Destroking 964 3.6 to a 3.4

[stownsen914]

Henry - those look like stock rocker arms? I'm thinking of building a smaller displacement revver now that my short stroke 2.7 (93 x 66) is coming apart. I got ahold of a set of the early forged rockers for the build under the assumption that the cast ones wouldn't hold up ... Thank you in advance for any input you may give on this

Scott

[Henry Schmidt]

Originally Posted by Walt Fricke

This is why many end up opting for Spec Boxsters. Kind of out of reach for many. Nice to have customers like that, though.

"Spec Boxster" where you trundle around a track, hoping you don't find a head wind or 8500 rpm air-cooled song in the mountains of Sicily? To each his own.

This is why I generally don't answer "price " questions.

Like any other endeavor, it can be done first class or on a shoe string.
In this case the customer spent a couple of years collecting all the parts and when he was complete, he asked me to assemble his project. Because he is in the armed services, I obliged and at a discount to boot.
This is incredibly special engine that has components that have value.
It is a lot easier for me to justify these expenditures than $200 K for a 71 "S".

I am gearing up to build an air-cooled engine for my Riley DP. I could easily install a Ford, Lexus or even a water cooled Porsche but that's not what I do. I build/love air-cooled Porsche engines so I'll spend a little more money and give up a little technology to indulge my passion. This owner did the same.


Here's my car with a Porsche V8 in it. Yikes, how do you put the water in?

[Henry Schmidt]

Originally Posted by stownsen914

Henry - those look like stock rocker arms? I'm thinking of building a smaller displacement revver now that my short stroke 2.7 (93 x 66) is coming apart. I got ahold of a set of the early forged rockers for the build under the assumption that the cast ones wouldn't hold up ... Thank you in advance for any input you may give on this

Scott

They are early 2.0 forged rockers. Expensive but the next best thing to solid racing rocker.
We have them rechromed, replace the bushing, coat the pad with dry-film Moly and have the rockers cryo treated.

Some aftermarket guys are manufacturing a forged rocker that looks pretty sweet but right now I'm too busy to test these products. Once they are tested, who knows?

[Walt Fricke]

While a first class build like the one shown, with up to 9,000 rpm feasible, is going to benefit from forged rockers, the cast rockers on my motors have held up pretty well with 8,000 rpm upshift levels, and a bit beyond. I had one fail randomly on my 2.3 motor, and all 12 broke on the 2.7, but that was due to the aluminum IS gear losing all its teeth. 10,500 shown on the telltale tach from a missed shift didn't break any cast rockers (race springs recently installed must have done the trick).

I'd like to use the 993 RSR (RS?) rockers, but they are pretty expensive. They would go with a switch to the 993 style cam carrier, and its benefit is convenience - much easier (at it looks like it should be) to R&R rockers, and no leaks from the ends of the shafts. Those leaks aren't damaging, but a pain to clean when rebuild time comes around. But the cost differential between the stock stuff and such a switch for an older motor is a bit steep.