Breaking in a cam
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Breaking in a cam
Never done it, but I was gonna purchase a used 941 from a fellow FE board member and was curious if I needed to break in a used one. Does it only apply to new cams, or on a "less than 200 miles on it" cam also?
Thanks!
Mike
Thanks!
Mike
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Yes, new lifters will be installed with the used cam. Thank you for the info
Next question.....
What are the proper steps in breaking in the cam. As I mentioned, this is the first I'll be doing. Should it be done a little different since it is a used cam, or follow same steps as if it was a new one out of a box?
Thanks!
Mike
Next question.....
What are the proper steps in breaking in the cam. As I mentioned, this is the first I'll be doing. Should it be done a little different since it is a used cam, or follow same steps as if it was a new one out of a box?
Thanks!
Mike
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Joined: Jan 2003
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From: Iowa
Yes, any time you put new lifters on a cam you should follow the breakin procedure as you would on a new cam. Here's how I do it:
Start the engine, and IMMEDIATELY take it to about 2000rpm's. Then, for 1/2 hour, slowly vary the RPM's between 1500 and 2500. The reason is to get oil up to lubricate the cam while the lifters and cam wear into each other. Thus, DO NOT LET IT IDLE FOR THE FIRST 1/2 HOUR! Even a little. After the 1/2 hour, shut it down, change the oil, and you're done. Drive it normally.
Start the engine, and IMMEDIATELY take it to about 2000rpm's. Then, for 1/2 hour, slowly vary the RPM's between 1500 and 2500. The reason is to get oil up to lubricate the cam while the lifters and cam wear into each other. Thus, DO NOT LET IT IDLE FOR THE FIRST 1/2 HOUR! Even a little. After the 1/2 hour, shut it down, change the oil, and you're done. Drive it normally.
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Thank you guys for the info. I can't wait to build this motor! Just a couple more things to gather up and I should be ready to sit down in the shop with a warm fire, a box a beer, my Christ's book and my patience.........
Thanks for the help guys! I appreciate it.
Mike
Thanks for the help guys! I appreciate it.
Mike
Post Fiend
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From: Iowa
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For some reason, the old addage 20 for 20 (100/th rpm for minutes) sticks in my head everytime I think of cam break-ins.
--Mike
--Mike
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Ask him if he kept the lifter that came with the cam and if he kept them in order for the matching lobes of the cam. If he did you could inspect the lifters and to be safe disassemble them and clean them. Make sure that none of them are flat and that they are concave and not convex (I think I got that right) and even if you don't get the lifters you should at least inspect the lobes of the cam with your eyes for rounded lobes. If you can't get the original lifters in order then get a new set.
Senior User
Joined: Aug 2003
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From: Maple Ridge BC Canada
I would never re-use lifters for any reason...Cam will need to be broken in with new lifters, just like a new cam....Make sure you use moly.(lots)on the lobes and lifters. Static time to motor, and make sure the float bowl on the carb is full, as excessive cranking can and will round off cam lobes....d44hd
Post Fiend
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From: Iowa
Also (I have to throw this in) If you're going to re-use lifters, they have to be kept in order, on the same cam, and IN THE SAME BLOCK they came out of! Lifter holes can and are off ever so slightly from block to block, and that screws things up when trying to re-use lifters.
Just had to add that.
Just had to add that.
Posting Guru
Joined: Mar 2002
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From: Boise, Idaho
When you install the lifters, dip each on in STP, GM EOS, or some other oil additive that has ZDDP as an ingredient. I saw something at WalMart for $1.99 or so, that had the ZDDP and it was next to the STP on the shelf, Tech Lube or something.
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From: Long Island USA
Don't forget the moly cam break-in lube... like the Crane stuff that comes in the little black container... grey, shiny stuff... loaded with moly.
I didn't use it on my first 390 and it ate the cam in 5K miles. Disturbing to say the least, because I didn't realize it was going and it wiped every bearing, bore, piston, everything was wiped.
If it was me, I'd spend the extra money for a new cam... I wouldn't bother taking someone's hand-me-downs, especially after my bad luck with one. A little different line-bore, or a lifter bore not exactly the same angle as the motor it came out of, and you're asking for trouble. The only way I would re-use a cam is if it was going back into the same block with the lifters it was broken in with. Just not worth ruining an entire motor to save, what, $110 (from Summit) ??
But that's just my opinion, go for it if you want
I didn't use it on my first 390 and it ate the cam in 5K miles. Disturbing to say the least, because I didn't realize it was going and it wiped every bearing, bore, piston, everything was wiped.
If it was me, I'd spend the extra money for a new cam... I wouldn't bother taking someone's hand-me-downs, especially after my bad luck with one. A little different line-bore, or a lifter bore not exactly the same angle as the motor it came out of, and you're asking for trouble. The only way I would re-use a cam is if it was going back into the same block with the lifters it was broken in with. Just not worth ruining an entire motor to save, what, $110 (from Summit) ??
But that's just my opinion, go for it if you want