Date:         Tue, 22 Jan 2002 18:50:58 -0500
Reply-To:     Robert Donalds <bostneng@FCL-US.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Robert Donalds <bostneng@FCL-US.NET>
Subject:      Re: '80 Westfalia-- best way to drive over passes
Content-Type: text/plain; charset="iso-8859-1"

fellow vanagon types

air-cooled engines collect heat over time lets say you are driving down the highway for an hour or two 
in the heat of the summer and you then find that the road is in fact going to have a long incline. The engine that you have been driving for an hour or so is completely saturated with heat that means the oil is at around  225 f ( and that all the heat the oil will willingly absorb) the heads are at least at 300 350 f ( I don't believe most gauges ) and now you want to add more load to the engine. so the head temp will continue to climb as will the oil temp. The air cooled engine can and does have limits as to the load you can place upon it and those limits drop as the ambient air temp and road heat goes up because the air the fan pulls in is hotter can not absorb the heat off of the heads was fast as is needed when you push a fully warmed engine up a long grade in the heat of the day you might not blow the engine up but the engine will degrade (make less power) every time you do this So why would VW make an engine that cant take a licking and keep on ticking like it did last summer?. they did!!!   the difference is the fuel. the new fuels are very fancy they make better power and are what I like to call designer fuels they are blended to run a water cooled engine with head temps that are much lower and consistent. the air cooled engine has head temps that hit 450 500 F at the spark plug on a climb up a pass I DON'T CARE WHAT YOUR GAUGE SAYS it a toy not an instrument and is nice to look at but that's all.The fuel can let you down in a big way under these conditions. when the fuel has what I will call abnormal combustion it burns slower and hotter and none of this is good for the air-cooled engine  
The thing to do is to stop at the bottom of the pass for an hour and have lunch, make the van rock for a while, have a nap and let the engine cool down. The engine will never get anywhere as hot in the 10 or 15 mile of climb as it would if you hit the hills fully warmed up in the heat of the day doing 60 mph 
 BECAUSE THE ENGINE ACCUMULATES HEAT OVER TIME  and the amount of time depends on the air temp, load and we could also say fan intake air temp, air fuel ratio and some other stuff that I am afraid to go into  
Im not kidding so pack a lunch
all right reserved 
Bob Donalds 
http://www.bostonengine.com