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CVO Technical => Twin Cam => Topic started by: egeez on September 20, 2020, 12:09:52 PM
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Hello, All. Has anyone seen this type of lifter bore wear pattern? What could have caused it? My only experience is with iron block engines.
The bike is new to me. It is a 2000 FLHRI EFI RK with 22k miles. Original sales invoice says Stage 1 was added. It does have the K&N air cleaner and the SE slip-ons.
Went in to check tensioner shoes and also found frosting on all four cam lobes and this distinctive wear pattern (vertical striations) in the lifter bores. (I haven't attempted to measure anything yet.) All four appear to be smooth. I can't feel any grooves with finger or by lightly dragging a pic over the surfaces. The lifter rollers all seem to have normal wear.
The pic is included as an attachment. (I don't have a public file server at the moment) :(
Trying google drive link below here. May/may not work. Apologies.
(https://drive.google.com/file/d/14P54hjZOZFIQLgFIxIgQEJZ6tCiAttOv/view?usp=sharing)
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Fueling offer over sized lifters. I think S&S does too.
If the scoring is too deep, it may not be able to clean up the bore. At that point New Motor Cases maybe your only option.
https://www.feulingparts.com/category/Lifters
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Please, nobody flame me over this but hear me out. Here goes... you say it cannot be felt with a finger nail or pick. So the word "scoring" probably does not apply here. A measurement of the bore would be helpful. Many of the people running those machining centers at Pilgrim Road are "button pushers" (read temporary labor). Tool changes occur at pre-determined intervals. Those could very well be tool marks. Remember, most engines are "cold tested" so if the other parameters are met, a flaw like that would never be flagged. Also, there are people (these are highly skilled) that repair engines that are flagged off-line to get them to run and pass. That engine may have been that way from new. The frosting (your term) on the cam lobes is most likely unrelated. :nixweiss:
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Have seen others like this before. Measure the bores at a few depths. If the measurements are good and the holes are round combined with that you say there is nothing to be felt you're ok. Remember that lifters in that engine don't rotate at will. They only walk up and down and up and down.
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Happy Monday. Thanks for the replies. I'll measure the bores and come back with the results.
What would be an acceptable clearance for the lifters in a stock TC engine?
Unrelated to lifter bore issue: "frosting" on the cam surface. I didn't make that up. :) I heard it in a video in another forum. Did some
research. Here is a tech article that talks about possible causes of cam failure. "Frosting" is mentioned in there.
http://mechdesigner.support/index.htm?criteria-for-material-selection.htm (http://mechdesigner.support/index.htm?criteria-for-material-selection.htm)
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.0015" would be a good lifter bore to lifter clearance. I agree with Twolanerider. Get your clearances checked out and if they are in an acceptable range go with it. That's the path I would take.
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Hone and use an oversized lifter
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there are services that will hone the bore and services that will insert sleeves in the bores - you have real options......