Re: Piston cylinder wall clearance-Don't hate me for asking
[Re: VITC_GTX]
#1030398
07/11/11 08:44 PM
07/11/11 08:44 PM
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Joined: Aug 2005
Posts: 11,543
chicagoland,usa
buildanother
I Live Here
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I Live Here
Joined: Aug 2005
Posts: 11,543
chicagoland,usa
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If the worst bore is just .007" over stock bore size, you should be able to get some more time-miles out of it. Just don't get too crazy with the glaze breaking and if the ring grooves and piston tops and skirts look to be in decent shape, go for it. If you do put new rings in it, make sure you have a gap of 016" measuring at bottom of bore where the least amount of wear is. IIRC, the old shop manuals had around .007" for wear limit too. (440 4.320") i personnally drove a cava w/2.2 for 25k miles with one piston with .018" clearance, and I heard it rocking in there hot or cold, and did not use oil, ran strong. 
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Re: Piston cylinder wall clearance-Don't hate me for asking
[Re: VITC_GTX]
#1030401
07/11/11 09:59 PM
07/11/11 09:59 PM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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dingleberry hone for the right finish & get a set of cast rings (they're dirt cheap) as the taper is prob substantial. Break one of your old rings in two & grind a "hook" on a broken end & straighten the edge & use it to decarbon the grooves. CLEAN the cyl walls good.
live every 24 hour block of time like it's your last day on earth
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Re: Piston cylinder wall clearance-Don't hate me for as
[Re: 383man]
#1030408
07/12/11 11:35 PM
07/12/11 11:35 PM
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Joined: Jan 2003
Posts: 25,200
Upper Midwest
MoparforLife
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,200
Upper Midwest
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Quote:
Quote:
The old "knurling the pistons" trick, right, Chief?
It actually works. But try to find someone who knows how to do it!
About rings, the bore wear is probably greatest close to the top. If you use file-fit rings and set them to the correct gap at the top of the cylinder the odds are they'll be really close or butting at the bottom of the stroke.
I know my first reaction was "yuk" but I've run worse than this.
R.
The 2 machine shops in my area knew how to knurl a piston real easy. They only run a few lines of knurls on each side of the piston. Then they will usually be to big to fit in the cyl. Then you can file fit them and the knurls hold oil in them which is good for keeping oil on the cyl walls. Ron
Sure glad someone else mentioned knurling. Last time I did you would have thought that the world was coming to an end from all the perfectionists here. Knurling if done right will last many thousands of miles. ore than likely many more miles than any of use will put on these cars. Knurled valve guides will last many miles too if done right. 
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Re: Piston cylinder wall clearance-Don't hate me for as
[Re: MoparforLife]
#1030409
07/12/11 11:56 PM
07/12/11 11:56 PM
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Joined: Feb 2007
Posts: 1,025
Las Vegas, NV
dodgeboy11
super stock
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super stock
Joined: Feb 2007
Posts: 1,025
Las Vegas, NV
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And while you're at it, throw some c4 in the oil pan and make it a good explosion. Ok, so that may be a little bit dramatic, but you have the engine apart, build it right. You can't afford to do it right the first time, but you can afford to do it twice right? With taper in the bore, the rings are constantly expanding and contracting as they go up and down the bores. IF there's a groove at the top, you could possibly break rings when the pistons come to TDC. Do yourself a favor and do it right the first time. Piston slap is likely the least of the problems as you have a tall piston, but ring seal will be compromised and on top of that, if you get some new pistons, then you can get the compression up where it belongs and make some real power. Just a suggestion, but it's what I would do.
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Re: Piston cylinder wall clearance-Don't hate me for as
[Re: dodgeboy11]
#1030410
07/13/11 02:35 AM
07/13/11 02:35 AM
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Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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Quote:
And while you're at it, throw some c4 in the oil pan and make it a good explosion. Ok, so that may be a little bit dramatic, but you have the engine apart, build it right. You can't afford to do it right the first time, but you can afford to do it twice right? With taper in the bore, the rings are constantly expanding and contracting as they go up and down the bores. IF there's a groove at the top, you could possibly break rings when the pistons come to TDC. Do yourself a favor and do it right the first time. Piston slap is likely the least of the problems as you have a tall piston, but ring seal will be compromised and on top of that, if you get some new pistons, then you can get the compression up where it belongs and make some real power. Just a suggestion, but it's what I would do.
Knurling is good to take up the extra clearence in a bore for wear but you are right that if it has much cyl taper that has to be fixed. I was under the impression that it just had to much piston to wall clearence from cyl or piston wear but not alot of taper.
Knurling is good to close up the piston to cyl wall room and works very good if done right. In fact it is very good for holding small amounts of oil in the knurls and helps keep the piston and cyl wall wear down with the oil in the knurls that keeps extra oil between the cyl wall and pistons. It is not a half a$$ job as it has been done for many years and holds up for a very long time. My old 383 still has the knurled pistons in it after 10 years on the road and the knurls still look good.
Many people are on a tight budget as I was and just cant afford knew pistons and all. I honed my cylinders alot to get it as close to round and as little taper as I could get. Then I knurled the pistons and file fit them for .0015 to .002 piston to wall clearence. It saved me alot of money on a budget build. I am not trying to be smart as you are correct in boring and replacing pistons to be the best way to repair it but done right knurling is very effective and is a good repair that will hold up for many years and miles. Ron
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All of the "loosies" I've overhauled did use a little oil but oil's cheaper than the alternative. 
