Lightened crank

[superscan811]

So how'd it balance out? That's a lot of metal to take off the CW's. Are you running aluminum rods? I'm surprised you didn't try to lighten the rod throws much, I would think it would need help to even out all the metal taken off the CW's.

I'll be running Forged H-Beam rods that are 20.1ounces, around 30% lighter than standard. The forged pistons are also 20% lighter than standard.

 

There has been a 22% weight reduction of the crank, the majority of that is from the counterweights but I'd guess around 4% was from the bigends.

While a fair bit of this was from the OD of the crank, hopefully there will still be enough weight to smooth out the load spike on the main bearings (the reason we have counterweights).

Time (ie: engine life) will tell.. I'll tear down the engine in a year and see if the bearings are still OK.

 

 

Cheers.

[The Rabbit1]

definitely want a vid of the throttle response when done pls

[superscan811]

definitely want a vid of the throttle response when done pls

Will do.

I also lightened an early (225mm I think) flywheel.

It's down to 17.6lbs and the material was only removed from the outer edges.

http://users.tpg.com.au/blackmas/SG/BAD_ENGINE/FW-BACK.jpg

 

http://users.tpg.com.au/blackmas/SG/BAD_ENGINE/FW-FRONT.jpg

 

I left a 1/8" lip so the ring gear can't be pushed off by the starter.

 

Could possibly remove another 2-3lbs but I'd rather not risk it with a standard cast flywheel.

 

Rods should arrive in 2 weeks, by which time the crank should be finished.

 

Everything is slowly coming together.

 

 

Cheers.

[ucw458]

why not just get an aluminum flywheel?

[Lizzord30]

why not just get an aluminum flywheel?

Haa thats what I was thinking why not go with a 240mm Aluminum one. Go thought all the work to make it so light then use that. but still great job with the engine!

[superscan811]

why not just get an aluminum flywheel?

To be honest, I'm not a big fan of Aluminium flywheels. a properly made steel flywheel will actually weigh less than an aluminium one.

 

How do I know???

 

My brother makes flywheels for a specialist clutch business here in Australia.

 

He makes them out of billet 4340 steel and actually cuts the teeth in them rather than using a ring-gear, then induction hardens the teeth.

 

Because there is only a small market for the starion flywheels in Australia, and despite me badgering him, he still hasn't made me one.

 

So, after thinking on it for a while, today I decided to tidy up my lightened cast flywheel a little.

It's now down to 15.4lbs and I still want to do a bit more to lighten the outside.

 

 

Currently.

http://110.174.47.143/SG/Flywheel/FLYWHEEL-MK2-000.jpg

 

http://110.174.47.143/SG/Flywheel/FLYWHEEL-MK2-001.jpg

 

The majority of the weight was removed by the 45deg cut behind the ring-gear, the rest of the surface was machined approx 0.040" to clean and even it all up.

 

 

Cheers.

Edited May 11, 2012 by superscan811

[StarquestRescue]

There is a steel one avaiable now over here.

 

http://www.ebay.com/itm/Competition-Clutch-15-25lb-Flywheel-88-89-Dodge-Conquest-Mitsubishi-Starion-/110870302562?hash=item19d0628f62&item=110870302562&pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr

[superscan811]

There is a steel one avaiable now over here.

 

http://www.ebay.com/...ssories&vxp=mtr

Thanks for looking but a lot of the Ebay steel flywheels remove the weight from the wrong areas, ie: they drill/slot holes in between the crank bolts and the clutch area.

While this does remove weight from the flywheel, it's in the worst possible area you want to weaken and has the least effect on engine response.

 

Removing 1lb on the outer edge of the flywheel is equal to removing 4lb 1/4 of the way out from the center. The center section also has to be able to handle a lot more torque than further out on the flywheel.

You start to understand that the inside area is NOT where you want to remove too much metal.

 

Several classes of motorsports here in Australia, require a specific minimum weight for flywheels. The richer racers get a dramatically underweight flywheel and attach a tungsten carbide ring to the center section of the flywheel (tungsten is nearly 3 times the weight of steel). The flywheel passes the weight restriction AND the weight is in the area where it has negligible effect on how quick the engine revs up.

 

Sorry for the soap box and I'm not having a go at anyone either. Just trying to educate the masses, whether they already know or not.

 

 

Cheers.

Edited May 15, 2012 by superscan811

[kidjc]

DERN... it was like reading a suspense thriller, glued to the pages; "Very En-Lightening!" Really... quite a learned experience! Thanx

[superscan811]

Thanks kidjc.

Most of the info I acquire from people who build and race their own cars. Most of them are tight on funds so they do, and have done, a fair bit of research before making changes because most can't afford to have their engine go up in smoke.

 

On another note, I've nearly finished the new quad motorbike carb manifold.

 

This is my old setup with quad 38mm carbies off a '93 GSX 750

http://users.tpg.com.au/ntome44/SG/Motorbike_carbs/38mm-top.jpg

http://users.tpg.com.au/ntome44/SG/Motorbike_carbs/38mm-front.jpg

http://users.tpg.com.au/ntome44/SG/Motorbike_carbs/38mm-side.jpg

http://110.174.47.143/SG/BASIC%20ENGINE%20BUILD/manifold.jpg

Just cut up a standard manifold and welded on a few pipes to match the spacing for these carbs.

It ran very well.

 

The new manifold has straight runners

http://110.174.47.143/SG/MANIFOLD/Mk2.jpg

 

and spacing the carbs to fit it.

 

These are 40mm CV carbs. They will need to mounted on a 45deg angle though.

http://users.tpg.com.au/ntome44/SG/CV-Carbs/Spaced-001.jpg

 

 

Also am looking at spacing out 2 sets (4 carbs in total) of 40mm Flat Slide carbs off a Skidoo?

http://110.174.47.143/SG/HC-ENGINE/FlatSlide-000.jpg

http://110.174.47.143/SG/HC-ENGINE/FlatSlide-001.jpg

http://110.174.47.143/SG/HC-ENGINE/FlatSlide-002.jpg

 

Still trying to decide which to use. Probably the first setup i finish.

 

Cheers.

[Komeuppance]

Nice work!! We've been planning the same idea, only with a plenum and fuel injectors... haha.

 

Now that we know it's going to be carb'd, what compression ratio are you shooting for?? And how many revs do you plan to turn??

 

-Robert

[The Rabbit1]

your running carbs designed for .75 liters on a 2.6 liter motor? huh?

[superscan811]

Nice work!! We've been planning the same idea, only with a plenum and fuel injectors... haha.

 

I've also made up a set of quad 42mm throttlebodies (off a GSXR 1300 this time), that I will be using later. Again, spaced out so I can use straight runners. Yet to start the plenum for them but most of the hard work is done.

http://110.174.47.143/SG/QUAD/001/Q01.jpg

http://110.174.47.143/SG/QUAD/001/Q05.jpg

 

 

 

Now that we know it's going to be carb'd, what compression ratio are you shooting for?? And how many revs do you plan to turn??

 

-Robert

The billet cam requires at least 12.5:1 so planing for around 14:1.

As for rpm, 7500rpm is as fast as I want to spin it. The load/wear difference between 5000rpm and 7500rpm is over double so I'll save the high rpm's for special occasions.

 

 

your running carbs designed for .75 liters on a 2.6 liter motor? huh?

Had a few comments tike that until they hear and see them go.

Those 750cc motorbikes put out over 130hp standard and their redline is around 13,000rpm. Do the math and you find that their carbs are quite well suited to the slower reving Astron.

 

Apart from that, 4x38mm carbs would have to be better than the 28mm primary, 30mm seconday you get with the standard setup.

 

On a relatively mild setup, 9.6:1 comp, standard internals and a Magna M7 head, the car had 134hp at the wheels (roughly 180hp at the flywheel). Aiming higher this time of course.

 

Cheers.

Edited May 16, 2012 by superscan811

[The Rabbit1]

On a relatively mild setup, 9.6:1 comp, standard internals and a Magna M7 head, the car had 134hp at the wheels (roughly 180hp at the flywheel). Aiming higher this time of course.

 

Cheers.

Ok, I'm following you.. now, how about torque levels though?

[superscan811]

Here are 2 Youtube vids of a sigma, before and after the motorbike carbs.

 

I loaned a quad carb setup to a group of guys who are doing motorkhana's in an old 1980 Sigma.

 

The engine is stock standard.

 

In the first vid ,

 

 

In the 2nd vid, the only difference is the

They ended up braking the diff but it's fixed now andback on the track.

 

 

Cheers.

[superscan811]

Ok, I'm following you.. now, how about torque levels though?

A lot..

I was running a 3.308 diff ratio and was able to take off, up a 20 degree incline,l towing approx 2 ton (car on a trailer, 3 gearboxes and an engine in the back of the wagon). The clutch would grab an the rpm would drop to around 800rpm, but it would still pull away.

It would also maintain 70mph up most hills in 5th gear doing 2600rpm with a full load in the back (around 1 ton).

 

Here's a picture of the old beast. Sadly she had too much rust in all the wrong places so she is no more..

http://110.174.47.143/SG/CARS/GN-WAGON.jpg

 

 

Cheers.

Edited May 17, 2012 by superscan811

[superscan811]

Just for fun, took this log late last year on the way to the tip, because they weigh you on the way in and out. Was towing a 6x4 box trailer with the old wagon.

 

It was done in 2nd gear from approx 20mph to 60mph.

 

http://110.174.47.143/SG/DYNO/Tip%20run%20-1806kg%20.JPG

 

 

The total weight (car and trailer) was approx 3980lb and on a straight stretch of road.

 

Can't wait to finish this engine engine build.

 

 

 

 

Cheers.

[JohnnyWadd]

Are you running the light crank yet? Cuious becuase i am thinking about it.

http://i1187.photobucket.com/albums/z388/starionkiller/th_imagejpeg952_2.jpg

http://i1187.photobucket.com/albums/z388/starionkiller/th_imagejpeg952_3.jpg

http://i1187.photobucket.com/albums/z388/starionkiller/th_imagejpeg952_4.jpg

[superscan811]

That looks like some pretty serious work been done to that crank.

 

Looks good.

 

 

Are you running the light crank yet?

Not yet, Still waiting on the rods.

 

I need them to accurately measure the piston height.

 

Just as a comparison, here is a pic of the height difference.

 

http://110.174.47.143/SG/Pistons/4G54-22R.jpg

 

 

The one on the left is for my turbo 4G54, the one on the right is for my Hi Comp 4G54. Its a 22R piston.

 

there is a .14" difference in compression height and the 22R piston already has a 24.7cc dome. I am wanting to get the pistons .012" above deck which means I'll need to chamfer the edges a bit and probably flycut for the valve relief.

 

All fun but I want the rods first before I start cutting.

 

Cheers.

[JohnnyWadd]

Dangit well i need some more feedback before i go getting a lite crank. Hurry up!

[superscan811]

You will gain more removing weight from the outside of the flywheel than you will removing it from the crank.

 

I've removed around 7lbs out of the flywheel and at least 90% of that is from the outer 2".

 

To achieve the same gain you would have to remove approx 14lb from the outer edges of the crank.

 

Removed around 8lbs from the crank, and even if I drilled out the big ends, I doubt I could safely remove more than another 3lbs without sacrificing reliability.

 

Also, it's a 1.5 hour job to remove the weight from the flywheel, but it takes at least 2 days (for me) to lighten the crank.

 

Another thing to consider is the total mass of the counterweights. A RELIABLE turbo engine requires a lot more mass in the counterweights to help smooth out the peak bearing loads, so the journals and bearings don't meet.

 

 

They act like a spring, absorbing the shock load and then slowly releasing it.

 

Too small and most of the shock load is directly transmitted to the bearings and journals.

 

Too big and they just slow everything down, which will make the engine sluggish but the bearings will last a lot longer.

 

Which to you think the manufacturers will go for??

 

If you are aiming for a quick and cheap option, go with a lightened flywheel. A lighter and/or smaller diameter pressure plate will also help.

 

If you have a lot of spare $ and are trying to get every last bit of performance out of the engine, or like me and enjoy tinkering, do the crank as well.

 

Just remember, a lightened flywheel and/or crank WON'T give you more hp AND will make bugger all difference in 4th and 5th gear.

It will however make a huge difference to the engine response in 1st and 2nd gear, and to a lesser degree in 3rd.

 

 

Cheers.

[Chad]

it won't yiled more peak HP, but will make HP faster [acceleraton]. spinning up that added mass takes power, power that could go to the wheels if the mass weren't there. During acceleration, it coudl be felt as mroe power, but at it's peak, the advantage would no longer exist. It woudl effectivly move the whole power curve to the left. We're only talkign a HP or three though.

[superscan811]

it won't yiled more peak HP, but will make HP faster [acceleraton].,,,

True. I have a formula somewhere that calculates the gains basically by working out the equivalent weight saving. When I removed 5lbs from the flywheel, in first gear it was roughly equivalent to removing 330lbs from the cars total mass.

 

...spinning up that added mass takes power, power that could go to the wheels if the mass weren't there.

True. On the dyno if your car weighs 10ton or 0.5ton, it makes no difference to the dyno result, but on the street, the lighter car would of course accelerate much faster.

 

During acceleration, it coudl be felt as mroe power, but at it's peak, the advantage would no longer exist. It woudl effectivly move the whole power curve to the left. We're only talkign a HP or three though.

Again true. The only HP gain you could get from this work is maybe from less windage from the crank. It won't be a big gain but it all helps.

 

 

Cheers.

[superscan811]

Found these rockers. They are for the 4D56 (Diesel Astron engine)

 

http://110.174.47.143/SG/Head/4D56/4D56-ROCKER.JPG

 

 

 

 

Getting a set to see if they fit. If they do, I'll be using these Scat Swivel foot valve adjusters.

 

http://110.174.47.143/SG/SCAT-20118-1.jpg

 

They have a ball bearing, with a flat spot, in the bottom of them.

They bolt straight into the non hydraulic rockers.

 

Should be interesting.

 

Cheers.

[Lizzord30]

wow very nice find on the rollers! Let us know how they work and what the ratio they are.