Highly DeveloPT Cruiser  pt1

This project began with the sober realization that I might be giving up my warranty on most if not all parts of my car. I got out of my 97 MK8, with 300 hp and rented a PT for the weekend, back in Aug. I was hooked! I can tell you that the small reduction in ride quality was more than offset by the sure footed, pure enjoyment of  DRIVING this "cruiser". I was not sure I would warm up to shifting on a full time basis, but that is no sweat either. The only thing I knew going into this deal was I would not be completly happy with the available power stock. I had another engine, (the "mule"), to modify a week after I got word I could switch to another PT, someone backed out on. I was lucky to get one so soon!

The inside of the "mule" engine looks great. If you haven't seen inside these things, they come with the neatest little roller/followers. The bottom end is very well laied out. The only thing that looks weak to me, (for 350+hp), is the rod design. The pistons look very nice, they just have too much compression for a turbo engine with 10 to 15 pounds of boost. So I am replacing the rods and pistons with Crower Rods and JE  8:1 turbo pistons from Hahn Racecraft. These pistons are forged from a special alum. alloy, which makes them much stronger. The top ring grove is moved down to prevent burning the top ring out from intense heat and pressure created by the turbo boost. The top of the piston is dished, instead of domed, to reduce the compression. The turbo shoves the air and fuel into the engine to make the extra power. The additional cylinder filling dynamicly increases the engines compression. So if you dont start with lower comp. than stock, you can end up with too much comp, which is not a good thing.

The next stop is the machine shop. I have known Greg Bunner for some time now and trust his judjement and experiance. He helped with the necessary machine work and balancing as well as the porting and flow bench work. The new crank assembly needed to be balanced; the block bored .020" to fit the pistons. The head work was next. I was lucky to find a core head from a salvage yard that someone had lost or broken the cam caps on. Without the caps the head is basicly NO GOOD. I picked it up for $50. This is the head I showed in the first Highly DeveloPT article. "We make our mistakes", if any, on a head that is already dead! In this case we faired pretty well on the flow bench. The exhaust port is very sensitive on these heads, so be careful if you plan to try this at home! Call us before you do, we'll be glad to tell you where "NOT" to cut!!

I have had a lot of experience porting heads, but these heads flow very well stock. If you don't try to change the shape of the port and JUST follow, smooth and gradually blend the last inch to the intake gasket, you should pick up 20 to 30 cfm on the intakes. The exhaust is trickier and we are still searching for the best approach. We are still whipping the "mule head", so I'll cover the exhaust ports in the next update, probably in a week or so. It is not always eaisy to find a machine shop that will take the time to experiment with these little four bangers. It is too eaisy and profitable to make the 5.0's and Z's go faster. But some of the compacts are embarrasing them at tracks all over the world.

Having access to a flow bench is key to real improvement on your heads. The slickest polish job could drop the flow of your head dramaticly and with that goes power and money. I have been building winning engines for over 25 years, and I felt I needed help with a completly new head design. This is not " Your Daddy's Chevrolet!" These 4 valve per cylinder, strange port shaped heads are computer designed and do not respond to the same "common sense" tried and true porting tricks from the Fords and Chevys. See ya next week or so with an update.               Bob Stockum

(Hightly develoPT 350 hp +)               PT 2

PT to Pronto in  $30,000.00

.r.stockum@cox.net