I am picking up my motor tomorrow and I have a big 4x4 event this weekend. I am running a little low on time and just wondering if it is OK to just break the cam in the correct way and then got to the events the next day and really beat on it. Or should I put a few road miles on it tomorrow after I put it back in. What do you guys recomend for cam break in. It is a solid/flat cam with .670 lift. thanks in advance.

 

For cam break-in, run the engine at 2000 rpm's for 20 minutes. Let it cool down and change the oil, and drive it easy and do the 500, 1500, 3000 mile oil changes. It's best if you can take it out on the highway and give it some road time varying between 55-65 mph's for a hundred miles or so.

But for the love of the G-man, don't run it too hard until it's broke in, a running engine is expensive but a broken engine is twice as expensive.

 

By the way, I wouldn't consider the engine broken in until you reach the 3000 mile mark, those piston rings can take awhile to seat properly.

 

OK, BUT HOW DO PEOPLE WITH PULL TRUCKS REALLY EVER GET THEIR ENGINES BROKE IN? nONE OF THEM EVER SEE 3000 MILES, tHESE MOTORS DON'T GET USED ON THE ROAD.

 

Well, those trucks aren't driven on the road and needed to get to work/school etc. from day to day. Second, those engines are typically, but not always, rebuilt after race season and they have high end race components in them and exhibit up to 12:1 compression. They also only work hard for 30 seconds at a time, not idling in traffic and stop and go traffic.

If this is a race only engine, then go for it. If this is a daily driver, I'd break it in properly before you stomp on it. Just my 2 pennies.

 

I've done several truck pulling motors. I break the cam in change oil and check everything including carb jetting and timing then go to the track and run them as hard as they'll run. If something isn't right you'll find it in the 20 minutes at 2,000 rpm.

 

ok, well this is not a daily driver. It is for pulling and occasional mud bog. I just got some really bad news anyway. The springs that I got are for stock length valves and my valves are longer than stock. the springs would have to be shimmed about .220. That is probably not too good. So I guess I will not be competing tomorrow. I now have plenty of time to break it in. Thanks for the info.

 

where are you competing at i run the bogs over here in west il around morrison and miles ia

 

Basically I suggest doing the cam break in like normal. change the oil and reset everything that needs set such as timing, valve lash (if solid lifter cam) etc then drive it just exaclty like you plan on driving it normally. IE a daily commutor vehicle driven on the freeway should be broken in by driving it on the freeway, if you always drive in town most of the time, then break it in by driving it in town. If it's a race motor then after the oil change go racing. My motor had approx 30 minutes run time on it, when I loaded it on the trailer and took it to the track and shifted the first race at over 7000rpm every pass, at the end of the season I still had great compression (less than 1psi diference between cylinders) and didn't even bother rehoning it or putting in new rings for this season.
Next the old myth about needing 3000 miles to seat the rings, not if the machine shop is half competent and knows how to hone properly instead of using a ball hone on a drill. if the hone marks are correct the rings will actually be sealed before the first time the engine is fired just by the turning it over by hand to adjust the valves and the checks that are done on engine assembly. Don't believe me do a compression test on a new unfired engine (I really hate doing that but if you prime the oil system first then not so bad) then do it after cam break in , and again at 3000 miles bet you see little to no difference in the comp tests, if the rings aren't seated by the time you break in the cam, they won't be seated at 3000 or even 30,000 miles.

 

Two things:
1. Break-in the cam per the manufacturer's directions. Normally, this means some sort of cam lube (I like Isky Rev-Lube) and running it at 2000-2500 for twenty minutes changing the rpms from time to time. I use diesel oil these days for the extra additives. Some people like to use GM EOS, but I never have.

2. The 3000 mile break-in deal is a total myth and may very well hurt the engine by glazing the cylinder walls. After cam break-in, you need to change the oil/filter and make several full throttle accellerations followed by no throttle decellerations (engine braking). Four or five runs through the RPM range and your rings should be all set. What this does is apply maximum pressure to the rings against the cylinder wall via combustion pressure that gets between the rings and allows them them to wear in to the cylinder.

After performing these processes, the engine is all set. Drive it however you wish--racing, cruising, whatever. Obviously you need to be carefull with the state of tune when seating the rings, but as long as you are conservitive with timing and liberal with jetting it shouldn't be a problem.

 

Just a queston by the un educated. Does this apply to hydralic cams as well or primarley the solid lifter/roller cams???

 

only on flat tappet cams. roller cams hyd/solid dont need break in time in my book roller motors we built went from motor stand to dyno run them in just to check oil pressure then full pulls the way we see it (if its going to break theres something wrong anyways) and we never lost any on dyno so use your own judgement and do it how you built it