Bigger Pushrods & Guideplates Legal in Stock now
 

In case anybody missed it, NHRA posted this in "2008 Rules revisions" yesterday.

Stock Cars

Section 9A

Engine: 1

Page 136 (05/08)

Camshaft/Lifters: Delete last sentences of paragraph and replace with “Larger diameter pushrods permitted. Pushrod guide plates permitted. Cylinder head may be clearenced for larger diameter pushrods.”


Dave

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

So who out there want's to take the ball and run with it in getting NHRA to accept roller rockers in Stock? :rolleyes:

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

Does the rule means that cars such as the Ford small blocks, Oldsmobile and Buick engines can runs guide plates? The interesting part of this rule is that for many years, many cars have been running larger pushrods. Prior to this rule change, there has never been a published specific pushrod diameter available.

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

ssdiv6 will you pm me please i just finished my stocker heads.

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

PM sent.

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

I am a "newby" to stock eliminator racing, but when I was building my motor, it would have been a lot easier and cheaper if I had been able to use roller rockers. It wasn't all that expensive for me to buy rocker arms, and adjustable push rods for my Olds, but I know the big block Chevrolet guys spend a small fortune on yours. Though I'm sure all the purists here have a point as well when they say that using roller rockers is getting away from stock racing.

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

I know a lot of you guys get killed by the stock rocker rule. We have it pretty easy as the 3800 has roller rockers from the factory.

Sportsman reps, take note
 

"Killer" yet legal valve-train for Stock:

1) Steel billet camshaft
Options: large cam journals (babbit or roller bearings) , change in firing order.
Cost: upwards of $1500 parts / labor (includes boring cam tunnel).

2) non-OEM lifters
Choices: Schubeck carbon composite heel or body, OEM style altered plunger conversions (available through various sources), tool-steel lifter bodies.
Options: various coatings to reduce wear.
Cost: upwards of $850.00

3) "Any size" pushrods
Choices: Manton as primary source, single or dual taper 7/16" to 3/8", .120" to .168" wall construction. Larger sizes available.
Cost: approximately $30 per pushrod or $480.00 per set.

4) rocker arms
Choice: BBC using 9/16" stud mount and 8.1L BBC rocker arms, various other treated / coated assemblies also available.
Cost: approximately $750.00

5) valve springs & retainers
Choice: Beehive or traditional to deliver 400-450#'s open pressure. Available from various suppliers. Retainers: tool steel
Cost: approximately $450.00

6) Guide plates
Choice: OEM to aftermarket.
Cost: ? $150 ?

Any Sportsman reps want to comment on why a roller rocker rule would "ruin" the sport?
Next to guide plates, your $289.00 Crane "Gold" rockers are the cheapest parts here yet the only parts that lead to engine longevity.

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

You're a little high, on several of your prices.

You left out 8620 bar stock rocker shafts found in more than a few of the shaft rocker engines.

You ignore the fact that roller rockers, especially on engines with shaft rockers, will allow ANOTHER escalation in tappet velocity, increasing both performance AND strain on other parts, especially for engines with larger diameter lifters.

Where does it end? $1K Jesel or T&D systems? Any tappet diameter? Roller lifters? No lift rule?

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

If I'm off on total pricing, it can't be more than 10%.

If you fix the "wobbly" end of the spectrum (the stud mounted rocker arm; as found on GM / AMC / FORD), I really don't see that it will increase strain to a point of breakage anywhere else on the engine. If the goal is limiting the performance or adhering to "Stocker Purity", i.e., valve-train limitations, then everything mentioned in my list should be banned outright and all components should resort to OEM parts and specifications only.

But I've always been lost on the concept of allowing full-bore race modifications and parts as listed below, but keeping one breakage prone part which can (and does) lead to complete engine failure.

I guess the wording of a rule would read something like "mounted in same configuration as OEM"

Where does it all go? I've often thought Stock will (regarding engine) eventually be limited to restrictions on factory valve lift, factory carb, intake, valve sizes, piston configuration, bore and stroke. If I missed something, I 'll assume you get my meaning.

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

A cheaper alternative for all this would be to go back to old time stocker specs of OEM duration, overlap and valve springs specs. The problem, and thus the explanation, was always that the tech people were not trained well enough to measure all that intricate stuff. Well, I dare say that we have all spent way more money than it would cost to have developed a management, education and certification system for NHRA tech people to do their job. I would easily agree to addition fees for setting records or tear-downs to fund better administration in the tech department for Stock and Super Stock.

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

I totally agree with Dwight, and it would require a lot of the specs issued by the OEM to be realistic!!! If can recall correctly,I remember the Chrysler 440 and 340 cam specs having something like 240 degrees of overlap and unreal durations specs. The same applied for other makes.

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

I totally agree with Dwight, and it would require a lot of the specs issued by the OEM to be realistic!!! If can recall correctly,I remember the Chrysler 440 and 340 cam specs having something like 240 degrees of overlap and unreal durations specs. The same applied for other makes

If you built an engine with the old Pontiac duration numbers (in the area of 324 degrees duration), I doubt you could even get the engine to start!

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

I agree...like I said, if the old rules are implemented...and enforced properly...there would be a lot of cars out.

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

I think the rule changing should stop during the racing season unless some immediate safety need arises. Think about the HP factor requests. They come in 2 times a year I think. Maybe there should be a specific time for requests and a process that is more transparent to the reps and the racers. It could mean that NHRA tech gets all requests and then the committee should then review then with reps once a year. After all that, the requests along with explainations get posted prior to giving a thumbs up or down. That way there is input from all to help with the committee decision.

The problem with the committee and system now is that it seems that the unintended consequences are not considered.In the current state of the rules, if you are afraid or unwilling to accept breakage, turn the rpm down, lower the pressure, etc. I have also seen many times even on this forum, the racer opinions of slow cars that are just thinking that if only they had this part or that part, then they would move up on the qualifying sheet or perhaps win class. The problem is that they don't often consider that everyone else faster will also benefit from the rule changes.
The rocker arm deal is one I understand, but is still is a limiting factor in engine design and cost. It should have been allowed and the spring pressure could have been limited, but it wasnt' so...We push our stuff as far as we think it will go. If we want to go quicker, we push it a little farther. That increases our risk of breakage. That is a decision each one of us makes and one that each one of us is responsible for. If roller rockers are made legal, It won't be that I just bolt them on, I will order cams and guidelplates and pushrods too. You think that the cam is square now, wait until the rocker arms are legal. The 396 cars will really put the sprng pressure on too.Someone mentioned that then Jesel rocker shafts are next $$$. Many others will push it. I guess the point is that there is no need for a mid season rule change in most cases. Maybe our reps should be part of a redesign of the rule change process. That really is the issue. Some of the committee members in NHRA tech could benefit from modern racer input too. This could be an opportunity to help everyone overall.

BTW, who was pushing for the guideplate pushrod deal? Curious on that one? Jim.

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

Whiney butts, that's who. Due to an unwritten policy-procedure that should have been addressed correctly many years ago, the BBC cars can use the Mk VI 9/16" studs and over-the-GM-counter 7/16" pushrods that were developed for the CanAm racers in the 60s and 70s. So, with poor logic as a weapon, the tech department gets assailed with "if they can do it then why shouldn't I be able to" until they cave.

An effective use of the committees would be to only allow rules changes that are authored within the committee (except human safety considerations). Then do everything we can to make the "voter turnout" be a higher statistical number than what happens during elections that determine the future of our nation.

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

I wouldn't be opposed to our committee members not only drafting proposals (based on racer requests) but voting on them. Similar to your state legislatures in concept. I think if you vote somebody into office you should suffer or benifit from their position. I personally think throwing everything onto a ballot is rediculous (sp?).

And Dwight, I'm curious as to why GM felt it neccessary to add 9/16" rocker studs on the late model 8.1L BBC. I just can't imagine there was enough strain on the previous design to warrant the engineering and tooling?

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

The 8.1 doesn't really have 9/16" studs. It has a 3/8" stud on the bottom and a shouldered nut that goes through the rocker to create what GM called a "net lash" system, which in plain terms means "non adjustable".

The limit to how "square" a flat tappet cam can be is lifter diameter. A Ford with an 0.875" lifter, a Chrysler with a 0.904" lifter, or an Olds with a 0.921" lifter can generate more tappet velocity (what makes a cam lobe "square") than any Chevy with an 0.842" lifter, regardless of spring pressure. It does not matter how much spring, or how good a rocker you put on it, the lifter diameter is the limit.

Re: Bigger Pushrods & Guideplates Legal in Stock now
 

I saw 0 HP increase with the bigger stuff on the dyno. If your engine turns above 7500 it might work but did nothing for me. I only see about 6400. I ended up putting back the 5/16 stuff so I could use the factory guide plates.

Slow down the rule changes
 

Look, the real issue isn't what is being duscussed now, it is that there is no formal process from NHRA. We don't need any mid year changes for non-safety items period.

Remember when Top Stock took off in IHRA. Those guys were as hard core as it comes and even they got worn out on their own rules changes.

This is not Comp Eliminator. I agree that we have what we have now and going back is not going to happen, but there are too many doors to slip these rule changes under. It appears that there is not careful consideration or control by NHRA.

Any Division reps care to take this on? I think there needs to be a defined process for any rule change proposals. I don't see it now and that is a concern. There are guys boring the cam journals and running roller cam bearings, wait until someone decides we should all have the mopar diameter lifters or who knows what.

Re: Slow down the rule changes
 

That would require that there would be accountability for decisions. Do you really think they will do that???

"Absolute power corrupts absolutely.": The failing of socialism.
"Assuming that more than half of the people are right more than half the time." The failing of democracy.

I agree with Jim.

Re: Slow down the rule changes
 

Jim, it's not that there isn't a defined process for rule changes. It is that we cannot see it and thus do not know how to influence it. We think we can influence change by using reason with our tech directors, whining on the internet or making a ruckus. By observation it seems that sometimes something works and sometimes it doesn't. So it follows a pattern that indicates the same rules apply that are prevalent in politics - good ole boy networks, what's in it for me, or fear of lawsuits.