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#1 |
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Join Date: Jun 2005
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I'm responding here since I'm not an active driver (yet).....I've got an idea that maybe nobody will like...Steve, I do agree that you need the roller rocker for your car and with all the stuff permitted now in Stock, it only makes sense....However I do agree with the Captain and Bob M. about where the Stock Elim. rules changes are taking the class....I believe that a Stock Elim. engine should have the same type or design rocker arm that came on from the factory....doesn't have to be a O.E.M. part number, just the same type, etc.....So what I'm proposing is how about a SPRING PRESSURE RULE??? ALLOW let's say an open pressure of maybe 100 lbs. or so over Stock O.E.M. specs. so that maybe we don't need to fork over the $$$$ for bigger this and high-tech that, etc. THE PROBLEM is mainly could it be POLICED properly? The number doesn't have to be 100......I chose it out of the blue...but should be a number that would give additional performance and somewhat reliability without having to go to mega-dollar engine parts....UNLESS you want to! So how about it guys! Of course some engines may respond to tons of extra spring pressure and some don't....and most Stock engine programs may have to go BACKWARDS a bit....but at least it would be a RULES CHANGE leading back to what STOCK should be!
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#2 |
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Join Date: Jul 2002
Location: Arkansas
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What you have to understand is that this problem has always been around, 30 years ago with stock-stock rules we still had a rocker breakage problem with BBC and it did not matter if it was solid or hyd. Even with the Crane rockers they still break so this is not a pressure related problem of late. Bob Pagano
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#3 |
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Wasn't aware of that Bob....need to get out more! What other engines are tough on rockers? Thought that the bigger pressures caused the problem....look at the pieces (and prep) needed to run the pressures! This is STOCK Eliminator???? Just my .02!
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#4 |
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Join Date: Feb 2003
Location: Glendale, Arizona
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Buick, AMC and Oldsmobiles also have the same problem. It is not only spring pressure but the rocker geometry, specially when you run a dwell lobe camshaft.
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#5 |
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Join Date: Jul 2002
Location: Arkansas
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Yes I am speaking about Stock BBC , I only ran SS two years with one of Jerry Steins Plymouths 71-72 and set the SS/EA record using stock rockers back in the day.
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#6 |
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Steve Calabro 1199 STK, SS |
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#7 |
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I have a friend that raced a brand new 340 Demon in H/S starting in 1972. It was killer fast for the day, ran 11.90's. He constantly broke rockers. And that's a shaft rocker in case you didn't know. He admitted to "cheating" and using Direct Connection rockers to cure that problem. Now you can run Isky "High Ductile Iron" adjustable replacement rockers even though 340's never came with anything similar except for the 340-6 (T/A & AAR only).
Vic G. (see how I avoided that difficult last name) who runs one of, if not the fastest D/SA cars in the country with his '71 429 SCJ Mustangs told me he breaks rockers (average) of every 2-3 runs. Myself, while racing Stock with my '70 AMX found the ONLY way to stop the breakage was careful lash adjustments (hand turn the engine over, lash each rocker not just "wiggle" test) on every other run. These rockers are just not designed for high-dwell cams as SSD6 pointed out. What plays on deaf ears here is the fact your front runners spend a lot of money trying to alleviate this problem. And they do. Price out BBC rockers that are offered that don't break? Not to far off the price of Jesel "Sportsman" series shaft racker conversion! So purists, tell me why you want $1400 forged rods & $800 Schubeck lifters and all that other stuff in the reciprocating assembly that is offered but not this?
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Jeff Lee 7494 D/S '70 AMX |
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#8 |
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Join Date: May 2006
Location: Murfreesboro TN
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Pandora's Box has been opened, and the genie has been let out of the bottle. You'll never get what came out of the box back in, and you'll do good to get the genie back in the bottle. The BEST you can hope for is to reach some sort of plateau, and put up a fence to keep everyone from getting too close to the slippery slope.
(How about that for a full paragraph of cliches?) Some of the racers, as well as NHRA, don't want to be bothered with an in depth tech inspection. So, the valve spring rule got opened up. Any valve spring so long as it is "stock appearing". Then the duration check was eliminated. Next thing you know, those valve springs pull the heads off of stock valves, so now you have one piece stainless valves (actually a good deal, saves the racer money in the long run). But then the killer valve springs combined with cheap cam cores and crappy motor oil starts killing lifters. So now you have ceramic foot lifters. Allowing a further escalation in valve spring pressure, and a serious increase in tappet velocity. Well, rocker arms were already breaking regularly, so the added load just pushed them further over the edge. Nothing in the valvetrain of a Stock Eliminator engine really resembles anything "stock" anymore. The problem now is that roller rockers will cure the problem of rocker breakage, but ONLY the problem of rocker breakage. The next issue will be rocker stud breakage. There's a REASON they valve train people sell truck loads of shaft rocker conversions OR shaft rocker systems. Because studs break. Last year a lousy stud (actually it was a good ARP stud) broke and wiped out an entire engine for us. Allow roller rockers and the engines with shaft style rockers gain a serious advantage again. Especially those with larger diameter lifters. Now, if you allow roller rockers and stud girdles (I doubt anyone will get NHRA to allow Jesel or T&D style conversions in Stock) that levels the field again, somewhat. I doubt you'll ever get rid of killer valve springs and trick lifters. So maybe roller rockers and stud girdles are a reasonable concession in light of the other stuff that is there already, that will be there from now on. I agree that the line needs to be drawn some where, and soon. However, realistically we cannot expect the line to be drawn back around 1990 and have everyone be forced to go back to there. Racers won't do it (at least most of them) and NHRA isn't going to do it, figuring it sells parts, and it's less tech for them. It all comes down to being careful what you wish for.
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Alan Roehrich 212A G/S |
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#9 |
Senior Member
Join Date: Jul 2007
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Well guys, from what i hear, Roller Rockers ain't gonna happen!
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Woodro Josey 2002 STK |
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#10 |
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I may have a option.
Many years ago, a friend and myself were searching for a way to minimize breakage in manual transmissions and differentials. We sent quite a few gears out to have them frozen. This cryogenic process is suppose to 'relieve the stress' of the parts. Can't say if it really helped, but it certainly didn't hurt. I would say on an average, any frozen gear lasted at least as long-if not longer-than the unfrozen gears. Some months ago, I spoke with Mike Long of G-Force and asked his opinion on freezing the gears in his transmissions. He said they tried it and didn't really see any advantage in the process. However, he said the cryogenics did seem to show improved durability in reciprocating parts. I had the same conversation with a friend who builds engines for late model circle track cars and he explained he had every connecting rod frozen in every engine he builds. I bought a set of Crane Nitro Carb rockers some 10 years ago and had them frozen with those transmission parts. Last month I broke the first one of those rockers. It broke about the 1000ft mark. I shut the motor off. Had the car pulled to the trailor, replaced the rocker, got back in line. Red light in the final...Yes, that was luck. Or was it? I'd say they had 400 runs on them. Maybe the cryogenics help. Maybe you just have to put X-amount of runs on them and throw them in the trash. I may run unfrozen transmissions but I will never run rockers that are not frozen! Andy Stone B/S 1102 |
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