Technical Here We Go Again - Cam Break-In

Always blows my mind that the guy that tries to do it just right has problems. The hack that just throws the cam in and knows nothing about breaking it in has no problem at all. I’ve done it both ways and never had a problem. I think it’s just luck of the draw with lifter material. Yes, I can be a hack at times!

 

Just a thought ; some may remember when connecting rods had grooves in the mating surfaces that sprayed the cam & cylinder walls , wonder if this design would be of value today ?

 

As for cooling while on the run stand, trash your radiator you have as it's not working. Install a fitting in the lower radiator hose that accepts a garden hose. In the top hose, install a fitting that accepts a garden hose long enough to run out in the driveway away from your feet. Fire the engine and adjust the water flow to keep the engine warm, not so much its cold, but enough it doesn't over heat. Keep some sort of fan running to blow the heat way from the exhaust.

 

I guess from reading all the different ideas here that there are many types of break in oil that you can use.

Why not follow the advice from the cam manufacturers and listen to what other top engine builders are doing and just follow their advice.
I think sometimes you listen to so many opinions on how to break in a New engine that you get overwhelmed, and then you are too close to the forest to see the trees!

While there are many reasons why new engines fail, many people seem to blame it on the break in process.

I have seen guy's spend a small fortune having a new engine built, but then not wanting to spend the extra money having who ever built the engine to dyno it for them.

You're getting much more than the dyno sheet as they are doing all the break in work for you and just the timing correct along with all the other setting is well worth the extra money.

For someone building their own motor maybe for the first or second time this final step can cost you big time if you do get it wrong.
So if you are not sure how to do it, STOP before you try it.

Jimbo

 

Lessions from my teens still apply - Make sure the parts you are assembling are clean. Make sure your lifters are lubed, drop in and spin in their bores easily before the engine is completely assembled. Pull them out and re-lube them after the spin check.
With a clean assembled engine add the oil of your choice (and additives) pre-lube it and fire it off. Complete your break in ritual. Clean & lubed saves the day.

 

How many cycles it takes to get the cam broken in isn't a big deal. But I do it all in one day, so oil is still not totally drained down overnight. I've often had situations where ambient temps were high that day, or I couldn't get good air flow inside a garage, so took 4 tries to finish breakin. But it still got done in less than 8 hrs. with cooling between stops.

 

You will get MANY different opinions. But the most important thing here is, keep us POSTED!! LET US KNOW IF YOU DO HAVE AN ISSUE!! BEST OF LUCK

 

Do it like some Car manufactures did in the 60s. They put the good springs in the trunk to be installed after a 1000 miles.

 

Ran the engine some more today and I'm going to declare the cam to be broken in. The little 305 sounds pretty strong. I have some tuning to do because other than the cam lope, which I expected, the RPM is surging. Have some video of it but trying to load it I get a message that the file is too big.

Lynn

 

My racing partner was a real old school mechanic. When race engine assembly time came, his garage was set up like an operation room. He would hang old bed sheets from the ceiling, set up sheets as drapes around the work table where we laid parts out.

He was a bug about keeping things clean. He was the 1st guy I saw who taped off any open hole in anything to keep loose hardware and anything else out of the engine. I still do that to this day.

 

Upload your video on YouTube then you can post the link to the video below your comment. Like this. Then we can watch it without having to worry about the size or length of the video.

 

I had a break in issue once, a couple pump shots and, wait wrong story. Sorry.

Anyways, so much of this is probably academic. Lately there's been a rash of flat tappet fails. Makes you think they want to push retrofit rollers if you're a conspiracy type. Still, assuming you got good parts and you had a high zinc break in oil then let it eat. Likely just fine. Also, coating the parts with heavy assembly lubes and the like, how long do we really think that shit stayed in place? All those heavy parts floppin around in there at high speeds, windage, oil washing over everything everywhere? I'd give it 20-30 seconds and think that's generous. Trace metals needed, light springs if you really wanna get techy, follow decades established processes. The rest is out of our hands. But again, you're probably ok.

 

With both crane ,& Isky recommending moly paste on the lifter face & the cam lobe , I'll abide by their wishes , more collective cam knowledge there than anywhere else !

 

I'll agree you might get some, and yes I'll agree on Isky and Crane tech. Still begs the question, how long do we really think it stays on? And, is it long enough to deposit the trace metals that aid in cam/ lifter longevity given the heat required to make thay happen? And for the record I'm not saying don't do it. Just a question in my head, for decades really.

 

Home made test stand??

 

Do they say anything about spring pressure??

 

Never had reason to investigate spring pressure anything I've built has had nothing more than a z-28 spring in it

 

Time to find another topic to wonder about !LOL

 

I've only done it twice, but I just followed what comp cams said to do. No problems. I figure they know better than I do.

 

Why would you go through all of that and then use "cheap oil from Walmart?"

 

If you've gone to the trouble of building a run stand, you must intend to use it more than once; in which case, you need to address the cooling system. Like anything, it's best to do it right once.

 

Don't think purpose-built run stand, it's a regular engine stand modified slightly, with water temp and oil pressure gauges, on/off switch and start button. The radiator (from a '65 Chevy Impala) is on a separate stand that attaches to the engine stand. Problem with cooling is that I made the attachment brackets too long so the fan is way to far away to do any good. I do use a box fan right in front of the radiator, but even on high it doesn't blow enough to keep temp down. Yeah, I know, make the changes and quit fighting the issue, but sometime I get in a hurry. (Like maybe just more than a couple of us here?) I've broken in 3 engines with my setup in the last 2 to 3 years and haven't lost a cam yet, but I just got wondering this time about the multiple, short-run method I have been dealing with.

Maybe I'll rebuild the radiator setup for the next time.

Lynn

 

I have hundreds of "wait, seriously?" topics around this life. Wives tales and urban legends abound. The paint stuff alone I hear sometimes, I mean it would be a 5 pager! How about groved cranks in BBCs or else you'll spin the bearings. Yeah, better to break the crank. Prick punch the combustion chamber to mix the fuel better. Please, make it stop!! AAHHGG!!!

 

Fashion up a round shroud out of anything. Doesn’t have to be perfect/driver stuff, just something to pull some air through the radiator

 

160° thermostat helps during break in...

 

I always broke my motors in after installing them in the cars.

I built my motors tight and after installing and breaking the cam in I'd let it set till evening. That night I'd fire it up and cruise the main street, let her get warmed up, drive in second then third (even auto trans), keep the rpms up and never kept the rpms constant.

Once the new motor started getting hot I'd pull in a car wash, spray water thru it until the Temps hit 130 or so and go cruise some more, shifting the trans at 3000 rpm or so then just vary speeds again, let her get hot and back to car wash and do it all again.

After the third or fourth time it was good to go, then I just drove the crap out of them.

Never lost a cam or any part, last know milage of 1 motor I built was over 130,000, only thing it ever needed was a carb rebuild. Never had a valve cover off it and smoke the tires as long as you wanted it to, it was basically a blue printed stock build with a nice performance cam. Last all out street motor I built still runs great today with 70,000 miles on its clock and never had a valve cover off of it (yep hydraulic cammed).

 

Over the years I've tried to seriously expunge things of that nature from my memory , unfortunately ( or fortunately ?) , of late , my memory seems to be self expunging a whole bunch of stuff !

 

Anyone used these?

 

My worthless opinion.
I’ve ran em for hours on a stand. Dialed em in then installed em. The exhaust temps in the ride under a load were much higher than on a stand.
Is the cam good? Probably. Is the engine broke in? Not in my worthless experience

I’ve used the same rotella, zinc additive and cam assembly lube on the last 2. No issues.

 

A guy I knew had a really quick drag car. By my standards as a teen anyway. He didn’t believe in a break in period. Build em, hit 9-10k rpm’s when leaving the line. If it held it was good. If not, build another one.
Guy won a lot of races.