New camshaft breakin
Discussion
Sardonicus said:
If the motor as already been run then the break-in stage as been and gone ..... probably 
its the initial 20-30 minutes running that dictates the camshafts life span 
who told you to take things easy? that's cods wallop 
I'm on 63K! its the initial 20-30 minutes running that dictates the camshafts life span who told you to take things easy? that's cods wallop Edited by Sardonicus on Wednesday 4th February 15:47
Cam run is is very specific to allow the lobes to bed in. The cam should have had a special lubricant on it to start with, then the engine should be started and taken to 2500 - 3000 rpm striaght away and held there for about 20 mins- a kinda noisy thing to do in a workshop, or take it out and drive it, and dont allow it to idle. This keeps the load on the cam lobes down as the load increases sharply at idle, and allows them to bed in and harden properly. Leave out this vital stage, and they dont bed in properly as micro welds rip the hardened surface off the cam at the high points,(that you are trying to smooth down without micro welds) so the surface becomes softer and the cam life is reduced. Bet you wish you had not asked. :-(
blitzracing said:
Cam run is is very specific to allow the lobes to bed in. The cam should have had a special lubricant on it to start with, then the engine should be started and taken to 2500 - 3000 rpm striaght away and held there for about 20 mins- a kinda noisy thing to do in a workshop, or take it out and drive it, and dont allow it to idle. This keeps the load on the cam lobes down as the load increases sharply at idle, and allows them to bed in and harden properly. Leave out this vital stage, and they dont bed in properly as micro welds rip the hardened surface off the cam at the high points,(that you are trying to smooth down without micro welds) so the surface becomes softer and the cam life is reduced. Bet you wish you had not asked. :-(
Nuff said 
Think Sardonicus mean the *cam shaft* has been run in, not the engine.
A new camshaft needs 20-25mins running at ~2500rpm AS SOON AS YOU FIRST START THE ENGINE once the new camshaft is in place (I know this sounds wrong, cold oil, etc).
If you let it idle or similar, the cam shaft is essentially scrap.
HTH,
Dom
--- Edited to say: Whoops, beaten to it
---
A new camshaft needs 20-25mins running at ~2500rpm AS SOON AS YOU FIRST START THE ENGINE once the new camshaft is in place (I know this sounds wrong, cold oil, etc).
If you let it idle or similar, the cam shaft is essentially scrap.
HTH,
Dom
--- Edited to say: Whoops, beaten to it
---
PapaButch said:
Hang on a minute...do you only need to run an engine in that has had piston and bore work? what about the crank bearings, rocker shafts, lifters etc??
Crank bearings should be right from the off. Forget rockers and lifters.Re bores and rings I`m on the side of new engine = thrash it and load it up.
t anyway Cylinder break-in (as opposed to camshaft break-in) is about getting a good seal between piston rings and the honing pattern on the surface of the bores. Imagine that pattern as a load of microscopic peaks and valleys - you have to wear off the sharp points of the peaks so they make a gas- and oil-tight seal with the rings, and you need to do that before the oil forms a glaze in the "valleys". The only way to do that is to put the engine under some load, creating good cylinder pressure which gets in behind the rings and pushes them outwards against the bores. Failing to do this will lead to poor compression and oil consumption, and the only way to fix it is a re-hone.
So whatever you do, don't "baby" the engine! Use varied throttle pressure, including some firm pushes (though avoid labouring). Use varied revs so that the rings don't sit in one position all the time - the motorway is not ideal for breaking in, so change down a gear and give it some welly from time to time. Twisty roads with lots of acceleration are perfect. Avoid very high revs though.
During this period it's normal to use a non-synthetic mineral oil, because a synthetic oil gives too much lubrication and doesn't allow enough wearing down of the hone pattern.
But all of the above is irrelevant to camshaft break-in, which has been described very well. This is only relevant to new pistons/rings, and a re-hone of the cylinders.
So whatever you do, don't "baby" the engine! Use varied throttle pressure, including some firm pushes (though avoid labouring). Use varied revs so that the rings don't sit in one position all the time - the motorway is not ideal for breaking in, so change down a gear and give it some welly from time to time. Twisty roads with lots of acceleration are perfect. Avoid very high revs though.
During this period it's normal to use a non-synthetic mineral oil, because a synthetic oil gives too much lubrication and doesn't allow enough wearing down of the hone pattern.
But all of the above is irrelevant to camshaft break-in, which has been described very well. This is only relevant to new pistons/rings, and a re-hone of the cylinders.
Edited by Dr Mike Oxgreen on Thursday 5th February 06:31
Sardonicus said:
WokingWedger said:
Surely who ever fitted the cam will have broken it in ?
Lets hope so This
For the OPs peace of mind;
I seriously doubt any garage would have fitted the cam, re-fitted all the engine components and then walked away to wait for the owner to collect it, never having started it
As described above; the cam break in will have been done by the mechanic.
The engine isn't new, so irrespective of any arguments about the best way to run in a new engine, it's not a new engine so it's all good to go.
That said, always do what your engine builder / mechanic tells you; he's the one providing support and warranty.
Other than that, the engine should have been filled with high zinc content oil to protect the new cam.
But again; always follow the engine builder's and manufacturer's instructions.
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