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VFR750's Avatar
 
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The heads were fully disassembled and inspected. Guide clearances had not changed. Cleaned and reassembled and considered good to go.

Just waiting on rings.

Old 09-08-2015, 11:27 AM
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You should have good luck with True Seal. I put them in 700 miles ago and have nearly zero oil consumption. I drove it fairly hard right out of the gate, but was careful to keep the temps down on any given run. Lots of hills are key IMHO. Run up the revs with just a touch of boost, then coast, repeat. In my guesstimation they were seated within 300 miles on VR1.
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Old 09-08-2015, 06:31 PM
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Nice to hear you had good experience with total seal. Thanks for sharing that.
Old 09-09-2015, 03:38 AM
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Unless I missed it no one mentioned having the rings installed upside down--although this will usually only cause a problem with one cylinder (unless you are really not paying attention)
I have had problem with Total Seal Gapless Rings aligning the two piece ring gaps causing bad leakdown and blowby after 10 to 15 hours of operation. This was over a fair amount of time and involved more than 6 race engines that had to be tore down and re-ringed. When I talked to Total Seal about fixing the problem they did not seem to be concerned. (I quit using Total Seal)
The hone crosshatch rotates the rings on start-up and less as the engine breaks in and the hone wears. You should get 2% to 10% leakdown even across the cylinders on initial assembly--2% to 4% on used Nikasil cylinders that have been red-scotch-brited with new rings and 10% on cast iron cylinders honed with 400 grit.
I leak check the cylinder to head interface with soapy water and check all the valve sealing with solvent (not vacuum) for leaks.
Millennium keeps all their tolerance extremely tight---if I had any complaints it would be that their average cylinder wall RA is rougher than I want it and I have started honing the new cylinders with red scotch-brite before assembly for the RA I want.

Over the years I have had a couple of seating problems--as Steve said it is a complicated subject---I was lucky and solved one problem on a chassis dyno and the other one over a race week-end when I did not have time to do a tear-down and re-ring.

I would use new rings
aws
Old 09-11-2015, 09:55 PM
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Je ring groove dimensions are the same as factory porsche?
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Old 09-12-2015, 03:07 AM
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JE top ring groove is tighter than factory.

JE standard piston spec is .0015" verses. 0.0027" for the top groove for Porsche.

Mine measured between. 0.0015-0.002"
Old 09-12-2015, 03:29 AM
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Aws

I would agree that the surface finish from millenium looks very rough. After the scotchbrite process they looked smoother but less shiny.

If I were to spec a new set I think I'd ask for a smoother surface. It just seems the system is set up for hard rings and running surface. We should be able to start with something a little closer to the optimal.

Otherwise we spend too much effort setting tight ring gaps, that open up trying to get the rings and rough surface to bed in.

No doubt ring rotation occurred. Plus I checked; all rings were installed correctly. The wild card on where the rings stop rotating is one thing that worried me.

Hopefully resurfacing by scotchbrite and new rings will tame the beast.
Old 09-12-2015, 03:40 AM
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Over the years I have progressively gone to finer stones when honing cylinders---ending up with red scotch-brite ( A trick I learned from Henry many years ago, when I was having trouble finding hone stones finer than 800 grit--) Unless I have scoring--and I then using nothing rougher than 800 grit stones. The noticeable difference on refresh tear downs is ring gaps.
Good luck with the re-ring--from looking at this thread you have certainly covered all the bases.

aws
Old 09-13-2015, 01:18 PM
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Hey Mike,
Just saw this thread. I think these guys ( Esp Steve) have you on the right track
Sorry to hear of your troubles. Knowing you I'm sure you were very careful with this project
Hope to see you back at the track soon
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Old 09-13-2015, 04:30 PM
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Thanks Dan. It's been a long journey.

Hopefully I'll make the November DE at LRP. That's my goal for 2015.
Old 09-13-2015, 06:05 PM
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Rings will arrive Friday. I'll post a comparison.
Old 09-14-2015, 07:56 AM
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Are you guys just using a regular scotchbrite pad manually with your hand?
Old 09-14-2015, 09:10 AM
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Yes. Hand scrubbing with soapy water. Scrubbing in twisting motion like the existing honing marks. Both directions.

Clean up with isopropyl alcohol. Then wipe with lightly oiled wipe to get the residue out of the grooves. Then remove the residual oil with isopropyl alcohol.
Old 09-14-2015, 05:24 PM
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Quote:
Originally Posted by Dpmulvan View Post
Are you guys just using a regular scotchbrite pad manually with your hand?
Maybe if you're really talented and know what you're doing from experience.

If you want the surface scuffing as even as possible top to bottom and you're doing it by hand you could carefully wrap the scotchbrite pads around the 3 stones of a spring loaded engine cylinder hone with fishing line, string, or whatever and chuck it into a relatively slow rpm 1/2" drill.
Then have at it going in and out the cylinder as fast as you can so the cross hatch scratches in the cylinder are at a similar angle as a machine shop would do.

Try not to over do it.
Maybe use a timer while doing each cylinder so you do them all the same amount and if the phone rings while doing this ignore it.
Or do stuff like this on Sundays or really early in the morning before business hours so there's no interruptions and you can concentrate 100% and do the best work you can in peace
Old 09-14-2015, 08:28 PM
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Fair point on the rotary home with pads. I thought about doing that. But my situation is a little different. If I was deglazing cylinders with 100,000 miles I'd do the rotary process.

I have only 900 miles. The original cross hatch is present. All I am trying to do is remove the shiny areas and give the overall surface a slight smoothing. My goal was to make the rough surface finish a little smoother, with appropriate pattern of scuff. Every cylinder was in different state of break in. Time and effort varied to get all to look the same.
Old 09-15-2015, 02:04 AM
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^ Did you mean, make the smoother surfaces rough?
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Old 09-15-2015, 03:23 AM
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No. I meant a little smoother. The honing on the millenium surface is very rough. Too rough. Scotchbrite will never make it that rough. This is a point of much discussion. So be careful in terms of my particular issue verses a general process. I was looking to even out the roughens to be a little closer to a scotchbrite surface which is still smoother that a honed surface from millenium.
Old 09-15-2015, 03:48 AM
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To be clear, I only have 900 miles on the refinished barrels. The rings have not seated. The cross hatch is still very visible.

My goal was to deglaze the shiny. And to even out the surface appearance.

The observation was the scotchbrite surface has visible roughness. But it is significantly smoother than the un-run portions of the barrel.

I am attempting to even out the surface roughness across the running surface without overdoing it. I am erring on the rough side.
Old 09-15-2015, 03:59 AM
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Where can I find more information on the scotchbrite method? Sorry don't mean to hijack the thread.
Old 09-15-2015, 01:20 PM
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There are a lot of threads. Some date back to 2004 or so. Not really a hijack. But a lot has been said before.

I found them by searching on "deglazing cylinders"

I imagine if you search "scotchbrite" you would find them too.

I didn't cut and paste a link because there are many posts and they have to be read as a collective for you to decide what you believe is the truth. I have mine, I've posted it here. Others have commented. I have given them consideration. I have tweaked my thinking process based on input. And here I am, ready to commit my build to my process.

Old 09-17-2015, 02:24 AM
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