Jeff -

I recently swapped my Throttle Body onto a 2.1 Center Air Plenum when I did my 2.1 conversion. My only advice for tightening is to tighten it with the "tangs" of the Throttle Body just about flush with the Plenum screw flanges (Bentley does not offer a clue to the torque specs). You don't want it loose or semi tight though, otherwise vibration will cause it to come loose further and again you'll have the vacuum leak. Due to the shaping of the Throttle Body, the Seal, the Plenum and the tapered fit, the chances of "deforming" the seal is quite remote. The seal is ribbed to take advantage of the tapered fit of the part(s) and the "flanging edge" of the TB Seal should be the only part showing when tightened down. I don't recommend using a sealing agent such as Permatex(tm) as these pieces appear to have a very close fit and may not seat properly (mine would not when I tried) and I installed mine dry, so make sure all pieces are quite clean before assembly (See Piece of advice below).

One further note about tightening - be sure you have the securing screws aimed just right when initially installing the Throttle Body. If you cross-thread, you may have to find another Plenum. Of course, I had the Plenum and TB out of the vehicle while putting together the engine - it's a lot easier to do this way. If you're doing this job with the Plenum still installed onto the case in the vehicle, it's even more important to be careful when initially attaching these screws.

Piece of advice. While you have the Throttle Body off, take some Carburetor Cleaner spray and clean the gunk/junk off of the Throttle Butterfly and the throat of the Throttle Body too. Mine was pretty gunked up after 82,000 miles due to the Oil Breathing function (which is proper of course). Do not remove any pieces off of the Throttle Body to do this, just spray clean it. Don't fiddle with the large "Idle Bypass Screw" either - do that when you've put everything back together and re-set everything according to the Bentley Bible. Be sure the mating surface of the Plenum is clean of gunk as well.

Hope this helps :-)

Jim 84 Westy 2.1 * 62 Beetle (Father was orig. owner) Sherwood Automotive * The Old Volks Home (oldvolkshome1@juno.com) (916)221-5342

On Mon, 30 Jun 1997 02:59:29 -0500 Oxroad@aol.com writes:

>Hello again, > >Thanks for the info on checking for my vacuum leak with WD 40 on my >newly-purchased 83 water-cooled Westy. I got no response between the >air >distributor and the manifolds and was beginning to get depressed. THEN >I hit >the spot where the throttle body meets the air distributor and >VROOOOOM. So I >ordered a new throttle body gasket for that spot. > >My question is once I install the new gasket how tight do I torque the >screws >that hold the throttle body to the air distributor? The two screws are >currently tightened all the way home, that seems to compromise the >gasket, >kind of jamming it till it buckles out a bit. Although it may just be >because >the gasket is old and stiff. > >The other question is, will this prove to be the whole problem? > >(Just for history, my engine, a VW of Canada rebuilt long block with >about >1,000 miles idles rough and uneven. At higher revs it seems Ok. I just >cleaned up all the connections on all the ground wires I could find, >and the >braided ground on the left side.) > >Thanks also for the previous exhaust tips. I caught some thread on the >#4 >cylinder exhaust bolt that the DPO "mechanic" had cross-threaded on >installation which lead to a connection that was less than insulated. >He also >chose not to install the second bolt at that cylinder, which I, since >I'm >kind of old-fashioned, decided to install. > >Thanks again for any tips and info. >Jeff >83 Westy > >