Now one of the major changes I decided to implement on this rebuild, even though it is basically a stock-ish engine with basic dual carbs is the use of the VW Type 3 under cylinder cooling tins instead of the small Type 1 deflector tins.
Given that the aftermarket top cylinder tins all seem to lack the internal air vane that VW had on their original tins, I figured that I would see if the Type 3 style tins could help compensate for the lack of air vane directing the air from the fan should down. I’m thinking they can obviously contain the cooler air and direct it down and around the cylinders more fully than the small deflectors do. Since the lack of internal vanes means the air is not being force directed to each cylinder this style of tin may help.
I’ve read a few positive things about them and no negative things so I don’t really have any fears of changing to these. I mean, the Type 3 engine is basically a variant of the Type 1 engine and these were designed by VW to cool that engine as efficiently as possible.
Air vanes? What the hell are you talking about?
So I noticed that all of the original VW tins differ from the aftermarket ones. I am making the assumption that pretty much all of the aftermarket ones, regardless of vendor, are more or less EMPI products made in China and for whatever reason, a part of the internal facing side of the tins is missing, no doubt to save on production costs as I can’t see any way of including it without welding.
In the VW air-cooled engine, air is forced down from the fan shroud through one of two rectangular openings (A), one over each set of cylinders. This part of the fan shroud locks into the two top cylinder tins (B) ensuring the air is forced down onto the tops of the cylinder heads and around them. The air rushing past the fins of the cylinders is what reduces the heat, thereby cooling the engine.
Inside each original VW top cylinder tin is a metal vane. This metal vane forces and directs the downward moving air over and around both cylinders heads, allowing the heads fins to take away additional heat as the car moves and the air blows down. Without the internal vane, it is not directed to the same extent and is more or less shunted downwards between the cylinders where it would normally hit the small metal internal deflector and shunt it over the bottom of the cylinders.
The Type 3 cylinder cooling tin completely replaced the small internal deflector, wrapping around the sides of each cylinder and contains the air moving past it downwards and out through a 1 rectangular opening for each cylinder.
Now I have no proof that the Type 3 tins can compensate for the lack of the internal top air vane, However, I can see it making a difference in the way it forces the air down and around the entire jugs and not just between them.
Given the fact that the aftermarket tins are no doubt heavily used throughout the VW community, I imagine that they perform adequately for stock use but I cannot fathom how a higher horse power engine, moving far more oil and needing far more air to flow to cool it, can compensate for the change in the design. Again. I have no proof of anything. I’m purely going on this based on the airflow patterns of the engine.
Now I was happy to find a vendor in Vanlue, Ohio of all places named Awesome Powdercoat who is producing the proper shaped vanes that can be installed into the aftermarket tins. Unfortunately, you need to weld (or at least rivet) the vanes into the tins. I plan on going that route for the future Żuczek B. mild street engine should I not be able to fully repair and restore the original VW tins.
Actually, the vendor also produces the small the small cylinder head tin deflectors as well. I’m moving the deflectors from the AH engine’s heads to the EMPI GTV-2 Dual Port 98-1331-B heads going on the rebuild.