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On 2 Jun 2003 at 12:19, Edward Morris wrote: > Q1: I was at Pomona yesterday and, for $5 each, > picked up a couple of used 'finned' valve covers for > the 1969 Fastback. They're not the bright chrome ones > (they look similar to 'brushed aluminum'). My > thinking? -with with additional finned surface area > the heat transfer should be improved. My thoughts 24 > hours later... if it was an easy heat xfer improvement > why wouldn't the VW engineers have adopted it? While Steve is right that these won't directly transfer cyl head heat to the outside, there really is a lot of oil that sloshes around in there and this is very effective at transferring heat to the valve covers. Anything you can do to enhance heat removal is certainly a good thing, but this COULD be a problem in very cold weather. There's another down side: while the alum is certainly a better heat conductor, the steel covers are much thinner. In the end the heat transfer is probably similar. The fins may help, but not as much as we might like, since the heat has to flow so much farther to get out. > Q2: Second question - are there differences in Type 1 > and Type 3 "J tubes" or are they interchangable? I think they are different in almost every possible way: different diameter, different shape, different length. The only thing that is the same is the flange to the exhaust port. -- ******************************* Jim Adney, jadney@vwtype3.org Madison, Wisconsin, USA ******************************* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org