The never ending debate

[S204STi]

I wouldn't take that wiki article verbatim.  According to that, the pushrod OHV is an older design than the OHC OHV, which is incorrect.

However, it is generally accepted terminology that OHV = pushrod.  The pushrod was essentially a way to retrofit the overhead valves of an OHC motor onto a cam-in-block flathead design.  OHV indicates that the valves are overhead but the cam is not.

Yep, that's all I was going for. 

[ChrisV]

Sure it does, anyone who knows anything about engines knows that.  The point is that OHV is the common shorthand for pushrod engines.  Any knowledgeable automotive enthusiast should know that.

Boy, smilies indicating lighthearted ribbing are sure wasted on some people around here....  Guess I won't try that anymore...

Yes, OHV is shorthand for pushrods. And it became shorthand because people were to fucking lazy to use the correct terminology. Kind of like how roadster now means any fucking convertible with slightly sporting intentions.

Go fuck yerself. I mean that. 

[Cookie Monster]

Boy, smilies indicating lighthearted ribbing are sure wasted on some people around here....  Guess I won't try that anymore...

Yes, OHV is shorthand for pushrods. And it became shorthand because people were to fucking lazy to use the correct terminology. Kind of like how roadster now means any fucking convertible with slightly sporting intentions.

Go fuck yerself. I mean that. 

Yeah it seemed like R-inge overreacted there.

One of the few times you're joking around and people still get mad at you.

In any case, your BMW has an OHV engine. How do you feel about that?

[ChrisV]

Yeah it seemed like R-inge overreacted there.

One of the few times you're joking around and people still get mad at you.

Actually I joke around quite a bit, but when I want to emphasize that, I put in the smilies, 'cause it's hard to read intent on the web. Oh well.

In any case, your BMW has an OHV engine. How do you feel about that?

All I care about is that it continues running and does the job it's asked to do. 

Wonder what it'd be like with a supercharged big block Chevy? 

[Cookie Monster]

Actually I joke around quite a bit, but when I want to emphasize that, I put in the smilies, 'cause it's hard to read intent on the web. Oh well.


All I care about is that it continues running and does the job it's asked to do. 

Wonder what it'd be like with a supercharged big block Chevy? 

Manual transmission swap. Maybe put in a rotary too for good measure.

[GoCougs]

And, as I have pointed out, a very large number of OHC engines are also ancient throwbacks.  At least they are direct decendants of ancient machines. 

There are zero modern, or "new," engine designs on the market with every design having at least 50 years on them now.

But in terms of new engine families, i.e., that which the automakers have invested in recently, only two have been pushrod (Hemi an LSx); all others have been OHC.

[GoCougs]

You never explained how parallel processing reduces cost in manufacturing.  I tried to drag it out of you for 7 pages, but apparently you refuse to.

It only reduces inventory between processes.  I'd still like to hear your answer.

I did, and it is duplicated below by others:

Lean manufacturing 101.

IMO it would work like this:  with an OHC engine, one team can be working on assembling the engine while another team assembles the heads with a complete valve train.  Final assembly would just require installing the timing chain and covers, pulleys, and drop into the engine.  With OHV much more of the engine assembly time is taken up by setting up the cam, lifters, and pushrods in the engine assembly.  The heads are comparatively simple to assemble since they just have the valves and springs.  

Sooo.... if you can have less overlap between jobs while assembling a part (lets call it modular) you can have two workers assembling an engine in less overall time.  Maybe I misunderstand the principles involved, correct me if I'm wrong.

Nice on the below, hounddog - got a bit of Theory of Constraints in there (Goldratt's The Goal) in there, too:

Shortest possible answer;

Parallel processing cuts costs when the constraint machine is mirrored, then that decreases throughput time and increases capacity, which in turn decreases inventory.

One person should be able to run both the constraint machine and duplicate machine, which would also cut throughput time.



As for product development;
If you run parallel processes (concurring engineering) and focus on reduction of the cycle time on the critical path, it allows a product to be brought to market sooner, therefore, reducing product development costs and increasing the likelihood of capturing a large portion of market share before competition is introduced into the marketplace.

I would (again) add to the above the value in the option of outsourcing the heads as a complete sub assembly; this allows for labor and/or cost savings as they can be built on different shifts, in different areas of the plant, at a different plant, or at a supplier, allowing the supplier to save costs through balancing labor and/or reducing direct labor through scale (as in outsourcing to a supplier). This kitting value also exists for pushrod heads, but it is less since much less can be done with the heads off the engine (can't install rockers, pushrods, valve covers, coil packs and can't adjust the valves).

[hotrodalex]

Wonder what it'd be like with a supercharged big block Chevy? 

1000+ HP would go very nicely with the car, I think.

[Cookie Monster]

1000+ HP would go very nicely with the car, I think.

Manual transmission is better.

[hotrodalex]

Manual transmission is better.

Can't have both, so power wins. He can get something else with manual.

[Cookie Monster]

Can't have both, so power wins. He can get something else with manual.

Um, no.

You can have both. V12 swap + manual + turbo.

And who are you to decide that power wins?


redneck

[hotrodalex]

Um, no.

You can have both. V12 swap + manual + turbo.

And who are you to decide that power wins?


redneck

What transmission are you using then? Most can't handle 1000+ HP.

[Cookie Monster]

What transmission are you using then? Most can't handle 1000+ HP.

I dunno but I know that Chris posted pics of the worlds fastest 7 series and it has a manual and a V12 I blv.

And who said anything about 1000+ hp?

[hotrodalex]

I dunno but I know that Chris posted pics of the worlds fastest 7 series and it has a manual and a V12 I blv.

And who said anything about 1000+ hp?

Well he said he wanted a S/C big block, so if it's any good it will put out 1000+.

One thing you have to look with big power and a manual transmission is how often do they use the power. If they rarely, if ever, use all that power than a manual can be fine. But it needs to be built up if they are going to use the power.

[Cookie Monster]

Well he said he wanted a S/C big block, so if it's any good it will put out 1000+.

One thing you have to look with big power and a manual transmission is how often do they use the power. If they rarely, if ever, use all that power than a manual can be fine. But it needs to be built up if they are going to use the power.

Yeah... the Tremec TR6060 can only take 600 lbs/ft of torque anyways. Still, a 650-700 hp, 600 lbs/ft 7 series with a 6 speed manual would be nice.

[ChrisV]

The one I posted was a manual and a supercharged V8.

And it cost $50k to get 600 hp.

I think one could do better with pushrods.

[Cookie Monster]

The one I posted was a manual and a supercharged V8.

And it cost $50k to get 600 hp.

I think one could do better with pushrods.

Oh.

Well then just get a ZR1 drivetrain then. Hopefully someone wrecked one already.

[sportyaccordy]

The one I posted was a manual and a supercharged V8.

And it cost $50k to get 600 hp.

I think one could do better with pushrods.

Which V8, the one from the M5?

Yea you could cobble together some Detroit iron for prob 2/5 the price of that no problem and make the same power.

[GoCougs]

Boy, smilies indicating lighthearted ribbing are sure wasted on some people around here....   Guess I won't try that anymore...

Yes, OHV is shorthand for pushrods. And it became shorthand because people were to fucking lazy to use the correct terminology. Kind of like how roadster now means any fucking convertible with slightly sporting intentions.

Go fuck yerself. I mean that.  

So would it meet with your approval to use the diversionary "cam in block" advertising spiel?

And no, it's not shorthand. It's an accurate description as a stand alone entity, but becomes even more appropriate in context, as the displaced technology was the "underhead" valve train, where the valves were, well, under the head and in the block.

Ford flathead V8 clearly showing the valves in the block (and by extension under the head):

[r0tor]

Which V8, the one from the M5?

Yea you could cobble together some Detroit iron for prob 2/5 the price of that no problem and make the same power.

have you ever tried to drive a 600hp small block chevy?  Hope you don't mind spending a good 10 minutes each start-up to try and get it to idle and not stall on you or have an appetite for a really high idle

[ChrisV]

So would it meet with your approval to use the diversionary "cam in block" advertising spiel?

And no, it's not shorthand. It's an accurate description as a stand alone entity, but becomes even more appropriate in context, as the displaced technology was the "underhead" valve train, where the valves were, well, under the head and in the block.

Ford flathead V8 clearly showing the valves in the block (and by extension under the head):

As I said, I was playing around with him for the lulz, and put the smilies on to prove it, and was going to leave it at that. But since you're just a dick regardless....

That would be true if the ONLY tech it "displaced" was flathead engines, but since OHC engines were already around with overhead valves, that argument loses merit. The use of OHV to describe pushrods ONLY is a relatively recent development, just like the terminology of roadster meaning every sporty convertible is fairly recent.

I like all the engines, be they flathead, pushrod, OHC, or even that wonderful little magic spinning triangle one with no cam or valves. Anyone who cares enough about how the valves in an engine are actuated that they would denigrate and put down that which isn't their favorite method of valve actuation () on a constant basis is worthless waste of air that hopefully will die without passing on his genetic material.

[ChrisV]

have you ever tried to drive a 600hp small block chevy?  Hope you don't mind spending a good 10 minutes each start-up to try and get it to idle and not stall on you or have an appetite for a really high idle

Actually, a 600hp modern small block with modern injection has no problems with those things. But I was talking big block. I already built a carburated big block Ford that had almost that much hp and over 700 lb ft of torque that was a smooth daily driver, as easy to drive as a stock 5.0. My 500plus hp carburated big block Chevy was also pretty smooth and easy to drive. Adding another hundred hp to it's not that much of an issue these days.

[Cookie Monster]

So would it meet with your approval to use the diversionary "cam in block" advertising spiel?

And no, it's not shorthand. It's an accurate description as a stand alone entity, but becomes even more appropriate in context, as the displaced technology was the "underhead" valve train, where the valves were, well, under the head and in the block.

Ford flathead V8 clearly showing the valves in the block (and by extension under the head):

That looks really weird.

How do flatheads work?

[S204STi]

That looks really weird.

How do flatheads work?

This is a good explanation I think: http://auto.howstuffworks.com/hemi1.htm

It compares the OHV Hemi to a Flathead design, so you get a good explanation of each one and their valve train layout.

[S204STi]

Additionally, if you're curious about the differences between the GM OHV and Chrysler Hemi OHV engines, I will explain.  Give me a minute to gather material on it...

Here are some pics to illustrate: (The first two are GM, the last two are Chrysler)









Basically the head on the GM is relatively flush with a sort of wedge shape, and the valves are located side by side and enter the cylinder at the same angle.  The head on the Chrysler has splayed valves and a dished opening, and the valves enter at opposite angles.  This results in theoretically better airflow through the engine.

Typically OHC engines are a sort of pent-roof hemi (imagine the end profile of a house's roof) with similar arrangement to the Hemi, but with four smaller valves.

[Cookie Monster]

This is a good explanation I think: http://auto.howstuffworks.com/hemi1.htm

It compares the OHV Hemi to a Flathead design, so you get a good explanation of each one and their valve train layout.

Oh, cool, thanks.

It works kind of like how I imagined it would. That's really cool! It looks pretty complex though.

[GoCougs]

As I said, I was playing around with him for the lulz, and put the smilies on to prove it, and was going to leave it at that. But since you're just a dick regardless....

That would be true if the ONLY tech it "displaced" was flathead engines, but since OHC engines were already around with overhead valves, that argument loses merit. The use of OHV to describe pushrods ONLY is a relatively recent development, just like the terminology of roadster meaning every sporty convertible is fairly recent.

I like all the engines, be they flathead, pushrod, OHC, or even that wonderful little magic spinning triangle one with no cam or valves. Anyone who cares enough about how the valves in an engine are actuated that they would denigrate and put down that which isn't their favorite method of valve actuation () on a constant basis is worthless waste of air that hopefully will die without passing on his genetic material.

But the volume of the technology displaced was overwhelmingly that of flathead, which was the vast majority if not virtually 98% of the engine technology used in the vehicles sold in the US until the 1950s.

I don't have any preference really; and in practicality can't; there are so few pushrod-powered vehicles today, most all of which aren't my cup of tea for various reasons, that I'll never have the option. Further, I'm only explaining why pushrod engines have been phased out by the world's automakers the last few decades.

Your continually bankrupt approach to discussion is entertaining - I don't think I've ever been attacked so. I gotta give you props for that.

[GoCougs]

I think Chrysler has the better pushrod design; not only due to the valve configuration but that Chrysler for decades has mounted their rocker arms on shafts (as opposed to Chevy's pedestal mount).

[NomisR]

Further, I'm only explaining why pushrod engines have been phased out by the world's automakers the last few decades.

Your continually bankrupt approach to discussion is entertaining - I don't think I've ever been attacked so. I gotta give you props for that.

Isn't the main reason why pushrods are phased out mainly due to government regulations and taxations?  By placing high taxes on high displacement cars even if the said engine is more compact, more powerful and consume less fuel than a smaller displacement car, all in the name of fuel economy? 

[hotrodalex]

This is a good explanation I think: http://auto.howstuffworks.com/hemi1.htm

It compares the OHV Hemi to a Flathead design, so you get a good explanation of each one and their valve train layout.

Very good explanation. It keeps things simple and you can see everything in the pictures.

Isn't the main reason why pushrods are phased out mainly due to government regulations and taxations?  By placing high taxes on high displacement cars even if the said engine is more compact, more powerful and consume less fuel than a smaller displacement car, all in the name of fuel economy? 

Yes, for the most part. Also, a lot of pushrods are neglected and haven't been improved for 15-20 years. (I don't count adding more displacement as improved)