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Is there evidence that the roller lifters give longer service?
Seems like it would take a large fleet operator a long time to establish any differences. |
Here is a link to a flyer for a purported solution to the problem that does not involve roller lifters. This originates from the web page for which an incorrect link was given below.
http://thenewfirewallforward.com/lin..._lube_info.pdf Erich |
Good catch Kevin. To have such an issue in four years, I would be highly suspicious about the heat treating. The intake lobes are shared so they do twice the work and take out the other lifter if there is a failure.
In this part of the world, it is well known that Lycoming had a bad batch of these parts. I'm not sure which part number it was, but they were the ones immediately before the hyperbolic units. Enough spalled that at least one major engine builder only puts Superior P/N SL72877 lifters in now (will not buy a Lycoming cam kit which says something as they probably forego the Lycoming warranty by doing so). They will not touch the new hyperbolic units either. It seems that Superior still use the original manufacturer which industry found to be reliable.... so there is probably some truth to a high failure rate with the superseded parts. Anecdotally, Lycoming change part numbers whenever they change supplier. I have heard the Lycoming rep tell people that the roller cams completely cured the problem with spalled lifters (no kidding they removed the lifters). There have still been issues with the roller cams though. Not to mention the rollers are mandatory replacement at overhaul/prop strike. If it were me, you have a reasonably low time engine. Assuming you have the time and can find someone with experience to help you, I would pull it apart and do the job yourself. Sounds like you have made very little metal at this point, so you may well do well. Looks like you have a cylinder to hone/replace and cam/lifters to go in. If the oil filter has done its job, the bearings and crank will be fine. You may need a new oil pump housing or resurface of the pad - but this is easy to get done. Make sure to check the accessories for metal too. If you really want an engine with roller cams I would just buy a new one from Vans and sell the current unit once repaired. |
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Very unfortunately that the defective part will require a tear down. Larry |
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