on the gears; with the pin released the belt is quite taught.

I wonder if the belt install could be made before the tensioner, after the plate, lever and roller install?

the flyin' scotsman

1500km, is that a typo? missing a '0'

PorKen

You can install the plate, then the belt, then the parts. In fact, it makes it easier to torque the bolts.

I don't have pictures of that procedure, so I haven't changed the manual. I was so used to R&R'ing the tensioner system with the balancer in place, that I was still stuck on pre-installing the parts when I wrote the manual.

15,000Km = 9600 miles. I found the belt stretches to it's max pretty quickly.

Thanks for the info!