Sprockets

iTrader: (6)

If I'm posting this in the wrong section, please let me know. I just got my car back with a fully built engine which consists of brand new ITR cams. The car had been started and idled on one day, then towed to a separate location for part throttle tuning on the dyno a week later, so I could break it in gently on the street. (I don't want to get into a discussion about engine break-in methods, because I know some people like to hammer it from the start.) It wasn't until afterwards when I was picking up the car that I was listening to what I thought might be the valvetrain making more noise than it should, when I mentioned that they were brand new ITR cams to the mechanic. It was then that he told me that had he known, he would have broken in the cams for me by holding the RPMs at I believe 2000 for a certain period of time. I didn't have another ride home, and had to get the car out of there, so I drove it home and it's in my garage now. Is it too late to do any kind of break-in procedure on these cams, and what are the chances that irregular wear has occurred?

2kdrift

never heard of breaking in cams as long as installed properly and lubed you should be fine. you sure your not hearing something else like piston slap?

https://honda-tech.com/all-motor-nat...break-2017908/

motoxxxman

I've never followed a break-in procedure for honda cams ever, never any issues. domestic engines, definitely, but import motors rarely need an actual break-in. the part throttle tuning probably took care of it anyway.

but, considering everything is brand new, you should really check/adjust the valve lash asap. it may or may not have been adjusted to begin with, and even if it was it probably is out of spec already from the "break-in" thats already occurred

blackeg

i also vote for check the valve lash again

Sprockets

iTrader: (6)

Thanks for the reassurance that things are OK and the suggestion. I do plan to have the valve lash adjusted.

According to the spec sheet, the Piston skirt clearance is .0043, although JE recommends .004. There is some piston slap, but nothing like I used to hear from my old Arias pistons. This is more like a "ticking" noise. Several people in the link you provided above also recommend keeping the RPMS at 2000 for 20 minutes, so now I'm not sure what to do.

TomCat39

Doesn't it depend on the cam manufacturer?

From what I understand, the cam break in is basically a heat treating of sorts. So if the cam maker already does all the heat treatments beforehand it's a moot point?

Pro-SeriesFab

Cam "break-in" is to establish an even wear pattern as soon as possible.

In the old days with OHV engines and flat tappet lifters, you needed this for oiling concerns on the lobes because the lifters spin on the lobes while the motor is running hence the need for a higher than idle RPM for oil pressure.

I have a harder time seeing the need specifically for a cam break-in on a OHC setup.

I would check the lash for sure . . . additionally the head stud/bolt torque. A new motor on the first couple of heat cycles is going to expand and contract to the point where the fasteners are going to be looser than you would want.