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Title: piston/cylinder clearance Post by: Garrick Clark on January 10, 2016, 23:13:41 pm Hi guys.
I have a type 4 turbo motor using AA 96 mm pistons. I have had some trouble with scoring of the cylinders and the piston skirts. I did overlook the ring end gap. Some rings only had 2 thou clearance. I have now had the cylinders honed and got the piston skirts cleaned up. I now have 4 thou piston/cylinder clearance. Is this enough for turbo use. I think the pistons are hypers but not to sure as no info came with the kit. Title: Re: piston/cylinder clearance Post by: spanners on January 11, 2016, 00:41:24 am .004" is acceptable provided taper, barrelling and ovality is correct with installed torque values, the liners expand more near the top with heat and pressure, up to .008" is OK in the lower half, taper honing gets a blank stare these days, I presume you mean ring end gap, you were lucky with end gap at .002", tho they often come like that or even less from new, scoring tells me chrome rings, I like a radius on the ends to help with that, just a wet stone working.
Title: Re: piston/cylinder clearance Post by: modnrod on January 11, 2016, 02:11:56 am https://www.google.com.au/search?q=ring+end+gap+turbo&espv=2&biw=1578&bih=973&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiIu7m6yaDKAhXj3aYKHRYXAIgQsAQIJw#imgrc=E-lhbcbg2fFslM%3A
Title: Re: piston/cylinder clearance Post by: Garrick Clark on January 11, 2016, 20:43:18 pm Hey thanks for the replies guys.
I did the oven test tonight. I put a piston and cylinder in the oven at 200 for 20 minutes. My piston to cylinder clearance is 4 thou cold 2 thou hot. Skirt clearance not ring area Am I right in thinking the hot clearance is too tight. |