Got to wondering, do all "V" configuration engines these days use push rods and rocker arms?


#1

You know, V6’s and V8’s. Or do some of these use overhead cams that push directly down on the valves, like is done w/most modern in-line 4’s?


#2

Almost all v6 are OHC, most DOHC. GM and Chrysler V8s are pushrod. Others are DOHC.


#3

+1 to Texases post.

There are also various methods used to “push directly down on the valves”. Some designs have the camshaft between a fulcrum and the valve stem, pushing down on the top of the rocker. Some have the fulcrum in between the cam and the valvestem, pushing one end o f the rocker up to push the valvestem down. Some cams push directly down on the valvestem. All use some form of lifter or tappet, some hydraulic and some mechanical.

Here’s a link that will show you a number of different ways a cam lobe can push a valvestem.
https://www.bing.com/images/search?q=automobile+engine+valvetrain+configuration+diagrams&qpvt=eutomobile+engine+valvetrain+configuration+diagrams&qpvt=eutomobile+engine+valvetrain+configuration+diagrams&qpvt=eutomobile+engine+valvetrain+configuration+diagrams&FORM=IGRE


#4

All Nascar Sprint cup engines are pushrod by rule.


#5

NASCAR is way too phony for me. There seems to be nothing STOCK about the cars. Dirt track racing is a lot more realistic and fun to watch.


#6

Interesting. So Ford V8’s are overhead cam designs now? Does that include their Coyote crate engine too?


#7

Ford has been using overhead cams for a long time. The first Lincoln Mark VIIIs in 1993 are dual overhead cammed. I’m pretty sure all of the Coyote engines are OHC also.
My daugher’s '05 Mustang is OHC also.

I agree with Rod Knox about NASCAR. I gave them up a long time ago and judging from the TV ratings and half empty stands along with massive amounts of seat removal I’d say I’m not alone.
The local 3/8 mile dirt track here has racing that is much more enjoyable to watch compared to NASCAR. They’re also not constantly playing games with the rules and making childish changes to the points system.


#8

Here’s everything you wanted to know about the OHC Ford V8 (and V10).


#9

@GeorgeSanJose

Ford went to OHC well over 20 years ago for many of their V8 engines. I believe they haven’t had any pushrod V8 for quite some time now. The 7.5 liter V8 big block was a holdout, but even that’s been out of production nearly 20 years now

GM has for the most part doggedly stuck to the pushrod V8. I have no idea about the Corvette, that’s why I said for the most part

Even mopar went the ohc route some time ago. I think they started with the 4.7 liter V8

I know that the european fords used pushrod V6 and V8 engines back in the days of your truck, but not lately

as for Toyota, I think the LS400 might have been their first V8, and I think it was dohc right from the start

BTW . . . what brought this about?

Are you going to be new car shopping?

Or are you trying to win some kind of bet with a beer drinking buddy? . . . ?! :sweat_smile:


#10

GM’s V8’s are all pushrod, including the Corvette. They have modern cylinder de-activation, variable valve timing and direct injection, but still use a cam-in-block and pushrods. It makes a small and very tidy engine package.

My 07 Mustang has a 3 valve 4.6 liter V8 with 3 roller rocker arms running on a single OHC per bank. My new Coyote equipped '13 has 4 roller rockers acting on 2 camshafts per bank- and the heads on that engine are BIG.

Lots of DOHC engine use rocker arms because you can add roller followers and hydraulic valve lash adjusters. Direct acting cam-on-valve designs are sliding followers with too much friction. Heck, my old '92 Saturn DOHC engine had rocker arms and hydraulic lash adjusters.


#11

Only DOHC Corvette was the 90-95 ZR-1. The high performance was matched by a high price, almost twice the base price Corvette of the time.


#12

NASCAR is phony ? You mean that is not really a front wheel drive Camry with all those sponsor stickers on it ?


#13

NASCAR use to about the car and driver. Now it’s all about the driver since the cars are identical (at least they’re suppose to be).


#14

Certainly the “Stock” in “National Association of Stock Car Racers” has long since become a farce, but as much as I don’t enjoy or appreciate a bunch of fiberglass clamshells, all EXACTLY the same on EXACTLY the same chassis, going around in circles all day, I commend their having made it big business. NASCAR has created its own stars, groupies, and all the shazam and pizzazz of any big-top event. They’ve made it a ginormous enterprize.

But no, I don’t watch it. Carbon-copy cars going around and around in a circle all day just doesn’t interest me.


#15
But no, I don't watch it. Carbon-copy cars going around and around in a circle all day just doesn't interest me

That is the same reason I don’t watch, but ironically it’s the reason it got so popular. It’s a soap opera on wheels.


#16

IMHO It’s the “soap opera” part that’s made it so popular. The tirades, the vendettas, the rivalries between the drivers. The racing itself has become secondary. It’s sort of like professional baseball with cars.


#17

Really? You guys think NASCAR has become a soap opera with tirades and vendettas? I think it’s become waaaaay too squeaky corporate clean.

Give the me days when we had drivers like Junior Johnson, an admitted ex-moonshine runner. who was known for firing drivers because the cars would be “too clean” after a race, meaning they weren’t pushing the cars hard enough, or shoving other drivers out of their way, or Curtis Turner, who was known to prefer driving with a ripping hangover, because he felt it “sharpened” his senses.

THEMZ the good old days, to me.


#18

I do.
In the days of the moonshine runners (which is where it all started) it was real racing. Now the cars are so exacting and so carbon-copy that the tirades and vendettas are what the organization highlights. And they’ve made drama stars of the drivers. NASCAR has been turned into a ginormous business enterprize, with cookie-cutter cars, and IMHO it’s no longer any fun. While I happen to find Danica Patrick extremely attractive, and have great respect for her driving skills, she isn’t a star because she wins races… which she doesn’t really. She’s a star because of her looks and her tantrums.

I mean absolutely no disrespect to those who love NASCAR. Everybody has his/her own taste in entertainment. But if you want real racing, if you want different manufacturers competing with each their own factory prepped cars, you gotta turn to European road racing. That, to me, is real racing.


#19

Wow,blast em good Guys ,I dont think Toyota makes the V8 engines that power their cars,I wish they would stop calling them “Stock Cars” I guess the seventies and early eighties were sort of the death kneel for having some fierce competition among the drives and builders ,but you have to admit they do a great deal with a mid size V8 engine and a not particularly large 4bbl carb.
I lost interest a long time ago ,it reminds me of professional wrestling .A fair amount of go and a lot of show .


#20

I’m not going to join the NASCAR bashing bandwagon. You can level the same “cookie cutter” sameness criticism on Indy Cars and F1, where the rules dictate not only the exact displacement but also the engine’s exact bore and stroke and cylinder count and V bank angle. Take the decals and paint off of them and you can’t tell one from another.
As far as watching them, it’s just as much fun to watch the last dozen laps in a NASCAR race as the last dozen laps of an Indy car race, and the last dozen laps or so is usually the only part of the race I actually watch.
Why it’s important for the cars to be ultra trick and high tech, I don’t know. What’s more low tech than horses? Yet the Kentucky Derby draws huge crowds.
Or how about the epic tacking duels between Dennis Conner and John Bertrand in the 1983 America’s Cup? Talk about a race involving an obsolete form of transportation.