Hi again (I seem too be posting a lot today ),

having spent some time looking for power options for my L48, I've come across a lot of info saying that flat tappet cams need to be run in straight after the first engine start - typically by revving the engine to 2000rpm and holding it there for twenty minutes. Why is that?

The reason I'm asking is mainly because I've never heard of that being necessary on european flat tappet engines, such as Alfas, VWs etc.

Cheers

Es

 

Been that way forever with pushrod motors, the lifters spin and form a pattern to the cam lobe.
Ive skipped the whole procedure, made sure the pushrods spun and immediatlely driven it wouldnt recommend it though.

Follow instructions use a good oil for FT engines and enjoy.

 

COMP CAMS HAS A REAL GOOD ARTICLE ON BREAKIN PROCEDURES. You must use a oil that is for flat tappets, Do not use regular oil off the shelf or you will destroy your camshaft.
Todays oil does not have zink in it because of environment bullsh*t and most engines today are roller cams and do not need zink for the cam.
Pepboys sell a good oil for older engines.
Read sticky from 540Rat on what is a good oil for these engines, remember that what he lists on the best oil might not be available in your town.
Just use his list as a guideline for what ppm zink you need .

 

Make sure the engine is set at cylinder #1 ignition stroke. Then remove the distributor. Now using a good quality priming tool and a corded drill . Spin the oil pump with the drill for about a minute then using a breaker bar, turn the engine a quarter turn and spin the drill again for a minute or so. Continue this process till you have manually turn to engine for two full revolutions. Set your timing mark to 10° btc. Slide the distributor back in. Make sure the rotor points to the number 1 plug wire terminal. And fire it up. Once running, immediately take it up to about 2200-2300 rpms and keep it there for about a half hour , while giving it slight rev ever few minutes. After the time runs out, shut it down and change the oil and filter. Use the same kind of oil and filter that you used for the cam break in. To check if your cam survived the break in process,. Remove the valve covers agai, disconnect the 12 volt feed to the distributor and have somebody crank the starter. Then observe to push rods. They should all be turning as the engine cranks over. If any fail to spin.... Well... Let's hope that isn't the case. Anyway, drive it for about 500 miles and change the oil and filter again and use whatever oil you want. I use Joe Gibbs br30 braek in oil or amsoil break in oil for the can break in and the first 500 miles. Have done this way for years and haven't lost a cam yet. My .02
Also. Take the valve covers off while priming the engine so you can observe and make sure all the rocker arms are being fed oil up through the push rods. Reinstall covers before engine start.

 

YOu dont want to hold it at 2000 rpm steady. You want to vary it between 2000 rpm and 2500 rpm. I believe most of the european motors are overhead cams that you may be referring to. And Comp Cams has come out with a newer procedure claiming that you want to do 2 sessions of 10 minutes each. And as stated its to get the cam and lifter mated

 

I get the carb full of gas......and MAKE SURE the distributor is on #1....then advance it slightly and lock it down, but not tight. Have a timing light hooked up and ready....also have a fire extinguisher nearby (Don't ask me why). Turn the idle screw a couple of turns clockwise to crack the throttle plate. Start the engine.......now I have a digital timing light that shows RPM, get this to 2200 rpm as soon as possible after ignition. Now shoot the timing tab and see where you are at and adjust accordingly (on my small blocks, 2200 rpm is about 28 degrees).....you are running this engine for 20 minutes, time it immediately as to not cook your new shiny ceramic headers (This is how they get ruined during start-up...not because of friction or Demons or Gandolf not letting you pass). Now that it is in time, get your stop watch out and start clicking. 20 minutes is my number, others go 30....I find that long to be unnecessary. Have a long thin screw drive in your hand and gradually fluctuate RPM from 2000 to 2500 (this is why I start at 2200). Run for twenty minutes and shut off.....congrats, the cam is now broke in. Now check everything for issues or leaks and go run the **** out of it to seat in the rings......3-4 full throttle 1/2 mile runs on the expressway should do it. Done.

Now let me explain why you break in a cam. The camshaft lobe on a pushrod flat tappet is actually ground at a 1 degree angle (You can't see it), and the lifter foot is actually convex. The cam and lifter only contact each other in a very small area....you will see it as a ring on the bottom of an old lifter. You want to get the lifters spinning AS SOON AS POSSIBLE! If the lifter does not spin right away, it will grind away at the cam.
The cam is oiled by oil slinging of the crank going upward.......it is a spray. The change in RPM makes a different spray pattern from 2000 to 2500 rpm.....this is why you do that.

OHC European stuff is either like a motorcycle (shim and bucket) or has a follower. Either way...the WHOLE lobe of these type of cams hits the shim or the follower, therefore no break-in required. But on an old MG or any other OHV engine.....the same procedure applies.

Jebby

 

What did the factory do when they made millions of these engines for cars and trucks.

 

Prior to the mid 80’s...oil with a lot of Zinc in it was commonplace....that and weak valve springs made it a non-issue....after 86-87, everything had a roller in it....

Jebby

 

ya slower ramp rate cams and not a lot of spring pressure probably allowed the fatctory not to break in cams. But everyone say in the 1970s using factory cams, lifters and springs from the 60s hypo cams we always broke them in.

 

Didn't the factory fire them on natural gas or similar?
I remember personally seeing a brand new crate engine that had a very light golden color to both the pistons and the valves, as well as a pic somewhere of a big hose hooked up to the carb inlet.
Not sure how long they ran them tho....

 

https://www.compcams.com/pub/media/w...chBulletin.pdf

 

They're not firearms ... How else would they move them from lines to yards and then onto haulers / rail cars / ships?

 

If everyone is so concerned about "splash oiling" why not just overfill with oil the first fire-up?

 

Becasue it would make no difference and if overfilled too much could cause failure to components if the crank is slinging in an oil bath…..
The “splash” you speak of is not splash at all but an oil spray….which pisses past and out the rod and main bearings and gets sprayed of the crank like a centrifuge…..this spray is critical to the first seconds of cam break-in and has nothing to do with oil level.

Jebby

 

20 sec engine burn in at Flint and start/go at the end of the assembly line at St. Louis.

 

a lost bit of info I think is important,
non-detergent oil

 

I just looked up engine oil recommendations in 1970 owners manual and non detergent oils are not recommended and if you look at the oil dip stick it states GM 6041-M oil. The manual also states that GM 6041-M was installed at the factory.

 

do you have a point?

 

He just made it...

 

he is alright then.
just use that specific oil and no need to do anything.
thx