piston skirt coatings for worn bores

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machinedave
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piston skirt coatings for worn bores

Post by machinedave »

I've got a 226 continental inline 6 block in the shop that is already .060" oversize with .005" taper at the ridge. This is the 4th block that he has brought for me to machine and the only one of them that is not a complete basket case. Have any of you had your pistons treated to those coatings that add .004" to the skirts for worn out bores? Have any of you examined the quality after several years and thousands of miles of use? Who have you used that you like?
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Re: piston skirt coatings for worn bores

Post by fdicrasto »

I can only vouch for the fact that Swain coatings did a good job but don't know the down the road evaluation.
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Re: piston skirt coatings for worn bores

Post by statsystems »

machinedave wrote:I've got a 226 continental inline 6 block in the shop that is already .060" oversize with .005" taper at the ridge. This is the 4th block that he has brought for me to machine and the only one of them that is not a complete basket case. Have any of you had your pistons treated to those coatings that add .004" to the skirts for worn out bores? Have any of you examined the quality after several years and thousands of miles of use? Who have you used that you like?

I just sleeved them because coatings weren't available. Setting 6 sleeves is more money up front. But probably cheaper in the long run.
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Re: piston skirt coatings for worn bores

Post by MadBill »

I had abradable coatings by https://www.line2linecoatings.com/ added to my Can Am BBC pistons to cover off loose pistons (~0.010") plus a 0.005" overbore. They can add up to 0.020" and recommend coating pistons to zero thous 'clearance'; the coating quickly wears to conform as required, increasing the contact area and stabilizing. (Their core work is coating factory supercharger rotors.)
Can Am Block 001.JPG
Haven't run it yet so no feedback.
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Re: piston skirt coatings for worn bores

Post by modok »

I'd knurl the pistons :P
you could hone the bores good enough to run and end up only .003-.004 oversize, that is totally reasonable IMO, unless the new pistons are hyper, but I doubt it
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Re: piston skirt coatings for worn bores

Post by Jeff Lee »

MadBill wrote:I had abradable coatings by https://www.line2linecoatings.com/ added to my Can Am BBC pistons to cover off loose pistons (~0.010") plus a 0.005" overbore. They can add up to 0.020" and recommend coating pistons to zero thous 'clearance'; the coating quickly wears to conform as required, increasing the contact area and stabilizing. (Their core work is coating factory supercharger rotors.)
Can Am Block 001.JPG
Haven't run it yet so no feedback.
x2. Just finished engine assembly with .0095" Cylinder wall clearance tightened up to .001” on my Super Stock engine.
After seeing this, a buddy did the same on his Super Stock engine and a customers Stocker engine. So that’s 3 in my circle waiting for first runs.
This coating came highly recommended by Total Seal & Diamond Pistons. Search here for more info.
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Re: piston skirt coatings for worn bores

Post by modok »

I have high hopes for the coating, not against it at all but, can't endorse what i don't know to be proven.
.....let us know results!
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Re: piston skirt coatings for worn bores

Post by In-Tech »

modok wrote:I have high hopes for the coating, not against it at all but, can't endorse what i don't know to be proven.
.....let us know results!

Good call Glen, I would like to learn as well.
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Re: piston skirt coatings for worn bores

Post by Speedbump »

I used Line to Line coating through KB Pistons for a Jr. Dragster engine for my grandson. It's a little funky doing the zero clearance coating using scotch brite pads to get the "snug in the bore" fit they want but the little engine has about 20 passes on it now and is stronger with each outing. Runs on alcohol if that matters and I haven't taken it apart for inspection yet but it is working as advertised so far.
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Re: piston skirt coatings for worn bores

Post by ec1 »

Line 2 Line skirt coating just plain works! I was a huge skeptic until i was in a bind and tried them out. Lots of guys using them but they keep it a secret. I have saved many pistons and bores with their skirt coatings. Go to their website for all the tech and videos. I ran a set in a full filled block that even held up great for 60 passes before he torched the head gasket real bad. The coating held up great. In that app the I got the job after someone honed the block all over the place so i made them all +.005 and had the skirts coated to the bore size. Saved the customer time and money to not have to get custom pistons made. I still have the pistons here to show my customers.
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Re: piston skirt coatings for worn bores

Post by Jeff Lee »

This is used in aircraft industry. After hearing “use it” from Total Seal, Diamond Pistons, and finally my friend that is a AP mechanic, I did it. He told me the Abrade-able Powder Coating was the difference on a turbine engine of “18,000 #’s of thrust vs. coated and 22,000 #’s of thrust”.
This is not something new. But ups do need to break in the coating under load before you go banzai down the track.
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Re: piston skirt coatings for worn bores

Post by n2xlr8n »

fdicrasto wrote:I can only vouch for the fact that Swain coatings did a good job but don't know the down the road evaluation.
I can vouch for their skirt build up- I've used it on a few Subarus (terribly short skirts and piston wear) that were in my cars with E85 and lots of boost. Looked fabulous at teardown.

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Re: piston skirt coatings for worn bores

Post by machinedave »

Thanks all for the good feedback. Customer ordered new .060" pistons and he is sending them out for a buildup coating.
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Re: piston skirt coatings for worn bores

Post by maxlre »

Can't go wrong with Line2Line coatings use on many engines with great results
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Re: piston skirt coatings for worn bores

Post by RevTheory »

I checked out line2line's website yesterday and it looks like a pretty cool product. I have a question for you guys: Is a certain break-in oil needed? Basically, can an oil be too slick for the coating to wear into shape properly?
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