Rod and Main bearing clearance

[tig1]

I checked out the main, rod, and piston to pin clearance for the Ford Fusion 2.3 and 2.5 engines I now own.

Main: .0007 to .0013 = 6 10 thousandths of an inch.

Rod bearing clearance: .001 to .002 = 1 thousandths of an inch

Piston to wrist pin clearance: .0003 t0 .0006. 3 10 thousandths of an inch.

I also checked the main clearance in a 30 year old Ford 4.0 ( aprox age) and the clearance was about 3 times the clearance of my Ford engines I own now. Something like .0005 to .0022. That's .0017 10 thousandths of an inch. Seems to be a good argument for 20 wt oils.

I would guess these clearances are the same for the Mazda engines as well.

 

[PeterPolyol]

Those clearances came from Hiroshima, so it wouldn't be such a fair comparison to the 4.0L which is a German engine. Not much surprising, really. The Germans value their HTHS and KV, while the Japanese circa 2000s on ward really focused on low HTHS and economy. Different bearing materials too, IIRC

 

[StevieC]

Originally Posted by tig1
I checked out the main, rod, and piston to pin clearance for the Ford Fusion 2.3 and 2.5 engines I now own.

Main: .0007 to .0013 = 6 10 thousandths of an inch.

Rod bearing clearance: .001 to .002 = 1 thousandths of an inch

Piston to wrist pin clearance: .0003 t0 .0006. 3 10 thousandths of an inch.

I also checked the main clearance in a 30 year old Ford 4.0 ( aprox age) and the clearance was about 3 times the clearance of my Ford engines I own now. Something like .0005 to .0022. That's .0017 10 thousandths of an inch. Seems to be a good argument for 20 wt oils.

I would guess these clearances are the same for the Mazda engines as well.

Thank you for this real world evidence tig1, I was chewed apart for the Amsoil article I posted that claimed clearances could be as low as you have measured.

This is going to break BITOG.

 

[OVERKILL]

Originally Posted by tig1
I checked out the main, rod, and piston to pin clearance for the Ford Fusion 2.3 and 2.5 engines I now own.

Main: .0007 to .0013 = 6 10 thousandths of an inch.

Rod bearing clearance: .001 to .002 = 1 thousandths of an inch

Piston to wrist pin clearance: .0003 t0 .0006. 3 10 thousandths of an inch.


For an additional reference, 1985 Ford 302 Windsor:

main bearing
desired 0.0004 to 0.0015 in
allowable 0.0004 to 0.0026 in

conecting rod journal
desired 0.0008 to 0.0015 in
allowable 0.0008 to 0.0026 in

You'll note that the mains are quite similar with rod bearings being even tighter. Desired clearance depends on diameter and width, if it was as simple as your posit, the 302 would be an ideal candidate for 0w-8. As with many things, this is a far more complex topic than it is often presented.

 

[demarpaint]

Originally Posted by OVERKILL
Originally Posted by tig1
I checked out the main, rod, and piston to pin clearance for the Ford Fusion 2.3 and 2.5 engines I now own.

Main: .0007 to .0013 = 6 10 thousandths of an inch.

Rod bearing clearance: .001 to .002 = 1 thousandths of an inch

Piston to wrist pin clearance: .0003 t0 .0006. 3 10 thousandths of an inch.


For an additional reference, 1985 Ford 302 Windsor:

main bearing
desired 0.0004 to 0.0015 in
allowable 0.0004 to 0.0026 in

conecting rod journal
desired 0.0008 to 0.0015 in
allowable 0.0008 to 0.0026 in

You'll note that the mains are quite similar with rod bearings being even tighter. Desired clearance depends on diameter and width, if it was as simple as your posit, the 302 would be an ideal candidate for 0w-8. As with many things, this is a far more complex topic than it is often presented.


Exactly.

 

[StevieC]

I think we need to trust the engineers that made the vehicle and this is proven by the longer OCI's that tig1 does and with low viscosity oils. His engines haven't shown any reason not to decrease the OCI or increase the oil weight and has decent miles to prove it along with others here.

I think this is more trust worthy than what folks on an oil forum think is best. Heck we even have really high mileage engines on here run on these 20wt's and they have all survived just fine well past tig1's mileages.

I think it's overblown outside of certain applications that need it. Towing/Turbo's/racing and the like.

 

[Bryanccfshr]

Are we trying to compare iron block and cast iron crank clearances to an engine with a forged crank and aluminum block?

"Aluminum blocks expand more than iron blocks, so many engine builders will tighten up the main bearing clearance when building the engine at room temperature, knowing that when the engine attains operating temperature, the clearance will have expanded"

https://www.enginelabs.com/engine-tech/engine/clearing-the-air-on-bearing-clearances/

 

[oghl]

What are the diameters of these bearings? What are the maximum bearing speeds they will see? What are the expected operating temperatures? Are the rods/cranks/etc expected to have some flex?

There are many more variables that should be part of the consideration, in order to reach a valid conclusion.

 

[OVERKILL]

Originally Posted by StevieC
I think we need to trust the engineers that made the vehicle and this is proven by the longer OCI's that tig1 does and with low viscosity oils. His engines haven't shown any reason not to decrease the OCI or increase the oil weight and has decent miles to prove it along with others here.

I think this is more trust worthy than what folks on an oil forum think is best. Heck we even have really high mileage engines on here run on these 20wt's and they have all survived just fine well past tig1's mileages.

I think it's overblown outside of certain applications that need it. Towing/Turbo's/racing and the like.

But that's not what the topic of the OP was, nor your snipe at the direction your Amsoil thread went, where this topic was discussed in detail. I even posted the exact same clearance numbers for the 302 in that very thread. You obviously didn't come away from that discussion with more knowledge about the topic than when you made it, otherwise your initial post in this thread would have been one of education rather than sour grapes.

Bearing clearances haven't changed significantly. We had boats that spec'd 20W back in the day for cold weather operation and many tractor manuals recommended thinning your oil with kerosene in colder months. Engines are generally quite tolerant as to viscosity selection which is why many engines were safely back-spec'd to 5w-20 when it became widely available. Architectural changes such as block rigidity (deep skirting, multi-bolt mains) has been where the effort was placed, since things moving around has a negative impact on component life, particularly when viscosity is reduced.

Does Ford have a generally solid track record of performance in applications spec'ing xW-20 lubricants in the past two decades or so? Yes. Have bearing clearances changed to accommodate that? No. That's why the Coyote was able to simultaneously spec 5w-20 and 5w-50 depending on the trim level of your Mustang GT, which I also posted in your thread. Have there been structure changes to these engines to facilitate this success? Yes. Both the HEMI (which simultaneously spec's 5w-20 and 0w-40) and the Modular family have deep-skirted blocks with multi-bolt mains designed to provide an extremely rigid structure to house the crankshaft.

So no, the argument that the bearing clearances presented in the OP doesn't make a case for 20-weight oils, just as remarking on the rod bearing clearances for the 302 doesn't make a case for 0w-8.

His track record of performance using the lubricant spec'd by the manufacturer validates Ford/Mazda's designs and testing that resulted in them determining that xW-20 was an appropriate lubricant for these engines under the intended and expected operating conditions, not the fact that the rod bearing clearances are tighter than the Cologne 4.0L V6 or looser than the ancient Windsor, it's a red herring.

 

[oghl]

Here's another thought/question (please check my math):

0.001 inch ~= 25.4 um.
I saw in other posts that oil filters are good for filtering out 20-30um particles. So would the 0.001 inch bearing clearance become larger in short order because of the larger particles left in the oil?

 

[PeterPolyol]

Most aluminum blocks will have iron journal bearing carriers


Originally Posted by OVERKILL


You'll note that the mains are quite similar with rod bearings being even tighter. Desired clearance depends on diameter and width, if it was as simple as your posit, the 302 would be an ideal candidate for 0w-8. As with many things, this is a far more complex topic than it is often presented.

It might be a candidate for thin oils, except for the other lacking things..... surface finishing (microfinishing, induction hardened from the factory on a 302? lol), forged steel vs cast iron, metallurgy (iron alloy), and most likely a sub-par oiling system by today's standard. If a 302 has all that, plus minimal manufacturing part varience and a top notch oiling system like a newer engine series, why not then. Not that a 302 is a tighter or looser engine than the Duratec, it's just got a wider (see: sloppier) tolerance. There's not a chance 302 were realistically being pumped out with the narrow, consistent variations than engines leaving the assy line now days are

 

[demarpaint]

Originally Posted by OVERKILL
Originally Posted by StevieC
I think we need to trust the engineers that made the vehicle and this is proven by the longer OCI's that tig1 does and with low viscosity oils. His engines haven't shown any reason not to decrease the OCI or increase the oil weight and has decent miles to prove it along with others here.

I think this is more trust worthy than what folks on an oil forum think is best. Heck we even have really high mileage engines on here run on these 20wt's and they have all survived just fine well past tig1's mileages.

I think it's overblown outside of certain applications that need it. Towing/Turbo's/racing and the like.

But that's not what the topic of the OP was, nor your snipe at the direction your Amsoil thread went, where this topic was discussed in detail. I even posted the exact same clearance numbers for the 302 in that very thread. You obviously didn't come away from that discussion with more knowledge about the topic than when you made it, otherwise your initial post in this thread would have been one of education rather than sour grapes.

Bearing clearances haven't changed significantly. We had boats that spec'd 20W back in the day for cold weather operation and many tractor manuals recommended thinning your oil with kerosene in colder months. Engines are generally quite tolerant as to viscosity selection which is why many engines were safely back-spec'd to 5w-20 when it became widely available. Architectural changes such as block rigidity (deep skirting, multi-bolt mains) has been where the effort was placed, since things moving around has a negative impact on component life, particularly when viscosity is reduced.

Does Ford have a generally solid track record of performance in applications spec'ing xW-20 lubricants in the past two decades or so? Yes. Have bearing clearances changed to accommodate that? No. That's why the Coyote was able to simultaneously spec 5w-20 and 5w-50 depending on the trim level of your Mustang GT, which I also posted in your thread. Have there been structure changes to these engines to facilitate this success? Yes. Both the HEMI (which simultaneously spec's 5w-20 and 0w-40) and the Modular family have deep-skirted blocks with multi-bolt mains designed to provide an extremely rigid structure to house the crankshaft.

So no, the argument that the bearing clearances presented in the OP doesn't make a case for 20-weight oils, just as remarking on the rod bearing clearances for the 302 doesn't make a case for 0w-8.

His track record of performance using the lubricant spec'd by the manufacturer validates Ford/Mazda's designs and testing that resulted in them determining that xW-20 was an appropriate lubricant for these engines under the intended and expected operating conditions, not the fact that the rod bearing clearances are tighter than the Cologne 4.0L V6 or looser than the ancient Windsor, it's a red herring.


Merry Christmas, and thanks for shedding light on/repeating what has been said over and over again when these topics come up.

 

[OVERKILL]

Originally Posted by PeterPolyol
Most aluminum blocks will have iron journal bearing carriers


Originally Posted by OVERKILL


You'll note that the mains are quite similar with rod bearings being even tighter. Desired clearance depends on diameter and width, if it was as simple as your posit, the 302 would be an ideal candidate for 0w-8. As with many things, this is a far more complex topic than it is often presented.

It might be a candidate for thin oils, except for the other lacking things..... surface finishing (microfinishing, induction hardened from the factory on a 302? lol), forged steel vs cast iron, metallurgy (iron alloy), and most likely a sub-par oiling system by today's standard. If a 302 has all that, plus minimal manufacturing part varience and a top notch oiling system like a newer engine series, why not then. Not that a 302 is a tighter or looser engine than the Duratec, it's just got a wider (see: sloppier) tolerance. There's not a chance Windsors were realistically being pumped out with the narrow, consistent variations than engines leaving the assy line now days are


Not only that, but the flimsy 2-bolt mains on the Windsor and thin wall casting guaranteed that your junk was moving around.

The 4.6L (and 5.4L) featured a cast crank as well (in most applications), but of course spec'd 5w-20. The structure of the block was one of the big differences.

 

[fdcg27]

Originally Posted by StevieC
I think we need to trust the engineers that made the vehicle and this is proven by the longer OCI's that tig1 does and with low viscosity oils. His engines haven't shown any reason not to decrease the OCI or increase the oil weight and has decent miles to prove it along with others here.

I think this is more trust worthy than what folks on an oil forum think is best. Heck we even have really high mileage engines on here run on these 20wt's and they have all survived just fine well past tig1's mileages.

I think it's overblown outside of certain applications that need it. Towing/Turbo's/racing and the like.

Which engineers should we trust from which market?
It's been well known here for years that different grades are recommended in different markets.
The simple fact is that most engines will run happily on a variety of grades and this has always been the case.
20W-20 was among the recommended grades for warm ambient temperatures here before I was even born.

 

[PeterPolyol]

Originally Posted by OVERKILL
Originally Posted by PeterPolyol
Most aluminum blocks will have iron journal bearing carriers


Originally Posted by OVERKILL


You'll note that the mains are quite similar with rod bearings being even tighter. Desired clearance depends on diameter and width, if it was as simple as your posit, the 302 would be an ideal candidate for 0w-8. As with many things, this is a far more complex topic than it is often presented.

It might be a candidate for thin oils, except for the other lacking things..... surface finishing (microfinishing, induction hardened from the factory on a 302? lol), forged steel vs cast iron, metallurgy (iron alloy), and most likely a sub-par oiling system by today's standard. If a 302 has all that, plus minimal manufacturing part varience and a top notch oiling system like a newer engine series, why not then. Not that a 302 is a tighter or looser engine than the Duratec, it's just got a wider (see: sloppier) tolerance. There's not a chance Windsors were realistically being pumped out with the narrow, consistent variations than engines leaving the assy line now days are


Not only that, but the flimsy 2-bolt mains on the Windsor and thin wall casting guaranteed that your junk was moving around.

The 4.6L (and 5.4L) featured a cast crank as well (in most applications), but of course spec'd 5w-20. The structure of the block was one of the big differences.



Good points
Yea, bearing clearance isn't an immediate license for thin lubes that's for sure.. but looks like tig found that one supporting example this time with the 4.0L that specced 30 right till EOL. May never know officially the exact reasoning (oiling system etc) but the clearance spec seems to favour higher visco

 

[OVERKILL]

Originally Posted by PeterPolyol
Originally Posted by OVERKILL
Originally Posted by PeterPolyol
Most aluminum blocks will have iron journal bearing carriers


Originally Posted by OVERKILL


You'll note that the mains are quite similar with rod bearings being even tighter. Desired clearance depends on diameter and width, if it was as simple as your posit, the 302 would be an ideal candidate for 0w-8. As with many things, this is a far more complex topic than it is often presented.

It might be a candidate for thin oils, except for the other lacking things..... surface finishing (microfinishing, induction hardened from the factory on a 302? lol), forged steel vs cast iron, metallurgy (iron alloy), and most likely a sub-par oiling system by today's standard. If a 302 has all that, plus minimal manufacturing part varience and a top notch oiling system like a newer engine series, why not then. Not that a 302 is a tighter or looser engine than the Duratec, it's just got a wider (see: sloppier) tolerance. There's not a chance Windsors were realistically being pumped out with the narrow, consistent variations than engines leaving the assy line now days are


Not only that, but the flimsy 2-bolt mains on the Windsor and thin wall casting guaranteed that your junk was moving around.

The 4.6L (and 5.4L) featured a cast crank as well (in most applications), but of course spec'd 5w-20. The structure of the block was one of the big differences.



Good points
Yea, bearing clearance isn't an immediate license for thin lubes that's for sure.. but looks like tig found that one supporting example this time with the 4.0L that specced 30 right till EOL. May never know officially the exact reasoning (oiling system etc) but the clearance spec seems to favour higher visco


Yeah, the whacky Cologne engine with its front and rear timing chains was certainly an exception to the "back-spec everything to 5w-20" thing Ford had going. They even back-spec'd the 302

 

[StevieC]

My point is we shouldn't be playing engineer here. If the engineer calls for a 20wt, use a 20wt. If they call for a 30wt use a 30wt. But blanket statements here of using 30 or 40 weights in applications that call for 20wts because it will somehow offer better protection because of international manuals allowing for 30wts to be used is just ridiculous.

Tig's experiences along with others here using what the manufacturer calls for proves that.

That said I will report back when I get to 1/2 a million kilometers again in the PentaStar which shouldn't take too long considering I have gotten to 14K already. But I'm sure that will be explained away with "Yeah but those are highway miles"

or some other excuse followed by and if you think it was Amsoil that gave your those miles any shelf oil would have done the same as I'm sure will be the case if I'm lucky enough to get to 1,000,000km or 1.6M KM.

It's hilarious because over a decade ago it was the 20w50 crowd against the 30wt crowd, now it's the 30wt / 0w40 crowd over the 20wt folks.

 

[demarpaint]

Originally Posted by StevieC
My point is we shouldn't be playing engineer here. If the engineer calls for a 20wt, use a 20wt. If they call for a 30wt use a 30wt. But blanket statements here of using 30 or 40 weights in applications that call for 20wts because it will somehow offer better protection because of international manuals allowing for 30wts to be used is just ridiculous.

Tig's experiences along with others here using what the manufacturer calls for proves that.

That said I will report back when I get to 1/2 a million kilometers again in the PentaStar which shouldn't take too long considering I have gotten to 14K already. But I'm sure that will be explained away with "Yeah but those are highway miles"

or some other excuse followed by and if you think it was Amsoil that gave your those miles any shelf oil would have done the same as I'm sure will be the case if I'm lucky enough to get to 1,000,000km or 1.6M KM.

I get the feeling you're looking for an argument. People have gotten great results bumping up a grade too, and thinking out of the box. It's Christmas, enjoy the day. Save the fighting for tomorrow. LOL Over and out for now........

 

[OVERKILL]

Also, FWIW, the BMW S62 (which spec'd 10w-60) apparently had rod bearing clearances of 0.029mm to 0.067mm; 0.0011 to 0.0026 thou, VERY similar to the Duratec.

 

[StevieC]

Not looking for an argument, but the nonsense here drives me crazy. Especially when real world evidence contradicts it. Enjoy your day as well.