Oil Temps Again

[Kyler]

I discovered this weekend that the oil in my racing hack gets at least 302 degrees in lap 4 and stays that way through the 6 lap race. The oil analysis reports don't seem to show any issues. My temp gauge maxes out at 302 so I don't know what the real temp is.

Does anyone know what the oil temp should be?

 

[Nessism]

180-220 F is about right. 300+ doesn't surprise me, bet it's pushing 350 F or so.

 

[posplayr]

It would be interesting if you put a Series R/R in and see if your temps drop.

 

[Kyler]

It would be interesting if you put a Series R/R in and see if your temps drop.

Series R/R is a what? sorry for being

 

[posplayr]

Series R/R is a what? sorry for being

See my signature on GS Charging Health. There is a link right at the top on Compufire Series R/R. It lowers the temperature substantially on big block bikes.

 

[Nessism]

Suckers bet to think an R/R is going to drop oil temp. Buyer beware...

 

[posplayr]

Suckers bet to think an R/R is going to drop oil temp. Buyer beware...

Quite harsh words there Ed. You can't give it a rest?

 

[Nessism]

Yes Jim, a bit harsh on my part. I apologize.

Let me rephrase. R/R's do not affect oil temperature beyond, possibly, a very small amount. It doesn't make sense from a technical standpoint and I proved it already with back to back testing using different R/R's.

 

[Guest]

I discovered this weekend that the oil in my racing hack gets at least 302 degrees in lap 4 and stays that way through the 6 lap race.

Nice looking rig there, OP.

I assume you have an oil cooler? Can you put a bigger one in and/or improve the ducting to the one you have? What about better ducting to the engine itself?

As Nessism says, oil temps should be in the low to mid 200's F in a perfect world. Hot enough to burn off any moisture the oil picks up, but not so hot it roasts the oil and degrades its performance. OTOH, you can really abuse your oil if you run short races and change oil very frequently. Current 4 stroke MX bikes really hammer their oil but they seem fine as long as change intervals are short. I used to go 5hrs at most between changes on my RMZ-450.

It would be interesting if you put a Series R/R in and see if your temps drop.

Does OP even have a charging system? It is a purpose built racing sidecar rig, I wouldn't be surprised if he just runs a total loss battery ignition.

That aside, how do the R/R and stator affect oil temperatures?


Mark

 

[Kyler]

Nice looking rig there, OP.

I assume you have an oil cooler? Can you put a bigger one in and/or improve the ducting to the one you have? What about better ducting to the engine itself?

As Nessism says, oil temps should be in the low to mid 200's F in a perfect world. Hot enough to burn off any moisture the oil picks up, but not so hot it roasts the oil and degrades its performance. OTOH, you can really abuse your oil if you run short races and change oil very frequently. Current 4 stroke MX bikes really hammer their oil but they seem fine as long as change intervals are short. I used to go 5hrs at most between changes on my RMZ-450.

thanks - new paint job btw since that pic was taken

You can barely see the oil cooler in these two pictures. I'm thinking of making ducting to funnel all the air into the cooler. I'm also looking at bigger/higher flow coolers.

You are right on the MX bikes and frequent oil changes. KTM says to change the oil on my 450EXC after every weekend.

On this rig, I rarely go more than 2 race weekends on the oil and always get an analysis after every race weekend.

and thanks for the comments everyone - I'm going to try to get oil temps in the high 200s - I needed a target to shoot and and now I have one!

and one because I love my new logo

 

[posplayr]

Yes Jim, a bit harsh on my part. I apologize.

Let me rephrase. R/R's do not affect oil temperature beyond, possibly, a very small amount. It doesn't make sense from a technical standpoint and I proved it already with back to back testing using different R/R's.

R/R's do not affect oil temperature beyond, possibly, a very small amount.

Unbiased FACT: This unilateral statement has been proven false by several members here including myself.

It doesn't make sense from a technical standpoint

I AGREE, that it is a surprising result.

I proved it already with back to back testing using different R/R's

I AGREE again: It does not make any difference on your bike. That does not do anything to diminish the other results showing large drops in operating temperature. The results are motor specific and to date the only motors have been GS1100E's and es[pecially those with 1166 , 1229 and 1327's (Samsanite).

 

[posplayr]

Does OP even have a charging system? It is a purpose built racing sidecar rig, I wouldn't be surprised if he just runs a total loss battery ignition.

That aside, how do the R/R and stator affect oil temperatures?


Mark

The OP is being coy about answering the question, so I would not press him. Maybe a PM?

There is documented evidence that several GS1100E 16V motors that are big block have reduced operating temperatures using a Series R/R. I know this first hand as well.

http://www.thegsresources.com/_forum/showthread.php?t=161397

Obviously you will read Ed's unilateral conclusion (for all motorcycles ever built presumably) from his testing on an a single 8V GS1000.

 

[Guest]

You can barely see the oil cooler in these two pictures. I'm thinking of making ducting to funnel all the air into the cooler. I'm also looking at bigger/higher flow coolers.

Is that it on the monkey side, behind that open rectangular hole? Before you look for a bigger cooler definitely try ducting that properly to the cooler. It will make a huge difference to the amount of air getting to the cooler and may solve your issues all by itself. The duct needs to be sealed to the inlet and the cooler so that all the air coming in actually gets forced through the fins on the cooler. Also make sure the air exiting the cooler has somewhere to go without hitting a bunch of obstructions.


Mark

 

[Kyler]

Is that it on the monkey side, behind that open rectangular hole? Before you look for a bigger cooler definitely try ducting that properly to the cooler. It will make a huge difference to the amount of air getting to the cooler and may solve your issues all by itself. The duct needs to be sealed to the inlet and the cooler so that all the air coming in actually gets forced through the fins on the cooler. Also make sure the air exiting the cooler has somewhere to go without hitting a bunch of obstructions.


Mark

yes that is it. Behind it is the tank and the overflow catch bottle. There isn't a lot of room but the air can move over those and out the back. Not ideal.

I'm contemplating a new cooler that could be mounted in the opening or immediately behind it. That would make it easier to get air into and out of the cooler.

and on the R/R, the original stator and original '80 GS750 charging system is there. I have no idea if it works. The bike rarely runs more than 15 minutes at a time.

I'm going to focus on simple ducting for now and if I get some relief, then get a new cooler and mount it further forward.

again, thanks everybody!

 

[Guest]

yes that is it. Behind it is the tank and the overflow catch bottle. There isn't a lot of room but the air can move over those and out the back. Not ideal.

No, it isn't. Unless ducted properly the incoming air will simply try to go around the cooler because that is the path of least resistance. 15 minutes with some scrap coroplast (the corrugated plastic used for election signs and the like) and some duct tape would probably get you a workable duct to try before you do anything else. I bet you can cut the inlet hole size by 2/3 if you put a sealed duct in to force the air through the cooler.

Ideally the inlet hole area is quite a bit smaller than the cooler area and the ducting smoothly expands from the inlet out to the cooler. This slows the air down and lets it recover pressure before passing through the cooler fins, then the exhaust air should be ducted smoothly out into a low pressure zone. Done really well it results in a low temperature jet engine that actually produces a bit of thrust. I understand that F1 cars have close to zero cooling drag because the thrust offsets the drag of forcing the air through the radiators.

Light aircraft cool a couple hundred horsepower with less inlet area than you have there because they carefully duct the air in and force it through jackets that make it go through the engine cooling fins. You can use the same approach to improve your system as well. I would make your test duct up to go over top of the overflow bottle and would just block off the portion of the inlet hole that is in front of the bottle. From what I see in the pic it looks like that would leave you about 3/4 of the inlet area to feed the cooler, which should be way more than you need.

PM me if you want to discuss details off forum, or we can keep going here if you like.


Mark

 

[Kyler]

No, it isn't. Unless ducted properly the incoming air will simply try to go around the cooler because that is the path of least resistance. 15 minutes with some scrap coroplast (the corrugated plastic used for election signs and the like) and some duct tape would probably get you a workable duct to try before you do anything else. I bet you can cut the inlet hole size by 2/3 if you put a sealed duct in to force the air through the cooler.

Ideally the inlet hole area is quite a bit smaller than the cooler area and the ducting smoothly expands from the inlet out to the cooler. This slows the air down and lets it recover pressure before passing through the cooler fins, then the exhaust air should be ducted smoothly out into a low pressure zone. Done really well it results in a low temperature jet engine that actually produces a bit of thrust. I understand that F1 cars have close to zero cooling drag because the thrust offsets the drag of forcing the air through the radiators.

Light aircraft cool a couple hundred horsepower with less inlet area than you have there because they carefully duct the air in and force it through jackets that make it go through the engine cooling fins. You can use the same approach to improve your system as well. I would make your test duct up to go over top of the overflow bottle and would just block off the portion of the inlet hole that is in front of the bottle. From what I see in the pic it looks like that would leave you about 3/4 of the inlet area to feed the cooler, which should be way more than you need.

PM me if you want to discuss details off forum, or we can keep going here if you like.


Mark

tomorrow I'll get some better photos and post here. Just finished unloading the rig and its time for some beers. I don't mind the open discussion but hope we can focus on airflow and oil cooling. If not, we'll take it off-line.

 

[Kyler]

Here are some bigger pics of the oil cooler

The black tray is a mount for my Nexus. I use it for datalogging with the RaceChrono app.

Looks like I can get a reasonably close fit to the cooler but will have to slot around the oil lines.

 

[Guest]

Looks like I can get a reasonably close fit to the cooler but will have to slot around the oil lines.

Those are good shots, I can see what you have there. My first test attempt would be a simple rectangular duct as I described before, straight from the inlet hole to the face of the cooler just to see what happens to the oil temps. Slotting around the lines is no big issue for the initial testing, just tape off the slots once the duct is in place. I would put the bottom of the duct straight over the oil filter just for convenience. If you can manage it, try to seal the duct to the cooler face as well, to force the incoming air through the cooler instead of around it. Even sealing 2 or 3 sides will help a lot on that. I wouldn't worry about the exhaust side of the cooler for the moment, it looks to have a reasonable amount of area available for the hot air to get out and the space behind the bodywork there should be a fairly low pressure zone to draw the air through the cooler.

Depending on the results you can then go to refining the amount of inlet area to balance how much cooling you get and to work around the other components you have in the same space. What do you do for getting cooling air to the engine itself? It may be running very hot and cooking the oil along the way.

When do you get to the track next?


Mark

 

[Kyler]

Depending on the results you can then go to refining the amount of inlet area to balance how much cooling you get and to work around the other components you have in the same space. What do you do for getting cooling air to the engine itself? It may be running very hot and cooking the oil along the way.

When do you get to the track next?

I like this plan. Is sorta what I was thinking too. I'll work on that this weekend. Next race is July 11-13 at NJMP - the Thunderbolt track. I race there twice in back-to-back weekends.

standby!

 

[Kyler]

This is interesting. It appears the thermocouple I used isn't compatible with the thermometer in the Koso gauge. I'll be ordering a new one.

I warmed the motor up to test the air flow through the cooler (see mod below and thanks to all the local politicians for donating their signs) and to get another oil sample.

First, because the oil filter is right in front of the cooler, I couldn't get the bottom of the ducting to the bottom of the oil cooler. It misses about 2" on the right and slopes to the left. If this works I'll move the oil filter and ensure I use all the cooler area. I put a 21" box fan in front of the oil cooler and you could definitely feel air moving through the cooler.

Then I decided to check the temperatures around the motor using my pyrometer. The temp gauge was reading 295 degrees.

Coming out of the motor (temp taken on the fitting) the oil was 195.

On the fins of the cooler on the input side, temp was 170.

On the fins of the cooler on the exit side, temp was 125 (45 deg drop)

Returning into the motor (temp taken on the fitting) the oil was 160 (35 deg drop).

Weird. Does anyone know how much temperature drop I should expect?