Thread: Tutorial Vid on final touches and cam breakin of Flat tappet engine

Interesting.... I wonder how you get a good ring/liner seal when you have let the motor roll over for 25minutes with no load on it to break the camshaft in .... You have probably worn the most aggresive cross hatching off the liners without loading the engine.

seeya,
Shane L.

What happened in the old days when people just used to run engines in the car without "breaking in" cams? Seems a fairly recent fashion of the last 20 years or so.

Rover v8’s can be hard on camshaft lobes I knocked one off one cam. It’s not uncommon. The worst offender used to be 308 holdens. Many’s the time we swapped the cans due to missing love. But the cross hatching typically is still visible on engines with lots of miles on them. We’ve been running in cams since 70’s then once done go out and bed rings in. Peter Brock used to take new Torana XU1’s on road to run in their favourite road was Dandenong to Phillip Island which was initially nice and reasonably flat- good for cam then hilly - good for rings.

Auto correct missing lobe

Originally Posted by DoubleChevron

Interesting.... I wonder how you get a good ring/liner seal when you have let the motor roll over for 25minutes with no load on it to break the camshaft in .... You have probably worn the most aggresive cross hatching off the liners without loading the engine.

seeya,
Shane L.

Originally Posted by Fourgearsticks

What happened in the old days when people just used to run engines in the car without "breaking in" cams? Seems a fairly recent fashion of the last 20 years or so.

Flat tappet cams have always needed breaking in, I was taught to do this building race engines in the early nineties by a then 50yo engine builder as they had too many cam failures if not done. He built NASCAR and Touring car engines, and it wasn't new then. He'd do it on the dyno before bedding the rings properly and doing power runs.
Everyone struggled with the conflict of ring seating vs running in the cam.
Running in the cam won.

To prevent the problem of no load on the rings after start up a mate built a cam running in rig, basically all old block with an electrically driven cam drive.
We'd run the cam and lifters at 2200RPM for 20minutes prior to fitting in the 'real' engine.

Originally Posted by Fourgearsticks

What happened in the old days when people just used to run engines in the car without "breaking in" cams? Seems a fairly recent fashion of the last 20 years or so.

True,,
two points to ponder.
one is the common oils back then were designed for flat tappets,
and two, in the last twenty years, Internet.