Recommended engine break in after mods/rebuild?

[Frostbite]

I sent my head, cylinders and power valves to SLP this past spring so they could do their magic on them for their Perfromance Edition Package.

I bought new engine gaskets to reassemble the engine and now I'm wondering if I should replace the piston rings too when I put the engine back together?

It's an 09 and the sled only has maybe 500 miles on it because I bought it late in the season. Also, I was thinking I probably need to adjust my powervalve cables to make sure they are spot on.

I see Cat says to add 100:1 oil to the first tank of gas for break in and I intended on doing that for my first ride. Yes, I will vary my throttle position and all that other good stuff.

When I do run the engine for the first time is their a recommended re-breakin procedure and period of time that it takes to accomplish?

Is there anything else I need to be careful about or just aware of before reassembling the engine?

Thanks

 

[WyoBoy1000]

i would just reassemble and go, if the 100:1 makes you feel better go for it, but the motor was already broke in. make sure you get all the air out of the cooling system.

 

[backcountryislife]

On the 800, pretty much pull & go. Take it easy for a few minutes & vary the throttle. With 500 miles on the sled, it's not worth changing pistons or rings in my opinion so you don't have to do much.

If you change rings, then it's essentially another break in to get the rings to seat.

 

[JHG]

I personally would put a new top end in while the motor is taken apart. It's like another $200 if you do it now and you start fresh. Here is Cat's 09 break in procedure, I would follow it regardless of a new top end or not, you will want to re-seat the rings if you've had the pistons out of the motor.

1. Slowly vary the engine RPM and throttle position
gradually from idle position to a maximum of
6000 RPM until the Coolant Temperature Warning
Icon stays constantly lit while making sure not to
exceed 6000 RPM. Continue varying the throttle
and RPM for an additional 1-2 minutes.

NOTE: Make sure to lubricate the slide rails with
water if you use water it will not over heat like they want or other appropriate coolant/lubricant to prevent
melting of the wear strip.

2. Allow the engine to cool to ambient temperature
(at least 30 minutes).

As part of the standard operating procedure, operate
the snowmobile during the first 1 to 2 miles
under 6500 RPM to properly warm the engine
prior to extended wide-open throttle use.
__________________

 

[Frostbite]

Thanks guys but not suprisingly, we seem to have a difference of opinion.

I was wondering especially about the piston rings. Yes, they were broken in but, yes again, they were broken in to fit the stock cylinders. The cylinder internal walls should still be the same, after SLPs process, right?

The bore wasn't changed, it was just the ports being opened up a bit to the best of my knowledge. So, the hash marks on the piston rings and cylinders could but, probably won't line up. I guess the big question is, does this drive piston ring replacement?

 

[JHG]

I just don't like to put used internal parts in a motor when I put it back together. Not saying it's right or wrong, just me. I will say that my sled is usually not the one that gets towed home.

 

[smoothdawg]

I agree with BigHoe. It will never be easier than it is right now. JMO.

 

[vdog0531]

i wouldn't be asking if you should, i would asking why you shouldn't??? if it's all apart, why not just do it when you put it back together?

 

[Frostbite]

Sounds good, I'll order some rings to go with the new gaskets. I just never thought of it earlier.

They can't be too much money and I have a Free Agent parts list started anyway.

Thanks

 

[m8magicandmystery]

get the rings...and your first tank of fuel should be mixed with regular petroleum 2 stroke oil...NOT synthetic...idle under 2 thousand rpm aprox 5 mins...cool...then 5 mins jack stand between 2/4 rpm...cool...then ride as per your original instuctions when bought

 

[m8magicandmystery]

ps...coat all cyl/ring grooves/pistons/rings with stp and put two ounces of 2 cycle oil each in each side of crankcase cavity before assembly..permatex spray a gasket is a nice light coating for both sides of base gasket...

 

[kane13]

I would go with a light honing/deglazing too i never seen it mentioned but it is important , if you don't want to go that far i would just use your old rings they are already conformed to the cylinders. Make sure you get someone who knows what they are doing to do it and prep the cylinders for install and measure everything before and after to be sure all tolerences are ok. Nothing like opening up a can of worms lol, then break in as new.

 

[m8magicandmystery]

I would go with a light honing/deglazing too i never seen it mentioned but it is important , if you don't want to go that far i would just use your old rings they are already conformed to the cylinders. Make sure you get someone who knows what they are doing to do it and prep the cylinders for install and measure everything before and after to be sure all tolerences are ok. Nothing like opening up a can of worms lol, then break in as new.

slp will have the honing done...all you will have to do is wash cyl with warm soapy water

 

[kane13]

slp will have the honing done...all you will have to do is wash cyl with warm soapy water

Cool i kinda figured maybe thx, still measure everything though and foresure go with new rings then.

 

[WyoBoy1000]

I think it is over kill, 500 miles is just broke in seen well over 5000 miles, the more you change the more trouble your asking for. If you where a AC mechanic and doing this all the time i'd replace everything. If you still have the rings on the pistons so they will be going back on the same way they came off, I would reinstall.

 

[bart0678]

I think it is over kill, 500 miles is just broke in seen well over 5000 miles, the more you change the more trouble your asking for. If you where a AC mechanic and doing this all the time i'd replace everything. If you still have the rings on the pistons so they will be going back on the same way they came off, I would reinstall.

at 500 miles on a stock motor(until now) i would totally agree.
adam

 

[Frostbite]

Very compelling arguement WyoBoy1000.

This is exactly why I asked the question. Frankly, I could go either way on this one. Both sides of the issue make very compelling arguement.

 

[ItDoAble]

I think it is over kill, 500 miles is just broke in seen well over 5000 miles, the more you change the more trouble your asking for. If you where a AC mechanic and doing this all the time i'd replace everything. If you still have the rings on the pistons so they will be going back on the same way they came off, I would reinstall.

X2 ..

New cat pistons come with the rings pre-installed. Why take the chance of screwing something up with only 500mi on the top end? Just re-install the old (appropriately), pull the handle and go. Nothing to really break-in as all the bearings, seals, etc. are already good. Clean head/jug with Dawn soap just in case there's residue from the work SLP did (RKT's recommendation when they did me a port job).

Also, if SLP ported it, make sure you trim down the inside of the jug/y-pipe gasket to the same size as the port. Doesn't do much good to have a nice port job and then restrict it with a gasket

I did a complete top end rebuild last year and Donovan at Xtreme told me to just pull the handle and let er rip. Baby it and you get just that ...

 

[kane13]

You may be ok to do that Frostbite, but there is only one way to have guaranteed results. Who knows maybe it will last you for 5000 miles but there is a chance it will not, i only know one way but we are all our own right, either way hope it all works out your sled should rip.

 

[Frostbite]

Get tip Itdoable!

"Also, if SLP ported it, make sure you trim down the inside of the jug/y-pipe gasket to the same size as the port. Doesn't do much good to have a nice port job and then restrict it with a gasket".

I will make a point to trim the gaskets to the perfect fit.

Frosty