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Discussion Starter · #1 ·
Hoping you guys can offer some insight:

I did a complete rebuild on a cheap 2005 Summit 1000 SDI. It ran rough to begin with, and had scoring on the intake sides of the pistons/cylinders. I thought for sure this was belt-dust related.

After replacing quite a few parts (pistons, rings, trued/inspected crank, cleaned injectors, new gaskets/isoflex) and a pretty meticulous rebuild (albeit my first time this deep into a sled), the sled still runs rough. It misfires now, and in my short 1/2 hour test ride, it ended up over heating.

After sitting for a while, I found ice on the MAG side sparkplug. I pulled the reeds and found ice caked all over them. So I must have a coolant leak, correct? I did notice the coolant get somewhat lower in the bottle, but I thought it was from a leaky hose on my thermostat upgrade. The spark plugs looked great on my test run...

In addition, I'm seeing that my new pistons have scoring on the intake side! Can a coolant leak cause this? Is there a way to tell if the leak is in the head seal vs. the water pump? Does it make sense that I'm finding WATER (ice), not coolant and coolant residue? Will the gods of mountain-sledding ever shine upon me?
 

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Any water found in the gas?

Did the engine leak test pass prior to tear-down? That should give us a good idea.

Can you provide pictures of the scoring on the intake side of the pistons the sled came with, and the new pistons?

Not sure where you read about intake side scoring was caused by belt dust? The scoring is in line with the injectors.
 

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Discussion Starter · #3 ·
Thanks Daag.

I did not preform the leak test before or after the rebuild.

I will have to check the gas to see if there is water in it. Would be great if it was that simple...

Here is a view of new piston via intake:

Automotive tire Wood Grey Gas Bumper

Here is what the old piston looks like. Both pistons looked about the same.

Computer Input device Personal computer Laptop Peripheral
 

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Those are a nice pistons. I bet you really want to know if it was snow, coolant, or belt debris ingestion.
 

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New piston photo looks looks like lots of moisture in the intake. Snow ingestion likely the cause. Did you have something setup to deter snow from getting into the throttle bodies?
 

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Discussion Starter · #8 ·
I have filters to install as soon as she starts running right... Nothing for now.

The pistons in the sled have only seen about 1/2 hour of packed trail, plus on-and-off "test" idling while I sit there scratching my head. I don't think its snow ingestion...

If I had coolant leaking into the engine, would it evaporate and turn to water while staying in the engine? Or would it remain as coolant?

I'm definitely seeing water... my reeds were caked with ice!
 

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Wow, icing on the reed petals. Never thought I'd see that. The only thing I can think of is the bottom of the monoblock has often been found to leak. Nd2 has one himself.

How are the o-rings and what torque were the head bolts?

Is it possible the water content in the coolant was too high? I really don't know, just throwing it out there.
 

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You must have a leak on that side to have ice on the reeds. Thermostat I don't want to sound rude but i have to ask was it installed correctly? Did you bleed the air out of the coolent system? Did you have the oil pump apart when you did the motor? If you did you also must bleed the air from it as well. After i rebuilt my engine the impeller in the water pump self destructed causeing it to over heat. This was caused by not warming it up and putting it in reverse, with the thermostat installed and closed there was back psi in the coolent system. When you put it in reverse the water pump spins backwards as well and it twisted the blades right off the impeller.

Its possible the over heat blew a base or head gasket. The water would wash the oil off and cause scoring but i can't see it happening that fast unless there was very little oil getting to that side.
 

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I've found ice on the reeds before in my old 97 Mach 1. It was pretty damp then was well below freezing after I was done riding. I was changing oil lines and decided to just go through everything and found this....
 

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"Thermostat I don't want to sound rude but i have to ask was it installed correctly?"

Huh? What thermostat?
 

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X2 what thermostat? ????
Adding a t-stat is common among Summit RT owners. The idea is to keep the coolant temps from dropping too low. I have read accounts of the coolant temps dropping as low as 46F and EGTs down to 850-900F. From what I gathered the Summits owners were divided on the issue.
 

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I did read it right he said he had installed a thermostat. Just trying to through out a couple ideas to check before tearing into the motor. I know once you install the t stat its a real pain to bleed the air out of it. I also know that with the tstat you can wreck the pump impellers in reverse. Ask me how i found out.....
 

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Discussion Starter · #18 ·
Yah.... Garage temps got down to right about 0, even with it attached to the house. Cold winter here in Michigan... regularly -10 to -20 for lows all of January and February.

Anyways... yep, I installed an in-line thermostat, as is recommended for the over-cooled RT Summit (and did try to bleed it well). I appreciate all of the ideas here.. they have gotten me thinking in new ways that would have otherwise not happened.

I disconnected the fuel line and sprayed some fuel into a plastic bag. The gas looks to be just fine. No water.

I am going to take the head off and see what I can see. If that doesn't yield any answers, I am going to pull the engine and disassemble. I will do a leak test prior and after this time. And inspect all bottom end components.

Since I am seeing water in the engine... I'm guessing it would be a poor decision to let it sit all summer, even though a tear-down at this point is going to be a logistical challenge with summer storage about 200 miles away... hmm... Maybe I could drain coolant then circulate air through the bottom end to dry it out?
 

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Before you tear it down pull the coolent line off the top of the motor and stick it in a bucket and make sure the pump is pumping. If it over heated bad most of the time it will take a head gasket out or in this case a o ring. Thats what i have found with past limited experiance. I would also check the head bolts for torque before i remove the motor.

Now for storage. Remove the motor you can do this in about 2 hrs tops. Take the sled out to where ever you are going to store the sled and keep the motor at the house. Take the cyl off so you can inspect the base gasket and make sure you put a staight edge across the case to check for warping if it over heated. Blow all the water out of the crank bearings and lubricate the crank bearings the last thing you want is rust any place on that expensive crank. Lubricate them well and store it till you can rebuild it. I guess you could leave the motor in the sled and fill the crank with oil but you take a chance of the water sitting in a bearing rusting it. With any sorta luck its something simple, the leak test will tell you there is a leak for sure. It will be hard to pin point exactly where it is from.

When i store my sled i run it till its warm and i hold the oil cable open for a few minutes with a vise grip. It gets really smokey and when i can't bare it any more i turn it of and cover it up. It always gets parked in my barn where there is not a lot of temp changes to eliminate some condensation. 2 or 3 times through the sumer i pull the cord over a few times but don't start the sled. This gets the oil that has settled down to the bottom of the bearings all through them again. I don't like starting it because the heat caused by this draws moisture inside the motor.

Any ways i have rambled enough good luck and don't give up on it.
 

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yes because its a struggle to keep this thing cool in poor snow conditions. and if the tstat sticks closed youll over heat the motor i believe
 
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