Date: Wed, 23 Jan 2002 01:54:12 -0600
Reply-To: Max Wellhouse <maxjoyce@IPA.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Max Wellhouse <maxjoyce@IPA.NET>
Subject: Re: '80 Westfalia-- best way to drive over passes
In-Reply-To: <012301c1a39f$b9463c40$99890fce@vern>
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Bob and Listees: Having owned a modified 79 Type IV loaf, I never gave the
accumulated heat thing much thought. While modifying my engine, I did take
in to account some of the Berg Philosophy on keeping air cooled engines
alive. IE Lower Compression Ratio( I was down to 6.6-6.9 IMS), One venturi
per cylinder(dual 44IDF Webers) Ported and big valve heads from FAT
Performance), Mild Cam, balanced parts and 009 ignition with Jacobs
Compusensor ignition and a Phoenix header system.
This engine also had a modified Harrison(GM) Evaporator coil(converted to
an oil cooler from a 1975 Monte Carlo) with its own external air scoop
mounted on the driver's side rear quarter panel and duct work to channel
the air over the cooler and out the bottom of the area opposite the battery
area(on passenger side). It also had the Aeroquip teflon stainless steel
#8 hoses and an Amot in line thermostat that would open at 165 F and be at
full flow at 185F. Used stock timing specs. It got 17-20 MPG and never
reached oil temps over 210F including a 12 mile climb to Sewanee TN in 95
degree heat with the roof rack loaded with canoes and kayaks. I agree that
the VDO head temp gauge is anything but accurate but I mounted my sensor
ring on the exhaust nut on the #3 cylinder so I could get as instant of
results as possible when head temps fluctuated. The VDO gauge never got
over 450 F, but the value of the gauge was for comparason more than the
numbers.
This engine lasted over 100,000 miles and ran like a scalded dog. Berg
didn't believe in external coolers, but this system made a believer of
me. Setting up a Vanangon AC to do all this would be problematic at best
as the deck clearance for tall manifolds would be a problem and getting the
ducting for the oil cooler would also be hard. It was critical to not have
the hot air from the oil cooler get sucked into the cooling fan and thereby
recycle the heat to the heads.
Maybe if I'd stoppped in Chattanooga for food and to let it cool, it
would've lasted twice as long!! I guess drive thrus at all the
McWendyKings are costing us precious engine hours after all.
Dimwitted moose and Flying Squirrel
-0500, Robert Donalds wrote:
>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
