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Wed Jul 08, 2015 11:36 am

Just wanted to get some feedback on the oil temps of larger engines.

We recently had some hot weather here and the oil temp of my 2109 was getting up there 235-240 was the highest I saw. This past weekend I pulled the 2109 (I need to fix an oil leak at the cylinder to case) I put in my 1760 for the time being.

The oil temp of the 1760 is much cooler than the 2109 (actually too cool) 190-195 is the highest I've seen. I used the same gauge, sender, oil cooler, fan shroud. Both engines used 15-40 oil, 26mm oil pump, Bosch 3500 filter. I have a 1 qt sump on the 2109, no sump on the 1760.

Cylinder head temp is actually a bit hotter on the 1760.

Both engines are built on dual relief AH cases 8mm studs.

Wed Jul 08, 2015 11:55 am

2276 11 cr, 2 cht sensors on #4 & 2 ( cb crankfire program and vdo gauge - at 268/269 HT, 92 octane pump gas, 72 pass extra oil cooler fan, hoover bit, and stock cooling dh system. Operating temperature 195-200. Temp lately in Hawaii in low 90s. No front tin due to Trans raise kit. All tins less sleds and no engine seal.

Wed Jul 08, 2015 1:40 pm

Of course you are going to see higher temps on a bigger engine. The VW cooling system can only remove a certain amount of heat. Everything being equal. The larger engine will be pulling in a larger fuel/air charge. This larger charge will result in a larger combustion event, which in turn creates more heat.

Wed Jul 08, 2015 2:06 pm

Most likely cause is fuel mixture.

Wed Jul 08, 2015 2:12 pm

oil pressures? Change oil to a thinner one (10-30) and see if temps drop. They often do. Each engine has different needs, don't confuse the wants of one with a different engine. Listen to what the engine wants.

Wed Jul 08, 2015 2:13 pm

I've said this a million times. 210-220*F is normal oil temps and perfectly safe. Do not confuse normal 180* water temps of a water cooled engine with oil temps. Oil must get hot enough to boil out water and other acid contaminants that collect from condensation every time the engine is run then shut off and cooled down. If you do not believe me then ask the oil companies directly how to use their products.

When conventional dyno oil get 235-240*F you need to pull over and stop. When synthetic oil get 245-250*F you need to stop.

The last few years the Fed Gov't has changed the regulation and you should no longer use 15W-40 diesel engine oils in any gasoline engines.

Oil temps are related more to RPM's then engine size. The higher you rev an engine the hotter the oil will get. Engines with dual valve springs will run 10-15* hotter the engines with single valve springs.

Wed Jul 08, 2015 2:16 pm

Do u drive at exactly same speed? Heat is related to horsepower and power is related to speed. Same car at same speed on same road will produce same power and same heat no matter how big engine..... if all is same znd you still have temp difference you have to troubleshoot

Wed Jul 08, 2015 5:09 pm

Multi69s wrote: Of course you are going to see higher temps on a bigger engine. The VW cooling system can only remove a certain amount of heat. Everything being equal. The larger engine will be pulling in a larger fuel/air charge. This larger charge will result in a larger combustion event, which in turn creates more heat.
So wouldn't I see higher head temps on the 2109? head temps average about 10* hotter on the 1760

[email protected] wrote: oil pressures? Change oil to a thinner one (10-30) and see if temps drop. They often do. Each engine has different needs, don't confuse the wants of one with a different engine. Listen to what the engine wants.
I had 10-30 in the 2109 during the winter, but when the weather warmed up my pressure would dip below 10 psi at idle.

vwracerdave wrote: I've said this a million times. 210-220*F is normal oil temps and perfectly safe
I understand what temps are good and acceptable, I'm just looking for reasons why the temps are so different between the two engines.

vwracerdave wrote: Oil temps are related more to RPM's then engine size. The higher you rev an engine the hotter the oil will get. Engines with dual valve springs will run 10-15* hotter the engines with single valve springs.
There we go the 2109 has dual springs and the 1760 has single heavy springs, that's something! Its not like Im revving the piss out of the 2109, I don't have to it has plenty of power down low.

ozzo wrote: Do u drive at exactly same speed? Heat is related to horsepower and power is related to speed. Same car at same speed on same road will produce same power and same heat no matter how big engine..... if all is same znd you still have temp difference you have to troubleshoot
yes, I could understand if I was pulling big hills at high rpm on the freeway and saw 230 but this was normal in town driving just in the heat of the day.

Wed Jul 08, 2015 7:33 pm

the stock warning light goes on at 2.5psi. Changing oil because of a 10psi idle is an over-reaction. I suggest you try the thinner oil. If the temps don't drop you can switch back.

Wed Jul 08, 2015 7:41 pm

vugbug68 wrote: So wouldn't I see higher head temps on the 2109? head temps average about 10* hotter on the 1760

There are hundreds of reasons why one engine will run hotter than the next. You will never find the answer here.

Do both engines have identical matched length fan belts? A shorter belt will spin the fan faster and cool better. What about the pulleys? Are they the same?

Do both engines have the exact same fan shroud? If you're using a late Type 1 DH shroud, did you know there are several different versions? The differences cause more or less air to go through the cooler.

What about the depth of the fan into the shroud? Did you assemble it like most and just drop it in, or did you set the depth?

The cooling fins on the heads have a huge effect. Some castings are plugged between the intake and exh ports, some are very open. Casting flashing beside the exh port flange can block a lot of air. When I prep an engine, I port the cooling fins.

Do both have identical exhaust systems? If one has the J pipes arranged very close to the pushrod tubes, a LOT of heat will be radiated from the exh into the oil draining back to the case in the tubes.

Have you mapped the advance curve of both distributors? (I'm assuming you are using the same type on both engines.) Differences in timing will cause different temps.

Wed Jul 08, 2015 8:44 pm

[email protected] wrote: the stock warning light goes on at 2.5psi. Changing oil because of a 10psi idle is an over-reaction. I suggest you try the thinner oil. If the temps don't drop you can switch back.
The oil temps stayed the same when I changed the oil, The weather was cool enough then that my oil temp didn't worry me. It seems like outside air temp has the biggest effect on my oil temp, when its a cool day I can cruise up hills on the freeway spinning 4k and my oil temp will never pass 215-220, but a hot day just cruising around my oil will get past 220 and wont cool down unless I shut it off.

Wed Jul 08, 2015 8:50 pm

but the temp change won't be apparent unless it's hot. It's like saying "my oil temp is fine" when it's 10F out. That is irrelevant compared to 110F ambient.

vugbug68 wrote: The oil temps stayed the same when I changed the oil, The weather was cool enough then that my oil temp didn't worry me. It seems like outside air temp has the biggest effect on my oil temp, when its a cool day I can cruise up hills on the freeway spinning 4k and my oil temp will never pass 215-220, but a hot day just cruising around my oil will get past 220 and wont cool down unless I shut it off.

Wed Jul 08, 2015 9:49 pm

[email protected] wrote: but the temp change won't be apparent unless it's hot. It's like saying "my oil temp is fine" when it's 10F out. That is irrelevant compared to 110F ambient.

vugbug68 wrote: The oil temps stayed the same when I changed the oil, The weather was cool enough then that my oil temp didn't worry me. It seems like outside air temp has the biggest effect on my oil temp, when its a cool day I can cruise up hills on the freeway spinning 4k and my oil temp will never pass 215-220, but a hot day just cruising around my oil will get past 220 and wont cool down unless I shut it off.

I understand that, my post was just explaining more symptoms. My reason for going to 15-40 was to get a little bit more pressure and it only increased by 2-5 psi throughout the rpms, I didn't see any change to the temp by just changing the oil.

Wed Jul 08, 2015 9:50 pm

Bruce wrote: vugbug68 wrote: So wouldn't I see higher head temps on the 2109? head temps average about 10* hotter on the 1760

There are hundreds of reasons why one engine will run hotter than the next. You will never find the answer here.

Do both engines have identical matched length fan belts? A shorter belt will spin the fan faster and cool better. What about the pulleys? Are they the same?

Do both engines have the exact same fan shroud? If you're using a late Type 1 DH shroud, did you know there are several different versions? The differences cause more or less air to go through the cooler.

What about the depth of the fan into the shroud? Did you assemble it like most and just drop it in, or did you set the depth?

The cooling fins on the heads have a huge effect. Some castings are plugged between the intake and exh ports, some are very open. Casting flashing beside the exh port flange can block a lot of air. When I prep an engine, I port the cooling fins.

Do both have identical exhaust systems? If one has the J pipes arranged very close to the pushrod tubes, a LOT of heat will be radiated from the exh into the oil draining back to the case in the tubes.

Have you mapped the advance curve of both distributors? (I'm assuming you are using the same type on both engines.) Differences in timing will cause different temps.

I kept everything the same when I did the swap to narrow it down as much as possible. Yes the two longblocks are different but every single component is the same. I took everything off the 2109 to put on the 1760. I know two different engines will run at different temps, but I am amazed by how much given the parts are the same.

I wonder if the relief valve in the 2109 case is not seating properly and letting some oil bypass the cooler

Thu Jul 09, 2015 3:05 am

The differences could come BECAUSE you used the same components, and they were not re-sized to keep certain relationships more constant between builds.

Also, vehicle dynamics can play a big role in temps. For instance, are you now using a higher gear to maintain the same speeds as with the smaller engine, because now you can, with the extra torque of the big engine? (so running lower fan speed) etc...

I am also fascinated at how similar engines behave differently, in my case in a 1303 vs. in a type 2.

Thu Jul 09, 2015 4:53 am

vugbug68 wrote: My reason for going to 15-40 was to get a little bit more pressure and it only increased by 2-5 psi throughout the rpms, I didn't see any change to the temp by just changing the oil.

Are you using 15W-40 Diesel engine oil? There was a thread a few months ago about a guy that experienced a 15* rise in oil temp when he switched to it. He imedatly got 15* lower oil temp when he took the diesel oil out. The oil regulations have changed and diesel oil should no longer be used is gas engines.

Read what Berg said about linebored cases. It has an effect on oil pressure and oil temps.

Thu Jul 09, 2015 8:03 am

I'm surprised no one has mentioned the latest Hot VW magazine. There is an article that states oil temps over 200 are bad and lead to destruction of your engine. My son and I drove his bug with a 2332 from Phoenix to Vegas (about 300 miles), sometimes at 80 mph and our oil temp remained about 220. It went up some when climbing hills but cooled back down when we leveled out. He decided to go turbo and when we freshened up the bottom end, the bearings were fine, though we put new ones in since we were in there anyway. My point is running 220 oil temp for hours at a time didn't seem to hurt the bearings at all.

Thu Jul 09, 2015 9:26 am

Haven't read the article, but 200 F isn't that much. I would start to worry about it if it came closer to 250.
Do they advertise any products related to the article?

Thu Jul 09, 2015 9:27 am

vwracerdave wrote: vugbug68 wrote: My reason for going to 15-40 was to get a little bit more pressure and it only increased by 2-5 psi throughout the rpms, I didn't see any change to the temp by just changing the oil.

Are you using 15W-40 Diesel engine oil? There was a thread a few months ago about a guy that experienced a 15* rise in oil temp when he switched to it. He imedatly got 15* lower oil temp when he took the diesel oil out. The oil regulations have changed and diesel oil should no longer be used is gas engines.

Read what Berg said about linebored cases. It has an effect on oil pressure and oil temps.
I read the same thing on here about rotella and diesel oils, I've used both regular 10-30 and rotella in this engine and did not see any change in oil temp, but had a bit better pressure with rotella, and by better I don't mean too high, I like 10 psi per 1000 rpm.

Thu Jul 09, 2015 9:40 am

Ellis' Bug wrote: I'm surprised no one has mentioned the latest Hot VW magazine. There is an article that states oil temps over 200 are bad and lead to destruction of your engine. My son and I drove his bug with a 2332 from Phoenix to Vegas (about 300 miles), sometimes at 80 mph and our oil temp remained about 220. It went up some when climbing hills but cooled back down when we leveled out. He decided to go turbo and when we freshened up the bottom end, the bearings were fine, though we put new ones in since we were in there anyway. My point is running 220 oil temp for hours at a time didn't seem to hurt the bearings at all.

It figures that Hot VW's would say that, but they probably don't drive their cars far enough to see over 200 oil temps haha

Thanks for the post with real world numbers, are you running an external oil cooler?