j.kenzie@sbcglobal.net

Ken,
Don't let us down, please. Porkensioer sounds like a fabulous idea. I plan to buy one and have on hand for my next TB/WP.
Thanks for your efforts,

EB338

Add me to the Porkensioner list! Any plans to make more of those cam timing indicators?

PorKen

Hey, this is the PKVVTS thread! (Here's the PorKensioner thread.)
...

Erich,

I do plan on making more of the cam tools, and conversions. I've about used up my Porsche alotment again, and have to work on the house again, so I wanted to do something new...

I will be posting a combination thread for the cam stuff, but I have to in a position to keep track of all the deposits, and deal with the laser cutter, etc.
...

The PorKensioner will get made, but I don't want to make any mistakes with it, so I'm not going to rush!

Normy

There are cam gears available for the 8 valve Volkswagen four cylinder engine that drives every Rabbit, Golf, Jetta, Scirocco, Corrado, and a bunch of the Passats that run down our highways and get in our ways every day.

[Note: some of those cars have VR6 engines, and no belt. Caveat in reverse~]

THEY sell a cam gear which centrifugally changes the position of your cams. Since the M28 V8 and the EA847 VW four cylinder are very similar...it occurs to me that either, 1. The company that produces the VW aftermarket performance part could easily produce a part for our cars, or 2. It would be real easy to modify the VW cam timing "core" to work with the M28 belt. Take the variable timing portion of the VW cam gear, cut it off, and bolt it back on to a 928 part that consists of the outer ring of belt teeth.

Give it a try with a non-interference engine; I won't do it on my car, but if you make it work I'll buy it!

N!

AO

Ken-
Great thinking. Keep 'em coming.

PorKen

I put my ebrake handle back in and used that for the actuator. The cable loops under the driver's seat, across the floor under the carpet, out the rubber grommet behind the dead pedal, and through the fender where the cruise cable used to be.

The cable is attached to the fixed bracket, and the cable housing pushes the bar down. The spring returns the bar to the neutral position.



At full tension I can get (5°) crank, as measured with the timing light. That's (2.5°) cam, added to the (3°) cam static advance I run, gives a total of (5.5°) cam + (5°) more ignition advance.

It is noticeably peppier and growly at low rpms, even in third gear (auto). I tried a mini high rpm run, up to 80 in second, and could feel it start breathing better once I released the advance.

So it's a nice little boost for city driving, but a lot of work for a little. It would be better for sure, if it were automatic, and variable with rpm/load.

mulik51

Even though I don't understand a yota of it, I have a profound feeling of something awsome.
However, could anyone clarify this to me: you basically change timing by changing the tension ont he belt? How? Or dies it work in a different way?

Thanks,

Klim

PorKen

Klim,

In the neutral state, the passenger side pulley is pushing down on the belt, 'storing' extra belt before the tensioner pulley. The driver's side is just resting on the belt. The PorKensioner adjusts to keep the belt tension basically the same at all times.



When the driver's side is pushed down, the extra belt tranfers over to the driver's side of the crank gear, making it longer on that side. This extra length means the cams have rotated a few degrees, but the crank has not. This translates to the cams being advanced in relation to the crank.

More advance means more torque at low rpms, but less horsepower at high rpms, so by making it variable, you get a flatter torque 'curve', with the same top horsepower.

F451

Very cool Ken!

And thanks for the "Variable Timing For Dummies" explaination. You have a good way of communicating seemingly complex issues in a way that is easily understood, and not many people can do that well. -Ed

PorKen

Thanks Ed!

BTW, I fixed the text above. I was feeling a bit woosy from being in the sun all day, and got the cams and crank reversed!

Bill Ball

Ken:

This just about nails your certification as a crazy genius. You don't just come up with wild ideas, you actually execute them. Parking brake actuator! Unreal!

PorKen

Wow! I was out kickin' it on a grocery run, and it's actually a pleasant improvement for driving around town.

I usually shift into [2] for most city driving, to keep the rpms up. With the (5)ish advance, I can leave it in [3], and still have little to no bog, even from a dead stop. Roll-on is improved too, as there's some power in [3], even before the kickdown.

The intake makes an even more satifying whoosh when I mash the pedal too, as the car is accelerating too, instead of just making noise.

I did have to put 'Plus' in the tank, as I was getting a bit of pinging.

zoltan944

so you only need to drop the ebrake down when you are getting into high rpms?

PorKen

Yep. I rarely get above 3500rpm around town with the automatic, so I only really need to drop the ebrake if I start driving at highway speeds.

Since the range is too small to bother with a smooth transition, I'm thinking about using something like a 100lb door opening solenoid (for shaved door handles), connected via a heavy spring to the cable to reduce the shock.

mulik51

Awesome explanation, thanks.
Klim