Parts list posted in another thread: http://www.ferrarichat.com/forum/showpost.php?p=139935902&postcount=44 Bottom line is that some VW parts can be made to fit on a Porsche, but often they were used as cheap replacements back when 356s were cheap old cars.
Heard from him via email. I like the idea, and love the execution, although, the fact that his heads are cut, then welded makes me nervous. I want the engine to withstand 25+ lbs of boost, having a possible weak point in my heads would worry me too much. But.... $35K for an engine is too much for this project. That is almost the same amount as what my student loans are at. I could find a 911 and re-build it for that. I also dont really like the whole limited to 2600cc thing. If I am dropping that kind of money, I expect the ability to go as big as I damn well please. Looks like I will be either building them until they quit exploding, or will go with Pauter. I can get a 3.2L air-cooled flat four from them for $16K, and they will build to suit. They currently are powering the worlds fastest flat four drag car. This is one of the last runs it made as a slingshot configuration. They have since placed the engine in a NHRA style rail, with the engine behind the driver. http://www.youtube.com/watch?v=v_Lu7IlU-w4
Well played. I do like how the only distributor part listed is the shaft. Holds to what I was saying about the mechanical advance and vacuum advance types. As I have understood it, the first early run of 356 had engines provided by Wolfsburg, as Stuttgart was not ready to produce those components at the time. The deciding factor came when the engines were dynoed at the end of assembly. Any engine that produced more then 40hp was sent to Stuttgart, and engines that produced 40 or less stayed in Wolfsburg. Once Stuttgart was able to, they started casting their own heads and cases, but those were still based on the Typ1 engine. All they did was improve on the original design, and address issues that could not have been address with the Typ1. That would be 1948 - 1952 ish. If I have my dates right. As is often the case, what you can not make, you buy and modify. I would like to do a side by side of the case halves and heads from '48 to about '60. Does anyone have pictures of rebuilds, or tear downs? Anyone know where I can lay hands on those parts in one place?
The cylinder head was redesigned by Porsche for the first 356, so it's not quite as random as you suggest. The Beetle was a 25bhp machine, and the initial 356 was ~40bhp. However, you're correct that the 1948-1952 cars borrowed heavily from VW in the engine and suspension (and brakes). But if you follow the engineering memos (see Dirk Conradt's book for a dull but informative narrative), once you get beyond the true museum-piece, split-windscreen 356s the cars rapidly lost their VW content.
Were they casting the heads themselves? I have not had a chance to tear apart a pre '56 356 engine. All I have worked on with the real old ones was basic maintenance. The last 356 I helped build came in without an engine, and left with a 1915cc with dual Kadrons. I would like to get into the internals on one of the early engines, and check the casting marks. It is not hard to understand why the heads would get touched first, the single port heads suck. For Porsche to make any improvement for the 356, they would have had to remold, and recast the heads, or modify the stock ones. Even the dual port heads can flow much better. If they did not have the capacity to cast their own heads, they would have had to use the VW heads. Its not hard, they would have enlarged the valves, or at least re-cut, port and polish the runners, re-cut the combustion chamber (which they may not have even done), and beef up the valve train with hardened seats, stiffer springs, and higher ratio rocker arms. All which could be produced on a quicker time table then head castings. Same for the case. They would have modified the VW product to suit while ramping up production of their own castings. Case mods would likely be better flowing oil passages, better baffles in the sump, metal was probably removed from the interior of the case, to lighten it, oil pressure regulator was replaced with a higher pressure unit, and the clearances for the roller crank would have been made, (if needed), and pushrods would have been replaces with stronger units. The Porsche flat four was based on the VW flat four. Changed? Yes, it was improved. But it was still based on the VW. Ill go back and edit the "identical" to include "only on the outside".
I don't know whether Porsche cast their own heads back in the late '40s and early '50s, although it's an interesting question. A good place to ask would be the 356 Registry, where they consider this common bar banter. A lot of 356s got VW or 912 engines when they were cheap cars, so I'm not surprised that the ones you've seen are a mixed bag. The complete rebuild costs on a 356 four are several times what it costs to do a VW four, again citing costs from Conradt. It just wasn't worth doing it right when 356s were $6000 heaps that you drove because you couldn't afford a 911. And yes, it was based on the VW engine, arguably through the end of the 356 range in 1965. But the differences are a lot more than people tend to think based on looking at the cars. FYI, here's a classic film of the 1960 Porsche production process, in five parts: http://www.youtube.com/watch?v=LQBrQ5qd5w8 Some nice engine manufacturing clips in here: http://www.youtube.com/watch?v=u53haOMYcH0
