More Oil Temperature Questions, Hot Oil, Cool Head Options

[Mblizzard]

the temps you are seeing are similar to the temps i have been seeing as well, but also found out that checking and calibrating my dipstick thermometer that my gauge was reading 30-40 degrees warmer than dipstick.
- i have the same billet deep tuna can and also the billet tuna can replacement as does Jim Hoyland. I have ordered a new VDO gauge that iwll match the sender properly and should give a more accurate indication of oil temp. my current gauge is off brand from before and not correct.
- i just switched to a 10-40 oil from 20/50 and while i only have one day of driving this past weekend after the oil change it appears this made a measurable difference in my temps, i did not measure an oil temp over 205-210 this weekend and i had been pushing that 240 range before. the real test will be when i take it out on a hot day for more spirited driving. i was and still may consider replacing the stock cooler with the set up that Chris Foley has, or just an add-on aux. cooler that several other members have put in that seems to have worked well for them. - i still am going to go back to recheck my timing as that will matter for overal engine temp but if you have good head temps i would say that is not your problem. - a good racing oil will not break down at 250 or even 275, but som oils will begin to do that at that point. last year at octeenerfest i talked to John Forbes about this, because when pushing hard going up the mountain with our group i hit that 250 point and was very concerned.
see how much change it makes with the other oil as i am before spending a bunch of extra cash on something else.

Chris's oil bypass spring made a huge difference in my temps. Essentialy all oil goes through cooler.

[DRPHIL914]

the temps you are seeing are similar to the temps i have been seeing as well, but also found out that checking and calibrating my dipstick thermometer that my gauge was reading 30-40 degrees warmer than dipstick.
- i have the same billet deep tuna can and also the billet tuna can replacement as does Jim Hoyland. I have ordered a new VDO gauge that iwll match the sender properly and should give a more accurate indication of oil temp. my current gauge is off brand from before and not correct.
- i just switched to a 10-40 oil from 20/50 and while i only have one day of driving this past weekend after the oil change it appears this made a measurable difference in my temps, i did not measure an oil temp over 205-210 this weekend and i had been pushing that 240 range before. the real test will be when i take it out on a hot day for more spirited driving. i was and still may consider replacing the stock cooler with the set up that Chris Foley has, or just an add-on aux. cooler that several other members have put in that seems to have worked well for them. - i still am going to go back to recheck my timing as that will matter for overal engine temp but if you have good head temps i would say that is not your problem. - a good racing oil will not break down at 250 or even 275, but som oils will begin to do that at that point. last year at octeenerfest i talked to John Forbes about this, because when pushing hard going up the mountain with our group i hit that 250 point and was very concerned.
see how much change it makes with the other oil as i am before spending a bunch of extra cash on something else.

Chris's oil bypass spring made a huge difference in my temps. Essentialy all oil goes through cooler.

I did the bypass valve first, helped a bit, next i did the deep tuna can, and now went back to the 10/40 oil and i have seen about a 15-20 degree decrease in our hot temps. If it really makes that much of a difference and i see that the temps stay around 220 - 230 max when hot and driving hard, or at highway speeds then i will not do the oil cooler. I want to prevent high cylinder head temps , so i might put in a cht sensor on #3 and see where that is as well - how did you install yours?

[914itis]

I know that others may not agree, but the oil weight makes a huge difference. when I changed to 20/50 I noticed the surge within 15 minutes of hard driving.

Now I run under 200 .

[BeatNavy]

Now I run under 200 .

You noticed it dropped back down when you switched away from 20/50? To what?

[Mark Henry]

I know that others may not agree, but the oil weight makes a huge difference. when I changed to 20/50 I noticed the surge within 15 minutes of hard driving.

Now I run under 200 .

Up or down? Sorry but your post does't make much sense.

[914itis]

I know that others may not agree, but the oil weight makes a huge difference. when I changed to 20/50 I noticed the surge within 15 minutes of hard driving.

Now I run under 200 .

Up or down? Sorry but your post does't make much sense.

I was initially using 10/40, I did an oil change using 20/50 and the temp surged 20 degrees F.
I went back to 10/40 and I am running back to normal 20 degrees less.

[Jake Raby]

Ambient temps and gearing heavily impact oil temperature. Tuning has impacts as well, mostly in regard to timing being too far retarded.

[saigon71]

I run my 2.0 D-jet with a stock cooling system pretty hard in the summer months with a mix of cruising & stop and go traffic. I run Quaker State Defy 10w30 semi-synthetic oil. I don't ever recall oil temps going above 220 on the VDO oil temp gauge.

Do you have the plastic air flaps attached to the rear of the floor pan? I've been told they create a negative pressure in the engine bay and assist with cooling at speed.

[Geezer914]

I run Brad Penn 15/40w and added a Scat 1.5 qt. sump. Runs cool as a cucumber. If you did not look at your oil cooler real close when you rebuilt your engine the fins are full of oil and dirt. (IMG:style_emoticons/default/idea.gif)

[BeatNavy]

I don't think the oil cooler was in bad shape. Here's a pic when I replaced the seals before installing the car. The engine was fairly clean when I got it and I cleaned it up some more and powdercoated the tin, so I got a chance to look over it pretty good.



Bob, I do NOT have those undercarriage flaps or air baffles (or whatever they are) on my '72. I have seen people mention those before, but not sure how effective or important they are.

I have some Brad Penn 10W40 on order. Gonna try running that while it's still hot outside to see if it makes a difference. Also have a VDO on order to help me monitor it while I'm driving.

[Mark Henry]

Ambient temps and gearing heavily impact oil temperature. Tuning has impacts as well, mostly in regard to timing being too far retarded.

I agree and this can be what is causing hot oil and cold head condition, verify your timing.

[BeatNavy]

Ambient temps and gearing heavily impact oil temperature. Tuning has impacts as well, mostly in regard to timing being too far retarded.

I agree and this can be what is causing hot oil and cold head condition, verify your timing.

Hi Mark - I did. It should be right on now. I said it was slightly advanced before when I meant to say slightly retarded. That may have contributed some.

[DRPHIL914]

Ambient temps and gearing heavily impact oil temperature. Tuning has impacts as well, mostly in regard to timing being too far retarded.

I agree and this can be what is causing hot oil and cold head condition, verify your timing.

Hi Mark - I did. It should be right on now. I said it was slightly advanced before when I meant to say slightly retarded. That may have contributed some.

interesting, as i have to verify this but my idle si really too low since being in the shop the last time and i think the timing is a bit too retarded as well, so i'm going to go back and verify this tonight.
BTW those flaps matter. get them and install them. I think on these cars, especially the 2.0 every little bit matters. BTW i think on the oil issue the factory recommended 30 wt oil.
Phil

[DRPHIL914]

I don't think the oil cooler was in bad shape. Here's a pic when I replaced the seals before installing the car. The engine was fairly clean when I got it and I cleaned it up some more and powdercoated the tin, so I got a chance to look over it pretty good.



Bob, I do NOT have those undercarriage flaps or air baffles (or whatever they are) on my '72. I have seen people mention those before, but not sure how effective or important they are.

I have some Brad Penn 10W40 on order. Gonna try running that while it's still hot outside to see if it makes a difference. Also have a VDO on order to help me monitor it while I'm driving.

which VDO gauge did you get?( been looking but did not purchase yet)

[DRPHIL914]

http://www.corvetteforum.com/forums/c3-tec...-test-data.html

FYI - found this interesting

I ran across this while trying to get more imformation on oil wear, zppd, etc etc.

its a list of highest rated oils for wear protection and breakdown, and how the test on "load carrying capacity and film strenght"
one thing to remember is dino oils will smoke and break down at a lower temp.
Zinc, ZPPD may extend the protective life of the oil but does not necessarily increase the protection, there is a difference.

i know a lot of ink has been spilled on this subject, and i know Jake may chime in because he has more experience in real world engine testing and development of both engines and oil, so he may shed more light on the subject and how these numbers can be interpeted.

[BeatNavy]

Just a small follow-up on this thread. Last weekend I changed the oil and replaced the 20/50 with 10/40. Only got a little time to run it while hot outside, but it seems like it's running 10 degree cooler or more. I also purchased an oil temp gauge that matches my sending unit (AutoMeter) and tested it out before a full install. Interestingly enough that looks like it might be showing a significantly lower temp than the oil dipstick temp gauge.

Finally, got a pair of undercarriage cooling flaps in the mail, donated from a very active member here from PA (who has a thing for red 914's (IMG:style_emoticons/default/smile.gif) ). Gotta love the World! I'll try putting those on this weekend.

[Jake Raby]

Clean the cooling fan....

Also ensure that timing is correct. I see lots of engines with retarded timing that run high OT and cool CHT,