"K-Roll-PorscheTamer" (k-roll390)
03/27/2018 at 15:37 • Filed to: dumb questions
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"K-Roll-PorscheTamer" (k-roll390)
03/27/2018 at 15:37 • Filed to: dumb questions | 2
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Is there a difference between slant, and inline engines other than the slant being at an angle? What benefits does a slant engine have over an inline or vice-versa? I know that they’re both technically “inline”, but there’s still a distinction between the two and I wanna know why and how.
HammerheadFistpunch
> K-Roll-PorscheTamer
03/27/2018 at 15:56 |
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not really, other than the fact that their ancillary parts are designed to fit horizontal in parts. I mean, most transverse engines are “slant” in that they are installed canted
Smallbear wants a modern Syclone, local Maple Leafs spammer
> K-Roll-PorscheTamer
03/27/2018 at 15:58 |
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Lower hood height, and that’s about it
RamblinRover Luxury-Yacht
> K-Roll-PorscheTamer
03/27/2018 at 16:01 |
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The technical definition is probably that the bearing caps/bottom of block are not orthogonal to the bore orientation. As to advantages, disadvantages, whatever, I think it’s mostly down to packaging. A slant (particularly OHC) is shorter and wider, so more popular in low hood applications or where a turbo should be fitted without making the package lopsided. It also might be required by the internals dimensions - a long stroke, for example. A traditional straight six is usually taller, but with American style rocker oiling and engine building, simpler to assemble and less likely to leak, to a point - and works well with narrow, long, and tall bays. Big sedans and trucks, lots of room to work on them.
crowmolly
> K-Roll-PorscheTamer
03/27/2018 at 16:02 |
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Inline can be shorter, but will be wider.
Might be able to make a case for piston wear/loads being different.
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K-Roll-PorscheTamer
> RamblinRover Luxury-Yacht
03/27/2018 at 16:13 |
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These are the answers I love Oppo for!
Shift24
> K-Roll-PorscheTamer
03/27/2018 at 16:23 |
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They are virtrally the same but I remember something about how depending on rotation as it fires, gravity helps/hurts its rotation. Granted if it is true, the affect is very very miniscule and more about hood line but it’s just something I saw
and 100 more
> K-Roll-PorscheTamer
03/27/2018 at 16:28 |
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Oppos who know better, please feel free to correct me here...
An inline engine and a “slant” engine are not the same. The most obvious difference being that an inline engine has a crossflow head (intake on one side, exhaust on the other, like 90% of the engines you’ve ever seen), whereas a slant engine (e.g. the Chrysler Slant-6) actually has the exhaust and intake runners running next to each other and attached to the same side of the head. Slant engines, because of this, also have different oiling and cooling configurations than a standard inline configuration, I believe the pistons are asymmetrical (larger skirt on the down-side).
I know older inline BMW engines were often tilted, as were some Honda engines (mid-80s to late-90s) were leaned back toward the firewall for a lowered hoodline... These were NOT “slant” engines however.
https://www.allpar.com/slant6.html
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RamblinRover Luxury-Yacht
> K-Roll-PorscheTamer
03/27/2018 at 16:37 |
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Another thing to think about - when the predominant setup for an inline was with a reverse-flow head, nobody cared that the package was lopsided, because it was so compact. Other than setups which invented problems for themselves by having a low hood, even going flathead to OHV wasn’t a problem. The induction was almost always taller than the block anyway.
Here’s a ‘53 Chrysler with a flathead:
A ‘48 Chevy with a stovebolt (OHV)
Some industrial FERDs and others had updraft carburetors for compact installations, but until the long’n’low trends in bodywork showed up, the valve cover was not usually the tallest thing.
Ford, as hoods started to become confining, was completely rational and didn’t do anything weird with their induction at all. Ha! Just kidding.
To be fair, though, they were sort of copying Hudson from earlier in the ‘50s, just backwards, because the Mileage Maker is not a flathead:
That same year (‘59), Chrysler rolled out their Slant Six, which, if I’m honest, didn’t actually need to be the way it was for packaging except to be more narrow on the left and allow long runners in the same size package.
If you’ll notice something, it’s actually a detriment to have a reverse-flow head slant engine, because it means it’s a little harder to pipe the exhaust out of the compartment. A Slant 6 exhaust manifold is extremely fucky:
...because it’s set up like a traditional reverse flow manifold with a heat riser to the intake, and has to reach the intake and past the side of the block.
Crossflow inline engines are wider overall, but they also have an “exhaust side” and an “intake side”. Because you can economize on the manifold design, making them slanty doesn’t necessarily hurt your package width as much, and it’s convenient - intake up, exhaust down.
e36Jeff now drives a ZHP
> and 100 more
03/27/2018 at 16:53 |
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that’s purely engine design, it has nothing to do with inline 6 vs slant 6. In reality there is no difference, they are the same thing. The only reason why we call some engines slant-sixes is because that’s what Chrysler called their inline 6's back in the day. If you want proof of that, look no further than BMW. You’ve likely never heard anyone refer to a BMW engine as a slant-6, yet every modern BMW inline 6 is canted over the the passenger side.
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RamblinRover Luxury-Yacht
> and 100 more
03/27/2018 at 16:56 |
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You probably saw me on this, but there are plenty of inlines from the old days that have reverse flow heads, and plenty of slant/tilted engines from modern times with crossflow. Interesting remark, but I’ve not know the skirt thing to be the case - I know it isn’t with Honda industrial small slant engines, nor does it appear to be the case with the old Mopars. The reasoning is sound, but the thrust on the piston skirt from the simple effort of running dwarfs any effects from gravity and blows any kind of asymmetric oiling effect out of the water.
I am not aware of anything that makes a “slant” engine definitionally distinct from a “tilted” engine, because in both cases the setup is designed for a “leaning” bore when the oil pan surface is flat.
Cooling and oiling more directly resemble a V-engine than an upright inline in some respects, but it’s a matter of details. Position of galleys, drain holes, etc.
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e36Jeff now drives a ZHP
> K-Roll-PorscheTamer
03/27/2018 at 16:58 |
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There is no distinction to them. a slant-six is simply someone referring to an inline six that isn’t vertical. An inline 6 is an inline 6 regardless of its orientation. The slant is done to fit under lower hoods than a vertical engine would allow.
Full of the sound of the Gran Fury, signifying nothing.
> K-Roll-PorscheTamer
03/27/2018 at 17:00 |
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Sometimes an inline can be a slant, without the changes that normally delineate the two. This is from a VW Vanagon Diesel, with the typical VW inline-4 cranked way over to fit under the engine cover. Just check out that oil pan to evaluate the angle at which this thing sits,
RacinBob
> K-Roll-PorscheTamer
03/27/2018 at 19:56 |
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There is also the Pontiac Tempest Slant 4 that was half an 8...
