Crane Xr3000 stable vs, HEI?

[Tony D]

"Timing mark still dances above 3000rpm.

Maybe they all do that??"

 

For the THIRD time: MECHANICAL DEVICES INHERENTLY HAVE SLOP FROM THE FIVE AREAS LISTED IN MY FIRST POST

 

What part of this aren't you absorbing.

 

I think it's the 'Mechanical Devices all have slop in them inherently and you can't eliminate it, only MINIMIZE it.'

 

The thing is smooth on the springs, until it hits the stops, then the inherent lash in the gears driving the upper parts comes into direct play.

 

"My motor man says the Crane XR3000 is a POS"

Probably because it's not the POS he sells at his shop. For your stated use, likely it's overkill.

 

Statement:

Way to take nothing, turn it into something, then solve a problem which doesn't exist in the first place.

 

Are you a government employee, bychance?

 

 

You want smooth, steady as a rock timing?

Do what the OEM's ALL did WITHOUT EXCEPTION: Crankfire Timing.

Edited October 22, 2011 by Tony D

[duragg]

Hey Tony, appreciate your message, but the tone makes you sound like an *******. You ask if i am a government employee? I will let that slide for now.

 

What part about mechanical devices don't YOU understand? I think its the part about centrifugal governors, so let me help you.

 

I own 2 aircraft now which have a combined total of 9 centrifugal devices of identical design which all function flawlessly. Ok? Prop govorners, fuel control units, overspeed and underspeed controllers, mag timing, etc plus a shitload more in various cars and aircraft I have owned, managed, flown and fixed over the years.

 

Yet this ONE is giving me trouble so I will investigate, determine cause, and fix it. That's what is going to happen here.

 

Please don't stampede through this public thread with the - I told you so- it can't be fixed. Just give up condescending bs. Ideas with merit are valuable. Typing condescending remarks in all caps is not valuable or helpful.

 

Crankfire is an option. But I also like the idea of the MSD box that does digital programable timing and delete the flyweights. Today for sport I will lock down the flyweights and see what happens.

 

 

Good morning!

Edited October 22, 2011 by duragg

[NewZed]

Why do I need any centrifugal advance at all?

 

This is a Rat-racer driven 5 times a month, mostly all at 3000+ RPM and full throttle.

A little cruising and idling around.

It stinks, full of holes, stripped interior, NOT a daily drive.

 

If it is hard to start... even better.

 

Running 50/50 100LL and 91 octane fuel.

 

Do I need it for starting? or for pinging reduction?

Educate me please.

 

Pretty sure that lots of static advance will make your engine hard to start and might have other consequences at low RPM.

 

If you're pondering taking out all of the adjustable advance, both vacuum and centrifugal, and it's just a "Rat-racer", why are you worried about a degree or two of timing error, at a specific narrow RPM range. The error probably averages out over all 6 cylinders and is such a high frequency that you don't feel it when driving. If you feel something, it's probably not the timing bouncing. I may be mistaken but I think that the main reason to worry about steady timing at high RPM is to get the most power from all cylinders without having random detonation events. Modern cars use the ECU and sensors to run at the "ping" threshold, so timing error would be more important, leading to crank fire. Or it could just be cheaper to manufacture. Car makers worry about pennies per car.

 

It's probably disturbing to see on the timing light but most likely has little effect, unless you're big-time racing. Have you quantified, in degrees, how much "scatter" you're getting?

[duragg]

Problem is the timing scatter begins right around cruise RPM (2500-3500) and with DCOE carbs that is a real tricky transition range between progression ports and mains. I run the motor pretty hard and it is on the ragged edge of detonation. I am guessing the timing mark dances about a total of 3 to 6 degrees. Could be more or less. Tried taking a video but it just caused my Android phone to shut down and reboot.

 

In the eternal pursuit of making the DCOE carbs happy I would prefer to spend some time getting ignition nailed down.

 

I want to either crucify or exonerate the Crane XR3000 which has been condenmed by some.

Heading to the shop to lock down the advance weights and try that. If it still scatters at least I know to leave the weights alone.

 

This type of mechanical detective work and creating solutions is a real pleasure to me, despite how it seems. So there is no pain in this process for me. All learning.

[Tony D]

"What part about mechanical devices don't YOU understand? I think its the part about centrifugal governors, so let me help you.

 

I own 2 aircraft now which have a combined total of 9 centrifugal devices of identical design which all function flawlessly. Ok? Prop govorners, fuel control units, overspeed and underspeed controllers, mag timing, etc plus a shitload more in various cars and aircraft I have owned, managed, flown and fixed over the years. "

 

You mean like a Woodward EGP or EGB, PG or PGL Steam Turbine Governor (or used on various ICE's for decades)? Or perhaps the Governors on Continental Lycoming Packette PE150's 90's and 75's...Been there, done that, Factory Repped it for a while...

 

(Incidentally, most one of those devices you mention rely on the flyweights dampened with springs and in constant fluid motion---in normal operation they NEVER should reach a 'locked' point where the levers push against a solid stop...other than the limit screws on the arms. THAT is why you see it in the distributor and not the other devices, they are on the ramp dampened by springs and in some instances hydraulic pressures and usually have VERY tight drive trains which don't have excessive lash or operate at reduced oeprational speeds so that this effect is minimized...)

 

The government employee reference was simply the obsession at using a DIGITAL DEVICE (the dial-back timing light) to quantify a mechanical device which has inherent lash in it: you invented an issue, which is not in practical application an issue whatsoever then are spending an inordinate amount of time looking for a solution, which ultimately will be what everybody (or at least I) was telling you was going to be the ultimate outcome: it's not going to change anything. It's my observation of many Governmental Programs, if it offends you then I apologize for calling you a Government Employee---it was a rhetorical analogy based on my observation of the similarities, nothing more. Nothing personal.

 

In all the above devices, when using a DIGITAL timing mechanism, you will see VARIATION in EVERY instance. They are not 'smooth and flawless' --- including those damnable governors. The fluctuations are EXTREME if you have the right analytical equipment. Using period correct diagnostic devices (in some cases FAA Dictated stuff) you will see 'rock solid' numbers when in fact the cyclic variations of the flyweights on the levers balanced against the hydraulic cushion is something that is VERY complex to get balanced. And even when you do...IT IS STILL A COMPROMISE.

 

Hence looking for something that is 'perfect' when 'perfect' doesn't exist!

 

I type all caps as in voice communication I would raise my voice one octave, or speak louder at that point to EMPHASIZE that point.

 

You asked if it can be fixed: yes it can, asked and answered: DIGITAL CONTROL OFF THE CRANKSHAFT.

It's even legal in SCCA Competition for some reason. The number of Electramotive Digital Timing boxes on Z's increases every year......

 

The Crane (as stated originally) only processes signals it receives. The reasons for any spark scatter have been delineated in detail. If you have spark scatter, it's not electrical switching error. Most definitely at that RPM point. If you ask for an answer, and want to ignore it, at least say that is what you're doing rather than continually restating the issue like nobody has addressed it previously.

 

I have already stated the universal fact that all OEM's have agreed exists: The timing variation can NOT 'be fixed' it can ONLY be 'minimized'---and for OEM's these days, that is not good enough! When you come to the same conclusion, you can look back on this I suppose. What you do at that point is up to you.

 

You're going to 'minimize it' you won't 'fix' it---which to me means totally eliminate it. Unless you start using more period correct instrumentation which will not reveal the scatter.

 

If you want the quickest fix, just static time it. Then you don't have any problem as you can't see anything. I know people who static time their cars using points and a test light and will argue up and down their car also 'runs flawlessly'...

 

To them, it does. They just don't understand the dynamics involved.

Edited October 23, 2011 by Tony D

[Tony D]

" But I also like the idea of the MSD box that does digital programable timing and delete the flyweights."

 

This will also suffer from occasional windup in the gears associated with the distributor drive.

As I stated in the past, we used the E-Motive small Hall Effect Pickup to time our Bonneville Car to 8500+ rpms, which is the limit of the smaller wheel per E-Motive.

 

We went to full sized crankfire on the damper for the engine running above that point as we started having intermittent failures from the poor resolution of the small disc on a hall-effect sensor even turning at half-engine speed.

 

The MSD box will not show spark scatter with the timing light you are currently using. It will 'fix' your problem. But if you start using the same test equipment we use, you will see that lash show up in timing variation.

 

Hell, we haven't even gotten into triggering of the timing light based on where the rotor fires to the cap tower variation...

 

I guess I don't have any understanding of this subject so I'll just bow out now. I'm kinda in the same boat as NewZed in this regard...I don't see the point for the stated usage. It's making work to no end effect.

[duragg]

The essense is:

I can't have the timing start dancing about in the 2800-3200 range.

If it starts dancing at 4000 I am fine with that as the DCOEs are firmly on the mains at that point.

 

I'll just have to experiment to see if I can delay the onset of instability.

 

There is a future and a plan with this car so these issues I am dealing with now will help down the road.