Nascar Rules

Because they can go along with a rake and collect scrap metal from the track.

Vestages of the "Good Old Boy" era of years ago!

NASCAR's heritage is rooted in the "old days" and moonshiners hopping up their cars to outrun the law.

Tradition rules and most American V-8 engines are still pushrod engines.

Development of OHV engines would cost millions of $ for each team and automakers are not ready to switch their legacy engines over yet so there is no source for OHV heads and the associated hardware.

They have just gone to fuel injection in the last few years.

OHV? They are OHV, don't you mean OHC? -- JHF

Of course!

Thanks.

Both types have OHV.

I worked in drag racing in California in the days when there was only 1 or 2 NASCAR races west of the Mississippi. I saw a lot of potent flat motors, but with only 3 main bearing they got real colorful when some of those parts said 'I want out - now!'

About a year after I sold my last 49 Ford the guy that bought it said it went 'rattle - rattle - BANG' and he could see the front half of the crank with rods and pistons still attached in the road behind him. He said 'I knew right away I was going to have car trouble.'

Miss them old flat motors (and my ex wife, about the same) -- JHF

It may have to do with legacy, consistency, corporate sponsorship, stubbornness or a hoard of other reasons. I cannot think of a good reason. Ask NASCAR.

Tradition and purity of the sport most likely.

So are carburetors and they still use them. I think what they intend are rules to level the playing field. The engines can only have two valves. So an overhead cam engine with multiple intake and exhaust is not that much an issue.

As far as efficient. Corvette's new V8 gets hwy 35mpg. There are a few but not many that can compare for the size of the engine.

29 mpg max highway ....more like 7 or 8 if you drive it right....

https://www.google.com/?gws_rd=ssl#safe=off&q=2016+corvette+mileage

http://www.autobytel.com/chevrolet/corvette/2016/mpg/

http://www.edmunds.com/car-news/fastest-most-efficient-version-of-2015-corvette-stingray-will-be-with-all-new-eight-speed-automatic.html

"Fuel efficiency for the Corvette Stingray with the new eight-speed automatic also reinforces the car's well-known ability to be surprisingly economical if you want to drive it that way: its combined fuel economy rating is 20 mpg. Several Corvette engineers claim the car is easily capable of highway cruising in the mid-30 mpg range, adding it fractionally missed a 30-mpg highway rating from the EPA. They hint that control-software tweaks in the coming months should win a 30-mpg rating for the automatic-transmission 2016 Corvette Stingray."

I wouldn't buy a corvette if you are concerned about mileage...nor do I think you could afford one if you are....

Carburetors are no longer used in the top level NASCAR Sprint Cup series.

Their days are numbered in the lower levels also.

$$$$$$$$

yeah a 2012 change.

Also talk of going to a super charged V6.

People have spent their entire lives tuning pushrod valve trains to get a 5 HP advantage over the competition.

As I said, Detroit still uses them. How many million small block Chevy engines are there in the world?

Increasing RPM only means more engine failures and that means wrecks and $$$$$$.

NASCAR has taken steps to reduce engine speed because of these failures. Gear ratios are one.

Fuel injection has been standard since 1985, I believe. It just got adopted in Sprint Cup. I still have a small block Chevy V-8 with an Edelbrock 4 bbl. (After market)

You do the math. Change takes time.

Tradition is strong in the sport.

I'm totally on-board with everything you said (wrote). Besides, just like the Fiddler on the Roof says . . . .

""One of them is not a big-cost problem and the other one is," he said. "If NASCAR comes back and redefines the engine right away, says we're going to a 4-valve, twin overhead cam package, that would be a death knell for a lot of teams in terms of what it would cost to re-power these things."

http://www.nascar.com/en_us/news-media/articles/2014/4/18/jack-roush-sprint-cup-series-possible-engine-changes.html

One potential reason goes beyond the no overhead cam engines limitation. It also prevents turbine (jet) engines from being used. In the Indy a couple of decades ago they finally let one car run with a turbine engine after relenting to numerous years of protests. The car did great! Gained a great position up front of the pack. Regretfully it dropped out for mechanical problems. Next year and every one after that turbines have not been permitted. Indy: no jets, NASCAR: no jets, Bonneville: jets (with no wings)welcome there.

Good Luck, Old Salt

Probably forced by GM: the latest Corvette and Camaro are still pushrod engines.

The way I understood it, NASCAR tried for a long time to keep it an American only "sport". They would not let anyone run OH Camshaft engines. The problems arose when Ford no longer produced any cars with an OH Valve V8 engine. Chrysler was also faced with a problem. The only OH Valve V8 engines they had in cars were the "hemi" which had been factored into an unfavorable displacement disadvantage from the late 60 series hemi. To resolve the problem, NASCAR allowed teams to use a custom engine package that was not built from a regular production engine. There were a book full of rules, but they were cast, and built just for NASCAR racing. Ford, and Chrysler spent the money to develop a competitive engine package. Toyota then fought to be allowed to do the same thing. NASCAR finally allowed Toyota to race the Camery-ish body with a custom built engine. Chevrolet continued to use some production derived block with custom cylinder heads for a short time, but ultimately switched to full custom engines also.

I don't think there will be any OH Cam motors in NASCAR soon, unless there is a big influx of fans=money to support the expensive engine changes that would have to be developed. Currently there is more power than is usable in some of the tracks. Keeping speeds in check seems more important than showcasing the latest technology.

I have a question, were these push rod OHV V8 engine blocks originally designed as such, or were they many years ago actually Side valve engine blocks that were converted in the dim and distant past to OHV?

The OHV engines that I worked on in the UK many years ago, were basically prewar side valve engines that were converted at some point to OHV, and I was wondering if the same is true in the USA....it saved on development costs.....

But with a word about reliability, OHC engines are generally speaking more reliable than OHV as there is less reciprocating weight, therefore less vibration....less wear and tear....and far fewer parts as well....

I would assume, as some have written already, its probably more to do with restricting costs and power in a formula car....though fuel efficiency is something that even F1 cars take VERY seriously nowadays....maybe NASCAR should too...?

Over Head Cam (OHC) engines are Over Head Valve (OHV) engines.

OHV is the terminology used to describe any combustion engine with the intake and exhaust valves located in the engine head assembly instead of in the engine block.

In OHC engines the camshaft(s) are mounted where the rocker-arm assembly is located in a pushrod type engine instead of inside the engine block.

OHC engines use metal discs of various widths to adjust the distance between the camshaft lobe and the valve stem instead of pushrods.

OHC engines minimize valve "floating" that occurs at high RPM due to the flex of pushrods and eliminate engine damage from pushrod failure.

You're thinking of Jaguar's OHC engines with their shims. Not all OHC engines adjust their valve lifters that way. Even my olde 1961 Mercedes 190b with its OHC 4-banger (exactly like the 190SL except for cam and carburetor): it had a screw-and-lock-nut arrangement on a rocker arm very much like pushrod engines. Difference was the rocker arm worked directly on the cam lobe instead of being pushed by a pushrod from beneath.

Another reason for OHC is to reduce the changes in valve train length and adjustment that comes from changes in engine temperature. A long pushrod is very prone to getting longer as it gets hotter. You don't have that problem with an OHC design.

Of course you have to drive that came one way or another. Some use gears; some use chains or belts. Ducati motorcycles, with their desmodromic valve design, use a turning shaft with a worm gear on each end.

Welcome to CR4.

We need more gearheads here.

Yea, what he said.

They put a cap on efficiency to limit the top speed in the interest of safety, I would assume.

Nascar, or as they show on every logo, NASCAR, is an acronym: National Assoctiation of Stock Car Racing (the second A is added to make it easier to pronounce, since your mouth wants to put a vowel between the hard C and the R anyway). Notice the key phrase in there, Stock Car, it used to indicate cars that were "Stock" from the factory, as in unmodified, but as automotive technology advanced, the "NASCAR Stock Car" began to deviate from "Factory Stock," so the association developed clear definitions on what constituted a "NASCAR Car."

The supposed draw of NASCAR racing (I'm not a racing fan myself, so there's no 'draw' for me from ANY style of auto racing) is that the cars are all "Stock" as in identical, so the machines do not matter in the final call, it's the SKILL of the drivers ALONE that determine the winner. The mechanics who tune the cars up do not matter, there's very little they can do to influence the race (aside from sucking at their job and leaving the out-of-tune and 'lame' on the track, but those guys are weeded out before the first qualifier race of the season), the 'sideline coaches' do not matter (aside from providing 'outside the car' spotting of traffic patterns), there is nobody sitting in the crew pit monitoring the engine by wireless and making timing tweaks by computer. It's just old-school man and machine, and the machine is just there to assist the man.

National

Association [of]

Stock

Car

Automobile

Racing

Thank you, I had never had it actually spelled out, and I thought 'Stock Cars' were already automobiles.

It would be like saying Automated Teller Machine Machine⁽¹⁾ or With With Sauce Sauce⁽²⁾, my mind was refusing to let me be needlessly redundant and repetitive.

Notes

1. ATM Machine
2. With au juis sauce
   

It's the National Assoctiation of Stock Car Auto Racing. (not automobile)

I disagree strongly with your incorrect assumption that the crew (and especially the crew chief) play no part in a race.

Without a great crew, the best driver on the track has a very poor chance of winning.

I do follow NASCAR very closely and have for 40 years, so I'm not speaking without some knowledge of the sport.

Also. looking at my avatar should give you an indication of my level of participation as I have driven de-tuned, retire Xfinity Series race cars at Phoenix International Raceway in Arizona (where two NASCAR Sprint Cup races are run every year, a number of times.

Member Jerrel Conway is also a racer)

I didn't mean it as a sign of disrespect, I was trying to pint out that unlike other racing leagues, where the latest advances are adopted quickly and the Lead Mechanic can practically overhaul the transmission and change the oil from a computer screen while the car is still on the track, the 'stockness' of the stock cars means that the pit crew can make the car into 'the best stock car out there,' which is to say, 'as good as any other car on the track.'

The crew Chief handles the Strategy (how many laps between pit stops, when to call the car in early because he doesn't like the way it shimmied on that last turn, etc.) and manages the pit crew so every pit stop is as fast and efficient as possible, to minimize the time lost to the other cars (and if you can make your pit stops two seconds faster than the other guy's pit stop, you just 'gained' two seconds on him). The driver handles the Tactics (which lane, when to draft, when to pass, when to cut the other guy off like he was a no-good carpetbagger).

I've seen shows about other racing leagues, and it seems that with some, there is so much that the pit crew do to the car wirelessly that the driver seems to be there only for ballast, and the cars vary wildly in specs; some optimised for top speed, others for acceleration, others for cornering. If I were to compare auto racing to fighting tournaments, NASCAR would be the traditional Karate tournament, while other leagues are more like MMA, or WWE Pro Wrestling⁽¹⁾.

The Grand Prix is all about who can build the 'fastest car,' but NASCAR is about who has the 'best driver.' That was the gist I was trying to get across.

Notes:

1. I'm not going to go into details about Pro Wrestling here, just in case there are people who don't want me to break kayfabe⁽²⁾.
2. If you didn't understand that last line, you're probably one of the people I was talking about. However, even some people who know about kayfabe prefer to not have it broken needlessly.
   

I didn't take offense at anything you said.

Ah, I misread your earlier post in 'Engineer Voice," where statements like "I strongly suggest..." mean "If you don't do this RIGHT NOW, there will be hell to pay." Therefore "I strongly disagree..." would have the connotations of "You just called my mother a WHAT!?!?"

So I erred on the side of Diplomatic caution and appologised profusely.

Hell, this is an engineering forum.

Just call 'em like you see 'em.

I'm envious Lyn.

Even though I lived very close to PIR when attending High School at Tolleson I was never able to test drive any of the cars due to my age and moved away before reaching legal age of consent.

I have driven race carts, sand rails, and miniatures as a teenager and as an adult but they aren't even close to driving a NASCAR or INDY machine.

My brother-in-law pitted for Al Unser back in the 60-70's and you are most certainly correct in that the pit crew makes or breaks the driver chances to win.

There is no way any race car driver can win without a good pit crew.

Yep. They are tons of fun to drive. Fast and really loud.

Until you get too cocky and pancake the entire side when you run into the wall.

That blue paint on the tire and down the side was on the wall, until I hit it.

Tire marks on the wall. OOPS, that hurt!

Too bad about the damage to the car but I am sure glad you are ok.

Too much speed? Wrong tires for the conditions maybe? Oil slick on the track? Or?

I can think of at least 10 reasons for the car "getting loose" that can sneak up on a driver without their having any knowledge.

My brother-in-law (Unser crew) decided to try 1/4 mile straight track and was very successful in every stock and modified stock class he entered. (His favorite car was a Gold & White stock class 57 Chevy named "Broad Minded". No one ever beat him in that car.)

Then one day he was offered a very lucrative opportunity to buy a rail and enter the alcohol & nitro world of drag racing.

Picked up the rail, then went straight to the track, rolled it off the trailer, and prepped it while he was getting dressed.

Put him in the car, strapped him in, and fired it up then rolled it up to the starting line for a no-competition test run.

The Christmas tree rolled through it's sequence, Al launched the rail, went about half way down the track when the car shut down and the parachute popped out.

Everyone ran down the track to the car worried about Al and what happened.

He had his helmet off an was out of the car when everyone got there.

When asked if he was ok he shook his head yes but didn't say anything.

We asked what happened and if the car was alright; He looked up and with his voice shaking and said; "I've never been so scared in all my life. This Sh*# is dangerous! Put that thing on the trailer and take it back to Fred. I'm done with this. You gotta be crazy out of your mind to drive one of these things."

We all laughed at his circumstance but we also understood the "why".

I miss the "good old days", the smell of nitro, the noise, and the good times we had.

When and where will you be racing again? I would really like to bring my family and watch you compete?

Drive fast and stay safe.

Sorry I didn't respond to your last question about driving.

I've hung up the helmet.

For two reasons. One, these cars are so loud and my hearing has deteriorated to the point that I don't want to make it any worse. It's hard to hear the radio. The last time I drove I had trouble hearing and didn't want to get in anyone's way.

Secondly, I have lost that "instinct" to push the car to, and beyond, the limit into and through the corners.

I wrecked coming out of turn four at PIR because I only saw the car half way down the straightaway in front of me and got back fully into the throttle before I was out of the corner trying to catch and pass it. I drifted out toward the wall, that's normal, but finally realized the I was getting too close. Turning the wheel to the left had no effect, a strange feeling to be sure. Then the problem became hitting the wall and bouncing off with the wheels turned to the left. Inside wall got really big, really fast. Got it under control and coasted to a stop thinking, damn, I'm done for the day.

I did it a few more times but hearing is more important than the thrill of driving fast.

Sorry to stretch this out but I don't get a chance to talk about it often.

Cheers.

I can appreciate your frustration but thankfully you are OK. Have been to many wrecks as a fireman but I only look at the vehicle as "the Devil" trying to hold a stranger from us and this world if it is a bad wreck. If isn't so bad my attitude is "someone up there likes you and has given you another chance".

Years ago my brother and I used to run on amateur days (he had a girl friend associated with the track) at Lyme Rock, CT. He had an Austin Healy 3000 Mk 3 and I had a Triumph. Another friend had an identical Healey which he drove also. One day the friend was T-boned and wouldn't have made it home if it wasn't for the local ambulance. There wasn't much car there to protect you. It was more like you protecting the car in an accident.

Again, thankfully you are in better condition than the car. Without you who would we have to give us a living example of "Short and Concise".

Good Luck, Old Salt

Guys,

I was fine, just bruises on my ribs where the seat wraps around you to keep you in place, and my left leg that hit the clutch pedal. Oh, and my helmet flew off my head because it was not properly secured when they put it on my head. The 5 point seat belt worked just fine.

The family was freaked out because they brought me back to the infield in an ambulance and checked me out. (mandatory)

The car was a little worse for the wear. Entire right side was trashed (never got a good pic of the car) Rear deck was separated from the body, flat tire, bent steering arm, etc. The tire marks on the wall tell a pretty good story themselves.

The deductible was $1,000.00, that I paid before I left the track. It was worth every penny.

I would not trade that experience for anything. I don't know anybody else who can say they wrecked an Xfinity (Nation Wide at the time) race car.

Thanks for asking.

Very simple answer - they want to be "American" (pronounced with a southern drawl), not Formula 1.

When you consider the dynamics involved in opening and closing a valve in the four stroke cycle with a long stick and a bell crank, push rod engines do a pretty good job.

I like to think of the shoulder cam engines that had a short stick but a big bite like the Vincent Black Shadow. Or the Pratt & Whitney Radials that were extremely reliable (Had to be).

Because push rods, the English/Imperial system of measurement and Harleys are American.