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PostPosted: Fri May 08, 2020 10:24 am 
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Thank you. Glad you like them. Yes I want them to learn something, that they will never learn in school. I may have said this in past, but also making a video history, so that when I am dead and gone, they can go back and see us all working together and remember their old Dad....

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PostPosted: Mon May 11, 2020 7:13 am 
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Soon.....
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PostPosted: Thu May 14, 2020 8:14 pm 
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Coooool Get'r Done! 8-)

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PostPosted: Fri May 15, 2020 9:17 am 
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Location: Stranded in Iowa - Better get the Breakdown squad out
blykins wrote:
........However, when you look at the coefficient of expansion, the Supracast is much higher than cast iron, almost 3 times as much. The thermal expansion is the clincher of all aluminum alloys.

I think the issue is aluminum has 3x the modulus of elasticity compared to iron (Young’s modulus), not that it thermally expands more. The latter can be addressed with how you set the engine up.

While it’s true that the coefficient of linear expansion of aluminum is greater than iron it is not 3x greater. Irons and steels are between 6 and 7 microstrain (in/in/F) and aluminum is between 12-13. But even at the extreme 13 does not equal 3 x 6. The difference between the two on the average for typical engine materials is about 6 microstrain. So for every 100F of temperature rise you could expect the dissimilar materials to experience about .0006” difference in growth per inch. So for a 4” bore about .0024” and for a 3” main, about 3/4 that. This assumes the two parts are always at the same temperature at any point in time as they heat or cool.

I think most people don’t appreciate how much lash changes from cold to hot in an all aluminum pushrod engines. You can compensate by setting them up tighter cold but for solid lifter engines it’s real tight and can take some real balls to do so, so you have to be very careful starting and bringing them to temp.

The materials in the vicinity of main bearings probably are about the same temperature at any one time. A piston and a cylinder wall probably are not as the piston will always see more temperature rise and expand even more. I don’t think growth in bearing clearance is particularly important to the subject of power changes. It certainly is for oil control and longevity but as you mention, you can just account for it with initial clearance.

I’ve heard the argument that thermal growth is the reason for power loss due to ring sealing and cylinder movement. Maybe if it wasn’t properly addressed in initial clearance but the ring argument doesn’t seem to consider the piston is aluminum and the cylinder iron. So the piston not only grows more than the cylinder wall diameter dues to the difference in coefficient of expansion, the average piston temperature will increase more than the cylinder wall causing the piston to grow even more so the operating clearance actually decreases as an aluminum pistoned iron block engine comes to temperature. In a drag racing engine that doesn’t become heat soaked, you may not see the full affect but in street and endurance engines you will.

The tensile strength of aluminum and iron are compared in the discussion above but the real property of concern is Young’s modulus which in lay terms relates to how stiff a material is….stress/strain. Aluminum does have 3x the elastic modulus of iron so it will exhibit 3x more strain for a given state of stress. But this is only true if the structures are identical in shape. You can account for this by adding more material where needed. Problem is, you can’t always do that when constrained to specific engine architecture. It’s also the case that aluminum is nearly 3x lighter than iron (not quite). But if you added three times the aluminum to achieve the same stiffness in the block, it would be 3x heavier and you haven’t gained anything by using a lighter material.

One other thing the whole change in piston clearance discussion neglects is the fact that (almost) all aluminum blocks have iron or in some cases alloy cylinder liners that are usually interference/shrink fit. Compared to just a bare aluminum cylinder this will affect (reduce) the growth of the cylinder wall compared to initial cold set up clearance due to both the fact it’s already in compression, and the liner has both a lower elastic modulus and coefficient of liner thermal expansion.

For heat management, in drag race engines it probably doesn’t matter but in endurance engines you’re probably better off with aluminum because although it will absorb more heat, it will also release more heat to the cooling system but usually means you need to move more coolant and have a bigger radiator for a given power level.
blykins wrote:
I have seen about 40 hp difference on Windsors and FEs with the block being the only variable......... I'm an engine builder but also a degreed mechanical engineer and spent more time than I want to remember in school with heat transfer, material properties, etc. Aluminum will never equal cast iron or steel in this aspect.

I’ve built a number of engines of all kinds over my life but don’t think that makes me an engine builder……..just channeling my inner nerd for ya Brent….engineer to engineer, and always the contrarian. -Your results may vary :D

Best,
Kelly


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PostPosted: Sun May 17, 2020 7:25 pm 
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That Mr. Coffield, was a dissertation on metallurgy, that I have never heard in detail. A lot was over my head, that was for sure. I know though that this aluminum alloy does not expand as others. The first trackboss was just dynoed, and for example, lash was set to .012 cold, when warm they increased to .015, one was .018, the main bearing clearance was no different than with iron block. Brent said he saw 40 hp, who knows anything is possible. Bottom line from Darin Morgan, is that you may loose 20hp between aluminum v iron, that is about it. Hell with the weight off the front end, be like gaining double that, when you figure in scaling and weight transfer. In truth, what does it matter, zip. Not sure where this debate of aluminum blocks being so terrible came from. I know Brent does not like them, that is for sure. If they were so weak, and power robbers why do all the big dogs with high Hp run them? I have a goal of 850hp, Morgan is helping me with this, and said, no problem, I can make that easy, he said. "withhim porting BT 3.6, designing a cam, from his 2000 lobe profile library, and Scott Cook making one of his race intakes, I got to trust him. He said I have to bore lifter bushings to .904, and 55 mm bearings, don't need roller ones. He said be really hard to try and make 850hp, without 55mm/.904 or .937 keyway. The stock lifters would be too weak, said they would turn to dust, lol. I have the 55 all ready, so it is going to machine shop after I get it deburred to my liking.

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PostPosted: Mon May 18, 2020 7:31 am 
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DragBoss wrote:
He said be really hard to try and make 850hp, without 55mm/.904 or .937 keyway. The stock lifters would be too weak, said they would turn to dust, lol. I have the 55 all ready, so it is going to machine shop after I get it deburred to my liking.


Is that because of the ramp rate on the lobe?

I doubt he'll steer you wrong, and he's got enough experience that I'd trust his judgement. If he says they're too small, I'd believe him.


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PostPosted: Mon May 18, 2020 10:51 am 
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Yes that is exactly right. I never knew that. the 409, I am finishing up, was making 752, he had ported heads and intake, so he said expect close to 10% increase. You do the math. It will be at the limit, I bet. The block will only last so long, key is to stop before it fails. All I want is a 9.50, then done with.

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PostPosted: Tue May 19, 2020 6:03 pm 
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KCoffield wrote:
blykins wrote:
........However, when you look at the coefficient of expansion, the Supracast is much higher than cast iron, almost 3 times as much. The thermal expansion is the clincher of all aluminum alloys.

I think the issue is aluminum has 3x the modulus of elasticity compared to iron (Young’s modulus), not that it thermally expands more. The latter can be addressed with how you set the engine up.

While it’s true that the coefficient of linear expansion of aluminum is greater than iron it is not 3x greater. Irons and steels are between 6 and 7 microstrain (in/in/F) and aluminum is between 12-13. But even at the extreme 13 does not equal 3 x 6. The difference between the two on the average for typical engine materials is about 6 microstrain. So for every 100F of temperature rise you could expect the dissimilar materials to experience about .0006” difference in growth per inch. So for a 4” bore about .0024” and for a 3” main, about 3/4 that. This assumes the two parts are always at the same temperature at any point in time as they heat or cool.

I think most people don’t appreciate how much lash changes from cold to hot in an all aluminum pushrod engines. You can compensate by setting them up tighter cold but for solid lifter engines it’s real tight and can take some real balls to do so, so you have to be very careful starting and bringing them to temp.

The materials in the vicinity of main bearings probably are about the same temperature at any one time. A piston and a cylinder wall probably are not as the piston will always see more temperature rise and expand even more. I don’t think growth in bearing clearance is particularly important to the subject of power changes. It certainly is for oil control and longevity but as you mention, you can just account for it with initial clearance.

I’ve heard the argument that thermal growth is the reason for power loss due to ring sealing and cylinder movement. Maybe if it wasn’t properly addressed in initial clearance but the ring argument doesn’t seem to consider the piston is aluminum and the cylinder iron. So the piston not only grows more than the cylinder wall diameter dues to the difference in coefficient of expansion, the average piston temperature will increase more than the cylinder wall causing the piston to grow even more so the operating clearance actually decreases as an aluminum pistoned iron block engine comes to temperature. In a drag racing engine that doesn’t become heat soaked, you may not see the full affect but in street and endurance engines you will.

The tensile strength of aluminum and iron are compared in the discussion above but the real property of concern is Young’s modulus which in lay terms relates to how stiff a material is….stress/strain. Aluminum does have 3x the elastic modulus of iron so it will exhibit 3x more strain for a given state of stress. But this is only true if the structures are identical in shape. You can account for this by adding more material where needed. Problem is, you can’t always do that when constrained to specific engine architecture. It’s also the case that aluminum is nearly 3x lighter than iron (not quite). But if you added three times the aluminum to achieve the same stiffness in the block, it would be 3x heavier and you haven’t gained anything by using a lighter material.

One other thing the whole change in piston clearance discussion neglects is the fact that (almost) all aluminum blocks have iron or in some cases alloy cylinder liners that are usually interference/shrink fit. Compared to just a bare aluminum cylinder this will affect (reduce) the growth of the cylinder wall compared to initial cold set up clearance due to both the fact it’s already in compression, and the liner has both a lower elastic modulus and coefficient of liner thermal expansion.

For heat management, in drag race engines it probably doesn’t matter but in endurance engines you’re probably better off with aluminum because although it will absorb more heat, it will also release more heat to the cooling system but usually means you need to move more coolant and have a bigger radiator for a given power level.
blykins wrote:
I have seen about 40 hp difference on Windsors and FEs with the block being the only variable......... I'm an engine builder but also a degreed mechanical engineer and spent more time than I want to remember in school with heat transfer, material properties, etc. Aluminum will never equal cast iron or steel in this aspect.

I’ve built a number of engines of all kinds over my life but don’t think that makes me an engine builder……..just channeling my inner nerd for ya Brent….engineer to engineer, and always the contrarian. -Your results may vary :D

Best,
Kelly


Nothing wrong with being a contrarian, as long as you're just contrary to opinion and not actual facts/data. :) I'm trying to catch up on all of my 'foruming' right now but I'll look back at the data for the aluminum that Tim Meyer uses and some cast iron. I generally don't exaggerate for the purpose of an argument, so if I found data that was "almost 3X", then I'm sure it was almost 3 times. :)

Over several different engine platforms, there's a consistent rule that aluminum gives up horsepower to iron. A couple of reasons can be accounted for at the time of the build (compression ratio change, etc.) but one major reason can't be accounted for: ring seal. It's not a matter of piston to cylinder wall, it's a matter of sleeve to surrounding material. As you know, cylinders must be very rigid for optimal ring seal. That's why we spend so much time with torque plates, using the correct head fastener when honing, etc. If the aluminum around the sleeve is moving at a different rate than the sleeve itself, then the cylinder will distort. I've plate honed aluminum blocks, assembled, dyno'd, then disassembled and have seen instances of "shadows" in the cylinders, just as though you hadn't plate honed at all. Now, I haven't done this with the Trackboss block, but the inherent nature of an aluminum block with a sleeve of another material will be consistent. We've had this conversation on multiple forums, with Speedtalk being one of them. I recall one of the dirt track builders making the comment that his all-aluminum SBC dirt track engines had trouble with pulling vacuum on dry sump applications, while his iron block combinations would allow for a lot of crankcase vacuum. I believe that Darin Morgan made the comment that Reher-Morrison saw a significant loss of horsepower and increased blow-by with aluminum block engines and it seemed to get better after the second or third freshen up.

Regardless, I'm convinced that the material being used here may be superior to other alloys, but the traits of aluminum that cause the issues we're discussing here will always be present, no matter the name of the aluminum alloy.

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PostPosted: Tue May 19, 2020 6:12 pm 
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DragBoss wrote:
That Mr. Coffield, was a dissertation on metallurgy, that I have never heard in detail. A lot was over my head, that was for sure. I know though that this aluminum alloy does not expand as others. The first trackboss was just dynoed, and for example, lash was set to .012 cold, when warm they increased to .015, one was .018, the main bearing clearance was no different than with iron block. Brent said he saw 40 hp, who knows anything is possible. Bottom line from Darin Morgan, is that you may loose 20hp between aluminum v iron, that is about it. Hell with the weight off the front end, be like gaining double that, when you figure in scaling and weight transfer. In truth, what does it matter, zip. Not sure where this debate of aluminum blocks being so terrible came from. I know Brent does not like them, that is for sure. If they were so weak, and power robbers why do all the big dogs with high Hp run them? I have a goal of 850hp, Morgan is helping me with this, and said, no problem, I can make that easy, he said. "withhim porting BT 3.6, designing a cam, from his 2000 lobe profile library, and Scott Cook making one of his race intakes, I got to trust him. He said I have to bore lifter bushings to .904, and 55 mm bearings, don't need roller ones. He said be really hard to try and make 850hp, without 55mm/.904 or .937 keyway. The stock lifters would be too weak, said they would turn to dust, lol. I have the 55 all ready, so it is going to machine shop after I get it deburred to my liking.


The big dogs with high hp use them because they are easy to repair. Aluminum is a lot easier to weld than cast iron, plus sleeves are able to be removed and replaced when necessary. BTW, I've never said aluminum blocks are weak. They are just structurally less rigid.

Lash grows extensively with heat with an all-aluminum engine. The amount of growth will depend on how hot the engine gets. If the water and oil temps don't get high then it's not going to grow as much as a heat-soaked engine that's been driven on the street, road race course, etc. If you're dyno'ing at 130-140° water temp and the oil temp isn't getting that hot, you're not going to see a lot of growth. Doesn't mean it won't happen. Same with main bearing clearances.

To me, aluminum blocks have their place. I just don't believe that most bracket classes are that place. That's my opinion. Even if you lose 100 lbs of weight, you will still lose 30-40 hp and then the delta isn't that great (I'd rather have the horsepower), especially when you're looking at a $2500 block versus a $6000 block. I would never ask one of my guys to spend that much money for one, just because the pros don't outweigh the cons. Good news is that it's a free country and guys are free to do whatever they want. :) However, I know quite a few engine builders, who when given the choice, would not choose an aluminum block over cast iron. I have seen 40 hp differences at the 700 hp level. A few other engine builder buddies (Rabotnick, Lance Smith, Blair Patrick, etc.) have also seen as much difference.

I'm not sure where all the debate has come from either. We've had this discussion on various forums and the majority of engine builders are aware of the inherent natures of aluminum blocks, but the end users are generally the ones who take offense to the discussions. My guess is that the average DIY'er who wants an aluminum block and spends $6000-7000 on one doesn't really want to hear that they are inferior in some ways to cast iron. I can understand the novelty to the average guy though. Aluminum blocks just aren't as plentiful and when we're dealing with Windsors, Clevelands, and FE's, you just don't see a lot of aluminum blocks. At the end of the day, you want what you want, and if you want to buy an aluminum block, you buy an aluminum block. I'm not trying to poo-poo on anyone's decisions, but I just feel like most guys aren't informed. I had a gentleman call to order a 496ci FE the other day and started the conversation by saying he wanted a Pond aluminum block. I explained to him that I generally see about 40 hp difference between cast iron and aluminum and the blocks were $2000-3000 more. He quickly changed his mind.

Bottom line, Tim, is that if you are happy, THAT'S ALL THAT MATTERS!!! And I'm happy that you got what you wanted.

I agree on the lifter bore diameter. I usually use .904" diameter lifters at least. Guys are kinda getting away from roller cam bearings. The larger diameter Babbitt bearings seem to work very well. My 9000 rpm 1200 hp pulling truck engines with 1300 lbs of open spring pressure use Babbitt. The key is to check the bearing clearance like you would a main/rod bearing. A 55mm cam journal needs about .0025-.003" oil clearance. I use a mic and a bore mic and check the clearances and then polish the cam journals to get clearance if necessary. High spring pressures put a lot of loading on the cam bearings. FWIW, I always green Loctite the cam bearings in, or pin them on aluminum blocks.

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PostPosted: Wed May 20, 2020 3:52 am 
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BTW, as an aside....

Certainly not to detract from Darin Morgan's knowledge or talent, but just to shine light on the process: I do believe he uses Comp Cams to grind his camshafts.....or at least he did a couple of years ago.

The 2000 lobes that he has access to is essentially the Comp Cams lobe catalog:

https://www.compcams.com/lobe-catalog

Reher-Morrison doesn't grind their own cams, so they do like a lot of builders and reach out to cam grinders (Comp, Bullet, etc.) to grind their cams for them, based off of a pattern of lobes, LSA, ICL, etc.

It's the same way I do it.

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