Best oil for break-in

[Green95Hoe]

Ive always used AMS Oil 0w40 in my Hondas from my 400 all the way back to my old CB750's. Synthetic without the friction modifiers. Im in teh process of building a 426 with a stage 2 Hotcam. I noticed it says not to use synthetic for the break-in. Any input on this. What do you guys recommend I use for the break-in?

~Brad

[prepracing]

yeah I have heard synthetic oil will not let the rings seat in correctly. I just honed and put new rings in mine...my local mechanic had me run regular 10w40 Honda oil for the break in, then I went to the honda 10w40 synthetic blend after the break in

[Rico]

You can use synthetic if you want, just during break in go out and ride it and give it hell...:cool:

I used synthetic after my last rebuild and broke the motor in with it. You just can't baby the motor, you need to drop the hammer and get the motor revving and hot ASAP....:macho

I was told to do this by a VERY good engine builder.

My motor runs strong and does not have any smoking due to blow by.

[Chino886]

Hey Rico, sent you a PM...

[Green95Hoe]

Thanx for the input guys, ill just run regular oil for the break in since its coming out anyway. Im a little confused on the general break in though. Based on what ive read the general consensus is to ride it hard for the break in but when it comes to the cam they want you to go easy for a while. Is this right. Maybe I have to read some more

~Brad

[Rico]

No matter what you do do NOT let it just sit and idle. Rev the motor during the break in no matter how you do it..:cool:

[wilkin250r]

There are lots of theories to proper engine break-in. Some say delicate heat cycles, others say drop the hammer.

I say they are both wrong. Or both right.

My theory (and what do I know) is that slow-delicate heat cycles are better for the piston. If you have very tight tolerances and cylinder/bore clearance, you run a serious risk of seizure if you drop the hammer during break-in. You need to give it it time to expand and contract, work out all it's internal stresses, and wear into the cylinder properly.

The flipside is that high cylinder pressures are good for seating the rings, and those high cylinder pressures aren't going to happen at idle. And if you have a loose cylinder/bore clearance, you BETTER get a good seal on those rings.

So, I say your break-in depends on your motor setup and piston material. If you have a tight clearance, break it in slowly. With a tight clearance, ring seal isn't quite as critical, because your piston seals better. However, if you have a loose clearance, drop the hammer.

Just my $.02

[Green95Hoe]

Looks like im gonna be middle of the road. Hotcams wants 20 min of throttle blip and then 40 of easy riding. After that I can go nuts I guess. How many hours should I let lapse before break in is complete

[underpowered]

check here for for how to break it in, http://www.mototuneusa.com/break_in_secrets.htm