Help- cylinder wall marks- is it a problem?
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,922
Likes: 8,027
From: poway
I agree with prodrag. Not normal.
That is the kind of pattern I've seen on my air-cooled VW drag race motors that have had the ring gaps butt solid. They deform almost into a clover leaf shape. Typically due to heat. Running lean, ring gaps set up just a bit too close etc. High performance air cooled VWs have much in common with HD motors.
A few years back, I brought the car with a fresh engine that had maybe 15 minutes of run time to the track. We won the event, but the last four rounds were only 15-20 minutes apart. Not enough time to cool down enough. It was a big event and the opportunity to win overcame my desire to keep the motor alive. Rather than withdraw to save the motor, I said "Screw it. I can fix it!" After I pulled up to the time slip booth after the final round, the motor shut itself off and wouldn't restart. Ah, good times!
Afterwards, the barrels looked like those in the original post and a couple were worse. I just replaced 'em since the dial bore gage revealed they were no longer round. The price of competition.
So, if they were mine, I'd run a dial bore gage in 'em checking several points. Should be done with torque plates to get a true reading. If they are still round, I'd run a rigid hone thru 'em to see if there are any low spots. If they'll clean up up without taking out a bunch of material....run 'em. If not....then weigh your options.
Even so, I'd say the rings are trash at the very least. But that's just my opinion. I'm still a rookie when it comes to HD motors, although the basic principles still apply.
That is the kind of pattern I've seen on my air-cooled VW drag race motors that have had the ring gaps butt solid. They deform almost into a clover leaf shape. Typically due to heat. Running lean, ring gaps set up just a bit too close etc. High performance air cooled VWs have much in common with HD motors.
A few years back, I brought the car with a fresh engine that had maybe 15 minutes of run time to the track. We won the event, but the last four rounds were only 15-20 minutes apart. Not enough time to cool down enough. It was a big event and the opportunity to win overcame my desire to keep the motor alive. Rather than withdraw to save the motor, I said "Screw it. I can fix it!" After I pulled up to the time slip booth after the final round, the motor shut itself off and wouldn't restart. Ah, good times!
Afterwards, the barrels looked like those in the original post and a couple were worse. I just replaced 'em since the dial bore gage revealed they were no longer round. The price of competition.
So, if they were mine, I'd run a dial bore gage in 'em checking several points. Should be done with torque plates to get a true reading. If they are still round, I'd run a rigid hone thru 'em to see if there are any low spots. If they'll clean up up without taking out a bunch of material....run 'em. If not....then weigh your options.
Even so, I'd say the rings are trash at the very least. But that's just my opinion. I'm still a rookie when it comes to HD motors, although the basic principles still apply.
Outstanding HDF Member
Joined: Jan 2014
Posts: 2,181
Likes: 488
From: Central California
This is good stuff.. I've not ever had issues with rings buttin' and bendin' I would guess at that point they stop spinning.. I would imagine you can see the blowby in the ring and it might be stuck in the piston also.. Plates and a quick fixed hone job will tell a lot about the condition of the cylinder.
Yeah, you wouldn't typically see that on a street deal. But then most of the times, one would not continue to make full throttle runs when their junk was already hotter than it should be.
Sacrifices to the gods of speed!
Seasoned HDF Member
Joined: Jan 2009
Posts: 12,689
Likes: 8,295
From: Ottawa, Ontario
1st post was the question
2nd post was it's normal
3rd post was it's not normal
4th post was me commenting on you got to love the internet re: different answers when you ask a question, that's all. Never even offered an opinion on his problem.
Appreciate the attempt at humor, sarcasm is a type of humor right?
2nd post was it's normal
3rd post was it's not normal
4th post was me commenting on you got to love the internet re: different answers when you ask a question, that's all. Never even offered an opinion on his problem.
Appreciate the attempt at humor, sarcasm is a type of humor right?
Club Member
Joined: Mar 2009
Posts: 66,125
Likes: 51,434
From: Niles Canyon Ca.
1st post was the question
2nd post was it's normal
3rd post was it's not normal
4th post was me commenting on you got to love the internet re: different answers when you ask a question, that's all. Never even offered an opinion on his problem.
Appreciate the attempt at humor, sarcasm is a type of humor right?
2nd post was it's normal
3rd post was it's not normal
4th post was me commenting on you got to love the internet re: different answers when you ask a question, that's all. Never even offered an opinion on his problem.
Appreciate the attempt at humor, sarcasm is a type of humor right?
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Seasoned HDF Member
Joined: Jan 2009
Posts: 12,689
Likes: 8,295
From: Ottawa, Ontario
I've always heard you should break in your engine gently, don't over rev it etc. But there is another school of thought that says the opposite. I've never babied them but I didn't go crazy for the first 1000 either, whether it be bikes, cars etc.
Club Member
Joined: Mar 2009
Posts: 66,125
Likes: 51,434
From: Niles Canyon Ca.
Air cooled engines particularly these newer big inch heat generators that first 50 to 100 is critical to setting the tome for how it breaks in and overall life span. Built & repaired far to many over the years to not know that's fact not myth.
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