Lamborghini Block Heating Expands Crank Clearances So Much That A 50 Weight Oil Is Required

OVERKILL

$100 Site Donor 2021
Joined
Apr 28, 2008
Messages
54,499
Location
Ontario, Canada
Yeah, that's not a real grade. Specs are:
Screen Shot 2022-11-30 at 2.39.17 PM.jpg


So if we look at J300:
Screen Shot 2022-11-30 at 2.44.13 PM.jpg


It's a 0W-8.
 
Joined
Dec 19, 2018
Messages
2,749
Location
Vancouver
That's a qualifying oil. They run that oil in racecars for qualifying laps only, to eek out every fraction of a horsepower, and then they drain and refill the dry sump with a heavier oil for the race when they require sustained protection.

Who is 'they' and what oil are you talking about?
 

UncleDave

$50 Site Donor 2023
Joined
Jun 2, 2014
Messages
8,003
Location
Ca.
Interesting build and why they use a 50 weight oil. Good explanation.





I doubt the owner's would wait for the engine to preheat too. Crazy the increase in bearing clearances at these lower temperatures!



Dealing with expansion in aluminum blocks at sustained high HP has always been a challenge that the chevy form factor has down.
You could get Donovan aluminum small block that put out frightening amounts of power for extended intervals with zero problem (until a rod leaves the block) - and even then they can be repaired.

The chevy formula cannot be beat here.
 
Joined
Oct 6, 2020
Messages
397
Here’s a bit of rough math. Steel expands by 0.07% for every 100F.

So, in his test, he heats the block by roughly 100F, from shop at 65 to 150, and the bearing internal size grows by about 2.5 thousandths. Then he claims that the bearing clearance grew by that much “because steel doesn’t expand”.

But steel does expand, it just does so at a different rate.

So, call the crank journal 2.0 inches. With 100F increase, same as the block was heated in the video, the crank will expand by 1.4 thousandths.

So, no, the bearing clearance didn’t increase by 2.5 thousands at 150F - the actual clearance grew by 2.5 - 1.4 or about ONE thousandth.

Because he failed to measure the crank expansion, overestimates the clearance expansion by a factor of three.

That is a huge fail.
You're smarter than the average bear.
 
Joined
Oct 6, 2020
Messages
397
Dealing with expansion in aluminum blocks at sustained high HP has always been a challenge that the chevy form factor has down.
You could get Donovan aluminum small block that put out frightening amounts of power for extended intervals with zero problem (until a rod leaves the block) - and even then they can be repaired.

The chevy formula cannot be beat here.
Ain't nothing "chevy" about a Donovan block or any parts installed into one. Please stop it.
 

UncleDave

$50 Site Donor 2023
Joined
Jun 2, 2014
Messages
8,003
Location
Ca.
Ain't nothing "chevy" about a Donovan block or any parts installed into one. Please stop it.

Since gm/chevy heads bolt right on Im going to disagree - thats the form factor thing I mentioned.

Call it "GM small block form factor" if that sounds better to you.
 
Last edited:
Joined
Sep 24, 2020
Messages
689
Location
New Bedford, MA
Tens of millions of cars with billions of miles over the last 30 years running 20 grade oils goes against his conclusions. Also, Lamborghini has not had any engine issues running 40 grade oils on the track. And it seems that many 40 grade oils thin to a 30 grade oil with hard use. I have not had issues running 20 grade oils in all sorts of 600plus BHP engines. I believe this is a poor experiment giving these conclusions.

Ali

PS
I am currently running 0W-5 in my Lincoln Navigator.
How much stress are you putting on your 600plus BHP motors you run the 20 grade oil in driving around town?
 
Joined
Mar 3, 2011
Messages
2,959
Location
California's Central Coast Wine Country
Tens of millions of cars with billions of miles over the last 30 years running 20 grade oils goes against his conclusions. Also, Lamborghini has not had any engine issues running 40 grade oils on the track. And it seems that many 40 grade oils thin to a 30 grade oil with hard use. I have not had issues running 20 grade oils in all sorts of 600plus BHP engines. I believe this is a poor experiment giving these conclusions.

Ali

PS
I am currently running 0W-5 in my Lincoln Navigator.
I think nearly everyone here knows you are a doctor, and a very successful one. Congratulations. Seriously.

I think your spending power is overlooked in these low viscosity discussions. If your Navigator blows its motor I suspect you have the financial power to simply go out and buy a new one that same day, and write a check for it.

This is unlike most of us and as a consequence most of us would not consider running a super low viscosity oil in a vehicle we cannot afford to repair or replace without putting a noticeable dent in our financial resources.

Respectfully,

Scott
 
Joined
May 17, 2009
Messages
19,055
Location
N.H, U.S.A.
I appreciate @Astro14 analysis. Another general note:
Larger bearing clearances can be beneficial in high power, high speed piston engines as the crankshaft will dynamically no longer be running "true" due to extreme side and torsional forces. And the unit will "ring" or "vibrate" at certain speeds and loadings which can lead to bearing contact forces and failure. Certain motorsports engines can have plain bearing clearances 0.0010in. or greater than that of passenger car engines. This is in a world of 1.5>2.5mil clearances. These applied larger clearances and heat will dictate a higher KV lubricant. Nothing too earth-shattering.
-Ken
 
Joined
Nov 5, 2022
Messages
84
Lamborghini recommends 20W-50 for track use or super high temperatures. Not surprising. Some even run 10W-60 with good results.
 
Joined
Oct 6, 2020
Messages
397
I have not had issues running 20 grade oils in all sorts of 600plus BHP engines. I believe this is a poor experiment giving these conclusions.

Ali

PS
I am currently running 0W-5 in my Lincoln Navigator.
If I remember your previous post about running 20 grade oils in "600" plus bhp engines, you were just using the car to putt around town....correct me if I'm wrong.

Yes, you can use that oil if you're just putting around town, but I GUARANTEE that engine was not making "600" plus hp at a cruising speed.

Big difference in oil requirements for a "600" plus hp engine turning 3/4k rpm under 50 percent load and a engine making 600hp at full load running 7k plus rpm.

The force of that combustion cycle and the crank pulling that piston down when not under combustion would eat that 20 grade alive....as well as those bearings.

Try it. Use a 20 grade and go for a spirited drive. Upshifts, downshift, use that car like it was intended. Report back.

MOFT matters. Sure hope your crank and bearings or rods and bearings don't have a Yoda moment and come together.
 
Joined
Oct 6, 2020
Messages
397
Since gm/chevy heads bolt right on Im going to disagree - thats the form factor thing I mentioned.

Call it "GM small block form factor" if that sounds better to you.
Doesn't sound better at all. Just because you can bolt the heads on it, it means nothing. Donovans have a raised cam location, you can get them with different bore spacing, etc etc etc. Nothing Chevy about it at all.

I can bolt LS heads on a SBF, does that make a sbf a LS block form factor???

I can bolt Poncho heads to a BBC. What form factor does that fall under???

Once you hot the aftermarket block option, "form factor" goes out the window as well as Ford, Chevy, etc.

There is no "Chevy" formula, no Ford formula, etc, once you hit the aftermarket for blocks.

One "formula" that seems to stay constant is the FANBOI formula.
 
Joined
Oct 6, 2020
Messages
397
I think nearly everyone here knows you are a doctor, and a very successful one. Congratulations. Seriously.

I think your spending power is overlooked in these low viscosity discussions. If your Navigator blows its motor I suspect you have the financial power to simply go out and buy a new one that same day, and write a check for it.

This is unlike most of us and as a consequence most of us would not consider running a super low viscosity oil in a vehicle we cannot afford to repair or replace without putting a noticeable dent in our financial resources.

Respectfully,

Scott
Man, just because he's a doctor does not mean he's an expert in every other field. It means he's an expert in his. He can afford to try things and pawn his opinion on internet message boards about his "experiments ", however skewed they may be to reflect and validate his opinion.

I don't care about his degree, he actually got his "doctor" behind owned by a few experts in this field.

"Don't let schooling get in the way of your education "
 

UncleDave

$50 Site Donor 2023
Joined
Jun 2, 2014
Messages
8,003
Location
Ca.
Doesn't sound better at all. Just because you can bolt the heads on it, it means nothing. Donovans have a raised cam location, you can get them with different bore spacing, etc etc etc. Nothing Chevy about it at all.

I can bolt LS heads on a SBF, does that make a sbf a LS block form factor???

I can bolt Poncho heads to a BBC. What form factor does that fall under???

Once you hot the aftermarket block option, "form factor" goes out the window as well as Ford, Chevy, etc.

There is no "Chevy" formula, no Ford formula, etc, once you hit the aftermarket for blocks.

One "formula" that seems to stay constant is the FANBOI formula.

You're really going here?

What does Donovan say?

Read the words for us.

As a guy with a different lamborghini designed block ( thats a gen3 viper marinized and built by ILMOR in my avatar and in my boat) Ill stick by the reality that in terms of dollar per HP with minimal problems the Chevy GM form factor cannot be beat.
You can make them ridiculously huge and there are more aftermarket parts available for this form factor than any other.




Screenshot 2022-12-04 at 10.38.54 AM.png

 
Last edited:
Top