Is the Patton aluminum crank hub enough weight?

[TR6BILL]

I pulled my fan off and replaced with an electric fan. I have Rick Patton's aluminum crank hub replacement and am wondering, is this enough weight? On the rear I have an aluminum flywheel and this hub so I wonder if I need more weight on my crank. I still am getting a very unnerving chugging noise out of my crank at low or stall rpms and am beginning to think I need more centrifugal weight on my crank. The crank is stock and has never been super-balanced. All the bearings are new and good shape. Wonder if Rick would make up a steel crank hub? Any thoughts???

 

[BobbyD]

Bill........ I've never heard of having too little weight as causing a problem but I haven't heard of lots of stuff. The only thing with Rick's fan kit is making sure you engage the two dowel holes so that it lays perfectly flat. Other then that, you torque the bolt to spec.

 

[DrEntropy]

The "too little weight" thing is NOT applicable to a crank. Out of balance maybe, but you've gone to extreme lengths to avoid that, too...

Look to timing... or better: don't "lug" it. With what "lightening" you've done, your "take-off" RPM will be much higher. 2,500 and OFF ya go. I think you're in a "reduced torque" issue due to not enuff rotating mass...


But that's just *MY* WAG.

 

[Brosky]

Mine is just fine with the aluminum flywheel and Patton eliminator.

That fan extension was hardly what one would call balanced and the whole strategy of a crankshaft directly spinning a fan is not based on increasing horsepower, better cooling and increased efficiency.

 

[sixer]

Hi Bill,

These replies are on the mark about as far as too little weight. Bob makes a good point about the dowel pins not being engaged but you would probably see a serious wobble if that were the case. You might check to be sure the eliminator fully bottoms against the harmonic balancer. TR6 crankshafts are cut off by a saw and are not always exactly the same length at the front. If you look at the end of a crank you can still see the saw marks. Anyway if yours was cut a tad long it's possible that the eliminator bottoms out before being completely tight against the harmonic balancer. Same thing can happen if the slinger or the shims inside the timing cover behind the harmonic balancer are omitted. Over the years I've seen three cases where the eliminator did not exert enough pressure on the balancer. The eliminators now produced are cut extra deep so this should never be a problem. No matter what the case, if there is a problem with the eliminator I'll glady replace it or even custom make one just for you. Please let me know what you find.

Rick Patton
75 TR6sci
74 TVR 250M
pattonmachine.com

 

[poolboy]

I sure noticed the difference without the red fan and extension and it was good. Seemed like I lost less rpms during gear changes.

 

[alfa33047]

Just a question; are Triumph motors, internally balanced or externally balanced. My best guess is internally balanced because we are able to swap flywheels with no problems of vibrations. I do not know. Bill C. Mesa, AZ

 

[Brosky]

Nothing but a drag on the engine, PB, so that would be a natural occurrence.

And hello Rick!

 

[TR6BILL]

Thanks, guys, and hello Rick. All good replies.

 

[angelfj1]

I sure noticed the difference without the red fan and extension and it was good. <span style="font-style: italic"><span style="font-weight: bold">Seemed like I lost less rpms during gear changes.</span></span>

poolboy

I disagree (respectfully)! :blush: What you are saying seems counterintuitive. Any rotating mass connected to the crank i.e. fan extension would tend to store rotational energy and thus dampen out variations in speed. For example, have you ever seen an antique hit-and-miss gas engine? These are typically one lungers. relatively speaking they had huge flywheels which served as energy storage devices. These were necessary because depending upon the load, these engines might not fire more than a few times PER MINUTE. Now this is an exaggeration to make a point. But, I would think that removing the fan hub extension would have the opposite effect and that you would actually lose speed would occur faster. To further support this theory, I believe that lightened flywheels are considered desireable by race engine designers because less rotational mass results in higher rotational acceleration or rate of increase of engine speed for the same fuel/air input. This is just my opinion. Maybe there's a mechanical engineer out there that can chime in.

 

[poolboy]

FJA, I can't argue with the laws of Physics, but that's what it feels like.
Giving it some more thought as to why I feel that's that way, I do come up with a couple of possibilities.
The actual fan doesn't weigh much at all, so it's not that much mass. It does, however, encounter quite a bit of wind resistance. I think that the engine is responding to the lack of air resistance rather than the weight of the fan.
As far as the fan extension, yep, it is heavy, but the weight is concentrated so near the axis of rotation of the crank that eliminating it wouldn't cause the crank to loose as much momentum as removing weight from something with more weight further out from the axis, like the flywheel.
That's just my theory, anyway. But it is true that's what I noticed and the car was only down for 2 days while I was doing all that, so I had a pretty good recollection of how the engine felt before.
The fan definitly doesn't add momentum to the equation and how much eliminating the extension reduced the momentum is speculation on my part, but the closer to the axis of rotation, seems like the less momentum effect.
Any of that make sense ?

 

[prb51]

Poolboy,
I had exactly the same 'feeling' (seat of the pants) when I removed the nose extension/fan on my TR3 and I believe your synopsis to be spot on. The fan immediatley slows the motor when allowed to (shifting..lifting the foot etc) and the engine spins more freely without the windmill up front.
There may be some rotating mass effect that's positive but I suspect it's very little (as per your explanation) and defeated by the wind resistance.
The first thing guys on Kas's site tell you is "drop the lump up front and the fan".

 

[19_again]

You've got me wondering whether to get one of Rick's rigs, but I am also confused with respect the idea of the fan providing a drag. Since you replace the mechanical fan with an electric one, where is the gain? I understand the weight issue, but a fan behind the radiator is still a fan, no?
Mike

 

[poolboy]

19, the difference is that with the TR fan, the crank is turning it, using HP to do so.
The electric fan is, well, electric and puts no drag on the engine per se.
I have Rick's fan eliminator as well.
BTW, I doubt if the electric fan will even come on, if it's thermostatically controlled, when you are traveling over 20-30 mph.
I know that mine doesn't and it get's into the 90's down here in the Summer. A manual overide switch in the cockpit is good to have though, for when you expect to get into traffic or you figure on spending some time at idle, like adjusting the carbs or ignition timing, just to get a head start on the cooling.

 

[Opa]

FJA
Yes hit n miss engines have huge flywheels and will be a source of energy storage,but more importantly the flywheels were for balance of the rotating mass.Also to be able to start this type of engine, heavy fly wheels were needed to assist in rotating the engine over top dead centre as they are mostly hand start engines. I have a number of these types of engines at our antique equipment mueseum.In the attached pic of our Waterloo boy you can see the counter weight cast into the flywheels.It's a 1 1/2 hp hopper cooled stationary engine 3 1/2 in bore by 5in stroke max 500 RPM. I also have John Deere 3HP,A Sandwich 1 1/2 hp,a Judson 3 hp,an IH 6hp horizontal Famous,a 6HP Witte headless,A 3 hp Atlas vertical constant runner,A "T" head Fairbanks Morse.The oldest of the bunch are the IH Famous 1906 and the "T"Fairbanks also 1906
As of yesterday a few of us have started resto on a Ruston Hornsby model 6H Diesel horizontal water cooled.
Specs. are 81/2 in bore x16 1/4 in stroke.approx 25-28 HP at max 320 RPM.Engine weight 2.5 ton,water cooled. If any body is interested in pics. can post some later.

Sorry didn't mean to hijack thread,but old engines are another hobby I enjoy.

 

[angelfj1]

To quote Will Smith,

<span style="font-size: 12pt"><span style="font-weight: bold"><span style="color: #FF0000">"I GOT TO GET ME ONE OF THEM"</span></span></span>

 

[kodanja]

<span style="font-size: 14pt"><span style="font-weight: bold">SHE THINKS MY TRACTOR'S SEXY!!!</span></span> <span style="color: #000099"> </span>

 

[angelfj1]

Casey: very nice engines! I live about 20 minutes from Kinzers, PA. Have you every heard of "Rough & Tumble"?

Rough & Tumble

If your ever out this way, check it out. They are primarily into live steam, but they have many gas units like yours.

 

[Opa]

...as a matter of fact ,she does!I mess with a few of those as well,here's my favorite rite now....must be the name 39 Case model D

 

[Opa]

WOW what a nice operation.......we are much smaller than that,I currently have about 100 fairly active members,and I am the current president(4th year).We are on 7 acres of land,of which approx 2 acres houses the buildings and static display areas. We have a sawmill on site which was steam operated until about 8 years ago and is now diesel powered.We still have a few live steam machines on site but they will soon become static displays as insurance costs have taken all the fun out of old,operational equipment.
I will put Rough and Tumble on my to do and see before I crook list. Would be a nice trip in the TR from here.