Re: Drooze & Teuton
 

Well...we just had this issue about rocker ratio's thoroughly discussed here.
And I still do not know what, f any, tolerance NHRA will allow. Does anyody? Is a 1.65 RR in the tolerance zone if 1.60 is in the books? Are these Hemi rockers somehow marked as delivered (like a crane rocker for example) or is it up to the racer to determine the actual ratio? And was 1 or all 16 out of spec?
Are modern Hemi's more exact in the RR or are they like engines of yesterday, all over the board and you must sort through 100 to get the 16 you need?
And I would bet my last dollar Teuton had the correct cam lift as measured at the valve.

Re: Drooze & Teuton
 

Jeff, the way I read Travis' reply was the tolerance is +0, -X, meaning you can be under by a reasonable amount, but not over by any amount.

Here is the thread you mentioned: http://classracer.com/classforum/showthread.php?t=25533

In that thread, Travis made it pretty clear that if the spec was 1.5:1, for example, that 1.50:1 was legal, and 1.51:1 was not.

Yes, it is up to the engine builder to determine the actual rocker ratio as the engine is being run, and the racer is responsible for it.

Engine builders are human, as are racers, and they make mistakes. Without naming anyone, it has not been that long that a very well known racer was DQ'd from a race for this very reason, and his engine builder is extremely well known as one of the very best in the business. Both parties involved are stand up individuals, and the size of the infraction would not have made any difference in power. All they did wrong was to not check for lift at every single rocker, so the tolerances stacked up and they got bit.

Re: Drooze & Teuton
 

Did Jeff run the Hemi package or the 5.9? These new Hemi's have a slidder rocker which could increase the rocker ratio with lift. Comp is the only company grinding cams with a1.60 ratio. Most others grind them with a 1.65 and Crane ground theirs at a 1.70.

Re: Drooze & Teuton
 

Just goes to show you, you are never too old to learn. We checked ok on everything, bore, stroke, cc on chamber, runners, throttle body, intake, cam lift, and everything else. The rocker arms are 1.65 and the spec says 1.60. Like I said the lift was ok. Consider this, how many rockers have anything written on them in Stock? We just discovered one pitfall of the new stuff. We actually had done everything for the record and were finished, the next morning after we made another run, we had to remove a valve cover and they looked again. So much for the weekend and the record. The cam checked and we honestly thought that was all it took. We were wrong. So we will get some 1.60 rockers and get a new cam.

Re: Drooze & Teuton
 

Frankly, as long as the total lift at the retainer is at or below the max allowed, why would anybody care what the rocker ratio was? It seems that most factory rockers are well under the advertised ratio (My 5.0 Ford spec is 1.60, but most OE rockers are 1.53-1.54), so if we can have a cam made with more lobe lift to compensate for the crappy rockers, why wouldn`t the opposite be true?

Re: Drooze & Teuton
 

Increasing the rocker ratio increases the speed of the valve. That can have a significant effect on performance. For a somewhat better explanation of how and why, see the thread I linked in the earlier post. That explanation, despite the efforts of Dwight Southerland, Adger Smith, myself, and others, still does not cover the benefits of increasing the rocker ratio.

Re: Drooze & Teuton
 

The stock rocker ratio rule has been this way for years. Jeff Warren was caught with 1.6 ratio rockers (remember those OEM appearing 1.6 rockers made by Crane) instead of 1.5 on his 350/255 HP 69 Camaro a long time ago and was tossed by NHRA even though the cam lift checked good at the retainer. I caught a couple of guys in IHRA years ago doing the same thing. Maybe its time some of you guys go back and recheck what you are running instead of "re-inventing the wheel" before its to late and you get tossed.

Re: Drooze & Teuton
 

Stuff sometimes just happens....

If there is something that can go wrong, it usually does. But that is racing and why everything gets checked again and again.

Obviously Jeff, you didn't try to cheat, and it is unfortunate that you got DQed after going through all of that, and checking out good on everything else.

But I have no doubt that you will put down another record with the right rockers..

David
The New Hemi Guy

Re: Drooze & Teuton
 

OMG, does that mean we can't run at Norwalk???

David
The New Hemi Guy

Re: Drooze & Teuton
 

I must be missing something here. If I ordered a cam and thought that I had 1.6 rockers, why would the manufacturer grind my cam short so that it would check ok with 1.65's? I would have thought that the lift should have checked too high if 1.65's were used on a cam ground for 1.6's. Go ahead and educate me.