Itinerant Air-Cooled

Hello new to this forum.
I recently bought a long block that included some engine tin with it. I posted this on the samba with one responce and researched futher and found same questions with no diffinative answers. My question is I have my OG tin from 79 fed 2.0 and the tin from the "new" long block. They are different as the 2.0 cyl cover tin has dents in it between cylinders and the new long block tin that was supposedly FI but from a carbed year does not have dents. I have read the the FI will and will not fit with either tin. I'm assuming the dented tin allows the vaccum lines and other assorted FI stuff to run across the engine easier. My main question is I feel the old style no dent tin would cool better? The 2.0 tin seems much more restrictive as far as air flow. Or mabey the dented tin created a faster air flow over the cylinders? Opinions please
Here is my OG samba post htt[album][/album]p://www.thesamba.com/vw/forum/viewtopic.php?t=502203

Sorry having problems with pic uploads tonight here is the other ones.

mtcamper wrote:Hello new to this forum.
I recently bought a long block that included some engine tin with it. I posted this on the samba with one responce and researched futher and found same questions with no diffinative answers. My question is I have my OG tin from 79 fed 2.0 and the tin from the "new" long block. They are different as the 2.0 cyl cover tin has dents in it between cylinders and the new long block tin that was supposedly FI but from a carbed year does not have dents. I have read the the FI will and will not fit with either tin. I'm assuming the dented tin allows the vaccum lines and other assorted FI stuff to run across the engine easier. My main question is I feel the old style no dent tin would cool better? The 2.0 tin seems much more restrictive as far as air flow. Or mabey the dented tin created a faster air flow over the cylinders? Opinions please
Here is my OG samba post htt[album][/album]p://www.thesamba.com/vw/forum/viewtopic.php?t=502203

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You do not need to give it another thought. There is no restriction at the upper covers.

They are waaay away from the fins. The "venturi" (point of maximum restriction) occurs much further down the sides of the cylinder barrels where the intermediate and lower deflector tins reach up. That entire cavern known as an upper cylinder cover, is just a plenum that has to hold the air to keep the proportionate flow through the heads and barrels regardless of fan speed. Put on the tins that agree with your intake set-up.
Colin

Cool thanks so much for a diffinative answer. I will run the og 79 tin. Still on a side note the 79 tin is about 1/2 inch off the cyl fins at the lowest point where as the the carb/old school FI tins are a good 2'" aboive the cyl fins. Who knows why VW did this? Must be for the vaccum lines etc. Anyways Thanks for the response Colin.
Ryan in MT

One more pic.

If it matters, the black tin has, near the # 2 spark plug hole, the nipple that attaches to your charcoal canister.

I may have missed it, but what will you be running? FI?

If so I think you will need the clearance for the plenum & Co..

I can see where that dent "might" reduce air flow up to the #1 but not by much.

Yeah I will be running FI. I think I will be using the black ones from my og engine. I think it is mainly for clearence for the FI stuff as well. On a side note the other tins were used with FI as well as there is a hole in the tin for the temp sensor in the old 1800 location.

Gypsie wrote:I may have missed it, but what will you be running? FI?

If so I think you will need the clearance for the plenum & Co..

I can see where that dent "might" reduce air flow up to the #1 but not by much.

Think less "fire hose" and more "water balloon". It is so not a "flow" issue as a "build up more air than the fins can digest" issue. There is planned resistance when you look down at an air-cooled VW engine. The deflectors underneath fit pretty tightly against the fins. That is "0" clearance, right? air has to travel between the cylinder fins and the surface of the deflector tins. That is it. Look at the front intermediate tins. They are crammed against the fins. Look at the rear intermediate tins (oil cooler on left, alternator on right) they are crammed against the fins. Look at the under cylinder deflectors. They block the air flow entirely through the middle. Now slap your big bad air balloon on top of the engine and notice that the air is going to flow proportionally exactly as VW wants at any speed. Every damn overheat on a VW engine has been due to dumb things like:
lean mixture
vacuum leak
embarrassing filth . . .
Colin

(p.s. #2 is our problem child in the Type 4s)

Amskeptic wrote:

Gypsie wrote:Every damn overheat on a VW engine has been due to dumb things like:
lean mixture
vacuum leak
embarrassing filth . . .
Colin

(p.s. #2 is our problem child in the Type 4s)

I can attest to this - after driving about an hour to a very rural festival my engine was smokin hot. In fact the girl selling tickets pointed out the smoke (which was the usual oil drops of oil leaking on the unusually hot engine).
Luckily as the evening progressed the weather cooled down so with taking it easy and coasting down hills I was able to get home without incident.
Very many head scratches and much investigating further, it was determined that there were not one but two vacuum leaks that had occurred at once. The tube running between the two carbs had just barely (but not quite visibly) popped off on the right side, and the idle cutoff solenoid had come loose in its threads on the left carb, which I only discovered when I bumped it and noticed a bit of movement. The latter was the more significant contributor.
These things can blow away a lot of time if you don't stay on top of regular sensible inspections.

Jim
72 1700 dual carb.