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moliver
01-08-2004, 09:45 AM
I did search through the archives but either I am a poor searcher or it hasn't been discussed.

I am just looking for some opinions on breaking in a rebuilt engine. Engine will be used for track events.

How do you guys do it? Engine has new bearing and valve job and pistons/rings.

Thanks for the input.

Mike

Harry
01-08-2004, 10:43 AM
Follow the instructions from the ring manufacturer. I would have used redline assembly lube when I built it. I use 5w-30w synthetic.Big magnet right at drain plug. Mobil one filter. steady 2000RPM until operation temp.
But I'm plumcrazy.
Dirty Harry http://Forums.ImprovedTouring.com/it/mad.gif

Tom Blaney
01-08-2004, 01:02 PM
Originally posted by moliver:
I did search through the archives but either I am a poor searcher or it hasn't been discussed.

I am just looking for some opinions on breaking in a rebuilt engine. Engine will be used for track events.

How do you guys do it? Engine has new bearing and valve job and pistons/rings.

Thanks for the input.

Mike

When I ship out Honda motors that I build for my clients, I strongly recommend that they do not use synthetic motor oil during breakin (about 1-2 hrs) after breakin is complete change the filter and then use synthetic. Use standard 30 or 40 wt non-synthetic oil, otherwise the piston rings will not seat correctly. After starting the engine, set the ignition timing as soon as possible and let the engine run up to normal operating temp. Shut it down, check for loose bolts and or leaks. Let it cool down and then run it up to temp again. Keep the rpm's between 1500 & 2000 for the first two runs. After that the motor should be able to be raced. I suggest that you check the torque on the head bolts and the valve clearances. Put fresh plugs and a clean air cleaner and have fun.

Knestis
01-08-2004, 01:05 PM
We actually used to use a non-detergent oil (from Texaco as I recall) during break-in. Old Racer Guy told us to...

K

Greg Amy
01-08-2004, 01:41 PM
You can buy non-detergent mineral engine oil from any local airport. Ask for AeroShell Oils 65, 80, 100 or 120

"AeroShell (straight mineral) Oils are available in four different viscosity grades (SAE 30, 40, 50 and 60). They are blended from selected high viscosity index base stocks and contain a minimum quantity of additives. These oils are especially appropriate during the break-in period of most new or recently overhauled four-stroke aircraft piston engines."

joeg
01-08-2004, 02:36 PM
After going through initial start-up (with non-synthetic)to set timing and check for leaks (and adjusting or fixing whatever needs attention), etc., drain the oil, change filter and refill with the nonsynthetic.

Go racing. Change to a synthetic after a full weekend's racing.

I didn't beleive this myself until I tried it and it works. There is no need for "gentle" breaking-in.

The one problem with the "simply go-racing" procedure is that you may find nuts and bolts on the exterior of the engine getting loose. Accordingly carefully check as many external engine fasteners between sessions as you can.

If you put in a new cam, you may want to extend the initial start-up to 10 minutes and keep the rpms from dropping below 2000.

Have fun!

racer_tim
01-08-2004, 04:01 PM
Don't use a synthetic oil for break in. Also, make sure that you use a pre-oiler to bring up the oil pressure before you first "crank" it. I used an old circular drill bit, and made a very large slot in it. I slipped a section of fuel hose over it so I wouldn't nick the distributor houseing, and just spun it with a drill. Once the drill starts to give some resistance, stop and install the distributor, and start the motor.

Make sure to keep an eye on the pressure and temp gages until it warms up. You don't want to blow the oil filter with 120 lbs of oil pressure.



------------------
Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit (Bent)
http://linerud.myvnc.com/racing/index.html

bill f
01-08-2004, 05:52 PM
We have first of all, used a "soft" piston ring to facilitate break-in. Initial start-up pretty much as described as described above, then about two to three easy laps on the track. After that, it is race time.

Change oil/filter after the first or second session (we use synthetic at this point) and it is now a race engine. I also recheck valve clearances and ignition timing at this time. Of course you must always check for fasteners loosening, and leakage...repair as needed.

We have never had a bottom end failure, either using this method.

Good racing.

Bill

[This message has been edited by bill f (edited January 08, 2004).]

Eric Parham
01-08-2004, 10:02 PM
Synthetic okay from the getgo only with iron rings. If chrome rings, break-in may take anywhere from one to several weekends with NON-synthetic, or several YEARS with synthetic (my own experience).