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How to Break in a New Cam

There are a couple of things that have changed. Read about them here.

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Break-In Procedures

Let's assume you've just finished bolting that killer new engine in your car. Before you hit the starter motor and shake the pavement with all that horsepower, there are a couple of crucial camshaft break-in procedures you should follow. Your first step should be to remove the distributor so you can prelube the engine. Prelubing uses an old distributor or a specialty tool to independently spin the oil pump.

We built an oil-pump primer out of an old point distributor for our small-block Chevy by removing the cam drive gear and cutting off the top of the distributor-shaft weight pivot. We then had a friend machine the top of the shaft so we could use either a 11/44- or 11/42-inch drill motor. A corded 11/42-inch drill motor has the most torque. We retained the distributor body, since it directs oil to both sides of the lifter galley. Without the distributor body, only one side is lubed. Engage the oil-pump driveshaft and spin the drill motor. It's also a good idea to rotate the engine by hand a quarter turn at a time to ensure all the lifters get oil. This process should only take about five minutes but can sometimes take longer. A big-block Chevy will take much longer to pump oil to all the rocker arms-perhaps as long as 20 minutes.

Now replace the distributor by positioning the engine at No. 1 cylinder at roughly 16 degrees before top dead center (BTDC) on the harmonic balancer. Line up the distributor rotor with the No. 1 spark-plug wire on the distributor cap and cinch the distributor down. This will ensure you have around 16 degrees of initial timing in the engine when you first hit the starter. Prime the carburetor by pouring some fuel into the primary fuel bowl through the vent tube. Work the accelerator linkage until you have fuel squirting into the manifold. Assuming you have also filled the engine with oil and the cooling system with water, you're ready to fire the engine. The reason for all this preparation is to minimize the amount of cranking necessary to start the engine. With everything set correctly, the engine will fire on the first or second revolution.

Once the engine fires, immediately bring the rpm up to between 2,000 and 3,000. All camshafts in V-8 engines are splash-lubricated from oil whipped up by the crankshaft. Spinning the engine at these higher speeds for the first 20 minutes ensures sufficient oil reaches the cam lobes. We prefer to have the full exhaust connected so we can hear the engine while it's running to listen for any misfire or engine problems. This is a good time to double-check the ignition timing. Also, make sure engine rpm never remains constant for the break-in period. Engine speed should vary between 2,000 and 3,000 the entire time. This ensures oil reaches all points on the camshaft. Do not merely set the fast idle on the choke and walk away from the engine. Also, use this break-in time to watch for leaks or other problem areas and to monitor the coolant level and temperature. We like to use tap water for this first break-in period so it can be easily drained if there is a problem

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59 comments
Brian Clausen
Brian Clausen

It will save your bearings when you add it into your oil when your going through the break-in period.

Jake Fitzpatrick
Jake Fitzpatrick

chuck gill, im with you there. same nightmare in an old 326

Kenneth Corbiere
Kenneth Corbiere

tried to put a 327 high lift cam into a 400 ci.....bad, bad, bad, and really, I knew better

Derek Bettencourt
Derek Bettencourt

did the same with a 350 and used 272 crane same lifters 4 months ago runs perfect lots of cam lube used though.

Nathan Britton
Nathan Britton

Oh, and don't try to support the cam by sticking your finger down the distributor hole... you will end up bleeding.

Nathan Britton
Nathan Britton

Just put a new Comp cam in my '79 Ford 300-6. Found out, literally just in the nick of time, that the lifter cover was upside down and puking all the oil out. ALWAYS check for oil leaks...

Page Crow
Page Crow

#1: Install that cam with the engine standing UP. That way, you don't bang it around inside the cam-bearings. It drops right in real sweet if you go vertical.

Kenneth Bircheat
Kenneth Bircheat

Trying to take a cam out that had snap in two in a 351 winzer.

Mike Edler
Mike Edler

installed new cams and trays in a 2010 BMW, it ran for about 8 seconds, then seized the motor. thank god after prying it back out the motor was o.k. still don't know what went wrong.....

Jason Wingnut Smith
Jason Wingnut Smith

wondered why i had a knock in the motor one mechanic said big end another said it was i was the gudgeon pin... pull the motor down and nothing to do with either of those turned out i had wore the lobes of the cam 3 where worn down into the cam and another was worn down even with the shaft fitted a new lumpy cam with new lifters and behold the beast was running perfect..

Steve Syvertsen
Steve Syvertsen

Too much spring seat pressure on a friends BBC, ate that Lunati Cam right up like the cookie monster. nomnomnom!

Nicholas Adams
Nicholas Adams

Had a few lobes go round on a 400sbc with a gear drive. Replaced the cam and lifters, broke it in with the Crane break in additive, switched to a timing chain, then I could hear all the noisy connecting rod bearings that got chewed up. The new cam broke in fine. Pulled the engine, tore it down, sent the crank back out, scrubbed every inch of it and did it again, the whole nine yards... Ran great after that.

Jake Lister
Jake Lister

Had a timing gear come apart at 5,000 rpm on a Chevy 350

Dodge Custom Royal Lancer
Dodge Custom Royal Lancer

I use Shell Rotella T with STP blue bottle ZDDP to break in cams, works like a champ every time :)

Elijah Rose
Elijah Rose

rebuild at school, "were going to try and reuse this cam, i dont want to spend the money for a new one" *slip* *bang*...... " well i guess i need a new one now... " great day -_-

James Doepel
James Doepel

Heavy duty truck oil . Rotella or. Dello will do .

Tim Howe
Tim Howe

I was pulling the cam out of a 75 Camaro and it came out fast and I smacked the back of my hand on the radiator support, drove myself the the ER and got 3 stitches!

Ricky Bobbie
Ricky Bobbie

Keep it above 2500 rpms for 30 minutes and use lots of break in lube and an additive in the oil

Dean Henderson
Dean Henderson

cheap summit cam and lifters. Break in oil with lots of ZDDP. 2000 rpm for 20 minutes with open headers. Neighbors calling because of the noise. priceless

Louie Eriacho
Louie Eriacho

I agree with you Mr. Timothy Bremm interesting ...

Cam Beaton
Cam Beaton

I instaled a Stock Elimiantor cam, that I got for free in a 350 Olds. It sounded tough, but it was guttless.

Timothy Bremm
Timothy Bremm

All of these answers are interesting.A learning experience.

Robert Bruce Carter
Robert Bruce Carter

Didn't have enough clearance on valve springs. Coil bind ! Expensive lesson..

Rick Maynhart
Rick Maynhart

Stephen.....when you do the cam and dizzy gear you need a matched set from Bulltear.

Christopher Doss
Christopher Doss

Had a lunati voodoo go flat on 3 exhaust in 5 days after doing everything I could and spending an extra 100 on all the best additives and lubes I could get and weak break in springs, that was my last flat tappet :-( got a comp thumper roller in the same motor (after ANOTHER rebuild and cleaning to get all the metal out) and it's been great and the only new thing I had to do was figure out custom pushrod sizing.

Gary Huddleston
Gary Huddleston

Went cheap..put in a used can with old lifters... Can you say flat lobes in 10 days?

William Schmitz
William Schmitz

270 Crower in a low compression SBC 350. 10 inches of manifold vacuum. A set of Rhodes lifters fixed it. Lesson learned.

Steve LaRiviere
Steve LaRiviere

The only cam problem I've had, and this was a long time ago (1980 or so) was with a Crane Fireball cam I put in a SBC. I took care to break it in right, but it still wore out in less than 5000 miles. I swear it must have been made of pencil lead. I've used Comp Cams, Isky, Crower, and Ford Motorsports cams and never had a problem with them.

Jon-David Jacobs
Jon-David Jacobs

rebuilt complete 350 and installed new valve springs at the wrong height. made the cam a whole lot smoother about 5 minutes into breaking in the engine. couldn't understand why the valves were so noisy!

Joe Jr Ferrell
Joe Jr Ferrell

If you knw the L.S.A of a cam and how they function and understand oil and viscosity. And knw what your doing ...you shouldnt have any problems. Unless its a manufacturing problem. .

Mike Gizzmo
Mike Gizzmo

not a problem but a funny/odd story. in 1970 I wet 2 work 4 the PA dept. of Trans.they had & still do have a engine rebuild shop. one of the old guys taught me 2 rebuild engines (gas at that time). so I'm installing a camshaft in a 450ci IHC 6 cylinder and it's a bit sung (high spot on a cam bearing). so one of the old guys says stand back.9this is the odd/wild/crazy part) and takes out a large long brass punch & a 5 pound hammre. he hits the camshaft on either side of all the cam bearings. on the lobes spins the cam 1/3 turn hits again .. the engine ran great on our dyno. Kids please don't do this at home. never on a stock Ford shaft they are very brittle !!! I retired with 35 years rebuilding engines. FUN WITH TOOLS. my hands are shot

Chris Pinney
Chris Pinney

This is 2013 buy a roller cam!!! Flat tappet hasn't been in SBC since '86 and SBF in '84 in mustangs.

Halim Amzika
Halim Amzika

Two successful swaps (xe268h and xe274h), no issues as of yet. Used resp. 10W40 dino diesel oil and 5W50 fullsynth Valvoline VR1. Of course break in with the moly lube and additive!

Chück Gill
Chück Gill

I runed two high lift flat tappet cams in a Pontiac 400HO before I found and article on zinc and phosphate. Third time and ZDDP was the charm.

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