Turbo Slug's 3800 rebuild (Page 2/3)
La fiera NOV 24, 01:39 PM
Totally agree with you Claude!
Another aspect that we take for granted is the viscosity required for the intented use.
What do I mean? Think about this scenario; the manufacturer's manual recommends 10w30 but now you have a turbo charger and you are constantly in the mid and upper RPM range demanding full power. You do this for 4 sessions of 30 minutes each in a span of 6 hours during a hot summer day. The rest of the week you barelly drive it exept to a car show here and there.
Question is; will you still use10W30 or use a different viscosity to compensate for the use of your engine?
ignorant prodigy NOV 24, 02:04 PM
pretty cool insights guys, thanks for sharing
claude dalpe NOV 25, 12:07 AM
To begin with Rei, if a manufacturer recommends the 10w30 it is not a modern car we agree.
So if that's what the manufacturer is asking for and I know I'm going to abuse the motor as you described in your scenario.
I would use if it was in the 80's / 90's, 10w40 oil but today I would prefer to use 5w40 synthetic oil.

But the most important is to warm up the engine well all the times before abusing it especially if you use a thicker grade of oil.
An example cold pistons are not not round but oval and becomes round as it warms up.

I think that if the engine will be abused I prefer that the grade of oil be a little thicker (40 instead of 30) to tolerate the abuse of power, but not too thick because the oil will circulate less quickly and will overheat more than lighter oil which circulates more quickly.
La fiera NOV 25, 08:59 PM

quote
Originally posted by claude dalpe:

To begin with Rei, if a manufacturer recommends the 10w30 it is not a modern car we agree.
So if that's what the manufacturer is asking for and I know I'm going to abuse the motor as you described in your scenario.
I would use if it was in the 80's / 90's, 10w40 oil but today I would prefer to use 5w40 synthetic oil.

But the most important is to warm up the engine well all the times before abusing it especially if you use a thicker grade of oil.
An example cold pistons are not not round but oval and becomes round as it warms up.

I think that if the engine will be abused I prefer that the grade of oil be a little thicker (40 instead of 30) to tolerate the abuse of power, but not too thick because the oil will circulate less quickly and will overheat more than lighter oil which circulates more quickly.



I agree with you Claude! The thicker oil will circulate less but it will cushion and resist evaporation better than the lighter oil due to the hi heat generation of the demand of power. Once the oil overheats it can no longer do its job. It won't suspend the dirt in the matrix, it will not cushion because its viscosity will flat line loosing its plasticity and once it cools off it will turn into black goo without life.
claude dalpe NOV 26, 09:57 AM
Here are some of my conclusion Rei few years ago I did tests with my Chevrolet V8 which had an engine and transmission oil temperature gauge.
I used this car to tow often, which is the reason for the temperature gauges.
What I have noticed with years of towing and different viscosity testing during oil changes.
The thicker the oil, the better the oil pressure but tend to have a higher oil temperature.
The manufacturer (GM) recommended 10w30 and I tried up to 20w50 in this engine.
It is with my results that I saw that the oil that is too thick is not necessarily better yes it keeps a good pressure under the crankshaft bearings but heats up more since it circulates less quickly.
I would have probably had to do more testing with an engine oil cooler as I had one for the transmission, the conclusions might have been different.
Today with the new variable cam motors it's impossible to change to much the viscosity without having problems with this system.
claude dalpe NOV 26, 10:01 AM
Curiosity frenchrafe : What grade of oil do you use in your 3800 turbo slug

Curiosité frenchrafe : Quel grade d'huile utilise tu dans ton 3800 turbo slug
La fiera NOV 26, 06:34 PM

quote
Originally posted by claude dalpe:
It is with my results that I saw that the oil that is too thick is not necessarily better yes it keeps a good pressure under the crankshaft bearings but heats up more since it circulates less quickly.
I would have probably had to do more testing with an engine oil cooler as I had one for the transmission, the conclusions might have been different.
Today with the new variable cam motors it's impossible to change to much the viscosity without having problems with this system.



Yes, you are right Claude. But the increase in temperature of the thicker oil doesn't mean it is a bad thing.
Water will boil much faster than olive oil but water will dissipate the heat faster than olive oil. While the water turns into vapor and dissapears at 212F the thicker olive oil is still liquid, and it will stay liquid up to about 375F! Also once that thick oil heats up its pressure drops which means its moving faster.
If you use a thicker oil and it gets very hot lets say 230F you start to release out the oil any compounds that boil below 230F, like fuel in the oil and moisture, etc.
The contrary is true with a thinner oil. So the take away is that regardless if you use thin or thick oil, what you want to avoid is using an oil for your aplication that will vaporize due to high temperatures. A lack of oil due to high heat vaporization between the crank journal and the bearing its an automatic failure. The journal only needs to hammer that bearing once for everyting else to go wrong.
claude dalpe NOV 26, 07:41 PM

quote
Originally posted by La fiera:
Water will boil much faster than olive oil but water will dissipate the heat faster than olive oil. While the water turns into vapor and dissapears at 212F the thicker olive oil is still liquid




I liked your comparison water/ oil Rei
This is why I mentioned that I liked having an oil cooler to do my oil tests on my V8. it is also for this reason that I do not really like the new 0w20 oil standards and even the new 0w16
I hope the oil makers add a lot of additives to increase their boiling points.

And when you said Rei:
So the take away is that regardless if you use thin or thick oil, what you want to avoid is using an oil for your aplication that will vaporize due to high temperatures.
I think that's why you have to buy very good quality oil and the right thickness.

[This message has been edited by claude dalpe (edited 11-26-2021).]

La fiera NOV 26, 09:51 PM

quote
Originally posted by claude dalpe:


I liked your comparison water/ oil Rei
This is why I mentioned that I liked having an oil cooler to do my oil tests on my V8. it is also for this reason that I do not really like the new 0w20 oil standards and even the new 0w16
I hope the oil makers add a lot of additives to increase their boiling points.

And when you said Rei:
So the take away is that regardless if you use thin or thick oil, what you want to avoid is using an oil for your aplication that will vaporize due to high temperatures.
I think that's why you have to buy very good quality oil and the right thickness.




Exactly!
La fiera NOV 26, 10:06 PM
You may ask, how do I know about oil? I invented this product for 4 stroke kart engines. I won the local 2014 4 Stroke kart championship locally and in 2015 they banned me from racing at that track while leading the championship. My competitor was non other than Amsoil and I kicked his ass!
Of course, I had to drive the kart to win but the oil gave a very little % advevantage. And in a 10HP engine every minute % counts.

https://www.boxstockproject...product_detail&p=286