Just rebuilt the top end on my wife's 2007 Honda 400ex for the first time since we bought it new. It's a four-stroke air cool single. I'm no expert by any means but I did just apparently make a mistake and I'm hoping it won't be an issue in the long run. I've been running Amsoil synthetic in it for as long as I can remember and have never had an issue. After going camping/riding this weekend for the first time since the rebuild I was told by someone that I shouldn't run synthetic during a break in period. I had never heard this before. We maybe put 2-3 hours of run time on the engine over the weekend. I changed the oil when we got home but this time put regular conventional oil in it. So my question is, if I continue to run conventional oil from this point forward will the break in process continue as it's supposed to or has the "damage" (or not) already been done? I would hate to have to put new rings in it after just one weekend! I know there are about a 100 opinions on how to break in an engine properly. I just wanted to see what you guys thought.
Break in after top end rebuild
- Thread starter bartmk
- Start date
- Status
I've never broken in an engine before, but I've watched Hot Rod TV, where they usually use a specific "Break in oil" which is only use for a short time (500 miles or so).
Amsoil has a break in oil.
http://www.amsoil.com/shop/by-product/motor-oil/gasoline/break-in-oil-(sae-30)/
Regards, JC.
Amsoil has a break in oil.
http://www.amsoil.com/shop/by-product/motor-oil/gasoline/break-in-oil-(sae-30)/
Regards, JC.
Last edited:
In a high performance engine with an aggressive cam you might be better off running a break-in oil. I doubt it will hurt anything on that air-cooled 400ex. Those are great machines.
nope its too late
either the rings are seated or they are not and you get to take a ball hone back to it and start over.
been there done that got the tshirt
but it mostly depends on if you did a dry build or wet build.
you will know soon enough if it starts sucking oil down and blowing out the exhaust
either the rings are seated or they are not and you get to take a ball hone back to it and start over.
been there done that got the tshirt
but it mostly depends on if you did a dry build or wet build.
you will know soon enough if it starts sucking oil down and blowing out the exhaust
I would use break in Oil just for heck of it, you went thru the trouble. might as well.
Now Royal Purple Break in , will break your wallet. I would mix it with any high quality oil and call it a day. I would use a syth blend with same weight and sleep well at night.
Now Royal Purple Break in , will break your wallet. I would mix it with any high quality oil and call it a day. I would use a syth blend with same weight and sleep well at night.
Last edited:
I use dino oil most of the time. But I have broken in engines using syn oil and has no issues. I doubt you will have any issues. 2-3 hours would be equivalent of 100 miles so your rings are seated. BTW, for break in I use Mobil 5000 or PYB.
Last edited:
Its too late to do anything now but drive it.
The only part of the top end that may would need real "break in" is the camshaft and rockers.
2500 RPM for the first 20 min after starting the engine with a new cam is the break in, after that its a done deal. That's why i say its too late now.
The only part of the top end that may would need real "break in" is the camshaft and rockers.
2500 RPM for the first 20 min after starting the engine with a new cam is the break in, after that its a done deal. That's why i say its too late now.
Yep, to late now.
I've read up on Motorcycle engines and there is a lot of good paperwork on how driving it like you stole it for the first 15-20 minutes is the best way to break it in. After that short 15-20 minutes it is done.
BTW, The reason that they recommend Conventional is that most of the lapping compounds are designed to dissolve and break up in Conventional. They don't do this so well in Synthetic.
I know some investors who lost a considerable amount of money on a Formula 1 Race car due to Technicians no realizing this. The car no longer had valves 1/4 into the race... BIG OOPS!
One short interval on Conventional is all that is needed before going back to Synthetic.
I've read up on Motorcycle engines and there is a lot of good paperwork on how driving it like you stole it for the first 15-20 minutes is the best way to break it in. After that short 15-20 minutes it is done.
BTW, The reason that they recommend Conventional is that most of the lapping compounds are designed to dissolve and break up in Conventional. They don't do this so well in Synthetic.
I know some investors who lost a considerable amount of money on a Formula 1 Race car due to Technicians no realizing this. The car no longer had valves 1/4 into the race... BIG OOPS!
One short interval on Conventional is all that is needed before going back to Synthetic.
So what would be the best plan? Should I just re-hone the cylinder? Or new rings and re-hone? Would a compression test tell me if the synthetic caused an issue?
not clear as to what you mean by top end rebuild. If it doesn't involve ring replacement + deglazing (or honing, depending on the service level), then it wouldn't matter whether you run full syn or conventional (all you ever care for is the cam lobe and valve guide lubrication.
If it's been re-ringed and honed/deglazed, then you may have issues with proper ring sealing....
So, please define what you mean by "top end rebuild".
Q.
If it's been re-ringed and honed/deglazed, then you may have issues with proper ring sealing....
So, please define what you mean by "top end rebuild".
Q.
I don't think it matters what type of oil is used during break in. Harley ships bikes from he factory with their version of synthetic oil in them, haven't heard of a motor blowing because of it. I'm sure they don't put 500 miles on it at the factory either. Corvettes also come with Mobil 1 from the factory.To me it sounds like you wasted some Amsoil. You did say you've run Amsoil without issue, then why did you have to rebuild a '07 motor ? Might not have been the correct oil for that motor.,,
By top end rebuild I mean I removed the cylinder, had it bored about 1mm over, replaced the piston and rings and reassembled.
Had a tranny issue to begin with so I figured if I had to split the case I may as well replace the piston too and start fresh.
What Amsoil formula did you use? If it was a motorcycle or powersports formula then I'd guess you'll be ok. Not so with their car oils. On the same note, I wouldn't be in a hurry to re-ring it either, just run it and let the engine tell you what it's doing. If it starts to smoke and looses power then you'll know, otherwise just go with it.
Originally Posted By: bartmk
So what would be the best plan? Should I just re-hone the cylinder? Or new rings and re-hone? Would a compression test tell me if the synthetic caused an issue?
Although you may not have broke it in ideally i wouldn't redo anything unless there is an issue like excessive oil consumption, smoking, etc.
IMO it will probably be just fine.
So what would be the best plan? Should I just re-hone the cylinder? Or new rings and re-hone? Would a compression test tell me if the synthetic caused an issue?
Although you may not have broke it in ideally i wouldn't redo anything unless there is an issue like excessive oil consumption, smoking, etc.
IMO it will probably be just fine.
Driving it normally will break it in just fine, unless crude honing and bad fitment exists.
Hard break in is a bit faster, but no real benefit.
Use whatever oil you want.
Hard break in is a bit faster, but no real benefit.
Use whatever oil you want.
Originally Posted By: bartmk
So what would be the best plan? Should I just re-hone the cylinder? Or new rings and re-hone? Would a compression test tell me if the synthetic caused an issue?
No...do nothing. After 10,000 miles see if you have any oil consumption. I doubt you will have any issues.
So what would be the best plan? Should I just re-hone the cylinder? Or new rings and re-hone? Would a compression test tell me if the synthetic caused an issue?
No...do nothing. After 10,000 miles see if you have any oil consumption. I doubt you will have any issues.
I've done six engines this way and it works, all six engines are still running good today.
http://www.mototuneusa.com/break_in_secrets.htm
ROD
http://www.mototuneusa.com/break_in_secrets.htm
ROD
And if you did it his way and the motors weren't fine,it's no skin off his nose. Because you listened to some guy on the internet who said to flog you motor to break it in.,,
We have to consider the umpteen jillion cars that are broken in perfectly with Mom and Pop driving sedately.
- Status
Similar threads
