Piston Rings

[Guest Phil Slater]

Hi Folks

 

I'd like to gather some opinions on replacing the piston rings on my engine. I am just starting to rebuild it after a basic overhaul. I took the block into a local engineering firm who have deep cleaned it, checked it over and concluded the cylinders just needed honing. This they have done and supplied a new set of piston rings.

 

My query arisies because there is a very slight ridge noticable in the cylinders just below the block face where no doubt the top ring reaches at TDC . The ridge is pretty much the same on all cylinders with just No1 being, if anything, slightly more noticable. Someone has mentioned that rings are availalble with a small step taken out on the top edge to avoid the ring breaking if it comes into contact with the ridge.

 

Given the firm supplied standard rings I'd value opinions on whether I should stay with them or try and get hold of some stepped ones.

 

What do you think?

 

 

Phil Slater

[Big Jim]

You should be OK with the standard rings providing you don't rev it too much for a few miles. Just make sure that you "gap" the rings on the pistons, ie. first put plenty of clean oil over them, then if the gudgeon pin is in the "quarter to three" position, looking at the top of the piston, then put the gap in the oil ring at about 27 mins to. the next ring (No 2 ring) put the gap at about 8 mins past. (ie opposite the oil ring) then with the top ring (compression) put the gap at about 22 mins past. you don't want any gaps directly over either the g/pin or on the thrust sides of the piston (ie 6 oclock position)

use proper piston ring compressors, and if you feel the rings turn, do them again!

 

Don't forget that sometimes the compression ring is "handed" it may havea distinct top & bottom edge, and should only be put on one way up (I don't know if your's are or not)

 

If you put one piston with rings in, then turn your engine, and it's reluctant to go over the "top" then you may need stepped rings, but I doubt it very much.

[Guest Phil Slater]

Jim

 

Thanks for your comments.

 

I checked things out with the engineering shop today and they said that with the honing they had done there was no need for stepped rings, quote, "even if you could find some"!!. So tonight with your tips on ring spacing the pistons are back in.

 

All the best

 

Phil Slater