Had a 103ci build done to my 07 Streetglide by a local shop. Andrews tw37h cams. No head work. After 1000 mi breakin with dino oil, I came back for the final tune, andI put Amsoil syn back in when I got home. Noticed lots of lifter noise after that. The builder said it was the syn Amsoil letting the lifters collapse. He put regular oil back in it and sure enough, the noise has pretty much subsided. He said he runs dino oil in all his engines. My issue is, I ran Amsoil before the build with no lifter noise. Any thoughts on this????

 

i had tappety noise with dino and when at 2.5k i switched to amsoil mcv the tappety noise carried on, no change. Its been driving me nuts, but from threads here i am fairly sure its normal, however now you got me thinking maybe i will try something different next oil change - pete

 

Am not familiar with those cams, but did they increase the lift any? It sounds like the Amsoil may have a slightly lower viscosity allowing the lifter to leak back as your mechanic suggested.

 

I would stick an oil pressure guage on your engine and see what you are running with that build. Some guys will install a 30lb baisley bypass spring to give them more oil pressure on the top end. Amsoil MCV is the highest viscosity syn 20w50 oil out there. With either oil I would guage the pressure just to make sure you are getting enough.

 

Re Adjust Valves?

 

Well, I'm going to throw some bs at you . I take it you understand how leak rates happen in lifters? Synthetic has uniform sized molecules, whereas dino is uneven sized. These uneven molecules tend to slow the leakdown rate in a lifter and keep it pumped up better. This shows up more with long duration cams as the load time is longer and in turn gives more leak down rate. If the oil pressure is not compensated for this the lifter will not recharge fast enough and noise will occur. Syn by nature with nice uniform molecules will show up problems in two areas. It will squeek through an opening faster if one of you gaskets are dicey and show a worn lifter faster than dino would. This gives the impression that dino 20/50 acts thicker than 20/50 syn but viscosity differences are negligable. I run Ams 20/50 in mine and did notice an ever soslight increase in engine noise at first, but no longer hear it.A slightly higher viscosity of syn would probably resolve some of these issues.Most people with stock engines may or may notnotice any difference between the two with tight tollerances in the lifters.The builder's opinion is somewhat correct in the noise as syn will flow intotight places for better lubrication and unfortuantely flow out of tight places under pressure,as in lifterleakdown. Thedown side of superior lubrication.
Ron

 

Try the Redline 20w60 at www.myoilshop.com

 

I personally think your " builder" doesn't have a clue. If you have lifters collapsing, it's a lifter or oil pressure problem, not an oil problem. Even if you were running straight 5w oil, there is no reason for a lifter collapsing unless there is no pressure, even 10lbs would be enough to prevent that from happening.

 

Don't completely agree. Many years ago we tried straight weight aircraft oil in a shovel . Loudest engine I've ever heard, even though viscosities were the same. It was immediately dumped.Some oils behave differently than others. Going one step further I've tried Castrol 20/50 oil in my aircraft and being that it's hand propping to start, lifter bleed down was insufficiant when cold to have reliable compression strokes when propping. Once hot it was fine.Neither are bad oils, but the enviroment they were exposed to made it seem that way with the way the hydraulic units behaved.
Ron

 

Question: wouldn't bleed down be more a function of film thickness and strength, rather than molecular size?