The mother of all projects - Implementation

[Datsun fan]

Hey! I just went through trying to make my old dream comes true!That's

all about 'inserting' an additional gearbox into Aro spartana truck.So bear with me.

Here are the specs of my previously modified spartana :

 

Weight : 1300 KG , 2 door truck .

Engine : Nissan A15 works great.

Gearbox : 3N71B very good condition.Ratios: 1st=2.458, 2nd=1.458, 3rd=1 .

A15 Max torque=11.6 kg.m/3200 , carb 66 kW at 5200 Rpm

MAX TORQUE: 11.6X2.458= 29 kg.m/3200 is the maximum torque the additional tranny will transfer .

Diff ratio : 4.444

Wheels : 205/75/R14 ,30 Psi .

 

Then I got a tranny from Kia/Asia Towner minitruck, the specs are:

 

weight1170 kg, 2 door minitruck .

Engine Kia CD 796 cc 3 inline cylinders,Truck Top speed : 140 Km/H

Max torque 6.5 kg.m/3200 Rpm "MPI" ,43 kW at 5400 Rpm .

Gearbox : Model is SK2 , 5 speed manual, remote cable shift,aluminum housing,cable actuated clutch .

weight is 21 kg .

approx ratios:

1st=3.900

2nd=2.300

3rd=1.350

4th=1

5th=0.800

Diff ratio : 5.125 .

Tire: 165/65/R12 .

 

So I cut the upper part of tranny bell housing (about 7 cm) so i t can be fit in the truck under the

rear seat, then fabricated 5 mm bell housing (Lid) just the same shape and bolts pattern, and cut

the flywheel 6 bolts piece from the crankshaft and welded it to fabricated input shaft that

comes out the lid through high speed bearing fixed into flange which is bolted (4 bolts) to the lid

this bearing is to center the flywheel and tranny input shaft and can withstand axial load especially

when using clutch! The fabricated input shaft that comes out the lid has male square flange on its end

so that it can be bolted(4 bolts) to shortened drive shaft end then the drive shaft goes to the 3N71B .

And for the rear I cut the manual spline tube and welded to u joint then to square flange

to be bolted to the diff flange.After I put the SK2 in place and some maneuvers to get the correct

position and slope and centering it in the tunnel, I used the stock Sk2 rear mount(transverse U shape

iron piece has 2 bolts to the chassis and 90 degree angle piece has 2 bolts to the rear of tranny and

then go between U piece and chassis a rubber cube between both pieces with 1 bolt goes through

each piece. For front mount, I drilled 8mm hole in left and right sides of bell housing the fabricated

crescent shape 5x50 mm iron piece to (hug) the downside of the bell housing and meet both drilled

8 mm holes then welded 2 (hands) to the crescent for both sides to meet a vertically-welded bolts to both

sides of the frame 12 mm bolts with 4 cm thick rubber donuts! then installed the stock Kia

clutch kit (17.3 cm dia organic clutch disk) then closed the starter opening and the bell housing

is closed completely! the ground clearance is 2 cm more than diff housing . After that I filled

with Gl4 Castrol and prepared shifting cables and fitted the shifter in the cockpit . I havn't

prepare pedal and clutch cable yet. Everything looks snug so its time to give it a try .....

I set manual to 3rd, start engine then put auto to D, the truck takeoff nicely! TADAAAAAAAA

it drive good low speed but once I step gas pedal 1/2 the way it will start to slip(clutch)

even with 80km/h once 1/2 pedal it will slip. I cannot takeoff from complete stop uphill,

whatever I step on gas pedal the truck will move backwards haha very embarrassing . So I inspected

the clutch system for something wrong with no luck , it is just the clutch slipping, tried another

disk/pp/fw and got only slightly different results, then I calculated the friction area of the

17.3 cm disk and found it 13.7 cm2 slightly bigger than Datsun A15 stock 18 cm area(13.55cm2) .

just to be mentioned, I tried to uninstall the clutch system and put fabricated adapter in place

and the truck drives great! then put manual to 2nd and I got superb wheel spin even the wheels could dig

some asphalt away! No whining no bad sounds, But there is suspension issue that rear became too stiff

I think it is related to unsprung weight and the rear mount needs amendment.

What should I do with clutch and rear mount?

I think of getting asbestos disk to increase friction and modding the pp so that it becomes stiffer .

Any suggestions?

[datzenmike]

So, let me get this right, you have a 3 speed automatic driving a 5 speed standard?

 

Why not get rid of the clutch? Have the automatic drive the 5 speed direct. You would have to shift to neutral and probably stop to select one of the 5 speeds.

 

 

Oh yeah, you'd better post some pictures of this. http://community.ratsun.net/topic/691-how-to-post-pictures-and-keep-online-photo-albums/

[Datsun fan]

So, let me get this right, you have a 3 speed automatic driving a 5 speed standard?

Correct

Why not get rid of the clutch? Have the automatic drive the 5 speed direct. You would have to shift to neutral and probably stop to select one of the 5 speeds.

For complete stop I can shift whatever except while in P position(The drive shaft needs to turn a lil). When driving I can shift/jumpshift just like stuck clutch vehicle(tapping gas pedal something like diesel truck .........) and in order to avoid these 2 situations I need the clutch!

Sorry I can't post pics from the place I stay in ( it is even dangerous!) :crying: .

[datzenmike]

Sorry I can't post pics from the place I stay in ( it is even dangerous!) :crying: .

 

Danm!!!!

[Datsun fan]

I don't think pics will do a lot after that write up, you're disappointing me man.

I just want to know what to do with that clutch to make further tests ........ :thumbup:

[datzenmike]

Have no idea what an Aro spartana truck and Kia/Asia Towner minitruck with Model is SK2 , 5 speed manual, remote cable shift is or would look like. Nice write-up and description but I'm no mind reader.

 

Know the Nissan A15 and 3N71B. Total guess is the clutch is slipping because the pressure plate not fully engaged. Clutch arm not fully released? release bearing collar (if it has one) too long? These are usually the causes on Datsuns but as stated I know nothing about Kiatransmissions.

[Datsun fan]

OK there is an update: I tried the whole clutch components I have in TOTALLY STOCK Kia towner minitruck (torture tests) and all worked awesome!

 

Man there is not any need for guessing, The tests mentioned proved that the slipping is the result of torque multiplication because of 3N71B that applies about 2.5X the torque that 13.7 cm2-friction-area clutch disk and pp and flywheel are designed to take without slipping, to rectify this I need more friction with the same components sizes .

I have 2 suggestions :

1 Installing woven asbestos type clutch disk instead of organic ( static friction coefficient for asbestos/cast iron is 2X of organic/cast iron one) .

2 Increasing the clamp force of the pp, I'm not sure but maybe strengthen the pp springs and/or machining 2-4 mm from mounting surface of pp so I get more grip of the clutch disk .

And keep in mind that the Mercedes Actros heavy truck (80 tonnes payload ) Clutch disk friction area is ONLY 100 cm2 of woven asbestos type.

I really need opinions/suggestions/walk throughs about those two suggestions of mine before I can get any further .

Mike I think you're the only one capable of giving me the advice!

What are the improvements you make for clutch system of heavily boosted engines?

I can't wait to hear from you guys :yawn:

[datzenmike]

I doubt that asbestos is used in anything clutch or brake related here.

 

Increasing clamping force is usually used here. That's easier than trying to increase the contact area. Datsun clutches are diaphragm type. My old Dodge pressure plate had coil springs... I guess they would be easier to put stiffer ones into.

[Datsun fan]

I have an asbestos clutch facing already but I can't make use of it until I get modified pp ready...............

The stock Kia/Asia pp is diaphragm type, I tried to get stiffer one from another make/brand with no luck. It seems I'm stuck with modifying stock pp.

What should I do to stock pp to make it stiffer ???

[Datsun fan]

And what about the rear mount modification?

[datzenmike]

And what about the rear mount modification?

 

Again a picture here would help. I have no idea what you have. To offer any opinion more, a lot more, information (pictures) is needed.

[Datsun fan]

Update

I grabbed a used stock pp and get it resurfaced and strengthened by adding additional set of drive straps and now it has 12 drive straps instead of stock 6 straps then assembled it so that the diaphragm springs look perfect and installed the clutch again and found that the clutch pedal is about 40% stiffer than new stock one ( the clutch facing I used is German new woven asbestos out of Actross heavy truck clutch then adjusted the cable and checked every thing is well done .

I drove the truck and found the slipping is still exist but I only got rid of about 30% of the slipping :poop: ( rpm tests and performance tests) the slipping is especially serious when take off uphill, I had to put very light foot on gas to get it moving and slap it to floor when take off will also make it move, then I got tired with clutch and decided to try something else for now so a friend of mine fabricated an"adapter" that bolts directly to flywheel 6 bolt mount (the round part of the crankshaft the flywheel bolts to that I used to make my own adapter to connect driveshaft flange to rear trans input shaft).

For both front mounts of the rear trans, I added left and right round rubber mounts out of Chevrolet Lacetti front suspension ,and for the rear mount I added the stock Kia rubber and iron mount ( Hamburger type) after slight amendments . Then test drive it and it was perfect and the truck passed a several "torture" tests including scary uphill climbing and off road driving, speed tests and even towing 8 ton city bus for 1.5 km uphill and I'm delighted in the truck :w00t: .

 

Well after the honeymoon and while I'm driving slowly in downtown suddenly I heard a clunking noise from the rear tranny with stuttering in truck movement something like broken one or more gear teeth or synchro :sneaky: , that was on 3rd so I tried the other gears and found them work fine except of slight clunking noise that increases a little with speed, then I checked drive shafts and U joints and mounts and found nothing bad .

Is it a fucked up tranny or the damage is limited to 3rd :confused: ?

Is it a formerly worn used 3rd gear or I just messed with the truck that became a weird tranny wrecking machine :devil: ?

I'll tear down the shot tranny soon so what to look or check in order to determine the cause?

[Datsun fan]

For human mind........ Ignorance is kind........ There is nothing fun in the truth.... PAIN IS ALL U FIND

[Skib]

[Datsun fan]

He heh he he heh eh thnx for the photo, Now the song became videoclip.

[datzenmike]

Why not get rid of the clutch? Have the automatic drive the 5 speed direct. You would have to shift to neutral and probably stop to select one of the 5 speeds.

 

 

Yeah better without it. With the auto you aren't going to need to shift it anyway. Start it 5th or 1st it won't matter. 1,2 and 3 would be low range gear choices, 4th the same as no 5 speed at all as it's straight through and 5th would be a slight overdrive for high speed on the highway.

 

 

Is it a fucked up tranny or the damage is limited to 3rd :confused: ?

Is it a formerly worn used 3rd gear or I just messed with the truck that became a weird tranny wrecking machine :devil: ?

I'll tear down the shot tranny soon so what to look or check in order to determine the cause?

 

Well you still have the lowest two gears. Third may have been overstressed because of the torque multiplication of the 3 speed in front of it. Were you towing a bus in 3rd? That might do it.

[Datsun fan]

Yeah better without it. With the auto you aren't going to need to shift it anyway. Start it 5th or 1st it won't matter. 1,2 and 3 would be low range gear choices, 4th the same as no 5 speed at all as it's straight through and 5th would be a slight overdrive for high speed on the highway.

 

Well you still have the lowest two gears. Third may have been overstressed because of the torque multiplication of the 3 speed in front of it. Were you towing a bus in 3rd? That might do it.

 

Without the clutch I'm forced to shift by rev matching only, currently it seems I cant get an adequate clutch system because of the torque multiplication of the auto. The truck now has a lot of power. Sounds more like a horse and a whole can of Viagra :rofl:

 

The bus I towed I used 1st gear for extra high torque and low speed in order to avoid killing the chassis or exploding the rear axle especially when take off .

Did I make tranny killing machine ?

I'm planning to tear down the manual, What/where to look/check in order to determine the cause?

[datzenmike]

Third does not go into gear?

[Datsun fan]

3rd does go into gear.

[datzenmike]

Third gear is close to the front of the transmission so if the counter bearing is going bad it will cause the counter gear to be unstable at the front. This will make lots of noise in 3rd maybe less in 1, 2, and 5/reverse. Fourth will be the quietest. If this is the case it will only get worse.

[Datsun fan]

Well it sounds like it's absolutely the case. Anyway I plan to tear down that pig soon and look for a clue about the cause of the failure. If I came out with something I'll let you know.

Again Mike, As far as I go after the limits of fabricating non-standard setups, you are the only one here to get advice from.

Thnx a lot

[Datsun fan]

OK after many calls of Ratsun audience, I decided to take chances and upload pics of the beast I fabricated!

 

 

 

 

 

 

[Datsun fan]

Mike.....

I teared down the SK2 tranny yesterday and found the oil and internal parts(bearings,synchros,gears......) are in great shape and a very little amount of metal shavings but

the front-bottom gear has 4 broken teeth (found them sunk in the bottom of the gear and the meshing gear has marks on it's teeth obviously as a result.

Is there a clue on what happened?

Is it worn used gear in the tranny or a good gear that overkilled?

Does that mean the gears in the tranny are a pussy and can't take the torque multiplied by the auto? How could I tow bus using 1st for 1.5 km?

[datzenmike]

That's some mad fabricating there. As to what caused what, probably a bit of both. Did the wheels hop? A sudden driveling shock like wheel hop could over stress the gears.

[Datsun fan]

That's some mad fabricating there.

 

Yes i know :w00t:

As to what caused what, probably a bit of both. Did the wheels hop? A sudden driveling shock like wheel hop could over stress the gears.

No they didn't , that damage in the tranny just happened without a warning .there was no whining or any kind of abnormal noise or vibration or metal shavings in the oil, the only thing is from day one the tranny shifted very good except the 3rd was a bit harder/stiffer .

What about that while driving another gear tried to engage which resulted in the damage?as it's remote shift the cables may acquired some sort of springy force and tried to mis-shift while moving/wiggling ? A similar thing happened to me in the past when I replaced the stock shift knob with an aftermarket heavier one and I had 2 teeth broken out of 2nd ,the car was Opel Ascona 240.