Breaking in Rebuilt 351 |
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chavonbravo
Newbie Joined: November-01-2005 Status: Offline Points: 35 |
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Posted: November-10-2005 at 1:14pm |
Any special procedures for this? I'm picking up an '85 Nautique tomorrow with 0hrs on rebuilt engine. Anything I should know/do?
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markb
Groupie Joined: December-24-2004 Location: Australia Status: Offline Points: 76 |
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Don't run it with any ballast if you are a boarder. There are 2 schools of thought though and this is sure to provide plenty of discussion. 1) Just get into it, drive it like you stole it. 2) gradually break the engine in, go really easy but continuously vary the revs for the first 10 hours or so. For both though a more frequent oil change is required after the run in period..generally 10 hours. |
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jbear
Grand Poobah Joined: January-21-2005 Location: Lake Wales FL. Status: Offline Points: 8193 |
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I vote for "drive it like ya stole it". Thats how I've broke all mine in and never had any trouble. I would however make sure I change the oil early and often. Don't scrimp on the oil or filter; buy the best at your local parts store. Have fun with it!
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"Loud pipes save lives"
AdamT sez "I'm Canadian and a beaver lover myself"... |
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JoeinNY
Grand Poobah Joined: October-19-2005 Location: United States Status: Offline Points: 5693 |
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Might as well weigh in..
Step 1 If there was a new cam and lifters involved you should spend about 20 minutes between 1500 and 2500 rpm in neutral before allowing it to idle. Step two adjust timing allow the motor to warm up to operating temperature, put it into gear hold on tight and floor it as soon as you can get in a position where it is safe to do so. Then drop it back to idle quick as if your about to hit something but dont put in neutral as your looking to do some engine braking here. Give it 4 to 5 of these all out to dead stop runs, (keeping a close eye on temp and oil pressure gauges of course) if everything is going well at this point captain and crew should be smiling liberally. Step 3 Ten painful hours of crusing under fairly light load (no skiing) trying not to remain at any one particular rpm for too long without varying it a bit. At ten hours change the oil and go skiing. The break in proceedure can be more/less important depending on what kind of rings were used but this one won't kill an engine that was put together right and I have never experienced any evidence of ring blow by after using it. Plus you get to find out right away how your new baby is going to perform. Btw, If your going to run synthetic oil don't start until after the second oil change. That is what has worked for me, although I am sure many out there have more rebuilds under their belt than I do so it will be interesting to see some other posts. Joe |
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AWhite70
Senior Member Joined: March-05-2004 Location: United States Status: Offline Points: 242 |
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Here is how I broke my engine in.
First, if the engine has never been started you need to break the cam in. Start the engine and immediately take it to 1500-2500rpm (in neutral). This gets the oil flow up between the cam and lifters. After 20-30 minutes take the engine back down to idle and then turn the engine off. At this point I changed the oil and filter to get out any metal shavings or other junk that might have been in the block. Let the engine cool completely before starting again. Next for breaking the engine in I put the boat in the water and drove it for about 10hrs varying the throttle position frequently with several WOT accelerations. Here is the break-in procedure from the PCM 351W manual: DO NOT OPERATE AT SUSTAINED FULL THROTTLE DURING THE FIRST 5 HOURS OF OPERATION. DO NOT OPERATE AT HIGH RPM'S IN NEUTRAL. After the engine is thoroughly warmed up, and the boat is underway, open the throttle wide until full RPM's are reached. DO NOT EXCEED MAXIMUM RPM. (RPM's should cease climbing after 10 to 20 seconds.) Reduce throttle to 2,800 to 3,000 RPM, and cruise at or below the speed for 1/2 hour. Reduce speed to idle, open throttle wide, and operate at that speed for approximately 1 minute; reduce to cruise throttle for a few minutes and repeat. (Bringing the engine from idle speed to full throttle will load the engine and assist in seating the piston rings.) This cycle can be repeated from time to time during the first 5 hours of operation, but full throttle should not be sustained for more than 1 to 2 minutes. FOLLOW THE PROCEDURE ONLY WHEN CONDITIONS ARE SUCH THAT IT CAN BE DONE IN COMPLETESAFETY. DO NOT ATTEMPT TO BREAK IN AN ENGINE BY PROLONGED IDLING OR RUNNING IN AT THE DOCK. During the early part of the break in period, correct propeller selection can be confirmed. (With a normal load aboard, the engine RPM's should reach, but not exceed, maximum RPM's as listed under specifications for your model.) During the break in, water temperature should be watched carefully, and speed reduced if overheating becomes evident. |
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chavonbravo
Newbie Joined: November-01-2005 Status: Offline Points: 35 |
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Nice Forum. :) Wealth of info. Thanx
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Munday
Gold Member Joined: August-17-2004 Location: United States Status: Offline Points: 538 |
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Those all sound good.
being old guy,drag racer motor head. if I get time to run her I ain't to worried about standard op procedue.Change Oil first couple times you come home.Feed that to lawn mower.Have fun in Boat,its gonna break sometime but it won't be the bottom end if done right Munday |
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