Ike from Ollie's just called me and said that nothing in the heads is blatantly off the mark, but he says that the guides and seals are worn and could have caused the oil smoke I was experiencing.

He also noted that 4 intake valves are marginal and should be replaced, especially if I intend to make this a high mileage motor. The exhaust valves cleaned up real nice and can/will be reused.

Should have the bottom end back from them either Monday or Tuesday next week and than can slowly begin the reassembly.

Ralph

Just talked to one of the head etch guys @ Mahle NA and took a look at Wayne's comments in the engine book.

I think you have taken Waynes' comments out of context. Of course the majority of the later 70s and on street engines were indeed cast pistons. Buying Mahle "motor sport" products was a guarantee of getting the same high performance parts Porsche used in their own race cars. For the prices Mahle charged you had better!

Rest assured the "motor sport" 911 products are indeed forged (read: all 911 Mahle after market P&C sets are forged pistons) and of the quality I expected and paid for.

Everyone's except yours, Ralph, of course ;)

That would certainly make sense, if you think about it logically why would Mahle/Porsche use a cast piston in a high boost 962 motor or even in a 930 based race engine?

BTW, the high prices are not just from Mahle Germany. You add in the layers of distribution (ex. Mahle to Andial to jobber to consumer or Mahle to Mahle NA to jobber to consumer) and the significant profit margins that are added on and you get the outlandish price that retail consumers are asked to pay. I know what these P's & C's cost from Mahle from my Andial days, if you didn't have the layered distribution channel and could buy from Mahle direct they would be fairly reasonable. You can't necessarily blame the Germans. Than again, shops have overhead and need to make a buck as well.

Thanks for clarifying the info. I guess I got the "special" set, eh?

Ralph

Mahle pistons in series-production 911s (at least 74+) are usually cast.
Mahle "sport" pistons like the 10.3:1 sets are forged.

schnellmann, thanks for posting. The key with 10.3:1 on lower octanes is absolutely twin plug. Looking at the 911 combustion chamber design, it is easy to see why twin plugs will allow more ignition advance with an engine combination that is otherwise the same.

Sorry, I should have been clear. Mahle "motor sport" pistons are forged, that would include all the after market, high performance 911 pistons including, the lower compression turbo pistons, the wedge style Max Moritz 98s and above in bore size and all the high compression RSR style, high dome pistons, intended for twin plug use. Ralph's included ;)

I disagree, the only cast pistons used in 911s were tha Alucils, while I have heard that Mahle made some Alucils I have never seen them. One of the reasons that the euro cars were often more desireable was that all of their pistons were forged while only some of North Americans were, the remainder being the Alucil versions

Bill,

Is it Mahle that may have manufactured these or was it perhaps Kolbenschmidt?

Ralph

Every Alucil I have ever seen has been made by KS( Kolbenschmidt)

Shoot, I said that wrong. I meant to say: "pistons in series-production 911s (at least 74+) are usually cast." This is based on my belief that more than half of US cars 74-89 had Alusil, which I agree are overwhelmingly KS.

I dont know if this was brought up earlier in the thread but with the time and money you are investing in this engine why not use the Supertec Performance head studs from Mr. Schmidt? Lifetime guarantee and all. One other thing, are you going to extrude hone or machine your intake runners to match the ports on your heads? Why not use the plastic intake runners, lighter, smoother on the inside? Just my .02. The plastic intake runner idea came from Tyson since my dad and I are still kicking around ideas on what to build for his car. Just seems like a logical and cost effective move. Anyway you go your engine sounds like it will be kick a$$. Best of luck and you know we are all picture sluts.

Good questons all, I am using the ARP head studs and rod bolts because we use them in our water-cooled VW engines (my day job) and don't have any problems. Since I have a relationship with ARP, it seems natural to use their excellent products for my personal motor as well.

Yes, the intake plenums are being Extrude Honed as I speak and will match the stock intake port size of the heads. I just had the heads polished, the port size is more than adequate for a street motor. With respect to the plastic 964 vs. 3.2L plenums, I am using the 3.2L plenums simply because I already have them. I didn't see any reason to change, this motor is not designed to get every last horsepower regardless of cost. If I were to have a more elaborate budget, I would use a better oil pump then the stock Carrera unit for that extra piece of mind but unfortunately I don't have a money tree growing in the back yard.:)

As you can see by the induction and cam choice as well as the emission law constraints I have, the motor is a compromise. Probably overbuilt for street use but also not race prepped for all-out competition. I hopefully will strike a happy medium.

Ralph