How exactly do you break in an engine for the first 500 miles? I already broke in the cam, it's ready to drive. I've heard I should drive at 50mph for 10 minutes then let it coast, then repeat? Do I really have to do that for 500 miles? And how do I know I want to go 50? I mean, with gearing and all, the rpm at 50 mph could vary a lot, depending on the vehicle. Or is the speed representative of engine load?

 

i always heard just at highway speed with not a lot of starting and stopping for 500 miles

 

Actually, I've always been told the opposite. You're supposed to drive at varying speeds instead of one constant R.P.M. to allow your rings to seat properly. I've always heard if you let them seat at one speed, you'll risk blowby at other speeds. Just drive it around town for the first 1000 miles, and you should be fine. Also, change the oil and filter again between 500-1000 miles. This will help get rid of any leftover metal particles from either the machine work or the break-in itself. Changing the filter again is especially important because if it gets plugged up with particles, your bypass valve will open, and any particles left in your oil will go right through your engine.I had this happen to me once. I changed the head gaskets on a V6, and didn't change the oil and filter afterwards. The filter plugged up with debris, which caused the bypass valve to open, and the result was a rod knock. I try not to exceed 3500-4000 R.P.M. during the first 1000 miles either. I like to make sure the bearings and rings have seated and wore in before really opening the motor up. I've followed these basic tips on every motor I've broken in and haven't had any problems yet.


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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."

 

After cam break in, I change the oil and filter.

500 miles later, I change it again.

Then 3000 mile intervals after that.

As far as how you should drive it....Just drive it normal. I just put them in, break them in, and let them go. The only thing I tell customers is not to tow anything for about 1500 miles.

Never had a problem.

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

[This message has been edited by Engineboy (edited December 20, 2000).]

 

The main thing is don't rev it very high or pull a heavy load. And change the oil. I always do the vary engine speed method.

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82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro

 

ive heard idling at 2000 in the yard for 30 mins

and drive 500 miles without goin over 50

*shrugs* id love to hear a definate answer myself

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AIM: grvkill
ICQ: 29298583

 

You must change the oil and filter RIGHT after the break-in of a flat tappet cam!!! The break-in lube gets stuck in the poors/fibers of the filter and can open the bypass rather easily. Just buy good filter $1.50/qt oil and change right after cam break in... Not like the extra $10 or so will break the bank but it's worth it for a new motor/cam... Then, change the oil/filter AGAIN at 500-1000 mi, as suggested...

 

The way it is recommended by GM is this.

Run it at 2000-2500 rpms varing the speed to break in the cam.

Take the car out and put it under varying loads for the first 50 miles, heavy loads, and light loads at all different RPMS.

Change oil and filter.


I do like the idea of changing the oil and filter right after the cam break in though.

Also prime it with gas from above and don't crank excessively or you'll destroy the new cam and don't forget to prime the oiling system.

The list is at www.paceparts.com

Drive the next 500 miles normally without long periods of high loading or rpms in excess of 5500 (although I'd recommend no higher than 4500).

Change oil and filter again


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1984 WS6 Trans Am Hartop
Former L69 Car under restoration
1984 WS6 Trans Am T-top car
4-bolt main 350, headers, Holley 650, T-5 and 3.23's.
Daily driver and restoration

 

Strait from GM:

RECOMMENDED ENGINE START-UP PROCEDURE
1. SAFETY FIRST! If the car is on the ground, be sure the emergency brake is set, the wheels
are chocked, and the transmission cannot fall into gear.
2. Be sure to check the oil level in the engine and prime the oil system
3. Run engine between 2,000 and 2,500 RPMs, with no-load on the engine for the first 30 min.
4. Adjust the distributor timing roughly by hand for a quick start up and smoothest idle possible.
5. Adjust the carburetor settings, if necessary.
6. After the first 30 minutes of the engine running, set the ignition timing (see install ignition
section for timing specifications).
7. Drive the vehicle with varying speeds and loads on the engine for the first 30 miles. Be sure
not to use a lot of throttle or high RPM.
8. Run five or six medium-throttle accelerations to about 5,000 RPM (55 to 60 MPH), then
letting off in gear and coasting back down to 20 MPH.
9. Run a couple hard-throttle accelerations up to about 5000 RPM (55 to 60 MPH), then letting
off in gear and coasting back down to 20 MPH.
10. Change the oil and filter with 10w30SG oil and PF1218 AC Delco oil filter (PN 251605610
11. Drive the next 500 miles normally, without high RPM's (below 5,000 RPM), hard use, or
extended periods of high loading.
12. Change the oil and oil filter again.
13. Your engine is now ready for many happy cruising miles!

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"The people always have some champion whom they set over them and nurse into greatness... This and no other is the root from which a tyrant springs; when he first appears he is a protector.
-Plato

 

In a nut, shell, which sums up GM's reccomendations, wha I've always done is what he said up to the first 30 miles. Then i drive normally, easy on the throttle. Then @ 500 miles I bring the rpms up high, but w/ an easy acceleration. Then @ 1,000 miles I hammered it.

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Justin 87 GTA--organizer: "NY2K" Gathering. Blk/Gld w/Superam, 355cid Trickflows, forged pistons 9.5:1. Auto 2,600 stall, 3.45 9 bolt disc, Best time & mph 13.567 @ 101.900 w/ a poor 60ft. Best mph: 104.3 *This car is 100% NYS emissions legal, w/ all emissions controls!* "If you want to have a fast car, hang out w/ those who do!"
http:// www.community.webtv.net/munks87/JustinsGTApage.com

 

Here's an excellent article written at Chevytalk.

Just click on the link in the first post.
http://forums.chevytalk.com/forums/F...ML/000007.html