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tassuperkart
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Post by tassuperkart »

Usually yes.
So long as the end float measurement are somewhere near spec, you can use whatever you like M8.

Dont place too much emphasis on them. The only real load they will take is thrust from the clutch release.

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Forcd4 wrote:Oh fuk no dude it's you a again, the oracle.
leayr
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Post by leayr »

me and my brother built one about 4 years ago r31 with a rb25det and we use a gt dash and a few other gt bits and pieces all up was about $3300 on the road but that's fathers rates on the front cut and all parts and we done all the labour our self 2 days it took to get running was fun but not fast we end up selling it for 6g and the young guy cleaned up a telegraph pole
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Damo
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Post by Damo »

leayr wrote:me and my brother built one about 4 years ago r31 with a rb25det and we use a gt dash and a few other gt bits and pieces all up was about $3300 on the road but that's fathers rates on the front cut and all parts and we done all the labour our self 2 days it took to get running was fun but not fast we end up selling it for 6g and the young guy cleaned up a telegraph pole
Cool, it would be great to be able to spend a good couple of days doing what's needed. Sadly :D , my life only allows me a couple of hrs a week on my projects. :wink:

I wouldn't considder dropping back from the 3ltr engine. There are multitudes of RB30 single cammers making bulk grunt, so bolting a hair drier to the side of one in the interim, and building a DET 30 on the side for later fitment is the go.
If it can be as quick as the ET without spending any unnesesary coin, with the N/A bottom end, sohc head and spare VG30 T3, it leaves me with the proceeds of the Pulsar parts sell off to fund it, whilst not pining for the ET's go.


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Ash
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Post by Ash »

well i have an RB30ET VL and i still love the little ET. not as quick or fun sideways but theres just something about em? they are just so raw and fun. i'd drop the 3 litre before the ET! honestly. thats me though.
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tassuperkart
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Post by tassuperkart »

It is Ash but, this is Damo we are considering here!!!!
He has a clear vision!!!!
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Post by Damo »

tassuperkart wrote:It is Ash but, this is Damo we are considering here!!!!
He has a clear vision!!!!
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'Clear vision', I'm finding I need to hold things futher and futher away from my face in order to see them clearly, but then struggle to see the detail needed from so far away.

Ahhhh.....................the main game is to keep the ET where it is, and build the 31 on the side with a couple of dollars from the "12years collecting N12 bits" sell off. :D
I still have that tasty exy manifold to go on the old girl.


Damo
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tassuperkart
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Post by tassuperkart »

Damo wrote: 'Clear vision', I'm finding I need to hold things futher and futher away from my face in order to see them clearly, but then struggle to see the detail needed from so far away.
Bwaaaaahahahahahah welcome to my world then Damo!!!!!
And yes, I have "peep over" magnifying glasses lmao!!

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Post by Damo »

Small update on the Skyline.

I figured while I had the Rb30 in bits, I was going to lend my hand at balancing the innards. How hard could it be?

I managed to pick up a set of old school 'teeter' scales (18mnths back). Came from an old wrecking yard building where they were used to measure the weight of paint for colour matching on cars. Very well made, and able to read down to the closest 1/2 gram off the scale, and with enough scale separation to extrapolate to the tenth of a gram!

After weighing all the rods, pistons and pins, I did a little research into how things 'should' be done. According to all the info I could be bothered to read, after the rods had been weighed, the big end (or little end) needed to be weighed. From that, you are able to work out the opposing end by subtracting the end weight from the total.

Sound easy don't it!

Problem is 'in' the weighing of the ends. To weigh an end properly, the rod needs to be perfectly horizontal as not to load/unload the end being weighed.
The opposing end needs to be supported at its center pivot while not imposing ANY friction to it turning, or incorrect weight is measured.
And the end being weighed also needs to be 'weighed' from the center of its pivot.

O.k, attempt #1 at weighing big ends.

As the scales I have teeter from one side the the other, I couldn't support the rod directly onto the scale surface, as the scale movement would push against where the little end was being supported and imparting a friction onto the pivot. So I devised to hang a length of fishing line over the edge of the scale (as vertical as I could measure to cancel out loading, and as long as practical to help limit angle change) with a loop in the end to connect to the rod bolt between the beaing cap and it's mating surface, which happens to be the center of the big end pivot.
With this done, I also had to figure how to support the little end.

I figured that the piston pin would be great. So I used 2 pistons to support the pin and rod. But this proved to be non ideal, as it was inducing at least a 5gram friction loss due to oil drag. After the scale had settled, I would load the scale and let it osilate till it settled again, and it would show a consistant inconsistancy.

Try #2

I then substituted the piston pin for a short length of 20 od plastic conduit, which was lubed as best I could. It worked better, but was still giving a 2gram variation as it was turning and moving in the pistons as the scale settled.

Try #3

I then figured I'd need to support the little end the same way as the big end to eliminate friction. After a bit of thought, (light blub moment) I balanced the little end on the point of a screw as close as I could measure to the center of it's pivot. Bingo! I was now able to duplicate readings to the 1/4 of a gram, and if I was to load the scale the same way each time, the error was down to less than 1/10 of a gram!
At that point, I also realised that the rod had to be exactly horizontal for a meaniful comparo in the future. So I shimmed up the screw to get the whole thing spot on.

I started noting down readings I was getting. About halfway through the set, I realized that there was an inconsistancy in my method. The problem was without fully bolting the caps down (I had to leave a small gap to allow the fishing line to loop the rod bolt and still move freely) I was essentialy introducing a variance I couldn't replicate on all the rods equaly.
So, I fully removed the caps and nuts and placed them on the scale itself rather than on the rod. This allowed me to check all the weights much quicker.

But thinking about this more, this method was also inaccurate because the weight of the rod caps wasn't consistant either, and that would compromise all the readings I had already recorded. :? :?
And in reality, this is a problem which isn't/wasn't addressed in any of the info I had read on the net. Being a novice at balancing, I would have thought that this would have been something that would have been though of and sovled decades ago. But I couldn't find anything about it on the net.

So I had a friendly chat with my machinist bloke. I asked him a few Q's in general about balancing. He only balances to the nearest gram when he balances bits, as his setup is only repeatable to the 1/2 gram. (YAY, I win!)

He also doesn't balance the rod caps. I threw in the idea that even if the big end weights were the same, the weight arond them may not be evenly distributed. But he still maintained that it wasn't needed.

Weigh the rod first, then weigh the big end. Work out you little end and balance those first. Go back and weigh the big ends, then match them up.

(And the bit of advice which only comes with experience, GOLD!) Don't take weight off the pistons, take it off the corresponding little end. Far less steel needs to be taken off v's alloy from the piston. He is very reluctant to take any material off pistons at all. His words "Rods are inherintly far stronger than needed, esspesialy compared to pistons. So take weight from them instead."

So armed with this new knowledge I went back to the drawing board. To get my figures to fit 100%, I would have to balance the rod caps anyway. So I did. After they were done, I re-weighed rods without the caps and nuts, as now they cancelled each other out alltogether.
I then balanced the little ends, but found I fucked up an instead of taking .25gram off one of the little ends, I took off 2.5grams!! :shock:
So after fixing that, I balance the rod side of the big ends.
ALL DONE!

I will have to post up some pics to make the whole story a little more understandable.

Also, does anyone have an opinion about balancing the rod caps first? As I think its vital, but no-one seems to bother.



Damo
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Post by Damo »

Forgot to mention, all the rods/slugs are now within .15gram from each other.

Pics
Image

E15 v's RB30

Image

Standard OEM piston! Notice the 4 valve relifes....for a 2 valve head.

Image

My set of scales.

Damo
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Post by Damo »

Update time.

The donk is together and in the car. Had to reuse the factory clutch in the interim.
Kicked in the guts, and she runs. Did the whole 30secs no coolant warmup myth thing. All good. Added coolant, and it starts pissing out of the water pump!!!!! Grrrrrrr........ Pull the bits off to get to it, swap it out and start it again. No leaks this time. YAY!
Take it for a quick fang round the suburb loading it up as much as I could, carting round the auto on the back seat, and manual box in the boot with flywheel and odd+ends.
Pulls realy well! I was very impressed, it feels like when the ET is starting to come into stride at 3500.
Super smooth, the only indication of revs is the sweet RB sound, no harshness at all. I'm going to video the 50c peice sitting on the valve cover while idling for youtube.

Temporarily fixed the dragging brake from the seized hand brake cable. Tightend up the swaybar bolts. Did up the other two prop shaft bolts I couldn't reach.........oooops :oops:.

Today I going to silicone up the bonnet and boot so it doesn't sound like a tin can when I close either of them.




Damo
Do humanity a favor, use your brain and fight the forces of WOO WOO!


http://www.youtube.com/watch?v=G1mrbxhWU5Y
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tassuperkart
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Post by tassuperkart »

Youve been busy grasshopper! Good to hear. Keep at it M8.
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Post by Panda_ET »

nice work
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Post by Damo »

Super smooooooth RB goodness :D

Although, she 'sounds' tappy.





Damo

Had to edit the youtube picture name, so this is the same vid under different #.
Last edited by Damo on Mon Dec 28, 2009 8:12 pm, edited 1 time in total.
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Post by Panda_ET »

Schmoove but big question and most importantly ...Does it skid ???? hot black snakes yet?
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Post by Damo »

Panda_ET wrote:Schmoove but big question and most importantly ...Does it skid ???? hot black snakes yet?
'Skid'? I do not understand what you are suggesting. :D Do you think I am some sort of Hoodlum with a need to break the law do you?

Besides, the only real skids when the car is already moving at 100kmh, FTW.

Mates 1J Carolla does em, other mates Newly tuned Mazda 20v 4AGZE (276kw atw with E85) will do em no probs, so basicly I have no choice, the peer pressure is unbearable! :D

I may have to sort the unis out first though, they are a little 'old'.



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