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Engine Mechanical TopicsDiscussion for motor builds, cams, head work, stripped bolts and other engine related issues. The good and the bad. If it goes round and around or up and down, post it here.
I have a 2015 street glide, bone stock. Ive always heard of the earlier twin cam engines and the timing chain tensioner issues. Ive read and heard that the newer hydraulic tensioners like used in my 2015 were good for waay longer than the older ones..Some say they last as long as the rest of the engine..Just looking for the truth in how long they really last on average, or is it bull and dont last any longer than the older ones? Mine has 38,000 miles.
IIRC the issue with the early model TC engines were that the tensioners were spring loaded. Hydraulic on the other hand should maintain a constant tension (so long as your have oil pressure). Keep in mind the shoe the chain rides on will still wear. The tensioner itself may last the life of the engine but that shoe will eventually wear down and need to be replaced. At the very least, i'd check it around 40k miles.
FWIW I'm running after market tensioners (hydraulic) and have > 50k miles on them. I checked at the 40k mark and although there was visible wear, they were still within spec from that manufacture. I'll check again and probably end up replacing around 70k mark.
The roller chain is what contributes to the longer life of the later chain tensioners. The links wear the tensioner down to the point that the tensioner comes in contact with the roller which basically stops the links wearing further into the groove as the chain rolls over the tensioner and the wear becomes the contact point between the chain roller and the tensioner, not between the tensioner and the chain links. I have seen a few pictures of failed later tensioners but I don't believe it happens very often.
The heavy pressure of the early spring loaded tensioners and the Morse link chain (non roller), the Delron tensioner material and the constant exposure to heat and oil was not a good combination for extended tensioner life.
1. The hydraulic tensioner doe not maintain constant tension. A simple spring does a better job. A hydraulic tensioner maintains does a better job of maintaining a constant position over varying loads just like a hydraulic lifter. The reason why they last longer is that they only need to handle enough load to keep the chain from slapping.
2. Morse chain are better for tensioners. They provide more bearing surface for the tensioner to ride against. than standard roller chain.. The problem is that the morse chains need to have the back side polished to achieve life, making them more expensive.
3, I don't think early tensioners used delrin. Delrin can't handle the temps. I suspect it was some form of Ultem..
1. The hydraulic tensioner doe not maintain constant tension. A simple spring does a better job. A hydraulic tensioner maintains does a better job of maintaining a constant position over varying loads just like a hydraulic lifter. The reason why they last longer is that they only need to handle enough load to keep the chain from slapping. Max, I think that it is what I said, just said a different way.
2. Morse chain are better for tensioners. They provide more bearing surface for the tensioner to ride against. than standard roller chain.. The problem is that the morse chains need to have the back side polished to achieve life, making them more expensive. OK, but the Morse chains are not polished on the back side, so the OEM is not better for tensioners in spite of more bearing surface.
3, I don't think early tensioners used delrin. Delrin can't handle the temps. I suspect it was some form of Ultem.. Could be wrong but pretty sure it was Delron. Don't know what Ultem is but if that is the material, it wasn't the best choice either.
In the last 10 years, I have only owned two Harleys. Bought a used '02 FLHT with 12K miles as a project bike and the first thing I checked was the tensioners; most of the oute was gone and chain was very near makint contact with the metal carrier and the inner was better but not by much. Bought a new '05 FXSTD and at and early mileage, decided to add cams to the Stage I configuration. Don't recall the exact mileage but somewhere between 4K-8K miles. The outer tensioner was badly worn beyond service limits but the inner wasn't that bad. Problem solved with gear drive cams on both bikes. So, based on my personal experience, I think the early tensioners and chain suck.
Heat and how you ride plays into how long they last. a guy who rides in 3-4th gear gear at higher RPM pushing his bike in the twisties is going to eat them faster due to higher oil temp and and more RPM than a guy who cruises the interstate at 70mph. Id recommend at least looking at them every 25-30k. But I think the roller chain design keeps them from totally self destructing, or at least prolongs that to a point youre much less likely to catch them before they do.
Im more the first guy than the second. Here are my tensioners at ~24,700mi, from my 2014 street bob (103 TC) They were replaced when installing new cams.
Last edited by 2500hdon37s; Oct 14, 2022 at 11:19 AM.
And yet on my '00 S/E Road Glide, the pads lasted until 83,000 miles (checked every 5,000 service,) with only the front shoe having been cracked at that time. (Gear drives went in at that time.)
In the last 10 years, I have only owned two Harleys. Bought a used '02 FLHT with 12K miles as a project bike and the first thing I checked was the tensioners; most of the oute was gone and chain was very near makint contact with the metal carrier and the inner was better but not by much. Bought a new '05 FXSTD and at and early mileage, decided to add cams to the Stage I configuration. Don't recall the exact mileage but somewhere between 4K-8K miles. The outer tensioner was badly worn beyond service limits but the inner wasn't that bad. Problem solved with gear drive cams on both bikes. So, based on my personal experience, I think the early tensioners and chain suck.
Yeah 1 wasn't addressed to you.. Mainly K-Weaver.
2. My 02 had RKC had the tensioners polished. I bought the bikes used with 14K on it.. It was a rental that a guy bought and put very little miles on.. I didn't find any evidence that it had been apart but at 20K the motor got torn down for a build and the tensioners were good. It still got gear cams..
My 2000 FXDX got chain cams at 7500 miles and was rebuilt as a 116 at 22.5K . Tensioners were still good and original and the chain wasn't polished. Camplate had loose bearing fit and ball rear cam bearing.
3. Ultem is a little more brittle.. It wouldn't surprise me if newer aftermarket tensioners are something like Vespel or Kelar impregnated PTFE.
Yeah 1 wasn't addressed to you.. Mainly K-Weaver..
OK, I thought it was. I wan't barking at ya, just trying to clarify a couple of points on the subject of early tensioners vs later. I run gear cams so don't have to worry with either.
OK, I thought it was. I wan't barking at ya, just trying to clarify a couple of points on the subject of early tensioners vs later. I run gear cams so don't have to worry with either.
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Later model timing chain tensioners?
