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Any input on what shaft mounted rockers to use?
For a 347 with Victor Jr. heads; which of the three options would you pick?
Please VOTE! The new shaft mounts with stainless steel rockers is my favourite, although in the adds there is much focus on top fuel and "really harsh" racing environment for these rockers. I'm currently using the Comp Cams stainless steel roller rockers on 7/16 studs, and it seems to work very well. Will any of these aluminium rocker options be a good choice, and is there anything that makes one better than the other? Post this poll simply because I have no 1. hand experience on shaft mounts and have few others to ask, besides from you, great lot! Use is mild solid roller cam (0.64" lift, 300 duration, up to 7500- 8000 rpm). did some searches and read quite alot without finding a favourite amongst the two poll options. Last list of parts I used were simply put together by manufacturers choice and my own eyes staring at the the glossy catalogue pages... RS |
I use T&D shaft mounted system, and have been for about 6 or 7 years now. At the rpm's I turn, I don't want to worry about twisting or any other rocker problems.
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T&D or Jesel.
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B. Mine, Harland Sharp, T+D, Jesel..they are all more then serviceable. If you're not racing it, what do you intend to gain by changing what works well already. If you are racing it....consider a stud girdle. |
T&D
~Earl J |
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Z. |
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Bearing press is critical. Unless you have the capability of sizing the hole accurately. If you can't, you are asking for real trouble. And, in my experience, the Chinese can make a hole any size you'd like. They can not, however, do it twice in a row. |
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Very well, then. |
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Frank |
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I'm willing to bet a 6 pack of your favorite brew, that with similar valve spring pressures, a 289 or 302 with the spark plugs out & with a flat tappet cam & roller rocker arms will be harder to turn over by hand than a 427 engine with the plugs out & with a similar non-roller camshaft. The difference won't be as much as with a small block with the stamped rocker arms, but the BB will still turn over easier. Z. |
Well, for what it's worth I have had Crane shaft mounted alum. roller rockers for 5 years and 8k miles. No problems whatsoever. Hydraulic cam, .565 intake lift on a 418W. Track race, street race, still good shape top side.
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Z. |
Outcome
Finally I settled with Jesel's.
Although, after timing the cam correctly and checking piston to valve clearance, I figured I could have ran 1.7 ratio exhaust- I was then tempted to go with Crower (which are even more expensive...) . But then a person talked me into sticking to the 1.6 ratio. Maybe a mistake. (Because the cam is symmetrical; lift & duration same on in and ex. And I stick to the theory that this engine will do better with a little more on the exhaust side....) And I also figured ot that the SS Crower parts were not more expensive than their aluminum stuff... Well; I will have to get an assymetric cam next time. Thanks for input |
Is this why they're called roller ROCKERS?
http://i1136.photobucket.com/albums/...d/DSC00046.jpg
http://i1136.photobucket.com/albums/...d/DSC00047.jpg As one can clearly see, the rocker stud has been eaten by the rockers.... This isn't the worst example. How long will it take to break one of these studs by the ROCKING action by the rockers? I'd guess there were 0,5mm missing from the stud, in a ring- shaped pattern around the circumference. Also, the rocker have clearly touched the valve retainer. Although when thesting on the work bench, the clearence is 2-3 mm. http://i1136.photobucket.com/albums/...d/DSC00048.jpg Hope the pics are shown this time. RS |
Easy back a little RS
caprimanic Before you get crazy on this, I have seen this before with windsor motors.
6 things cause this, There is too much clearance between the stud and the rocker. sloppy in the hole. There was no stud gridle to control the rockers and stablize the studs. How many times was the motor banged off the rev limiter? Poor oiling between the trunion and the stud.The wrong pushrod length. You also have the rockers hitting the springs, see the 2 marks on the under side. I think going back through the geometery of your valve train is needed. It looks like not enough clearance. Like to see the other rockers on the under side too. What was the coil bind on this? From the pictures, I am going with over revving and banging a limiter. Valves banging rockers and cause deflection. You might also want to recheck the valves, some of the stems have a wierd wear pattern on the shafts. Looks like the chrome is being worn off. Rick L. |
Check your valve guides for wear while you're looking things over.
Under very high rpm loads, parts will move all over the place. Rocker studs will deflect, rocker arms will deflect, valve guides will start to wear in one spot, etc. The combination of all of these will cause the problems that you're seeing. Everything is dancing around and moving and the areas where you had clearance before may not have clearance anymore. I'd say your problem will be solved with your shaft mounted rocker arm setup. I'd pop the valve seals off and do a quick "wiggle" test on the valve guides... |
Rick,
He has admitted in previous posts to turning (or trying to) this engine to 8000 rpm on many occasions.....therein lies the problem.... Parts do weird things at higher rpms without proper reinforcement and blueprinting....he's seeing the result of that. The valves do look worn, that's why I told him to check the valve guides. With all of the wear on the parts, I'd say the guides are catching the brunt of it. |
You are the man
blykins Brent we both have seen this for many years. He's liucky to not have a motor in his lap with this kind of abuse. Over revving and everything got smacked. Have a good one. Rick L.
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What's a rev limiter:cool:??
Yes, yes- I see all your arguments help explain the result here. Been thinking of stud girdle and rev kit, but hope lighter valvetrain & shaft mounted will do the trick. Yes, I'm also putting in a rev limiter. (But what should I dial in??? The knob goes all the way to 10.000....) Be seeing you for future, highly appreciated, discussions. |
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