Oil temp

hi all

What is the normal oil temp for a type 1 1776 engine without a oil cooler. Mine was reading 210

Thank in advance

Dick

180 to 220 is what you should be running.

Also, what is the normal oil temperature at which the fan on an auxiliary oil cooler should come on?

Robert,

My fan and by-pass thermostat both kick on at 180. Highway cruising at about 3700 rpm on a 90 degree day the oil gets up to about 195-200 then creeps back down to 180-185.

Jerome

"Normal" is relative; most performance VW engines run oil temps of 195 F to 220 F, and occasional temps of up to 240 F when cruising at speed on a hot summer day are possible.

Note that on many Porsches the factory changed the oil temp gauge by replacing temperature numbers with a green zone so that downers wouldn't freak out when temps got high.

Use a good quality oil of the right weight and change it at reasonable intervals if you have high oil temps; true synthetic oils like Mobil1 or AMSOIL are better (10/40 cold weather and 20/50 hot weather).

Make sure you have no other cooling issues - check the items listed in the "cooling" post in the KNOWLEDGE section.

For Referance...

(To go along with George's post)

My engine is basically a stock 1600 with dual Kadrons running Mobil Full Synthetic.

George:

I have heard that synthetic oils don't transfer heat as well as "natural" oils do, such that, when you run a synthetic in a VW engine, it doesn't pull heat as well from the heads and you get a false sense of security, i.e.; the head temperature increases (which most of don't have means to measure), while the oil temperature seems to go down. Have you any experience with this?

I don't have enough miles on my engine yet to feel comfortable with a synthetic oil in there, and while I've seen the oil temp decrease slightly (5 degrees F) when going from 10W-30 to straight 50 wt, I'm a bit concerned with initial (start-up) oil pressure and the fact that 50 wt. simply doesn't lubricate as well unless it's really hot.

To that end, I'm currently fab'ing the mounts for a full-flow cooler and filter similar to yours, so I can run the thinner oil AND keep everything cooler, too, but I was wondering what you (or anyone else) has heard about heat transfer and synthetic oils.

Thanks, Gordon

Gordon, how does the oil pull the heat from the heads? I thought that the oil cooled the motor's internals and the air cooled the oil via an oil cooler and cooled the heads via air over the fins.
Ron

Gordon: Synthetic oils tend to have a higher heat capacity. So it takes more energy to raise the temperature of a similar quantity of synthetic oil as compared to regular oil. Therefore a quart of hot synthetic oil can carry/transfer more energy than a quart of regular hot oil. Another way to think about it is if I have a hot head and expose them to both types of oil in the same way and for the same time and the same amount of energy is transferred then the synthetic will be at a lower temperature since it takes more energy to heat it up.

The quantity of oil really isn

Regardless of how the oils do it, all the synthetic oils claim to lower head temps. They support their claims by thermal imaging photos of the same engine where when the engine is running synthetic, it has lower head temps. In addition, there was a test done in one of the VW mags about 6 months ago where they tested synth oil against dino oil and tested with a laser temp gauge. They confirmed lower head temps with the synth oil, and also other locations on the engine were cooler as well.
Ron

Ron:
The oil does, indeed, cool the motor internals, but the heads are part of that, too. They get most of their cooling from the impinged air, but the oil plays a part, too, even if a much smaller part as it runs out of the rocker assy and back down the pushrod tubes.

OK, I'm impressed with the info. My question came from a 30 year old former life when I was working for a company which made gyroscopes and accelerometers for aerospace. These devices spun at 30,000 to 60,000 rpm and generated a lot of heat for their size. We ran the body immersed in an environment of pure silicone oil, not to lubricate it (it was totally sealed in a helium environment) but to cool it and dampen its' action (as in accelerometers). We found (through testing by our resident oil/coolant engineer) that certain types of silicone oils had far higher heat transfer coefficients than other things we'd tried, including synthetic oils similar to automotive lubricants. He found that, at that time, those "automotive" types of synthetic lubricants tended to reject heat as opposed to the silicone stuff that absorbed heat more readily and had a MUCH higher boil and flash point (some of those gyros could run well over 150 degrees c). Silicone oil is prohibitivly expensive for use in auto engines, but it looks like the synthetic oil companies have "tuned" their product for that use over the years.

I was only curious since VW engines are, by design, more prone to higher oil and running temps than are water cooled engines, which tend to be more stable, and I didn't know what effect synthetic oils would have on them.

Thanks!