Compression problem rear cylinder
Thread Starter
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Cruiser
Joined: Aug 2008
Posts: 190
Likes: 25
From: Rotterdam, Netherlands
No, they should not be really tight. Each of the scraper rings should pivot independently of the spacer ring. The spacer goes on first, then the bottom scraper, then the top. Check out the vid below, as you can see, one installed it's very little effort to rotate them.
https://www.youtube.com/watch?v=qbqoOq4vqNM
It's for a twin cam but the install is the same as the evo. Again, it should not be tight but not loose either. YD
https://www.youtube.com/watch?v=qbqoOq4vqNM
It's for a twin cam but the install is the same as the evo. Again, it should not be tight but not loose either. YD
Rotate they do just fine, not a problem with that. I can rotate both scrapers independently from the spacer just fine. The whole package just feels very firm and hard to compress when putting the piston into the cylinder.
I've seen this vid and understand what they are saying. I actually didn't start before I understood what he meant
(English isn't my first language)Its just that, both of the spacer's ends lean against each other when it is fitted into its groove, the scrapers lean against the edges of the profiled surface. So, in order to be able to compress the scrapers, you need to compress the spacer, but is does not have much room left because the ends are already touching... I hope this makes sense
Last edited by Daedalus; May 1, 2018 at 02:40 PM.
Thread Starter
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Cruiser
Joined: Aug 2008
Posts: 190
Likes: 25
From: Rotterdam, Netherlands
Just did the second cylinder after looking into some other vids. I always tend to (like the guy in previous vid) to first fit the piston into the cylinder before putting in the wrist pin. These other vids also showed the gentle squeezing in of the compression rings and the prying of the piston for the scraper rings, so thats what I did.
Both pistons are in, and are easy to revolve around their rings in the cylinder, so I guess thats good. What 'feels' awkward is the easy with which the compression rings slide into the barrel, and the steady hand the scraper rings need. But, for now, I guess thats me...
Both pistons are in, and are easy to revolve around their rings in the cylinder, so I guess thats good. What 'feels' awkward is the easy with which the compression rings slide into the barrel, and the steady hand the scraper rings need. But, for now, I guess thats me...
Grand HDF Member
Joined: Apr 2007
Posts: 3,712
Likes: 3,030
From: Brighton, MI
What brand pistons and rings? Sorry having a little bit of trouble following your description, but it's always good to double check everything.
I just recently installed wiseco pistons and hasting rings, did not notice any difficulty compressing them but I used a ring compressor. I did notice the scraper rings needed to be sort of coiled on when installing. They did not want to expand like the two top compression rings. YD
I just recently installed wiseco pistons and hasting rings, did not notice any difficulty compressing them but I used a ring compressor. I did notice the scraper rings needed to be sort of coiled on when installing. They did not want to expand like the two top compression rings. YD
Last edited by Yankee Dog; May 1, 2018 at 03:28 PM.
Thread Starter
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Cruiser
Joined: Aug 2008
Posts: 190
Likes: 25
From: Rotterdam, Netherlands
What brand pistons and rings? Sorry having a little bit of trouble following your description, but it's always good to double check everything.
I just recently installed wiseco pistons and hasting rings, did not notice any difficulty compressing them. I did notive the scraper rings needed to be sort of coiled on. They did not want to expand like the two top compression rings. YD
I just recently installed wiseco pistons and hasting rings, did not notice any difficulty compressing them. I did notive the scraper rings needed to be sort of coiled on. They did not want to expand like the two top compression rings. YD
Dunno which factory makes the original pistons.Your second paragraph kind of describes what I mean. I'm used to having a single scraping ring bearing a wired spring on the inside. These compress similar to a compression ring when fitting the piston into the cylinder. The HD scrapers feel almost like a solid package when assembled.
But as said, after fitting the piston into the cylinder, nothing is stuck. The piston turns smoothly around the rings so there is not much more I can do other than continuing
Seasoned HDF Member
Joined: Mar 2010
Posts: 38,300
Likes: 6,325
From: Honah Lee
Did you check the ring gap with the ring squared in the cylinder by putting the ring in the cylinder and squaring with the piston? Usually, standard stuff fits but obviously your piston and rings are over standard. How much oversize?
However, the term you used honed to first oversize is an incorrect term for me. You bore to first oversize and finish hone to do crosshatch and maybe if necessary remove a few ten thousands of an inch. (.0001 is one ten thousands of an inch)
Be sure the wavy scraper butts. Not overlaps and walk the scrapers in.
However, the term you used honed to first oversize is an incorrect term for me. You bore to first oversize and finish hone to do crosshatch and maybe if necessary remove a few ten thousands of an inch. (.0001 is one ten thousands of an inch)
Be sure the wavy scraper butts. Not overlaps and walk the scrapers in.
Last edited by Jackie Paper; May 1, 2018 at 03:44 PM.
Thread Starter
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Cruiser
Joined: Aug 2008
Posts: 190
Likes: 25
From: Rotterdam, Netherlands
Did you check the ring gap with the ring squared in the cylinder by putting the ring in the cylinder and squaring with the piston? Usually, standard stuff fits but obviously your piston and rings are over standard. How much oversize?
However, the term you used honed to first oversize is an incorrect term for me. You bore to first oversize and finish hone to do crosshatch and maybe if necessary remove a few ten thousands of an inch. (.0001 is one ten thousands of an inch)
Be sure the wavy scraper butts. Not overlaps and walk the scrapers in.
However, the term you used honed to first oversize is an incorrect term for me. You bore to first oversize and finish hone to do crosshatch and maybe if necessary remove a few ten thousands of an inch. (.0001 is one ten thousands of an inch)
Be sure the wavy scraper butts. Not overlaps and walk the scrapers in.
I didn't check the squared ring in the cylinder, but guessed it was OK because it fell well within the diameter of the piston. The scraper rings were sticking out a little, and those needed some force to pry in.
But good one, I'll try to get the scraping rings and spacer ring in without the piston, just to see what it does. Its just prolly just me needing to get used to something new
*edit*
They fit nicely, so yeah... must be alright then.
Last edited by Daedalus; May 1, 2018 at 04:42 PM.
Seasoned HDF Member
Joined: Mar 2010
Posts: 38,300
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From: Honah Lee
Once done correct with checking the gap space, all the rings should spin in their slots. And of course, sink below piston diameter. There is a side clearance you can check with a filler gage. I would check that on your scraper.
I just rebuild my Jeep 4 cylinder. I reused the piston since the failure was do to a freeze plug rusting out and overheating. I checked the side gap and OD carefully. That side clearance is pretty critical and actually wears since the rings expand out under compression and wear that lower face.
My guess is your side clearance on the oil scraper is .001 to max of .003 or so. .001 is not much..less then a sheet of notebook paper. The least burrs where they cut the grooves is going to hang the scraper. Spinning them with a little motor will smooth all. Don't forget to space all ring gaps correctly to manual. Wave oil control usually does not matter but scrapers do. Note the direction of #1 and 2 for those bevels and or marks.
I just rebuild my Jeep 4 cylinder. I reused the piston since the failure was do to a freeze plug rusting out and overheating. I checked the side gap and OD carefully. That side clearance is pretty critical and actually wears since the rings expand out under compression and wear that lower face.
My guess is your side clearance on the oil scraper is .001 to max of .003 or so. .001 is not much..less then a sheet of notebook paper. The least burrs where they cut the grooves is going to hang the scraper. Spinning them with a little motor will smooth all. Don't forget to space all ring gaps correctly to manual. Wave oil control usually does not matter but scrapers do. Note the direction of #1 and 2 for those bevels and or marks.
Thread Starter
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Cruiser
Joined: Aug 2008
Posts: 190
Likes: 25
From: Rotterdam, Netherlands
I took the stuff back to the workshop who did the bore an hone job for me, and they said all was normal. The leading mechanic has been wrenching on Harley's with his dad, when he was a kid, he is now in his late 50's, so I take his word for it. He said things were fine, so I put everything back together.
I just tried to start the bike, and it fired right up. I'm listening to a very nice "Dahdum Dahdum" at the moment, with a cold beer in my hand and a setting sun in my face.
Thanks all for your wise words, I'm happy
I just tried to start the bike, and it fired right up. I'm listening to a very nice "Dahdum Dahdum" at the moment, with a cold beer in my hand and a setting sun in my face.
Thanks all for your wise words, I'm happy
Last edited by Daedalus; May 5, 2018 at 01:43 PM.
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Grand HDF Member
Joined: Apr 2007
Posts: 3,712
Likes: 3,030
From: Brighton, MI
I took the stuff back to the workshop who did the bore an hone job for me, and they said all was normal. The leading mechanic has been wrenching on Harley's with his dad, when he was a kid, he is now in his late 50's, so I take his word for it. He said things were fine, so I put everything back together.
I just tried to start the bike, and it fired right up. I'm listening to a very nice "Dahdum Dahdum" at the moment, with a cold beer in my hand and a setting sun in my face.
Thanks all for your wise words, I'm happy
I just tried to start the bike, and it fired right up. I'm listening to a very nice "Dahdum Dahdum" at the moment, with a cold beer in my hand and a setting sun in my face.
Thanks all for your wise words, I'm happy