Custom Turbo Pistons...
 

Hi,

In the near future, I am looking at some custom Forged Turbo-spec pistons for my blown 3.2 Carrera (8.0:1 C/R), along with 964 CAMs, PhBr Valve Guides & ARP bolts.

My question to you avid engine builders out there is:-

Do I need to have pistons custom built/measured for my existing cylinders, or can I just purchase a set of off-the-shelf 95mm pistons for STOCK Carrera cylinders?

MotorMeister said they don't need my existing cylinders to spec out a set of pistons for me. As long as my cylinders are stock, they are just ordered & built to any C/R the customer requires.

I would have thought that cylinders need to be measured for clearances etc?!?!? Isn't this what the problem with JE pistons is? Incorrect clearances, thus reliability issues?

Advise much appreciated.

Merv,

I can't believe it! Some people aren't even happy with 400bhp! :D

What can I say Adam? That's why we're called "HP JUNKIES!" on this board. Just CAN'T get enough :D

It won't happen for another 6 months or so. Just doing some research now in preparation.

1.0 bar @ 8.0:1 C/R should be good for approx 520HP :)

WydRyd,
Since your cylinders may not be brand new, I'd suggest miking the IDs, then have the piston manufacturer size the pistons for each cylinder. With regular iron cylinders, one could hone the cylinders to arrive at the proper piston-to-bore clearance; can't do that as easily with Nikasil walls.

Sherwood Lee
http://members.rennlist.org/911pcars

Thanks for the input Sherwood. T

he problem in that is the cylinders have to be removed and ID's measured before the pistons are ordered to match & since there's a 4-6 week turn-around on these, it means the car is in the shop much longer :confused: Wrenches down here seem to think the longer a car is in their shop, they can surcharge you an extra few K on top of the bill for that alone :mad: The GREED factor strikes again :( Thus my query about pre-ordering the pistons before any teardown is performed :rolleyes:

Obviously if this is THE only way to go, then there's really no way around it, unless I get a good set of second hand Carrera cylinders that can be used and then just swap out the existing P&C's.

Anyone wanna sell a perfectly good set of 3.2 Carrera Cylinders dirt cheap?!?!?

BTW, how long does it typically take to do an overhaul anyway? 40, 50, 60 hours? I'm referring to valves, springs, guides, CAMs, head & rod bolts, bearings, piston squirters & fitment of the new pistons & rings?

Merv,

I wanted to jump in here and add my .02 cents. You commented on getting your pistons custom made by MOTORMEISTER. Is that the same Motor Meister as in the one in California?

Dan O

Hi Dan,

Yes, MotorMeister in CA.

Roy seems like a nice guy and willing to provide any technical info requested.

Merv,
I for one have no experience with Motor Meister, but have certainly read alot about them. I would suggest you do a search on this board and then decide. As I said- I have NO first hand knowledge of their work. Some peolple have negative comments, while others seem to be very happy with their work. Good luck. Let us know how it works out.

I don't think the quality of the Ross pistons used by MM is that great...

... just what I've read though. In addition, like JE, they don't expand at the same rate as the cylinders and hence they have to run a wider clearance when cold.

This is all stuff I have been told - no experience other than the JE 95mm 9.5c/r pistons in my car right now are pretty noisy when cold - hence I am swapping to Mahle 98mm.

Caveat Emptor.

Thanks for the feedback guys. Maybe I save a little longer and get a new set of P&C's, possibly RuF 3.4L's.