I'm sure it's lifter clatter I'm thinking of switching from Syn 3
to Amsoil to see if it helps.The motor is stock except for 4''
Rineharts.It quits rattling after just a quick second & the
lifters pump up.

 

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I wouldn't be surprised if it still does it with amoil too ,but if it doesnt act up at 1st with amsoil then i'd it may act up again after you get 1500-2k miles on the amsoil.

I hope it doesn't do that and works out for you with the Amsoil syn oil but if it still acts up with noisy lifter-s at cold start with the amsoil syn right off the bat or after geting some miles on it then try the std dino 25w-60 Spectro oil i posted the link to see if it holds a bit better viscosity not allowing lifters to bleed down as much overnight.

I found doing that fixed that issue for a few guys i rec trying it in the past with same issue when they were running syn oil because even though syn oil can perform better then std dino in extreem cond it doese seem to thin a bit more in same cond a quality std dino doesn't thin a much which seems to explain my above statement from the results i got.

But either way you choose to approach it dont forget to post the results back here in the same thread for continuity.

Good luck!

Scott

 

One of the lifters has a little piece of trash in it.? However, it just could be the piston clearance. If you have ever started a TC with collapsed lifters, it will scare you to death. It sounds just like a rod is getting ready to come out till they pump up and it takes them more then a few seconds to come up. That is why I think it could be piston slap.

 

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You must have missed the fact the OP said the clatter noise goes away right after motor starts and oil pressures fully up to normal like couple seconds later post cold start which would generally be an hd lifter pumping up and quieting down.

So with that said it's not piston slap because if it was piston slap the motor would 1st need to heat up to norm op temp to expand piston in the bore to take up the additional clearance before it would stop making noise or at least quiets down some and thats not the case here per OP's statment.

Scott

 

Might want to try a new oil filter as an experiment. If the anti-drainback valve is bad it could create the same symptoms. Kind of a longshot but worth a try since it's so cheap. I notice the same kind of sound each time I do an oil change when the motor first starts and the new filter is filling up.

 

Not really. I meant what I said and of course just my opinion. If a lifter is down flat, it takes quite a few seconds. I have heard them bang 15 seconds before quieting down when they are flat down. If it leaks, you would think it would go flat. If the clearance of a new engine is made up near maximum of the new allowable tolerance, just a splash of oil on start up can stop the slap. That first fire flash of burning gas also heats pretty quick. Harley do splash oil, they have almost 1 1/2" of oil in the base and cam galley that mainly lubricates the inner cam bearings. I was basing this on FP said split second. I think the bigger engines have a few more .0001 piston to cylinder clearance then the 88 and 96. The bottom line is, if it's quite within a few seconds, it's not going to hurt anything. But if it where mine, I would not be happy. Not sure I would be unhappy enough to want someone who may have worked at MickeyDs last year taking it apart however. If it is a lifter, a two ear stethoscope on the valve cover should pick it up. My guess is you will hear it on the side of the back cylinder.

 

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Will be curious to see what if anything improves his startup noise weather it be a lifter that bleeds down overnight or something else that's causing the noise till oil pressures up post cold fireup.

Scott.

 

Sure hope so. There have been 3 or more similar post and for some reason, an answer is never reveled.? Most seem to give up and take it in. Then getting a straight answer from the professional is like your wife asking for Aunt Jennets secret recipe.

 

I have a 2012 FLHTK with 50K on the clock. It rattles when I first start it up. Though it seems to be the norm, I dont think its lifters. At least mine sounds a bit loader than a lifter tap. I run full syn oil 20W50. I believe that it may be a bit of piston slap when cold as the oil does run down. IT will tap 3 or 4 times and then stop. Gonna try changing the oil filter back to a Harley one. FYI I am an automotive mechanic, so I do know a bit about lifter tap. See what the filter does worth a try.

 

I noticed the same noise shortly after having 4in Rinehart 2-1 installed. Goes away after a few minutes.