From:Dave Molnar e-mail:dave@impax.on.ca
Subject:RE: Temperatures Date:Wed Sep 28 08:06:39 2011
Response to:3750
Its kind of funny how no one whats to touch that question! I have experienced temparatures on my '28 high enough to bake spark plug wires under the tank! I think much of it has to do with cam and ignition timing. These engines do run hot anyway there is no doubt. Another factor I think might be in use and conditions. Some say that there is no "steam' supposed to vent from the case. Depending on conditions, no matter what I have tried so far, there is always at least some venting. The hotter it gets, the more it vents. I have found that when you run these motors so they vent a lot (hard work on a hot day), The pistons do get carboned up especially around the top ring on the pistons. This can cause the rings to stick. It comes back around to finding new ways to cool the top end such as the very clever set-up that Mark was trying with the oil jets. Timing remains a quetion for sure also. I am going to cast some aluminum valve caps to try. I have had some success with the aluminum heat sinks installed between the valve guides and the springs. More needs to be done to get this sorted out but I think we are on the right track!

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My '28 Deluxe is running hot. I measured 500 F (with a non-contact laser-aimed thermometer from Harbor Freight) at the point between the valve plug caps on all cylinders. Has anyone else taken measurements? What should I expect for reasonable temps?