Did VW ever put screens over the fan inlet? I found a Twizzler wrapper laying in my fan and a small piece of glass on top of of the tins. I would like to cover that fan to stop this from happening. That thing if one heck of a vacuum
I also need to know the torque figure for 8mm chrome moly studs. I've gotten two answers, 22 and 23 ft. lbs. I guess that's pretty much the same but I just want to make sure. Thanks
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F, 8mm studs take 18-20 lbs, 10mm take 20-22
Probably why VS puts hardware cloth over the circle vent hole in firewall for fan air. Dune buggies often use a fan screen - Empi 9195 Chrome Air Intake Screen ($12). I can easily see a plastic bag getting run over and sucked in.
My engine is sealed up real well around the tins by the engine seal, even over the bell housing area. If stuff got in it must have been in back by the tail lights. That screen in the pic only works if you have a lip around the fan inlet in the shroud and I'm not sure if the doghouse shroud does. I'll check it out though, thanks a lot guys.
CMC build manual shows upper and lower fiberglass panels in rear to seal above hot exhaust over past tail lights but open above transaxle (even has builder cutting out a half moon circle).
I keep a 1" - 1.5 " space between the lower bulkhead and the vertical motor tin for extra airflow and use a 1/4" square weave hardware cloth fastened to the motor fan intake.
Frank...I think your getting debris in from that open area back by the tail lights. I don't know why VS doesn't make a cover for that area. It's simple to make a template, finf some fiberglass sheeting and make one. I think you already have a screen over that firewall hole in front of the fan intake don't you? Since your engine and tranny is out, now is the time to do it. Here's a couple photos of what I did......Bruce
That's pretty cool, Bruce! Thanks for sharing that tech tip! 
I would think leaving that area open would also bring in hot air from the back of the car, causing a rise in operating temps. Better that the air intake be from in front of the engine...
AL...I'm sure it does. It's like a big scoop to bring the hot air from the engine back into the fan. The panel I made, blocks it off totally and is easily removed with two 10-32 machine screws tapped into the rear cross-frame. It can be removed with the engine installed if need be, to get to the wiring back there. I got the material from Kirk at VS. It's the same stuff he uses to trim out around the engine.
NOW...ask me about if there is enough air getting in thru the "Habachi Grill" in the rear deck lid. Almost is my answer. I blocked off that hole in the firewall that VS installs in front of the fan intake so that ALL the air for the fan has to come in thru that Grill.
I tested it with my trusty manometer and found that there is a restriction in that grill at 70mph or so but only about 1.5 inches of vacuum (negative pressure to me). So far this hasn't been a problem as my temp. monitoring of the oil and CHT have been acceptable. I figured that if I needed to...I could always uncover that firewall hole to eliminate that problem. So far...not necessary and it only has 3 screws to remove.
Last Summer I did a lot of testing on all sorts of things on my Speedster and am relieved to state that it is in pretty good shape as far as cooling and oil temps and negative pressures inside and ...actually outside...my car. This data will play a big part in what project I take on in the future. I know that some of you did follow what I reported back then. My findings and your encouragement and your suggestions were very well appreciated.....Upward and onward...information is power......Bruce
Regarding that rear open area: it sure as hell does bring in hot air. When I got my car that area was open although all engine tins were in place and there was an opening in the firewall. I took a piece of cardboard, made a template and cut a piece of stainless sheet and screwed it in from below. Made a huge difference in engine temps. Not fancy but dramatic temp drop.
Frank: I have a template (admittedly, for a CMC) that you can use to seal up the area at the rear of the engine bay, as well as around the tail lights. If you wish, I can make a copy and mail it to you (or see you at a local event). It is easy to make in HVAC sheet metal and does a terrific job of sealing that area.
gn
On the CMC, it is fiberglass flat panel (there is a lower one too) that gets fiberglassed to body section for a really good seal. Exhaust heat will not get past them.
WHAT?!?!?!?!?!?!?
I WAS SUPPOSED TO 'GLASS THEM IN? 
Actually, on Pearl, I never got those shields from CMC (although I had them in the next kit I built)
Glassing them in was too messy at the time. I made up some paper templates, cut them out of HVAC sheetmetal, then screwed them in with 10-32 screws (threaded the holes into the subframe).
The shields I did were slightly better at sealing than the CMC version, with a seal-strip along the edges and upward-bent wings on each end to block the vertical spaces at the ends. Screwing them in also allows you to easily get them out later, if you wish.
Just came from my friends shop where I was a 2110 torn down and #3 had a melted piston. They found a paper towel in the fan which covered over 75% of the fan.
Now i've never used a screen and in the 42 year of owning my car, never found anything inside the fan. if you your engine compartment is not totally sealed, you might want to get one.
