Any input on what shaft mounted rockers to use?

[blykins]

Set it at around 500-1000 rpm higher than the peak hp rpm. There's no use in turning the engine 8000 when it quits making hp at 6500.

[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...

[madmaxx]

I think the correct lenght pushrod would take care of the misalignment. It appears it is edge loading on the top relaxed position.

[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.

[Caprimaniac]

Oh, you're all awake at this time... I've having a bad morning with a hangover from yesterdays beer & that awful rom & coke.

Anyway, you all have good input, and I agree with you all -partly. Yes, it need to go with the shims. And yes, the roller will still hit the valve stem tip at the inner part (towards the shaft) of the diameter. This is desireable because the rate at start of valve opening will increase and a increase in valve giude wear can be accepted.

By using more/ other shims it might be able to get the geometry even better. But, after all I have read & understood, I cannot see there's much to gain.

Yes; I will check pattern on stem tip. After rolling over a cycle, it looked very promising, rolling to and fro the centre.

You are correct on the pushrod clearance, Blykins. Very tight, but OK with a 5/16" rod. (again by eye, will measure.) Although, I have been looking at going to 3/8" PR... What do you think?
A 5/16" cro-mo one piece 0.080 wall will hold up quite a bit?

And I'll need 0.05 shorter PR for the inlet than the exhaust as well.

What I thought of the Jesel parts? Looks quite sturdy. BUT. If I had the tools to fabricate, I might have done otherwise. Why not make the platform in aluminium instead of steel? The size makes it very heavy. And why not use a one- piece shaft? OK; much easier to change one unit with two shafts. And with a one piece shaft, it might be other issues regarding spacing the shafts.

But, I think the instructions that came with the parts are a bit too vague. I was also shure there were a PR lengthchecker in this kit, but there wasn't. (spent 30min making one up while I could have one for 11$).

Let's do some more work & this will be ready in a day or two.

[blykins]

What's your open spring pressure?

[RICK LAKE]

caprimaniac Any chance of getting a first name?
The supports for a T&D or Jesel setup need to be made from steel. These systems will turn 10,000 rpms. You have a couple of issues between the two. Aluminum weaker than steel, Aluminum more exspansion rate than steel, strength again goes to steel. Shorter life than steel with fatigue.
Aluminum is cheaper and lighter and could be used on system where a rpm limit of 7,000 rpms is done, but again how many heat cycles are the limit??
There are a couple of articles in HotRod,Car Craft, Hot Rodding, and race motor manuals that show you the correct geometery for the rockers to valve stem. As for custom pushrods, Smith does the quickest and best job for correct length needed. As far as going to 3/8 pushrods, make sure the rod clears the adjust location and doesn't hit the back side of the rocker. Make sure the opening in the head is large enough for clearance through the whole cycle of each pushrod. 3/8" has less defection than 5/16". You might want to look into tapered pushrods. If you are going to still do 8,000 rpm hits, 3/8" will hold up better but may endup with having to control more weight. Good luck. Didn't jesel have a light weight shaft setup of windsor motors? I thought they machine a "I" groove into the top of the rocker to remove weight. Rick L.

[SP01715]

I ran Jesel in a blown BB Chevy. We had some valve train failures prior to switching to Jesel, and no more failures after that.

[Rick Parker]

It would appear that the cam in use is putting the rockers at their maximum travel and past it, hence the marking of the studs. Perhaps a different choice of rocker might be needed, or a different ratio.

[Caprimaniac]

for all kind of input. Great news Jesel solved your problems, BBchevy.

Yes, Rick. I'm not sure what kind of name you are talking about, actually, but MY name is Rune. Like in the writing of the vikings. They used what are called the Rune alphabet. Carved in stone and wood. Ended around year 1100.

Yes, there's the Jesel Pro series, and they list applications for the SBF, including Edelbrock vic JR. "Mohawk" leightweigth versions as an option. 195 VS 210 grams for each rocker..... That's 7% lighter... Not much. Why didn't I choose these items? Maybe because I was in a hurry and needed to finnish the order before christmas. May have been a bad choice, but I haven't looked closely on what I could gain going pro. You can get needle rollers on the tip. for very high pressure springs.++ I guess the sportsman will be more than enough. (Untill my dream of a 10.000 rpm reliable V8 is coming through....)

On the rocker studs, Rick: I cannot see how the travel could run out on the opening movement of the rockers. The lift is only .613. They have the same carvings on both front- and backside as well.

What I have here for you is a not very good picture of the felt pen test (the ink had dried up to much before rollin'):



As you can see for yourselves, folks, it hits on the inner part and move maybe a bit over centre. Looks quite good.

And here's a funny picture showing what has to be done to the body to get the cam out while engine is sitting in the car. (Puh; this will have to be the last time I ever do engine work with the engine in. My back's hurting!):



(Maybe look familiar to someone who ever worked on a Capri MK1?)

Rune S.

[Caprimaniac]

Who forgot toclean under his nails?

Someone have to do the dirty work!

[Caprimaniac]

Let's get into the spring pressure discussion once more... Well. As it looks now, I wil have the springs installed at 1.87" height at 165 lbs. 435 lbs over the nose (1.27" height).

They used to be 145 lbs open and 380 lbs over the nose.

With lighter springs and hardware + the shaft rockers, my plan is that the spring pressure will be perfect (!). At least it's a starting point and there is no problem to shim the springs to 190 closed and 470 over the nose.

My plan is to order in the pushrods tonight. Any last calls on opinion on diameter? Thinking, personally, that 5/16" comp hitech will hold up to this. Or is 3/8" the way to go? (Both are cro-mo 008 wall thickness.)

Thanks
Rune Skiaker

[blykins]

How many rpms are you planning to turn?

On my 347 ci 1/8th mile engines, I run about 250 lbs seat with close to 600 lbs open pressure. These engines peak at about 6500 and are shifted at around 7000. An .080" 5/16" pushrod would work, but I would prefer to use a 3/8" pushrod if you have the room. Spring pressure is king here, especially when turning the rpms that I think you're going to try to turn. I run some hydraulic rollers at 165 lbs seat pressure. You need more.

[Caprimaniac]

Hmm. Ok; lots of folks telling 5/16 will be OK, so I'll stick with that. Even makes them couple of grams lighter.

Will set RPM limiter at 8000. But, since the "thing" is going on the dyno, I might put move it lower down on the scale then, depending, as you said earlier, on rpm at max HP.

In a discussion like this, "racing" is coming up often, yes. There are lots of various degrees of racing. Nascar, oval track, top fuel/ mod street drag (+canam, lemans series+++) are all serious "all out" constant maximum RPM racing. On the other hand we have grassroot oval/ street course racing, Historical classes, "GT-racer" (as seen on TV..) and other little more gentle & budget(?!) friendly "racing". Our racing are in the 2. category. We do not have the drivetrain nor the budget for an all out racing class- at this moment.

Is this making sense? Or is it like "if you make 8000 rpm at the end of that long staright in 10 laps in a row, you have to use 600 lbs springs"?

[blykins]

Street engines usually don't get pulled to 8000 rpm, that's my point. Race engines do.

I don't have a list of all components that you used in that engine, but knowing that you have a solid roller, I would not be comfortable with your valve springs for anything over 6000 rpm.

Valve springs keep your valves open/shut and the lifters on the lobes. Why take a chance of hanging a valve open? This is a very important part of the engine and since you have it all torn down, why not put the correct springs in?

I can't remember what you were using as a camshaft. Did you end up changing grinds, or did you reuse the same cast core camshaft? I, along with several other engine builders that have been watching this thread have advised you on which cam core to use, which springs to use, etc. I haven't really seen you take any of that advice, but yet you keep asking for it publically.

[Caprimaniac]

Hello again, Brent.

Yes, I see your point. But remember that this cam/ lobe profile (no, I didn't change it) is supposed to work WELL with 155 seat 420 open springs. And I don't think the engineers at Comp are that stupid, to be honest. I guess this means the cam has very "kind" open- and closing ramps.

The "wildest" I would dare to go (as a start) is 173 seat and 450 open (installed spring @ 1.850).

As you know, it's a waste to use too stiff springs. If someone comes up with a formula how to compute the "ultimate" valve spring for a given combination, I will gladly like to try it out.

As a fact, while I put up the "what valvesprings to choose" poll, most voted for the comp standard values for the cam.... But that doesn't tell us anything, does it?

But, it's kind of hard to choose when you have to guess.... On the other hand, I have no problem taking the valve springs off to shim the springs while the engine is in- in case of finding valve float or other problems during testing/ dyno.

Hey, someone: pick up my data and show it into your formulae. Let the math tell us the numbers. One of the few things to trust: exact science never go wrong.

Let me think for a day or two- or until someone comes up with the formulae.

RS

[blykins]

Capri....

I've spent a great amount of time to help you out with this engine and you have basically ignored everything that I (along with a couple of other professional engine builders) have said, only to put stock and faith in several forum polls. Now you're asking for a "formula" from a random forum member. Your chewed up rocker studs and rocker arms were not because of bad assembly procedures. It was because your engine was losing control of the valvetrain at high rpms as I told you from the very beginning. Now you have replaced the rocker arms with a very expensive shaft mounted setup and you will still lose control of your valvetrain at the rpms that you're wanting to turn.

If you would have bought a billet cam, the correct springs, and a stud girdle, all of this would have been an after-thought and you would have spent a lot less money.

Experience and past data are tremendous helpers in building the right engine. Forum polls and magic formulas are not.

Since I have been wasting my time typing all of this repeatedly across 2-3 different threads, I will now wish you the best of luck.

[Caprimaniac]

Actually, I thought was going to do some kind of appologize since last time I posted. I guess I'll do that anyway. Yes, and once again to thank for all kinds off input and help.

Anyway. After looking through the Crower camshaft catalogue, I noticed the cams were put up with a RPM "limit" following a +. Meaning, you can take them higher, sort of- maybe by changing the cam timing.

However. Crower also put up two different kits of valvesprings for these cams. One for "limited street use " and "68380X2-16 For rpm up to 8000 plus. Race only. Seat: 1.800" @ 197 lbs / Nose: 1.200" @ 470 lbs / Coil bind: 1.110"

This is the spring installed, although I did choose 1.85" installed height, which gives 173lbs seat.

I know I've been told otherwise- go 200 at seat. I will take responsibility if things go wrong, and even post a warning, yes.

Lets say... If installed at 1.8" height. 0,613 lift, will give height at fully open at 1,187" Coil bind is at 1.110. Will that be enough clearance? I think so. But what happens if I get a new cam with .925 or .680? There will be trouble. At least at .680.

Brent; It's been a pleasure discussing. Hope I some day get enough experience so we can really get into details.

Yes, I've been a real stabburn old man. And I fear I will be wrong in the end....