Just thought I would post up a few reasons as to why we at Hayward Rotary have our customers run their rebuilt engines in.
1.Compression definitely does go up after the run in. New Apex seals are crowned.(In other words not flat on the sealing face)
2.It gives time for all ancillaries to show up any problems without the likely hood of causing engine damage.
3.New parts in the engine have not been through a number of heat cycles but once run in is complete then this has happened quite a few times.The advantage of this is the any manufactured stress in new parts is relieved and the components can handle more power with better stability.
4.New bearings do need to be run in as they are too close a tolerance for higher RPM,and they tend to be quite uneven so actually work to a pattern that suits whatever they are supporting,that is why white metal is used,it is supposed to wear to correct tolerance.
5.If the new parts are treated to a gradual run in process then they actually end up being better tolerance than an engine that is thrashed from new,when an engine is driven hard from new the wear is much more aggressive,this effectively means that you start to wear out the parts quicker in the intial phase and subsequently end up with an engine that is overworn as opposed to being in tolerance for a long time.
There are other reasons too,but the above gives some idea.
Regards
Carl
cheers Carl,
what do you think about the theory that quicker run in can lead to higher compression?
The link Lima put in the other thread explains pretty well for pistons what possible advantages are, how do you feel that reflects on rotaries?
Quote from: Oedipus Rexcheers Carl,
what do you think about the theory that quicker run in can lead to higher compression?
The link Lima put in the other thread explains pretty well for pistons what possible advantages are, how do you feel that reflects on rotaries?
I have seen and heard that for many years but don\'t hold with it.
I have ran many rotaries in and tried both way\'s,the longer more progressive way is much better suited to the rotary engine as you almost allway\'s end up with lower compression trying to run in to quickly or harshly for a short time,and the compression never goes up after that,only down as you have to keep thrashing it harder to make it go.
Regards
Carl
Alas a very informative answer!
(\'Thank god as I was just speachless from the other similar thread raised\')
Good stroke Carl.... :Thumbs-up
.
Thanks for posting this...
Can I ask what run in proceedure you request for your rebuilds Carl ?
Not to mention the work hardening and heat-treating of parts to increase wear resistance and hardness that comes from gradually increasinmg temperature, and cycle upon cycle repetition ( so slow running and no temperature spikes (so boost and high combustion temperatures)
Good to hear from an expert!
I know the "hard" method (I don\'t personally think that\'s hard as you are just working the engine to it\'s fullest at a safe opportunity) works for 4 strokes, and it is 100% true.
My dad works for a BSB race team and they\'ve tried the softly softly approch and everytime they do that the engine ends up loosing more and more power and is down about 15 - 20 bhp by the 3rd meeting or so! It\'s a massive amount for a bike engine and even more in a race!
Obviously they also change the oil immediately after the "run in" and then keep it all fresh, which will also help a lot!
But it\'s good to know it\'s different on a rotary.
Carl, how many miles would you say it would take to run the bearings in? And after that?
It\'s just 1000 - 2000 miles as a run in just seem far too excessive IMHO.
Never in the field of human driving has one person been so careful with their beloved engine than I was with my running in period ....... errrr ..... more accurately run in era.
I followed your instructions Carl to the letter and did my 3,000 run in ...... winding up during the final 1,000 although kept off boost for the whole period.
I understand that you now advise 2,000 miles with the ceramics ...... is that true ? That is alot less painful.
Anyway, I am sure being so careful has played a big part in the superb performance of the engine even after 3 years of hard driving ......... surely it is totally logical the importance of running in.
James
I\'m interested to know why uk builders reccomend a running in period of 2-3k miles, when Mazda reccomend 300.
Not a dig, just a genuine question.
Quote from: James BI understand that you now advise 2,000 miles with the ceramics ...... is that true ? That is alot less painful.
Not all that much less painful James! at 1805 miles now, need to give Carl a call to get it mapped now :) :D :)
Quote from: Oedipus RexI\'m interested to know why uk builders reccomend a running in period of 2-3k miles, when Mazda reccomend 300.
Not a dig, just a genuine question.
The engines we build actually vary depending on what parts have been used,eg types of apex seals,and bearings and the like.
For most stock rebuilds 1000 to 1500 miles is good,but with ceramics (As James said) you do need alot longer,and I have seen this over and over again.
I guess if our customers want long life and reliable power from our engines then following the break in period would be a wise thing to do,and it also keeps the warranty,as for anyone who has built their own engine then they have a choice to make and are free to do so,they have no warranty either way.
Most of our engines are not standard spec in one way or another either.
Regards
Carl
is this because the Ceramic seals are harder and wear the housings quicker, leading to loss of acceptable tolerances quicker? or some other reason.
Quote from: Oedipus Rexis this because the Ceramic seals are harder and wear the housings quicker, leading to loss of acceptable tolerances quicker? or some other reason.
We have just pulled apart an engine that has run 36,000 miles in an FD on a single turbo during all of that time with well over 400 hp on ceramics,it had one blown apex seal,but the rest are fine, and the seals and rotor housing are fine and in fact reuseable.
Tolerances actually stay pretty much the same.Apex seals are not worn so as to be able to measure without a microscope!
Regards
Carl
cool, so why do the ceramic seals take a lot longer to run in?
(sorry, not trying to grill you here, just trying to understand the diffferences and reasons why)
I\'ve just completed a 2000 mile run in with a rebuild from Carl - 3000RPM first 500 miles, then oil change & filter and 4000RPM to 2000 miles. Oil change, filter and new plugs before mapping. It had 3mm seals, hence Carl wanted a longer run in.
Due to have it mapped on Friday, I can\'t wait!!!! :3gears-rh
The best reason to run-in an engine, as per Carl\'s instructions is............because you just spent £4000 on it!!! :rollin
unless you are one of these clever chaps that rebuilds it themselves