Will we ever see a pushrod-4 in a production car again?

Seems to me that GM is missing the mark and overdoing it with their current 4-banger lineup that just don't do the well (in terms of the lower-displacement turbo engines - their 2.0Ts are fine with the Ecotec).

With a pushrod-4, seems like you'd get that low-end torque that people would like as well as an even more simple and compact motor that could be re-used for both FWD/RWD applications.

S/o to Subaru's EA81 and GM's 2.2

Highly unlikely.

The reason pushrod engines have "low end torque" is because they can't spin as fast as OHC engines, so the cam profiles are set up the the ability of the system.  Which means and OHC  (even a DOHC) engine could have the same low end performance as a pushrod.

But, more important these days, to get any decent performance from the engine, an OHC engine ends up with a lot less friction and rotating inertia- which is really important when it comes to engine efficiency.  And that's the name of the game now.

I also shudder when I hear "more simple"- as a SOHC engine can have less parts, and a simpler assembly.

my buddy just bought a '69 nova that has the original pushrod 4 cyl (I believe it's the original Iron Duke).   i'm going to check it out this weekend.

but i'm guessing that's not what you meant.

In reply to alfadriver :

I would argue that manufacturers are not interested in making SOHC engines over DOHC - can't match that airflow

In reply to Dootz :

I very much agree to that, which makes it even less likely that a pushrod I4 gas motor will ever see it's way into a new car.

In reply to alfadriver :

I’m curious where the cam ends up in space on an in-line pushrod 4?

Also, has anyone played around with composite pushrods to reduce mass/inertia?

In reply to sleepyhead the buffalo :

In the block, next to the crankshaft.  It's a neater set up on a V engine, since it goes into an unused,but available place.  I'm sure that packaging issue is one of the reasons it went away quicker in I4's than other layouts.

Ok, that’s what came to mind... but I wasn’t sure if there was some trick cam-on-crank or other tricks to reduce packaging/weight for that configuration.

although, stepping back a minute, I wonder if slapping an OHV head onto a OHC block might be a short cut way to setting up an engine to use electronic cam control (activation?) while taking advantage of the reduced engine height

You want real simplicity, compactness, and low end torque, we need to revisit the valve-in-block design...

volvoclearinghouse said:

You want real simplicity, compactness, and low end torque, we need to revisit the valve-in-block design...

The French military used reverse-engineered knockoffs of the Ford flathead V8 into the 1990s in vehicles and generators for just that reason.

Given how tall the belt lines and front bumper areas are to meet pedestrian standards, we certainly don't have any packaging issues with OHC engines.

There is no reason to make an inline pushrod engine - there is no packaging advantage the same way V engines have.

And you have nothing but disadvantages - no way to (easily) do variable cam timing (I understand Vipers did it with some weird concentric hollow cams thing), you have to snake the ports through the pushrods, you now have no easy way to run the mechanical fuel pump that you will need since DI is pretty much standard now...

sleepyhead the buffalo said:

In reply to alfadriver :

I’m curious where the cam ends up in space on an in-line pushrod 4?

Also, has anyone played around with composite pushrods to reduce mass/inertia?

Everything I have heard about composite pushrods is that they are very short lived.  Like in the single digits of dragstrip runs or less.

Some engine builders claim that valvetrain inertia between the camshaft and valve tip is irrelevant for valve float.  Which makes sense, the pushrod doesn't actually move all that much, and rockers have a fairly small moment of inertia.

I think we need to revisit the walking-beam 4-cylinder. 

it's not in a production car but Cummins 2.8r crate engine is still a pushrod 4 banger, so there's that

So, half an LS?  Because someone would immedately LS swap it  
Wasn't the Mercury Marine 224 just half a Ford 460?

cdeforrest said:

So, half an LS?  Because someone would immedately LS swap it  
Wasn't the Mercury Marine 224 just half a Ford 460?

 

Welp, I now have a new favorite engine swap idea.

https://www.dragzine.com/news/homegrown-horsepower-four-cylinder-mercruiser-in-a-dragster/

Knurled. said:

sleepyhead the buffalo said:

In reply to alfadriver :

I’m curious where the cam ends up in space on an in-line pushrod 4?

Also, has anyone played around with composite pushrods to reduce mass/inertia?

Everything I have heard about composite pushrods is that they are very short lived.  Like in the single digits of dragstrip runs or less.

Some engine builders claim that valvetrain inertia between the camshaft and valve tip is irrelevant for valve float.  Which makes sense, the pushrod doesn't actually move all that much, and rockers have a fairly small moment of inertia.

 

While there is no real inertia, the bending forces are a bitch. That’s why pin hole oiling pushrods with stupid thick wall thickness pushrods are the greatest idea yet. This is especially important with 1200 plus pound valve springs.

slowbird said:

cdeforrest said:

So, half an LS?  Because someone would immedately LS swap it  
Wasn't the Mercury Marine 224 just half a Ford 460?

 

Welp, I now have a new favorite engine swap idea.

https://www.dragzine.com/news/homegrown-horsepower-four-cylinder-mercruiser-in-a-dragster/

One of our community is doing something with one of these engines.  Maybe with a Boss 429 head?

"Will we ever see a pushrod-4 in a production car again?"

One of my profs, (Back in the dark ages.) used to answer this sort of question with:

"Who knows?, Who cares?"

Not the most sensitive answer, but it did cause classmates to focus their questions....

Rog

to answer the OP.. I would give it a very slim chance. With ICE in thier swansong, it won't be too long till there are no engines in cars at all anymore

I would say its more likely to see a cam-less 4 cyl than a new pushrod design.

Although... if you were to do a V4, the packaging advantages over a DOHC would still exist.  And a V4 LS motor would leave room for lots of transmission (and electric motor)

ProDarwin said:

I would say its more likely to see a cam-less 4 cyl than a new pushrod design.

 

Although... if you were to do a V4, the packaging advantages over a DOHC would still exist.  And a V4 LS motor would leave room for lots of transmission (and electric motor)

 

Although IIRC the only thing it actually shared with an LS1 was the timing chain.

In reply to ProDarwin :

I did a tune-up on a friend's Saab 96 on the weekend. 

I thought that little Ford V4 was a nice design, fun to drive too.

sleepyhead the buffalo said:

In reply to alfadriver :

I’m curious where the cam ends up in space on an in-line pushrod 4?

Also, has anyone played around with composite pushrods to reduce mass/inertia?

Opel used a 4 cylinder engine with the cam high in the block, eliminating the push rod. An hydraulic tappet acted directly on a rocker arm. There's no need for pushrods in a modern engine- an OHC operating roller followers reduces friction, which lowers fuel consumption. Less parts means lower weight and man'fering costs.