8 replies to this topic

[tommypope]

the haynes manual says that i you can fit a 0.010 feeler between the piston and bore with rings removed it needs a rebore

now i can just about fit a 0.30mm feeler in being 0.011" is the hayne in " on mm i dont no lol

anywhoo

i realy could do with not having to rebore so what do you guys think

also this is a standard size 998

[sledgehammer]

Was it smoking / using oil ?

was it down on power ?

how much of a step was there at the top of the bore ?

what was the compression like ?

[ACDodd]

You need this measured properly, using a dial bore gauge and micrometers. Take it to an engineering shop for a measure up.

AC

[tommypope]

we used a bore guage all i remeber is it came up at 57somthing rather than 54?

compresion was ok but it did smoke alot wen i got it although it hadnt been started in neary 5 years lol

Edited by tommypope, 13 January 2013 - 02:22 PM.

[carbon]

As AC says best to get measured up by engineering shop.

Is there a pronounced lip at the top of the bores (you will need to clean up the bores first and remove the carbon)? If this is in good shape then chances are the pistons may be good and you could get away with hone and new rings.

Also for measuring piston-bore clearance are you checking the the bottom of the piston at right angles to the gudgeon pin?

[Vipernoir]

As a piston is tapered (the top is thinner) and not all pistons will be the same shape, I would guess that the .010" feeler gauge measurement is a load of *******.

If it's burning loads of oil and/or smooking, then at minimum you'll need a hone and new rings, but only proper measurement will allow you to assess this.

[tommypope]

this is my problem lol as the car never ran when i got it and i manged to get it fired up and switched it off and pulled the engine out lol

the was a fair bit of smoke but then it hadent ran in over 5 years

[Vipernoir]

Stood over time the rings can stick a bit and initially not scrape the oil off the bore properly. The valve stem seals can also go slack and let oil past into the cylinders.
The rings may or may not unstick themselves if you warm it up and rev the tits off it - and I know this is bad practice, but it can sometimes work and save a rebuild.

Stood that long though you are probably looking at a strip and rebuild for peace of mind.

[tommypope]

already doing a strip iv skimmed the head and decked the block as i can do that myself but dont realy want to rebore it