Just food for thought. Piston to valve, and or any "smiles" from float?

Couldn't he put a dial indicator on the cam and a degree wheel for one hole (intake & exhaust) and get the Gist of what the cam is. it wont get him all the info but he may be able to learn something. sounds like a radical cam with a blower (which isn't really needed)

I am no master engine builder but I do know the basics. right now I have to agree with what all of you are asking but until the OP can produce a cam card none of it matters. this cam could be .580 lift or .800 lift. with out knowing what the cam is the spring pressures, pushrods, etc, etc. are meaningless. I see he is in Australia so hopefully he can come back and figure out what he really has so that you guys can point him in the right direction.

Very good advice..and with the rest of the motor too.

Yup, it's like Marrying a girl before the beginning of your first date. All you really know is what she looks like clothed and have no idea what she act's like.

Huge chance she costs you a bunch of $$$$ and frustration.

Step back, get to know her every last detail and then when you are satisfied, lean into her like a pornstar on crack cocaine. :evilb:

Thanks for your feedback

I found cam specs

Valve setting Intake .020 Hot
Valve setting Exhaust .020 Hot

LIFT Intake @ cam 420 @ Valve 714
LIFT Exhaust @ cam 420 @ Valve 714

Rocker arm ratio 1.70


opens closes Advertised duration
Cam Timing @ .0205 Tappet lift Intake 44.0 BTDC 86.0 ABDC 310.0
opens closes
Exhaust 96.0 BBDC 42.0 ATDC 318.0




opens closes Max Lift Duration
Cam Timing @ .050 Tappet lift Intake 29.0 BTDC 69.0 ABDC 109 ATDC 278.0
opens closes
Exhaust 81.0 BBDC 25.0 ATDC 119 BTDC 286.0


spring requirments

part 96886

Loads closed 225 @ 2.000
open 658 @ 1.330

recomended RPM
Min 4400
Max 8400
float 9000


only thing i know we done was set the lash at 0 cold 77f ( this is what i was told was cold setting )

have never checked while hot

see what you guys make of this

anything else you think you need to know please ask

dont know piston to valve but there are no smiles
while we have the head off to repair we will be checking it

MrMalo
 

There is significant data regarding the well defined, finite levels of fatigue (and the specific cycle value) incurred using aluminum as a body material in a rocker arm construction. Durability testing (T & D) of shaft rocker systems has shown the point of failure of an aluminum rocker to be ~ 11 million cycles. That cycle rate, at an average RPM of 3500, is ~ 105 hours run time. That may not seem excessive, but to give a frame of reference, that is the cycle equivalent of running a Cup car 8500 RPM at Daytona for 43 hours. Lets emphasize here that is the point of first failure, not an average or sampling. As happened in your case, it is not uncommon to see closely sequenced batch failures when the arms are not cycled out at the end of their usable lifespan.

Fatigue is not necessarily a failure in design or manufacture; it is primarily inherent to the material property differences between Alum and steel. That figure represents the count the component reaches a cycle value that Alum becomes fatigued. The relatively low modulus (Ealum30.103 psi) of aluminum, in conjunction with the repeated cycling of the arm, through extension and compression of the spring, is the primary cause. From that point foreword potential failure becomes a possibility. There are a number of parameters that will influence the rate of degradation, but the rockers will, at some safe point, need to be cycled out or risk a failure.


What are the advantages of a steel rocker? First and most importantly are the stiffness advantage 4130 represents in comparison to aluminum. The elastic modulus of the materials is:

E steel 30.106 psi
E alum 30.103 psi

That 200% increase in stiffness is a huge advantage in minimizing deflection within the system. Any reduction in compliance nets a more accurate valve path, increasing lift at the valve while increasing the natural frequency of the rocker element of the system. I would also be wary of taking literally (and introducing into practice) the idea that compliance introduced into the system (by aluminum arms) is a valid way to damp unwanted “harmonics”.
What are the downsides to steel? There aren’t any. Steel does provide increase in mass due to the density of steel compared to Al. The good news is: with advance design and manufacturing capabilities it is possible to mitigate the mass penalty incurred using steel. A properly designed steel arm will incur only a small amount of mass increase over AL when properly executed. That increase is primarily at the pushrod side of the lever and therefore minimizes increases to the mass on the valve side. Any mass reduction on the valve side of the fulcrum, including valve diameter and mass of the spring itself pays far greater dividends than mass reduction on the PR, lifter system. The continued use of aluminum is driven largely to maintain a competitive price point in the market.

As far as value is concerned, it’s no contest. While steel has higher upfront costs, the perceived saving in aluminum is false economy. Steel has virtually infinite cycle value. With the exception of an occasional tip or bearing replacement steel will provide safe, reliable performance for the life of the engine. Aluminum will offer upfront cost reductions, however the renewal of the cycled parts will quickly eradicate the initial value.

Bob

Most solid rollers are set .015-.022" hot that I've seen. .020" super common.

Who told you O ?
Your cam card says .020 " lash hot.

The replacement schedule is probably why there are 14 pages of "good" used jesel rocker arms on eBay.

Unfortunately, I'm locked into the jesel shaft mount arms as my heads have been machined to accept the mounting apparatus for jesel stuff.

I rebuild a lot of Jesel rockers in my shop. The biggest point of failure I encounter is the bearing cages. They use a "loose" roller bearing and the cages have an extremely thin wall that doesn't offer much lateral support. They like to blow out the sides. They should always be disassembled and inspected during a rebuild. I have a grease pin that I pack them with before disassembly so the rollers stay in place for cage inspection. Often, you can feel when they are broken. They don't roll smooth.

The Torrington bearings I use when rebuilding them have the captured bearings and the ends of the cages are three times as thick as the originals.