Itinerant Air-Cooled

Bleyseng wrote:I am coming back from Idaho this morning dreading the heat. Coming I hit 106f and had vapor lock 3 times (no fuel to the fuel pump). Time to change to the 78-79 hot air dumps to direct it it away from the gas tank area. CHTs were 375-400f but oil temps were 235-240F. Heading back driving like a granny...

This is a quote from another thread and I wanted to use it to discuss oil temps. For an temp taken from the taco plate, what is considered too hot? I sometimes see temps in the 250 range but CHTs under 350F.

BellePlaine wrote:For an temp taken from the taco plate, what is considered too hot? I sometimes see temps in the 250 range but CHTs under 350F.

For people changing their oil at the 3,000 mile interval, occasional summertime 260*s are nothing to worry about. During the heatwave of 100* temps, expect that the engine will be hot.
Keep your crankcase fins and oil cooler fins clean. If your oil smells nice, not burnt, then your engine is happy. If the heads are shiny wet, not black, brown, baked acrid, just drive.
Colin

From what I have read sustained 250-260F will cook the oil. How long? Maybe an hour or two, three four?

My experience is that high oil temps can be timing related or due to a poor cooling system (notably that foam tht forces cooling air through the oil cooler).

Synthetic oils don't thermally break down as fast as dino oils do.

In my case the oil temps never go above 220F until it's above 90F. Then it was 230F and when it was 100F it was hitting 240F until I hit 250F at 110F climbing a long steep hill . I had 40psi of oil pressure so I was fine driving at 55mph and didn't burn any oil for the trip.
Have the rubber gasket installed, all the cooling tin, really no oil leaks and timing was checked before the trip at 27 degrees at 3500rpms.
I am running a stock VW used 72 muffler until I repair the S&S extractor I broke.

The boiling gas in the tank seems to be the big problem as when I was at a third of a tank I started losing power and ran hotter. Then I would get vapor lock and the engine would die. My guess is it was then running leaner with less power due to the heat control valves dumping that hot air right below the gas tank. I also think the case also gets heat soaked so the oil temps rise too.

Once I reached Wenatchee next to the river and the temps outside were cooling down to 95F I had no problems. Back up to 60-65 mph and cruised home via Highway 2 (which is beautiful compared to I90, Colin should take this route and enjoy a night in Leavenworth).
So I located a set of 79 control valves and the tubes to install and the test will be to see if this changes the gas tank issue. After that I'll install the S&S header to see if that makes a difference as before when the header was on I never had this issue traveling thru 100F heat.

So Randy, what is the foam you are talking about?

I was thinking about the foam seal below the metal frame that is on top of the oil cooler. KInd of like this one....

Randy in Maine wrote:My experience is that high oil temps can be timing related or due to a poor cooling system (notably that foam tht forces cooling air through the oil cooler).

When I first started watching the oil pressure gauge in my new to me bus years ago, I noticed oil pressure would dip after a hot climate hill climb, and it wouldn't go back up unless I slowed greatly or stopped to let it rest. The first time I removed the engine, about six months into owning it, I pulled the fan shroud to find no foam oil cooler dam. After installing one, I can see oil pressure (and thus temperature) climb back to homeostasis after a hot climb so I don't have to stop and wait anymore. They're beautiful things, details.

Robbie

Randy in Maine wrote:I was thinking about the foam seal below the metal frame that is on top of the oil cooler. KInd of like this one....

That's a rubber and have that installed to seal the oil cooler to the fan tin.

where does one buy a oil cooler seal?

greg in ga wrote:where does one buy a oil cooler seal?

Anybody that sells air cooled VW part will have them. You might search the area you're in for a VW shop.

Cool, do you happen to have a link?

wcfvw69 wrote:

greg in ga wrote:where does one buy a oil cooler seal?

Anybody that sells air cooled VW part will have them. You might search the area you're in for a VW shop.

I have never seen a new one for sale. I would inquire from one of the fine dismantlers out there. I am not even sure what the official name of it is.

I'm having a rough go trying to find one for sale online. I'll keep looking, but check with Walter at Bus Boys. Ken @ Bus Co always seems to have the obscure part that I need as well.

asiab3 wrote:I'm having a rough go trying to find one for sale online. I'll keep looking, but check with Walter at Bus Boys. Ken @ Bus Co always seems to have the obscure part that I need as well.

You can fabricate a seal out of foam door/window seal material. It needs to be a nice square cross section that is under enough compression when you set the intermediate tin down on the cooler that it conforms to the edge of the tin, this will make a groove in the foam that locks it in place.
Colin