Sports piston rings orientation and order

[Alan]

Which Newman cam do you have? Years ago I had a reground race cam from them. You could hardly feel any compression if you wound it over by hand, but it revved it’s little socks off. If your cam has a lot of overlap it could be like that.

[Tony Betts]

I would have thought if pistons are metric they would be directional.

These are the slipper pistons, I took over from quarry engineering.

Some of the earlier rings the word TOP was there but not that obvious.

Tony.

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[Howard Wright]

I tested compression with a compression tester and all 4 cylinders came out at little more than 50psi, which seems v low for HC head etc. though I have yet to test the volume of the cylinder head. What should the combustion chamber volume be for an HC head?

Valve clearances are all good though as the head is off I will clean the block surface and valves and then regrind to ensure valve seats are good. The only thing there is that they are very very large inlet valves so the seats are quite thin...

This all started as its seemingly impossible to get it running so that the plugs are anything other than carbon black and I already have it well less than 2 turns of mixture on my HS2 carb. It goes well but also won't rev which is v irritating as you can imagine.

Hi David

Have you tried a hotter spark plug?  Champion D21 plugs have vastly improved the sooty nature of the plugs on my engine. 

Cheers

Howard

[Colin Reed]

HI DAVID,
A Couple of  THINGS, how did you put a highly tuned Engine together with out Knowing the volume of the head.
the oil on  the top of the pistons could be bores being glazed so you will need to check bore size just below where the top ring comes to .
You will also have to pull engine out to rectify the loose flywheel because if you do manage to get it to rev you are very likely to end up with a very expensive repair Bill.

just take your time and check every thing from scratch.

All the Best
COLIN
NZ