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Rebuilding Rb25.......balancing???

lismo

By lismo,
in General Automotive Discussion

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lismo Community Regular

lismo

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Posted

Hi All,

Im currently rebuilding my R33 RB25 engine.....

I was asked by the guy doing the boring of my block and recondition of my head if i would like to get it balanced....

My uncle who has worked for nissan for many years and is rebuilding my engine said its not really necessary....

Being a girl and not knowing much about rebuilding engines, i thought a balance was something to do with the engine and the new parts going in it.....but i learnt it was to do with the pressure plate, flywheel and crank.....

As for the parts im only getting forged pistons, a metal head gasket, race bearings, a heavy duty clutch.....and everything else necessary for putting it back together as that is costing my around the $3500 mark and i really dont have the finances for even that....

To the people that had have experience in rebuilding enigines.....

IS IT REALLY NECESSARY TO HAVE IT BALANCED????

Thanks..............

liz :angry:

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GTRgeoff Grand Master

GTRgeoff

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Posted

Liz, having been down this path and done some engine rebuilding in my time and worked as a mechanic for a long time so I'd suggest:

dump the metal gasket and use a stock one, $80

get the block O ringed (a stainless ring about 0.6mm around each cylinder for the stock gasket) (around $120) $200 has to be less than the metal gasket which retail about 400

modify the oil system at the top face of the block. Close off the front feed of the 2 along the block. Sorry no pics but there is one for the VCT and 2 for the head oiling. Helps prevent over-oiling the head and lack of oil in the sump, hence oil surge if cornering hard. These are just standard inserts.

Straighten the crank, remove the oil plugs and tap and fully clean the galleries. Insert grub screws.

Balance from harmonic balancer to clutch. This will make it run and feel much smoother and is good for longevity of the engine and smooth power delivery if pushing hard (eg track)

Pull all welsh plugs and oil plugs. Acid dip block and fully clean ready for build after fitting pistons.($70)

ACL heat treated race bearings around $140 using RB30 mains and SR20 Big Ends (unless you can now get specific RB25/26 sets)

Use GTR rods(about $250), get them x rayed for integrity($30)

I had all this done and a few other things for around $1200 with a recommended reco shop in Melb, but I had no previous business there.

lismo Community Regular

lismo

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Posted

Hi....

Thanks for your response.....

I already have all the parts i need and the block and head are almost complete.

I got all my parts, the boring and headservice for just about cost as i know a friend that is a manager of our local repco.

I think i will get it balanced for a smoother delievery....i do like to take my car for a test and tune now and then but not as keen on the track yet.

Thanks!!!

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