FC-chan

I did search, but found no detailed results

http://www.mototuneusa.com/break_in_secrets.htm

One of the guys I autocross with reccomended this to me, but I havn't heard anything from any Rotary people who have actually done it. This will be a spirited daily driver, so i'm not intrested in doing another re-build very soon.

I have a moderate streetport in a S5 with ported intake and new rotor housings, seals, 6port sleeve inserts if that makes any diffrence.

Does anyone have any personal experience with this? This is my first rebuild and I want to make sure my baby is taken care of properly.

fc3sfreek

iTrader: (6)

the only thing that made sense to me was the part about changin ur oil within 20 miles but that still seems like way too little miles to change, and plus thats for piston engine which are very diffrent from ur rotards round' hurr :big thumb:

rick_tj

That's completely obsolete for Wankel owners. In the first paragraph he talks about how it pertains mostly to the "new" way of cylinder honing. Our housings aren't honed, and are incredibly smooth. I wouldn't listen to that at all. Keep the RPMs down (under 4000 I'd say), and don't boost (if turbo).

-Rick

RotaryEvolution

iTrader: (30)

it's a gamble, my personal engine i gave no break in period on and it now has 13k miles on it with 0 issues and plenty of mods, i'll show my sig for examples but this is an "at your own risk" subject.

plenty more mods to come as well.

RETed

A break-in might not be necessary, but it is HIGHLY RECOMMENDED.
You can argue about how you never did a break-in, and it's running fine, but that doesn't mean everyone else should follow your lead.

This has been a hot topic in the Single Turbo section since a couple of "enthusiastic" RX-7 owners managed to dyno decent numbers with one engine with NO break-in and another with a little over 100 miles on the break-in.

We're NOT saying this is impossible.
We're saying it's NOT RECOMMENDED.
There's a BIG difference.


-Ted

RoadRaceJosh

For piston engines this guy is dead on. With a piston engine that uses sliding cam followers you have to break in the cam(s) and then you can run it hard no problem. In fact diesel engines with hardened cylinder liners you absolutely must work the engine hard to seat the rings. This is so important the local Caterpillar dealer (Halton Co.) runs their rebuilds on their engine dyno to get the rings seated. They have large water columns (manometers) to measure crankcase pressure and the pressure drops off as the rings seat.

As Rick pointed out rotor housings are very smooth and they are also very hard. It's obvious when an engine with used housings is rebuilt that break-in takes longer. I'd say that with new housings and apex seals that aren't too hard that very little break in would be required.

FC-chan

well as this is the first time I've done anything more complicated than a brake job, I really appreciate the input. I would really hate to fukup a brand-new pair of rotor housings, amung other things.

I didn't think to check the turbo forum, 'cause I don't have one, I see I should have.

rick_tj

You're very welcome. If in doubt, for the love of God ask. I'd much rather answer a question now than have to tell you that that white smoke coming out the exhaust is a coolant seal that went bye-bye in about 3 months.

RotaryEvolution

iTrader: (30)

i never recommend it i was just answering the topic of the thread and my results.


in fact i tell all of my rebuild customer's to follow normal break in periods for my warranty(under 4k and no boost for 1k miles with an oil change at 500 and every 3k miles).

scathcart

I've tried a race break-in on one of my engines for personal use.
(I would never do this using new bearings, but I clearanced used bearings and supplied 130 psi to the system).

Idled at 1200 for 60 mins. Change oil. (SAE 30W)
No load, 5000 rpm idle, 30 minutes, feeding 15000cfm to rad/oil cooler.
Drive 150 kms 0-6000 rpm, varying throttle.
50 kms, up to redline, WOT runs in 1st and second gear (no sustained full throttle). Change oil. (SAE 40W)
No MOP, premix 150:1 during break-in. Change to 80:1 under normal driving.

That was it.... 120 actual driven miles; 4 hour break-in.

Taking the engine apart at the end of the season showed nothing abnormal at all. Compression was 125 psi at the end of the break in. Mazda apex seals, New rotor housings.

I plan on testing more engines to determine if I think a long break-in is necessary. Unfortunately, I will only test this on my own engine, and recommend to any other user of an engine I build a 2000 mile break-in.

scathcart

Break-in cannot hurt the engine. If you're worried, monitor the compression every 100 miles and stop the break-in once the compression reaches its peak. If its got new bearings, give it at least 2000 miles.

Makenzie71

Break-ins are a crock. Both my grandmothers made badass apple pies...so I learned from each of them. Recipes are COMPLETELY different...same results, yummy pie. Break ins are the same way. Some people do it this way, some people do it that way, some people don't do it...same results. If the motor is assembled propperly you'll not have any problems (as long as you're not stupid). If it's not assembled propperly, it doesn't matter how you break it in.

I personally drive and ride from day one how I intend to drive or ride through out that machine's life.

RotaryEvolution

iTrader: (30)

i would tend to agree but i don't like chatter on rotor housings, once it starts it won't stop.

ddub

Used bearings, short break-ins seem fine to me.

New bearings, no way. Mazda suggests a slight break-in from the factory on the rx8's, and I assume the rx7's too when they were new but I don't have an owners manual to confirm. To me this is mainly because of the bearings, but correct me if I'm wrong here? So if you're using new bearings, seems like a good idea, but what mileage is best for breaking in new bearings?