why so many "break-in" opnions?
05-21-07, 10:49 PM
#1
Rotary Enthusiast
Thread Starter
why so many "break-in" opnions?
i was wondering why so many people prefer to break in there 7's so differently? if there suppost to be one single way? or is it application specific? right now i have almost exactly 500 miles on my 87t2 with ceramic housings, and i havent taken it past 3k or boosted yet. was aiming for a reliable DD that could be auto X'd occasionaly. any suggestions?
05-21-07, 11:59 PM
#3
breaking in is done in different ways and differs from each other..like take a clutch for example..the manufacture's break in period for there clutch is about 1500 miles
till you can drag with it or run it hard what have you..breaking in a motor is another story it verys from builder to builder..i would say or guess about 3000 miles just to be safe..and thats with new rotor housing and apex seals, side seals, corner seals, oil rings you get it..call around and ask im sure they all fall within the same standards..then make your own discision..
:AA:
till you can drag with it or run it hard what have you..breaking in a motor is another story it verys from builder to builder..i would say or guess about 3000 miles just to be safe..and thats with new rotor housing and apex seals, side seals, corner seals, oil rings you get it..call around and ask im sure they all fall within the same standards..then make your own discision..
:AA:
05-22-07, 08:52 AM
#7
Banned. I got OWNED!!!
Join Date: Jun 2006
Location: South East
Posts: 698
Likes: 0
Received 0 Likes
on
0 Posts
the way i've done it and always will do it is this:
used bearings... do a few heat cycles then drive the **** out of it.
new bearings... put about 1000 miles of easy no boost driving on it.. then slowly get in to it.
never had an issue
used bearings... do a few heat cycles then drive the **** out of it.
new bearings... put about 1000 miles of easy no boost driving on it.. then slowly get in to it.
never had an issue
Trending Topics
05-22-07, 09:28 AM
#9
Engine, Not Motor
iTrader: (1)
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,789
Likes: 0
Received 109 Likes
on
92 Posts
In my opinion, breakins are a myth. Just drive easily for the first few hundred miles, then beat the snot out of it. Others will of course have a different opinion.
05-22-07, 10:02 AM
#10
Passing life by
For the most part I agree with aron. There is merit to braking it in but it depends on the motor and the internals used. We did a 544 to 502 tunnel ram air 14:1 compression motor making over 900hp NA on 101octane. It took about 700mi to brake the motor in. It used a quart of oil per 100 miles until it finished seating. this was mainly do to the chrome piston rings as chrome is very hard. But that is just an example of why motors are broke in and how it can very.
05-22-07, 10:04 AM
#11
I think the critical part is the first 500 miles of CITY type driving, under 4k rpm, no boost, then the first oil change at 500. Use cheap mineral oil like shell or castrol GTX for the first two oil fills at least. Synthetic very much prolongs break-in. I have seen engines that used synthetic from day 1 still show break in metals in the oil analysis at 15000 miles. Where as ones that used dino oil usually clear up break in evidence by 5k at most.
From 500 miles on seems to be where the most variation is. Seems like most builders want 1000 miles of easy driving, and you can mostly do what you want by the 2k mile mark. But others say 3k, and still others say you can beat on it from the 500 mile mark.
For myself Im going to at least get to the 1500 mile mark (1k after the first oil change). Drive it a little harder for 500 miles then change the oil at the 2k mark to synthetic and away we go.....
From 500 miles on seems to be where the most variation is. Seems like most builders want 1000 miles of easy driving, and you can mostly do what you want by the 2k mile mark. But others say 3k, and still others say you can beat on it from the 500 mile mark.
For myself Im going to at least get to the 1500 mile mark (1k after the first oil change). Drive it a little harder for 500 miles then change the oil at the 2k mark to synthetic and away we go.....
05-22-07, 12:24 PM
#15
Passing life by
There is merit to braking it in but it depends on the motor and the internals used.
It used a quart of oil per 100 miles until it finished seating. this was mainly do to the chrome piston rings as chrome is very hard. But that is just an example of why motors are broke in and how it can very.
It used a quart of oil per 100 miles until it finished seating. this was mainly do to the chrome piston rings as chrome is very hard. But that is just an example of why motors are broke in and how it can very.
05-22-07, 12:40 PM
#16
But as far as most rebuilds go (spec'd useable everything with new seals all around) there's very little to no breakin "required".
I've seen an engine built by one of Canada's leading builders go directly from the engine stand, to the engine bay, to full boost (14psi on the stocker) full throttle for around 5 hours on the track. Oh and it was tuned while driving also (SDS fuel managment). Oh and there was also no intercooler, just aquamist. With a locked distributor.
Still runs great after nearly 3 years of track abuse.
Breakin can't be *that* critical. But as said, it depends heavily on the parts used.
05-22-07, 06:37 PM
#21
It's only Rock and Roll
iTrader: (1)
Join Date: Sep 2004
Location: In a house...
Posts: 2,509
Likes: 0
Received 0 Likes
on
0 Posts
I just did what my engine builder (RotorSports Racing) told me to do. 500 miles, no boosting and under 3500 rpm. That was a little over 7 years ago. No problems yet.
05-22-07, 08:22 PM
#22
Cell Broadband Engine
iTrader: (1)
Join Date: Aug 2003
Location: USA
Posts: 515
Likes: 0
Received 0 Likes
on
0 Posts
Sean at A-spec built my motor, I have all new bearings, rotor housings, apex seals, etc.... His suggestion was first 250 miles shift at 3k, then every 250 miles or so increase by 1k rpm with no boost up until 1000miles then run 3-4psi, he said this is to allow the bearings to wear properly because no bearing surface is exactly perfect.
05-22-07, 09:07 PM
#24
FC Mobsta
Sean at A-spec built my motor, I have all new bearings, rotor housings, apex seals, etc.... His suggestion was first 250 miles shift at 3k, then every 250 miles or so increase by 1k rpm with no boost up until 1000miles then run 3-4psi, he said this is to allow the bearings to wear properly because no bearing surface is exactly perfect.
05-22-07, 09:51 PM
#25
MazdaTruckin.com Founder
Join Date: Mar 2003
Location: East Charlotte, NC
Posts: 402
Likes: 0
Received 0 Likes
on
0 Posts
I'm no rotary engine expert but I do work in a NASCAR engine shop so I will state my opinions and some facts.
First of all I scanned some used rotor and main bearings on our CMM, came out of an S4 with 150k miles on it, each rotor bearing was .0006" out of round with high wear spots inline with the leading edge of the combustion chamber, main bearings where close to .001" out of round. The bearings where scanned while still pressed into the rotors and the stationary gears as they where taken from the engine. My opinion did not change before or after testing these, I think anybody who installs used bearings in an engine is a moron. You're building an engine to function like new or better than new, spend the $150 or so and put new bearings in.
There are a couple things we look at when doing engine break in on a dyno, how much power the engine is putting out, how much compression and leakage it has, and how much metal is in the filter. When power between runs stops rising and starts to match, compression has reached a spec we have established from previous break in procedures, and there is little to no break in metal in the filter we consider the engine broke in. If power has come up and compression is where it should be and we still find metal traces come out of the engine then something is wrong.
At the same time cup engines primarily use combustion pressure to seal the rings just like in a rotary engine, in order for them to seal properly they must be put under full operating load at some point during break in. Without doing this they do not get enough force exerted on them to break in properly. Once the engine has warmed up and we have made a couple of easy passes to make sure the engine is mechanically sound, nothing sounds weird, no oil pressure fluctuations, etc... we start doing passes under high load to verying degrees.
I would think a rotary engine would be very similar, get her primed, fired and warmed up, checking and listening for any problems. Idle her around the block once or twice, then slowly make passes around the block at a slightly higher rpm each time, once you feel safe she can cruise at 3-4k rpm, put her in second or 3rd gear starting at about 2,000 rpm or whatever it will handle accelerating at without lugging and mat it to the floor until about 5-6k a couple times, idle her around once or twice, then mat it again to 6-7k or so a couple times. Take her inside, change the oil and filter, do a dry and wet compression check, then go out and do it one more time and check compression afterwards. If you like what you see drive it like normal.
This to me is what would make sense and I've stated the reasons why I think it makes sense. I'm sure there are reasons why this may not be ideal and I'm not advising anyone to perform their break in as described above as my opinion. I only stated it to put some additional thought to the discussion and not generalized guess work on what might be best.
Edit: Sorry took me an hour to write that, all engine parts will have wear since they all make contact with some other material if it be solid or liquid. Oil will erode and wear bearings just as water will erode and smooth rock as will the dirt particles suspended within the oil.
First of all I scanned some used rotor and main bearings on our CMM, came out of an S4 with 150k miles on it, each rotor bearing was .0006" out of round with high wear spots inline with the leading edge of the combustion chamber, main bearings where close to .001" out of round. The bearings where scanned while still pressed into the rotors and the stationary gears as they where taken from the engine. My opinion did not change before or after testing these, I think anybody who installs used bearings in an engine is a moron. You're building an engine to function like new or better than new, spend the $150 or so and put new bearings in.
There are a couple things we look at when doing engine break in on a dyno, how much power the engine is putting out, how much compression and leakage it has, and how much metal is in the filter. When power between runs stops rising and starts to match, compression has reached a spec we have established from previous break in procedures, and there is little to no break in metal in the filter we consider the engine broke in. If power has come up and compression is where it should be and we still find metal traces come out of the engine then something is wrong.
At the same time cup engines primarily use combustion pressure to seal the rings just like in a rotary engine, in order for them to seal properly they must be put under full operating load at some point during break in. Without doing this they do not get enough force exerted on them to break in properly. Once the engine has warmed up and we have made a couple of easy passes to make sure the engine is mechanically sound, nothing sounds weird, no oil pressure fluctuations, etc... we start doing passes under high load to verying degrees.
I would think a rotary engine would be very similar, get her primed, fired and warmed up, checking and listening for any problems. Idle her around the block once or twice, then slowly make passes around the block at a slightly higher rpm each time, once you feel safe she can cruise at 3-4k rpm, put her in second or 3rd gear starting at about 2,000 rpm or whatever it will handle accelerating at without lugging and mat it to the floor until about 5-6k a couple times, idle her around once or twice, then mat it again to 6-7k or so a couple times. Take her inside, change the oil and filter, do a dry and wet compression check, then go out and do it one more time and check compression afterwards. If you like what you see drive it like normal.
This to me is what would make sense and I've stated the reasons why I think it makes sense. I'm sure there are reasons why this may not be ideal and I'm not advising anyone to perform their break in as described above as my opinion. I only stated it to put some additional thought to the discussion and not generalized guess work on what might be best.
Edit: Sorry took me an hour to write that, all engine parts will have wear since they all make contact with some other material if it be solid or liquid. Oil will erode and wear bearings just as water will erode and smooth rock as will the dirt particles suspended within the oil.
Last edited by Kyrasis6; 05-22-07 at 09:57 PM.