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|Ford 460 EFI knocking / ticking after rebuild||Rob||7-12-15|
|Hello all! 1996 Holiday Rambler, 460 EFI. The engine started making a knocking type sound. I have spent HOURS upon hours on forums, youtube, google, etc. Both manifolds have been replaced with brand new manifolds and gaskets. Even though one was warped, and one was missing a bolt when they came out the new ones did not make a difference in the noise. Next, pulled the rods and lifters. Three of the lifters were different (although they were made for the ford 460, they were after market and of a different design than the other 13). One of the old rods appeared to be clogged. Replaced all of the lifters and rods with brand new. There was no wear at all on the lifters that came out, but I wanted them all to be the same. Ordered them from Ford by VIN number to ensure I received the correct parts. Anyway, I was sure I found the "smoking gun" with the clogged rod and the various designs of lifters that were installed. Put it all back together with the new parts, and still have the knocking / ticking sound. Tried using a stethescope and cannot isolate the origin (probably because of my untrained ear). I have done the spark plug wire trick, removing one at a time and no change in the noise. The engine only has 52k miles on it... hard to imagine a bearing being bad. I am looking for ANY ideas of something I have not tried short of pulling the engine out of the RV (a big, and expensive job I want to avoid if possible). Engine seems to run fine, seems to have plenty of power (except for the very high idle which I'm told may be an IAC valve issue or vacuum leak). It does seem to be louder until the engine reaches operating temperature. At that point, the noise is still very much there, but quieter. I am thinking that's because the oil has reached operating temperature and is flowing better through all of the parts... could just be my imagination though. The noise doesn't seem to go away at any point of operation, but it does seem to get quieter during deceleration. I have heard things like "check the flywheel" and some other things that don't seem to make much sense. Hoping an expert on here has some insight? Thanks...|
|Re: Ford 460 EFI knocking / ticking after rebuild||BUBBA THE BUS TECH||7-13-15|
|By description, Knock, gets quieter when hot, never goes away completly: Sounds like a "Colapsed Piston Skirt"|
It happens and rebuilt engines with aftermarket pistons it seems to happen more often.
Only a complete teardown and measurements will 100% confirm or deny. Usually when the pistons come out the problem one will be noticable worn on the power side of the skirt, but occaisionally only measurements will prove it.
Other suspects are rods, of course and a pan removal will reveal that fairly quick.
By the way 52K miles is a lot for a motor home motor (Shouldn't be worn out yet more like late middle age). So not unusual for a failure to happen at this milage.
|Re: Ford 460 EFI knocking / ticking after rebuild||Rob||7-14-15|
|Thank you for the reply. Not exactly what I was hoping to hear, but pretty much what I was expecting. I think I'll have to pull the motor regardless for further diagnosis. At that point, the labor will already be through the roof... may as well put a new crate motor in it's place. Just curious, would I be able to tell if this is the problem by pulling the heads and checking the pistons? Will the culprit feel loose at all, or have any sort of play in it or will it be so minimal that I wouldn't be able to tell without pulling it all apart?|