Engine knocking/rattling noise
Engine knocking/rattling noise
Bike is a '09 Super Glide. I built the motor about 8,000 miles ago with SE 103" pistons/jugs, mild ported heads, and Wood 555 cams. Stock lifters with Fuel Moto adjustable pushrods. Runs awesome, no issues until recently...
On the last ride of the year last fall, I remember it seeming to have a slightly different sound than I remember. So far this spring I've only had it out a couple times, once about 15 miles, as the ride went on I noticed the sound again. Normally I ride with a helmet, so that mutes a bit of noise. This weekend weather finally cooperated, so I got out for a short ride, intentionally not wearing a helmet to better hear the noise.
Motor sounds normal when cold, after it warms up it has a definite rattling noise, sounds like its coming from behind the cam cover. Its definitely lower on the motor, and on the exhaust side. If I shut it off, and let it cool down, the noise goes away, but returns when it warms up. It does vary with RPM. I've also noticed slight screeching noise, like a fan belt slipping on a car, on a couple occasions, that lasted for a couple seconds.
I'm thinking something in the cam chest/oil pump, or maybe a lifter. I'm fearing its a scissored crank... Doesn't sound like a rod knock, at least not a rod knock on a car engine. I'm planning on pulling the cam cover and hoping to see something apparent.
On the last ride of the year last fall, I remember it seeming to have a slightly different sound than I remember. So far this spring I've only had it out a couple times, once about 15 miles, as the ride went on I noticed the sound again. Normally I ride with a helmet, so that mutes a bit of noise. This weekend weather finally cooperated, so I got out for a short ride, intentionally not wearing a helmet to better hear the noise.
Motor sounds normal when cold, after it warms up it has a definite rattling noise, sounds like its coming from behind the cam cover. Its definitely lower on the motor, and on the exhaust side. If I shut it off, and let it cool down, the noise goes away, but returns when it warms up. It does vary with RPM. I've also noticed slight screeching noise, like a fan belt slipping on a car, on a couple occasions, that lasted for a couple seconds.
I'm thinking something in the cam chest/oil pump, or maybe a lifter. I'm fearing its a scissored crank... Doesn't sound like a rod knock, at least not a rod knock on a car engine. I'm planning on pulling the cam cover and hoping to see something apparent.
Last edited by Reindeer; Apr 13, 2015 at 09:26 AM.
Stellar HDF Member
Joined: Aug 2012
Posts: 2,664
Likes: 184
From: Indiana, USA
I hope you are wrong.... When a crank scissors, the right end of the crank will waller the cam support bearing out and the left side will tighten and slacken the primary chain progressively worse as the scissor worsens. As the cam support bearing goes away the oil pump will loose pressure at the cam support plate interface.
Lifter tick with low oil pressure and difficulty getting into neutral may indicate scissor. The only real way to know is open the cam box and put an indicator on the end of the crank.
Lifter tick with low oil pressure and difficulty getting into neutral may indicate scissor. The only real way to know is open the cam box and put an indicator on the end of the crank.
Stellar HDF Member
Joined: Aug 2012
Posts: 2,664
Likes: 184
From: Indiana, USA
Check the end of the crank, if it is scissored you will easily measure a larger bearing bore than the crank diameter as both wear.
For a welded assembly I used Revolution Performance at
http://www.revperf.com/
For a welded assembly I used Revolution Performance at
http://www.revperf.com/
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Bike is a '09 Super Glide. I built the motor about 8,000 miles ago with SE 103" pistons/jugs, mild ported heads, and Wood 555 cams. Stock lifters with Fuel Moto adjustable pushrods. Runs awesome, no issues until recently...
On the last ride of the year last fall, I remember it seeming to have a slightly different sound than I remember. So far this spring I've only had it out a couple times, once about 15 miles, as the ride went on I noticed the sound again. Normally I ride with a helmet, so that mutes a bit of noise. This weekend weather finally cooperated, so I got out for a short ride, intentionally not wearing a helmet to better hear the noise.
Motor sounds normal when cold, after it warms up it has a definite rattling noise, sounds like its coming from behind the cam cover. Its definitely lower on the motor, and on the exhaust side. If I shut it off, and let it cool down, the noise goes away, but returns when it warms up. It does vary with RPM. I've also noticed slight screeching noise, like a fan belt slipping on a car, on a couple occasions, that lasted for a couple seconds.
I'm thinking something in the cam chest/oil pump, or maybe a lifter. I'm fearing its a scissored crank... Doesn't sound like a rod knock, at least not a rod knock on a car engine. I'm planning on pulling the cam cover and hoping to see something apparent.
On the last ride of the year last fall, I remember it seeming to have a slightly different sound than I remember. So far this spring I've only had it out a couple times, once about 15 miles, as the ride went on I noticed the sound again. Normally I ride with a helmet, so that mutes a bit of noise. This weekend weather finally cooperated, so I got out for a short ride, intentionally not wearing a helmet to better hear the noise.
Motor sounds normal when cold, after it warms up it has a definite rattling noise, sounds like its coming from behind the cam cover. Its definitely lower on the motor, and on the exhaust side. If I shut it off, and let it cool down, the noise goes away, but returns when it warms up. It does vary with RPM. I've also noticed slight screeching noise, like a fan belt slipping on a car, on a couple occasions, that lasted for a couple seconds.
I'm thinking something in the cam chest/oil pump, or maybe a lifter. I'm fearing its a scissored crank... Doesn't sound like a rod knock, at least not a rod knock on a car engine. I'm planning on pulling the cam cover and hoping to see something apparent.
Yes, I'd head into the cam chest, as that is where most issues on a T/C engine, can be located/witnessed.
Scott
After doing some research in various places, that's what I'm leaning toward. I'll pull the lifters out and hopefully see something obvious.
HDF Community Team
Joined: Jun 2006
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Likes: 2,597
From: san antonio
I am betting crank has not been tweaked but would check run out for future reference while in the cam chest.
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Stellar HDF Member
Joined: Aug 2012
Posts: 2,664
Likes: 184
From: Indiana, USA
For the record, and I know this has been beat to death, are Chevrolet LS lifters a direct replacement for HD in a Twin Cam and is there any loss or benefit to using the GM Lifter?
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HDF Community Team
Joined: Jun 2006
Posts: 12,763
Likes: 2,597
From: san antonio
I was going to ask the question about GM lifters, but thats been answered. I'll stick with HD specific--assuming that I need new lifters.
Got the pushrods out last night, but couldn't find a short enough 3/16 allen in my toolbox to remove the lifter block covers. I'll pick one up today.
Got the pushrods out last night, but couldn't find a short enough 3/16 allen in my toolbox to remove the lifter block covers. I'll pick one up today.