I just rebuilt my 68 Pontiac 400 engine. Doe’s any one knows what are the proper break in procedures are?
Thank you
Brian
Thank you
Brian
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2 firebirds are better the 1. -
There are many different schools of thought.........
Ranging from baby it for 1000 miles to beat the heck out of it immediately......
Personally, I start my fresh motors and let them idle for a few minutes while I check for leaks and stuff, then I will run it at 2000 rpms for a few minutses to let the rings initially seat. Then, I will drive it normally for 500miles.....not babying it, but not beating it either. I give it the ocasional full throttle shot, but never spin it to redline......change the oil and then, after 1000 miles I hammer on it!96 WS6 Formula: Ram Air, 383 Stroker, Ported LT4 Heads and Manifold, 1.6 Crane Rollers, 58MM T.B., AS&M Headers, Borla Exhaust, Meziere Elec. H2O Pump, Canton Deep Sump Oil Pan, 100 HP OF TNT N2O!! , T56 Conversion w/ Pro 5.0 shifter, SPEC Stage 3 Clutch, Hotchkiss Subframe Conn., Lakewood Adj. Panhard Bar, Spohn Adj. LCA's, BMR Adj. T.A., Custom 12 bolt w/ 3:73's, Moser Axles, Eaton Posi, Moser Girdle
11.6 @ 123mph (1.6 60' - getting there
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Just so you know....... the engines are taken WOT during testing from the factory.
They have to make sure it won't come apart before it leaves.
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After my 381 LT1 stroker was completed, it was put on an engine dyno, and run at low load, varying low/moderate rpm for about an hour. Oil and filter were changed, all torque settings were checked. Engine was then tuned on the dyno, over a total of maybe 20 pulls, ranging from 450-500HP NA, then 700+HP nitrous pulls, culminating in a 762HP pull with a 250-shot. I think that's pretty much the norm.Fred
381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motorComment
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Yea, thats why I say opinions vary.....you'll probably have 10 different opinions on this thread.....96 WS6 Formula: Ram Air, 383 Stroker, Ported LT4 Heads and Manifold, 1.6 Crane Rollers, 58MM T.B., AS&M Headers, Borla Exhaust, Meziere Elec. H2O Pump, Canton Deep Sump Oil Pan, 100 HP OF TNT N2O!! , T56 Conversion w/ Pro 5.0 shifter, SPEC Stage 3 Clutch, Hotchkiss Subframe Conn., Lakewood Adj. Panhard Bar, Spohn Adj. LCA's, BMR Adj. T.A., Custom 12 bolt w/ 3:73's, Moser Axles, Eaton Posi, Moser Girdle
11.6 @ 123mph (1.6 60' - getting there )
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Thank's for everybody's help.2 firebirds are better the 1.Comment
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There is no one correct way to properly break in a motor.
The main thing to look at here is there is a difference between breaking in a roller motor as opposed to a non-roller motor (flat tappet). Bearing and ring break in will be the same on the two, however the frictional differences will obviously be different between the lobe of the cam and the lifter on the two.
This is just the bottom end. If you ask most valvespring companies, they will tell you it is a very good idea to heat cycle the new valvesprings before actually running the motor under a load out on the street. This process basically is performed by starting the fresh motor, lettting it idle until it reaches normal opertaing temp and then turning the motor off and lettting it completely cool to the outside ambient air temp. Then you start the motor once again and allow it to idle until it once again reaches normal operating temp and then at that point you can go put your break in miles on the car out on the street. After 500 miles, I would then change the oil to the normal operating oil and change the filter.
Since your motor most likely does not have a roller lifter, it will need to be broken in slightly different then that of a roller motor. The school of thought that I have always seen successful on non-roller motors was to use straight 30W oil for startup. Let the motor idle until it reaches normal operating temp then allow it to idle for about 2 hours. This is supposed to properly break in the lifter in its bore(since the lifter spins on a flat tappet), and the contact surface between the angled lobe on the cam and the lifter. Then reaplace the oil and filter with the normal operating oil and filter.
Then again if you ask most seasoned engine builders, they will quote you the infamous cliche....."It's either going to break in or break!"
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