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Crankshaft experiment

Posted: Mon Aug 24, 2015 7:24 am
by Jack Gifford
Just a glimpse into my world of the last few years. I'm building an inline four cylinder engine (3 liter hemi, blown methanol) for the lakester I bought sans engine. I see it as an opportunity to test some ideas. One of these is reduction of oil aeration, which is a concern at high engine speeds (building to redline @ 10,000 RPM). I just finished the machining of this "full-round" modification of the Moldex fully-counterweighted billet crankshaft- to eliminate windage of leading/trailing edges of counterweights. This wouldn't have been possible a decade ago, due to the development of high-strength wrought magnesium alloys during that time. I'm using Elektron-43 which has a tensile strength of 49 KSI. I first built a counterweight replica with sample magnesium filler and spin-tested it to verify the attachment scheme; got it to over 11,000 RPM a number of times, with no unexpected loss of fastener torques.

The likelihood of successful running is pretty slim, due to all of the "experiments" involved- including conversion of a M/T Pontiac hemi head to DOHC. Also, I've totally segregated oiling of the top-end from the bottom-end- each has its own drysump pressure and scavenge system.

Early-on I set a restraint of keeping a vintage appearance to the engine (14-71 Roots blower, rather than modern screw blower, etc.) to match the style of the drop-tank lakester. Designing the DOHC deal to fit under an original M/T rocker cover caused me many headaches!

Re: Crankshaft experiment

Posted: Mon Aug 24, 2015 7:32 am
by minetymenace
Gosh! looks like a wing or two might be needed to keep it on the ground :shock:

Re: Crankshaft experiment

Posted: Mon Aug 24, 2015 12:55 pm
by skippy
Interesting idea.

Re: Crankshaft experiment

Posted: Mon Aug 24, 2015 1:33 pm
by Mark Cook
Nice to see another fan of full circle flywheels, hope it works :grin:

Re: Crankshaft experiment

Posted: Mon Aug 24, 2015 8:17 pm
by beat
Ohhhh my dear,

how dos this looks like after the Bang when one ore two of the counterweighst have been going there own way ??

beat <201

Re: Crankshaft experiment

Posted: Tue Aug 25, 2015 6:52 am
by Jack Gifford
Minety- the lakester "stayed on the ground" quite well during the prior owner's 2008 Bonneville visit, at 260+ MPH. The record in the class I'll be running (F/BFL) is just over 260 MPH, so I needn't worry about the car "flying" [even if I could get anywhere near the record].

Beat- the potential "bang" is why I started by doing the stress/strain/deformation calculations of the fillers/fasteners arrangement, followed by the spin-test. The radial acceleration forces are by far the largest force experienced by the filler segments- at 10,000 RPM, about 8,500 G's at their center-of-mass. At ~8 oz. each, that's 4,250 lb. of force- which results in worst- case stresses in/around the fasteners that are safely under the yield strengths of the materials. Other accelerations (such as tangential acceleration due to torsional vibration) are certainly a couple of orders of magnitude less than 8,500 G's. So the spin-test (maximum RPM 11,158) gives a safety-margin of almost 25%.

Re: Crankshaft experiment

Posted: Tue Aug 25, 2015 8:19 am
by b50root
Intresting Reading. Keep up.

Rickard

Re: Crankshaft experiment

Posted: Tue Nov 03, 2015 6:07 am
by Jack Gifford
Still plugging away. Crankshaft finished, other than eventual balance job (fancy-colored TagNite conversion of the magnesium surfaces to prevent corrosion). Finished incoming inspection of the custom billet camshafts Crane made for me- only $1,600 each- yikes! But they are a spot-on match to my blueprints. Started spin-tests of the DOHC design- no faults found yet. But a 1HP electric motor can't get a cam beyond 1,650 RPM (3,300 engine RPM) due to the aggressive cam lobes and stiff springs (290# seat, 590# open). Began using my 7HP Kohler to spin it today. Got up to about 3,300 cam RPM, but wasn't getting consistent readings from the laser tach. I'll keep at it until I've seen the valvetrain be "happy" at 10,000 engine RPM.

Off-topic: It's amazing what a one-lung Kohler sounds like through 15' of 3" diameter exhaust hose- the ultimate "thumper" sound! Especially from outside the garage, with the Wheelhorse nowhere in sight... :laugh

Re: Crankshaft experiment

Posted: Tue Nov 03, 2015 8:33 pm
by minetymenace
how you oiling it during testing?

Re: Crankshaft experiment

Posted: Wed Nov 04, 2015 6:41 am
by Jack Gifford
Oiling for spin-testing is shown in picture #2- variable-speed drillmotor driving an old automotive oil pump, using the engine's top-end scavenge chamber as a temporary wetsump (1.5 qts.). The somewhat complex oiling scheme of the DOHC setup is working well. I began the testing without the cam cover, to keep an eye on everything- but it got messy really quickly, spitting oil every-which-way! After satisfying myself that cam bearings, lobes, and followers were all oiling properly, I buttoned it all up- much "nicer" to deal with now.

Got the laser tach squared away, but didn't make any progress on spin-speed today- had to retrace my steps a little. I had machined an adaptor to mate 3/4" bore pulleys with the Kohler's 1" shaft, but the "shortcut" I took wasn't working well. I had the pulleys' setscrews clamping against flats on the adaptor shaft- which kept loosening and threatening to be a disaster. So I had to re-do the adaptor to employ keyways, freeing the setscrews from transmitting any torque.

Re: Crankshaft experiment

Posted: Thu Nov 05, 2015 6:17 pm
by beat
:thumb :thumb

Re: Crankshaft experiment

Posted: Fri Nov 13, 2015 1:29 pm
by koncretekid
Jack,
Good to see you're still at it. You know a test run at Loring would not be out of the question although you might want front brakes at your targeted speed! Close to a mile to shut down before you run off into Canada. And it's certainly a lot easier on your motor because you can shut it down at any time after the mile and still get a speed if not the mile-and-a-half speed.

Here's hoping that the Salt Flats heal during our lifetime!

Tom

Re: Crankshaft experiment

Posted: Fri Feb 05, 2016 7:42 am
by Jack Gifford
After quite some valvetrain spinning, the test did what it was supposed to do- showed up a design fault in the followers- by breaking one! I've corrected the design, but decided against whittling out a new set of eight on a manual mill (as I first did- many, many hours)- I've farmed out CNC milling of a new set (along with 8 spares).

Made up the two crank hubs for cam sprocket and blower drive, so I could do the final bit of crank machiining- boring/reaming for 1/4" round keys (to eliminate square-corner stress risers of a normal keyway)- a "ticklish" job that I wasn't looking forward to doing. Had to "massage" my mill to allow hanging the crank off the table (moved the entire column/head 3" to one side, on 1" thick steel bars). Had to proceed VERY slowly (~.001"/sec downfeed) to avoid runout on the drills/reamer (2.700" deep). It came out good- glad that's finally done. Now I can cart the crank off to the balance shop.
round_key21.jpg
round_key11.jpg

Re: Crankshaft experiment

Posted: Wed Mar 09, 2016 6:52 am
by Jack Gifford
Revised design CNC-milled followers arrived a few days ago- paying for them left me muttering "Oh well, it's only money!" :roll: Some minor detailing of them, heat-treat, and assembly- then eventually another go at spin-testing. I've ordered a 5 HP motor, to [hopefully] be able to spin the valvetrain a decent speed.

Re: Crankshaft experiment

Posted: Tue Jun 14, 2016 6:56 am
by Jack Gifford
So... seven months :shock: after beginning "spinning" of the DOHC design, I finally wrapped it up yesterday, with successful testing at the equivalent of nearly 10,000 engine RPM (4,980 RPM on the exhaust, 4,870 on intakes). Besides the follower re-design & re-machining, I had to make a new set of pivot studs of better material (8740 alloy this time), since one original piece broke at just over 9,900. Also, a lot of time was spent creating special wrenches to adjust valve clearances (almost no room for wrenches, and locknuts need to be torqed to 67 ft.lb).

A friend finished the lathe work of making pulley hubs (cams, crank, and blower drive), which completes all of the Gilmer belt drive system. Blower manifold pieces are almost ready for TIG welding. Actual assembly of the engine should start pretty soon. About the only machining left will be to make mounts for stuff driven off the rear of the cams- magneto, drysump oil pumps, and fuel pump.

Re: Crankshaft experiment

Posted: Tue Jun 14, 2016 11:38 am
by Barry Creary
Wow Jack amazing work :thumb love reading your work you are a ledgand <917 <917 <917 <917 <917

Re: Crankshaft experiment

Posted: Tue Jun 14, 2016 8:11 pm
by beat
Jack Gifford wrote: I finally wrapped it up yesterday, with successful testing at the equivalent of nearly 10,000 engine RPM
:thumb :thumb :thumb

Re: Crankshaft experiment

Posted: Tue Jun 14, 2016 9:53 pm
by minetymenace
How about a video?

Re: Crankshaft experiment

Posted: Thu Jun 16, 2016 6:54 am
by Jack Gifford
I wouldn't even know how to make or post a video... :oops:

I could have made an audio recording, but a person would need a 500 watt amp/speaker system to play it at a realistic volume level! :shock:

Re: Crankshaft experiment

Posted: Wed Jun 29, 2016 7:26 am
by Jack Gifford
It feels good to FINALLY start actual assembly of the engine!

But assembly will still be interrupted by verifying stuff. For instance, I'll next be setting up the cam drives, orienting the cams to each other, and checking valve-to-valve clearances during overlap. Then, hopefully, the 5HP electric motor will be able to drive the crank temporarily to observe the whole cam drive in action (with the rods/pistons still not installed).

Re: Crankshaft experiment

Posted: Wed Jun 29, 2016 7:53 am
by Barry Creary
Wow Jack very impressed that you have built a engin that is such a masterpiece <917 <917 <917 <917

Re: Crankshaft experiment

Posted: Tue Jul 12, 2016 6:20 am
by Jack Gifford
Good progress on engine assembly. Hooked up the electric motor to spin the complete longblock- only about 700 RPM, for 6 -7 seconds to "settle in" the valvetrain before a final check of valve clearance settings. Didn't set up an oiling system, just depended on lots of Torco assembly lube on all surfaces. Still waiting for the welding shop to "stitch up" the blower manifold. Then there will be a trial fit in the lakester to look at clearance in the area of the pumps and magneto before fabricating their mountings to the rear of the camshafts.
hemi_four_asm4.jpg
hemi_four_asm4.jpg (21.76 KiB) Viewed 13713 times

Re: Crankshaft experiment

Posted: Sat Jul 23, 2016 9:55 pm
by koncretekid
Great to see you're still at it, Jack. Just wish I'd gotten to stop in to see when we were up your way.
Tom

Re: Crankshaft experiment

Posted: Sun Jul 24, 2016 5:37 am
by Jack Gifford
Not to worry... I DO plan to eventually see you at an event!

Re: Crankshaft experiment

Posted: Wed Jul 27, 2016 5:14 am
by Jack Gifford
14-71 from The Blower Shop (billet case, billet rotors) is a LOT of blower! Shipping weight (sans snout, etc.) was 100 lb.

Re: Crankshaft experiment

Posted: Thu Aug 11, 2016 4:55 am
by Jack Gifford
Trailered the engine project to the Ames Performance Pontiac Nationals (Summit Raceway, Norwalk, Ohio) for the weekend. There was a lot of interest in it.
Also witnessed the quickest/fastest ever quarter-mile run by a traditional Pontiac V8- 6.02 sec/232 MPH by the 'Boss Bird' nostalgia nitro funny car!

Re: Crankshaft experiment

Posted: Sun Sep 04, 2016 6:37 am
by Jack Gifford
After finishing up the crank scrapers and windage tray, engine is all buttoned up. Mount is completed for the oil/fuel pumps and magneto to drive off the rear of the camshafts. Custom 5-stage drysump pump now being built by Dailey Engineering, and Don Zig Magnetos is working on a retro-look magneto with sufficient output. I still need to source a Hilborn 4-port injector.

Re: Crankshaft experiment

Posted: Sun Sep 04, 2016 10:39 am
by skippy
How do you get the magneto to advance and how much.

Re: Crankshaft experiment

Posted: Mon Sep 05, 2016 5:13 am
by Jack Gifford
Fixed advance. My experience with a very similarly configured blown hemi V8 on alcohol was good with fixed advance. Both the V8 and this engine are for competition, with no need to be heavily loaded at less than about 4,000 RPM. The V8 "liked" 30.5 degrees advance to perform in the 4,000 to 9,000 RPM range. I expect this four cylinder will be very close to that, but possibly up to 10,000. I'll probably start dyno tests at 28 degrees and go from there.

Re: Crankshaft experiment

Posted: Mon Sep 05, 2016 9:15 am
by stew79
hi jack, what starter do you use to crank the engine over ? it must be able to withstand possible kick backs. wouldnt some automatic retard between 0 to 1000 rpm make things less stressed, without any effect on faster running?
stew

Re: Crankshaft experiment

Posted: Mon Sep 05, 2016 1:59 pm
by stew79
jack, i missed out the word "less" in my question. (just read it back) it should read ".....between 0 and 1000 rpm make things less stressed"
stew

Re: Crankshaft experiment

Posted: Tue Sep 06, 2016 4:08 am
by Jack Gifford
I'll be using a Tilton geared starter. In a dozen seasons of competition with my blown alky V8 with fixed timing, it never needed a start-retard- never any kick-back. Cam profiles ground for max power above 7,000 RPM have so much overlap that the engines crank over fine.

Re: Crankshaft experiment

Posted: Tue Sep 06, 2016 5:15 pm
by stew79
minety, you no all the tricks to make up for bad grammar etc, and jack, its different horses for causes. car stuff is quite different to bike world (again) but i wonder if a large single cylinder bike engine, had a heavy enough fly wheel, could be kick started at full ignition advance ? then would it tick over ? the mass of the fly wheel would need to be about 40kg ! throttle response would be slow, but if there were more cylinders it would work well. i will stick to some basic retard for starting my bikes, to keep the light fly wheel effect i like. (nothing blown, just carbs)
stew
ps what must help the car race engines start and run slowly, at full ig advance is the low compression. it must take 1000/2000 rpm to start to build up boost pressure ? so it all works out well. (the starter isnt fighting against any boost, so the combustion cant kick back)

Re: Crankshaft experiment

Posted: Tue Sep 06, 2016 7:44 pm
by minetymenace
stew79 wrote:the mass of the fly wheel would need to be about 40kg
Anyone with a Guzzi, please raise your hand.

Re: Crankshaft experiment

Posted: Wed Sep 07, 2016 6:28 am
by Jack Gifford
stew- you're basically correct about low compression aiding an automotive race engine to start and run at full advance (but usually only down to 1,200 RPM or so). However, this doesn't mean low static compression ratio- my V8 was just over 10:1 and this four cylinder is 12.4:1. What reduces effective compression is the timing of the intake valve closing event- which is typically very late in a multi-cylinder race engine- in combination with the large overlap preventing good cylinder filling on the intake stroke. Also- my experience is limited to methanol fuel; I believe gasoline would not be as forgiving of full advance for starting.

Minety- try a Guzzi V50 sometime- much less flywheel effect than the larger engines.

And... why St. George's Cross instead of the current flag of Great Britain?

Re: Crankshaft experiment

Posted: Wed Sep 07, 2016 12:33 pm
by minetymenace
Great Britain is a land mass ("great" meaning big) , like North America, there are three kingdoms on this land, who's flag is the Grand Union flag (Union Jack), it is made up by combining the flags of the three kingdoms, St Georges Cross for England, St Andy for the Scots and St Paddy for the Irish. The United Kingdom is represented on the EU flag as one of the stars, but as we are leaving I guess no one will use that!!

I tried a Guzzi V50 onetime- much less engine effect than the larger engines.

Re: Crankshaft experiment

Posted: Wed Sep 07, 2016 7:14 pm
by stew79
jack, i like your physics, and look forward to further up dates on your project.
good luck
stew

Re: Crankshaft experiment

Posted: Tue Oct 25, 2016 6:09 am
by Jack Gifford
I'm still plugging away. Engine is looking more complete. Ironing out details of setting it up at a local engine dyno shop- hopefully before this year is out.

Re: Crankshaft experiment

Posted: Tue Oct 25, 2016 5:44 pm
by beat
Jack Gifford wrote:setting it up at a local engine dyno shop
dyno shop must be somewhere in the desert ore build with very thick walls !

otherways next door neighbors won't sleep much whilst testing period.....
<020
beat :lol:

Re: Crankshaft experiment

Posted: Wed Oct 26, 2016 5:53 am
by Jack Gifford
I expect it will be LOUD!

It's a typical dyno cell of concrete block, with telemetry to the adjacent computerized control room, centrally located in a masonry industrial building. An old brick chimney is used to expel exhaust from the engine under test- makes for a very interesting sound for the neighbors.

The dyno itself is unique- the shop mostly works with turbo-diesel truck/tractor engines for pulling competition. It can measure up to 4,300 lb.ft. of torque at up to to 6,000 RPM! I obviously don't need that much torque capability. But I will need to utilize my inline quick-change gearbox bolted to the engine, to allow engine speeds up to 10,000 RPM while not exceeding the 6,000 RPM limit of the dyno brake (a water brake).