a mate of mine used to build 'racing' spec 308's, I believe he started by taking off the moulding/forging marks off the edges. i think he called it 'blue printing'.
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a mate of mine used to build 'racing' spec 308's, I believe he started by taking off the moulding/forging marks off the edges. i think he called it 'blue printing'.
That jig he uses helps big time.Quote:
Originally Posted by steveG
We used to do it half on, half off the scales, or two scales side by side, that's why I said it gets tricky.
You'll start to take some weight off one end and it can transfer the balance a bit too far the other way.
It can end up being a bit of a dog chasing it's tail syndrome, but by being careful it will work out.
The balancing marks on my con-rods look like they just linished the big-end caps.
IIRC the big ends were the biggest difference, around 27g from heaviest to lightest. Huge difference sorting that out.
About the boost, I don't remember, but 10psi sounds about right for industrial use.
What about balancing the pistons is there any tricks with balancing them ?
Not really, it's common sense but I'd also check the bowl volumes and equalise that too to try and equalise chamber pressures.Quote:
Originally Posted by c.h.i.e.f
Only problem I can foresee with that is the pistons are alfin so I'm assuming the tops should not be touched ?Quote:
Originally Posted by rick130
I don't know.Quote:
Originally Posted by c.h.i.e.f
Is Alfin a coating ?
I'd expect the pistons to be pretty close anyway. The alfin reinforcement is around the ring-lands. I'd expect your biggest contribution to combustion volume variation would be valve seat recession. Tip the head upside down and measure that volume if you're keen. I've never bothered.Quote:
Originally Posted by c.h.i.e.f
Al-fin process is used to bond an iron insert in the position where the top piston ring groove will be machined. This is necessary because of the high compression ratio of a diesel engine, compared to that of a gasoline engine and therefore the stress on the top ring groove is that much greater.Quote:
Originally Posted by rick130
I think you will be able to blueprint as long as you don't disturb the iron ring groove to aluminium piston joint.
Quote:
Originally Posted by Dougal
We always measured and equalised bowl volumes on Ford crossflow pistons ( Mahle) as they were out to buggery, but they were race engines too so IMO I could never ever go too far.
I was pedantic about valve protrusion too.
My head bloke used a Serdi machine and they were always equalised ( and maximised)