Any input on what shaft mounted rockers to use?

[zrayr]

Originally Posted by Zoom This

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.

just curious, what heads are you using ? I used to live up near you (Silverdale, WA) and still miss it 17 years later. Hope you made it thru the blizzard OK.

Z.

[Caprimaniac]

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

[Caprimaniac]

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.




Hope the pics are shown this time.

RS

[RICK LAKE]

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.

[blykins]

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...

[Zoom This]

Originally Posted by zrayr

just curious, what heads are you using ? I used to live up near you (Silverdale, WA) and still miss it 17 years later. Hope you made it thru the blizzard OK.

Z.

Heads are Edelbrock Victor Jr., polished, ported and bench flowed. Car just doesn't get the use and miles here as it did when we lived in the SF Bay Area 3 years ago. Getting to miss the sunshine during the winter months.

Bill

[Caprimaniac]

Hi.

while installing these Jesel shaft rockers, there were some issues. Instructions say use shims if you have 0.100 longer valves. Do I have longer valves in the edelbrock heads? No, they're 4.911 long.

Does it need to be shimmed, then? Well, lets look at the rocker geometry.

Here's picures showing how the roller tip will hit valve when at start of valve lift. First without, then with shims.

As far as I can see, the roller hits the valve tip "better" with shims.

I tried to measure horisontal roller axis VS fulcrum axis at 50% valve lift (no pics, sorry), but I couldn't really find much difference. Can do better by painting a line on the rocker, for instance.

So; do I use the shims or not?
(I did find some information here, but not very helpfull:http://www.hardcore50.com/vbulletin/...ad.php?t=51083 )
Anyway, here's the pics:




Hope your weekend is great...

[blykins]

Do what you have to do to make the geometry right. The second picture definitely looks better.

Take a felt tip marker and color in the top of the valve stem. Roll the engine over several times and see what pattern you have.

Make sure that you have the valve lash set for the particular rocker arm that you're looking at. Set the intake valve when the exhaust valve is starting to open, set the exhaust valve when the intake valve is starting to close.

Also check the pushrod clearance through the head. Sometimes with higher lift cams, you can get the pushrod very close to one side of the hole. Make sure it's clearing on the underside as well, where the pushrod goes up through the bottom of the head in the lifter valley.

[RICK LAKE]

caprimaniac Cap I got to be honest with you, both look poor IMP for geometery of the rocker on the valve stem. Did you give the info to who ever you got the rockers from about heads,camshaft lift, valve springs, head work?
IMP neither picture is a good geo for the head. Rocker is really pushing on the edge of the valve stem this is going to cause per wear out of the guide and valve seal. You know that look, blue smoke on startups and going down the road when running over time. I would fine out what the max shims you can add to the rockers. You need to make sure the rocker does hit the edge of the retain for the spring through FULL motion on the rocker. You are going to need custom length pushrods. Mark the top of the valve stem and do a test to where the roller on the rocker is rolling. The closer to center the better it is. You may not get perfect center through the complete cycle of the rocker but a would want it close as possible. The picture #2 looks like the rocker is closer to center of the stem?? You also will need to grind the inside of the rocker arms for a little more clearance. Put black marker or paint of the valve stem and do a cycle. Try and have the rocker at about 40% centered on the stem, run the cycle for center and then go from there. Raise the rocker a little and lengthen the pushrod until you are centered. The stud mount for the rocker studs will stablizer the assembly. Check this a couple of times after road testing for torque on the shafts and lock nuts. Rick L.