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Author Topic: Inline-four crankshaft  (Read 214382 times)

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Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #165 on: February 11, 2015, 12:57:22 AM »
Yes, I'll be "careful". One main attribute of my housing is its uninterrupted full-round internal shape. The fairly small clearance to the sample's O.D. makes the mounting of the housing possibly more of a concern than its integrity- especially considering the vibration energy if breakage occurs (causing imbalance).

Truth be told, I need to look harder at the shielding of the pulleys and belt- the belt speed will be around 150 ft./sec.! Way over any "intended usage" of a vee-belt. I've neglected to do any calculations of expected "ballooning" of the belt runs- guess I'd better look at that- might need idlers on the outside of the runs.

Elektron's robust design manual has a full chapter devoted to combustion considerations of magnesium alloys. I've read it at least twice so far. And this isn't my first time machining magnesium; the GE apprentice-tool&die shop I started in (1958) got some such jobs, and we had a couple of training sessions on the dangers.
« Last Edit: February 11, 2015, 01:06:22 AM by Jack Gifford »
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Offline jacksoni

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Re: Inline-four crankshaft
« Reply #166 on: February 21, 2015, 07:04:21 AM »
Designing "by proven example" (aftermarket belt cam drives of race V8 engines with cam loads/speeds similar to mine), I've decided the belt should be 8mm pitch and at least 30mm wide (170 tooth, 53.5", characteristics of Gates PowerGrip TT2 series). I haven't yet seen such an OEM drive.
JACK- Your reply to my thing abut cams in MM's thread prompted me to revisit this. I have designed a cam drive for my engine and the question of cam loads- that is how much power to run or torque to turn- has come to my mind- with the help of the Gates Design IQ3 software which asks for loads or hp or torque needed and it will tell you how big the belt needs to be. I am using a Polychain GT belt 21mm wide. The Polychain GT seems to be their best quality belt but I can't fit the next size up (36mm IIRC). Unless the load is way off what I think, this will be good. Anyway, have you tried the software and do you have any clue how much power it actually takes to run a valve train? There are lots of small Japanese and other 4 cyls with smaller belts but maybe not the spring pressures. I am using a DOHC, direct acting bucket follower with peak springs in the 300lb range. MY head was designed for chains and the cams are close together so that limits size of cam pulleys, thus crank pulley tooth count would be too low (I think) so am driving the cams from the front of the stock, Jesel belt driven, cam location. Bit convoluted, yet to be proven....... :|
Jack Iliff
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 G/GMS-182.144 2019

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #167 on: February 22, 2015, 01:32:37 AM »
I've gotten temporarily away from the cam-drive area the last few months. I'll get back to you in awhile.
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Offline generatorshovel

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Re: Inline-four crankshaft
« Reply #168 on: February 22, 2015, 03:16:48 PM »
Jack, I realize my load load levels are far below your needs, but I spun this engine to 12,000 rpm @ Lake Gairdner a few years back , with no problems

 HTD P24 5MH 25  ( Crank )
 HTD P48 5MH 25 ( Cams )
Tiny
Tiny (in OZ)
I would prefer to make horsepower, rather than buy, or hya it, regardless of the difficulties involved , as it would then be MINE

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #169 on: February 22, 2015, 10:09:28 PM »
Tiny (?)- I like the looks of that. Were there any unforeseen issues?
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Offline generatorshovel

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Re: Inline-four crankshaft
« Reply #170 on: February 22, 2015, 11:14:15 PM »
Tiny (?)- I like the looks of that. Were there any unforeseen issues?
No issues, apart from loosing partial oil supply to the big end one year, the following year it managed 87 mph on a 71 record, with my mate's "jockey" son on it, he had team orders, 11,500 rpm, no more,,well he noticed it was spinning at 12 in the 3, buttoned off and still got 87 ,,I told him NEVER to follow team orders again, lol.
It's full of goodies now,lost the radiator and gained a tank, upped the c/r to 11.7/1 (fuel) planned on APS mods, the got sidetracked with the 250.
I had concerns regarding the small crank gear, but like you, have limited room 'tween the 2 cams, there is no signs of belt stress after 9 wot miles + return & test runs
http://youtu.be/Uh6mtzR9Yr4
Tiny (in OZ)
I would prefer to make horsepower, rather than buy, or hya it, regardless of the difficulties involved , as it would then be MINE

Offline jacksoni

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Re: Inline-four crankshaft
« Reply #171 on: February 23, 2015, 07:57:05 AM »
In researching belts I was looking at the modified curvilinear tooth which is a bit "better" than the similar HTD which is better than the trapezoidal traditional ("Gilmer") tooth design. Most of the cam drive belts in HTD or modified curvilinear on factory engines were 8mm pitch, a few at 3/8 so I mostly looked only at those. It looks like you are using the 5mm pitch, Tiny, and it worked fine. Jesel belts are custom 3/8 pitch HTD belts and use a 24/48 or 27/54 (I think) pulley combo. These are not even close to fitting what I needed. The biggest I could fit  ended with a 34 tooth pulley on the cams which are about 3.8" diameter. That would require a 17 tooth crank gear that is less then 2" in diameter and not made that I could see in standard sizes though a custom might have been possible. That would have given less than 8 teeth engaged on the crank and though I did not speak with an engineer about it, reading suggested this was not going to work. Anyway, I am using the double belt set up I mentioned before with the best belt Gates makes and will see. I will let you know. I just finally heard from JE they are making my pistons ->1month on a 2 week guarantee for custom pistons :( - Hope to have running by early April (good luck with that !) so I can make the May ECTA meet.
Sorry for the hijack, Jack, but it sorta goes with what you are doing as well.
Jack Iliff
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 G/GC- 176.245  2018
 G/GMS-182.144 2019

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #172 on: February 24, 2015, 12:59:03 AM »
No hijack; it's all good.
To begin answering you- no, I haven't attempted to estimate the power to be transmitted through my belt drive. I'll probably skip that, and use the example of existing aftermarket belt cam drives (8mm pitch, 25 mm width), which are being used satisfactorily in drag engines with extreme loads, compared to what mine will be (close to 1" valve lifts, open valve loads up to 1,200 lbs versus my .625" lifts, open loads 590 lbs.). I've got room for 50-tooth cam sprockets, so it should work out with 30 mm width; just need to source the pieces, then machine custom hubs for my cams and crank.
I wouldn't call it "convoluted" to drive 1:2, then 1:1 to the cams. I considered that for my engine- since it would shorten the long belt spans I'll have. But in the interest of "shortness" in front of the block (also need to fit in a 3" wide blower belt), I decided against it. I've got room for idler pulleys outboard of both belt spans (about mid-span) that won't move the blower belt position ahead at all, and should control "ballooning" of the belts.

Progress on crank "fillers" testing: got the sample balanced today. Awaiting delivery of a 1 HP motor and 10" v-belt pulley (tomorrow?). Then it will be "show time"! :-D
« Last Edit: February 24, 2015, 01:04:46 AM by Jack Gifford »
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Offline jacksoni

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Re: Inline-four crankshaft
« Reply #173 on: February 24, 2015, 07:06:18 AM »
There are others but I used http://www.bbman.com/ as a source for my cam pulleys. Their online catalog is a big help with pulley diameters,  pitch, belts, tooth type etc etc. Takes a few minutes to figure it out but works well. 
Jack Iliff
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 G/GMS-182.144 2019

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #174 on: February 26, 2015, 12:15:48 AM »
Hmm... "accidental" lesson in fluid friction (dry air inside the close-fitting housing around an almost-full-round test piece)- 1 HP motor (117V single-phase) only gets it to 9,200 RPM, then trips the 20 amp breaker (would be 12,000 RPM at motor's rated 3450 RPM). I suspect a VFD (variable-frequency drive) might allow it to be "nudged" up to 12,000, but single-phase-output VFDs aren't easily available (translation- can't borrow one from local electrical contractor). So... I guess tomorrow I'll borrow the 2 HP motor from my mill and try again.
« Last Edit: February 26, 2015, 12:18:33 AM by Jack Gifford »
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Offline Rex Schimmer

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Re: Inline-four crankshaft
« Reply #175 on: February 26, 2015, 05:21:21 PM »
Jack,
If you aren't going to run it for a long period of time try going to a larger breaker, try 30 or 40 amp. What rates electric motors is the amount of heat they generate you can literally increase the amount of power you can get out of a electric motor by blowing cool air over it and through it if possible. But you will need a bigger breaker for more amps although at 20 amps and 120 volts single phase you are over 2 hp already. If you are looking for 12,000 rpm from a 3450 motor I would assume that your ratio between the motor and the "test stand" is around 4:1 which makes the torque required from the motor shaft to accelerate 16 times higher than is required with a 1:1 ratio. If the motor still accelerating when the breaker goes? If it is the air drag inside the test enclosure then you will definitely need more HP as aero load is a "power of 3" function so the hp required for 12,000 rpm would be about 2.2 times the amount of power you are using now which could easily be 5 hp. Hook you shop vacuum up to the test chamber and evacuate some air out of it.

Have fun, be careful and let us know what happens.

Rex


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Offline fordboy628

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Re: Inline-four crankshaft
« Reply #176 on: February 26, 2015, 05:59:11 PM »
Jack,

If you aren't going to run it for a long period of time try going to a larger breaker, try 30 or 40 amp.

Rex

Jack,

Check the insulation on the wires before substituting a larger amperage breaker.   If it is older or vinyl insulation, increasing the current MAY damage the insulation.
 :cheers:
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Offline JimL

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Re: Inline-four crankshaft
« Reply #177 on: February 26, 2015, 09:47:21 PM »
Jack...a pic of one of our engines (that we've never used.)  That cam belt is running 4 cams and a total of 24 Formula Atlantic valve spring packages.  The tension and guide rollers are all uneven spacing (length divisions between drive/driven components).  The "draw side" of the timing belt seems happiest with an idler that presses on the back of the belt, which has a web straightening effect at very high speed (beyond rated).

The multirib blower belt also has uneven run divisions, as well as a back-bending idler on the draw side of the belt.  This one is only enough to keep the whip out of the belt, but this engine doesn't run past 7800 rpm and blower speed is not that high.  During the dyno tune, we learned we were horsepower limited by the belt width on the blower (had to reduce boost).

On a smaller V6 with blower, I was spinning the blower beyond 15,000 and had to put the "deeper" idler higher on the draw side of the belt....nearer the blower pulley.  That was the only way to keep the belt on.  Trying to pull straight would pitch the belt instantly at high rpm.

This engine, by the way, is 3.65 liters and made 440 HP and 390 lb/ft torque on pump gas....pretty big cams in there for a street blower motor.  Maybe this is a grain of info to help your research.  The only thing I am sure of, is that you don't want to be symmetrical on those belt divisions between idlers and sprockets.  I don't think the pattern matters much, but it seems to work well to put the reverse bend pretty close to the smaller pulley or sprocket.  I have no technical explanation to offer, except experience from making things work years ago.

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #178 on: February 27, 2015, 12:15:11 AM »
Thanks. What''s that timing belt width- 40 mm?

For the spin-test: ordered yet another pulley to attempt driving with the 2 HP motor. But I'm beginning to think I may need to compromise the continuity of the housing by generously "ventilating" it. I imagine the least dangerous scheme would be "breathing" holes in the 3/4" thick end plates, leaving the total coverage of the circular housing alone.
« Last Edit: February 27, 2015, 12:21:54 AM by Jack Gifford »
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Offline JimL

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Re: Inline-four crankshaft
« Reply #179 on: February 27, 2015, 01:04:52 AM »
As best I remember its 40.  That engine is stored in SoCal and I havent seen it in a year or so.

One note about the blower on a banger.  You only have two big planes of vibration, so a side mounted blower/manifold tends to rip the studs right out of the head.  Inline 6, V6, V8.... no problem.  Inline 4 got really ugly in the 2.4-2.7 liter engines.  My best guess is that the blower rotating elements need to be as close to the crankshaft line as possible.  There is more going on than I understand, but those blowers were prying themselves off the head beginning toward the front (where youd think the belt would be pulling them inward).

I had very little involvement with that program and the final solution was to quit messing with it.

Strangely, a smaller 4-cylinder blower kit was serviceable except for the crank pulley bolt.  That took a really trick part to prevent breaking at long high RPM.  Weird science, aint it?

  Another lesson we learned was that you just about cant make a strong enough intercooler core when the blower is too tight to the ports.  The blower pulses get to dancing with the intake tuning and pieces crack off.  A long taper intercooler survives better than straight or flat.

Also....double 90degree bends in flexible hoses or lines will save you a bunch of time and repair costs because you dont have to transmit as much vibration from one component to another.  Even an air inlet hose can pump with those pulses, which makes it act like it is trying to pull or push its end components.  Thats why good 4-cylinder cars look the way they do under the hood.

OK....that is all I can remember that might be useful for you.  Good luck on your project and have fun with it.