Tech Hep Needed 440F oring head gasket - Snowmobile Forum: Your #1 Snowmobile Forum

Wirthy1 · 03-16-2008, 07:45 PM

hello everyone,

Having issues and in need of advice.
Recently bought 2 1999 Touring LE 2 ups 440 fan cooled. Both with 550 miles and "dealer Serviced" from an older couple that were the original owners.
I got one for my wife and one for myself to ride with my kids.

My first ride out, 28 miles, 25-38 Degrees out, trails in good shape.
Wifes sled ran great, she loved it.
My sled ran great for 26.5 miles and started to bog, poped threw the Intake and then quit. I was able to get it back home and found..
Right cylinder lost compression and the left cylinder had 125 psi. I removed the right cylinder head and found the rubber O-ring blown out. I replaced the o-ring, cleaned the carbon, new plugs, Drained the tank gas, and cleaned the float bowls and jets. both of which were nice and clean. I didnt mess with the Carb adjustment screws. I checked the left cylinder O-ring and it was Dry and cracked. I replaced it. Sled started and had 125 psi on both cylinders, thought i was good to go.

Second ride.. 30-40 degrees out, trails in good shape. 24 miles.
Wifes sled ran Perfect!
About mile 15 going up a Large steep hill, my sled lost power and i shut it down. I noticed oily residue coming out of the fan ductwork (thinking i blew another right side O-ring). I removed the Right side cylinder head on the trail and it was Perfect. i then removed the left one and found it Blown out. I was able to repair it on the trail and get back home.

Now.. what am i missing? I torqued the heads to spec. Fan belt is turning the fan and airflow is not blocked. Is it an over-heating issue? Am i too lean? On both cylinders? causing it to over heat? Could the Oil Injection system be miss adjusted? Wil that cause over heating? Do i need fatter jets (should be stock). Timing? (is there timing) My Wifes sled Ran fine all day and hers is 4 digits older on the vin Number.

any help would greatly be apretiated
thanks in advance
Derrick

**smallengineguy** · 03-17-2008, 07:07 AM

Did you run the sled up to temp after you replaced the O-rings, then retorque the bolts after it cooled down again?

Wirthy1 · 03-17-2008, 08:36 PM

Quote:

Originally Posted by smallengineguy

Did you run the sled up to temp after you replaced the O-rings, then retorque the bolts after it cooled down again?

I checked the torque after warming it up but not after it cooled (on the First gasket change). I just retorqued the head (second set of gaskets) because of being on the side of the mountain i had no torque wrench. I work in the automotive field and know that most aluminum heads need to be retorque while warm. Are Sleds different? I do not have a repair manual for this sled (its coming). I am a new comer to the snowmobile world, after all the snow in New England this year i got bit by the bug. So far my 2 rides have been great except for this...
I just checked the Fan blade belt, thinking it might not be tight enough to spin the fan fast enough at speeds but i see no adjustments. It does have flow out of the cowl.
thanks for the Input, any suggestions are always welcome.

**smallengineguy** · 03-18-2008, 10:35 AM

Most people just torque the bolts during a rebuild, then never do a retorque again. Just making sure you did. Are you using OEM O-rings?

Wirthy1 · 03-18-2008, 08:25 PM

Quote:

Originally Posted by smallengineguy

Most people just torque the bolts during a rebuild, then never do a retorque again. Just making sure you did. Are you using OEM O-rings?

Yes they are OEM o-rings from the Ski Doo dealer.
I think ive fixed it. I belive the fan belt was/is Slipping on the fan. Even though the fan spins with the motor at Idle and I have Air flow threw the cowl I think at higher Rpms it was just loose enough to slip. I took the fan apart and Found the Shims between the two pulley halves (Like an "old school" Volkswagon motor v belt) so i removed the shims and the belt got alot tighter and dosent seem like it will slip.
I think the O-rings blowing out was the Result of it over heating. The cause was the belt tension. Only thought i have is.. Is this the Ski-doo's way of belt tension? and is there a spec on it? and should i install a new belt?
I wont be able to test it out until saturday if we still have trails with snow on them.
Thanks for your input, it always helps
Derrick

**smallengineguy** · 03-19-2008, 07:34 AM

Just like a car, if the belt is all glazed looking (I assume it is if it has been slipping), replace it.

**RJ Gleason** · 03-19-2008, 08:43 AM

Belt tension should be such that you only have 1/4" of deflection.

Wirthy1 · 03-22-2008, 08:39 PM

After replacing the belt and getting 1/4 inch deflection on my fan drive belt, checking compersion on my second set of gaskets (125 psi)(i did run the engine 9 miles with Loose belt- possible overheated O-rings and damaged?) I headed out with the sleds for the 3rd time.
I wish i could say 3rd times a charm but...
I took my laser pointed infered thermometer with me.
19 degrees out trails in good shape 2-4 inches of fresh snow on 8-12 inch base. freshly groomed.
Both sleds ran nice. head/block temps both with 5-10 degrees @ 190-200 ish about 15 miles into the run. I again lost power and the wifes sled was fine. My head temps both @ 220 ish. I had a 50/50 chance on which side it was. I gambled and removed the left head (last time out it blew). It was fine. removed the Right side head and sure enough it was blown. Think it might have been damaged from riding that 9 miles with the loose belt?
3 trips - 1st trip 26.5 miles right side. replaced both head O-rings
2nd trip 15 miles Left side blew. replaced left side on trail. replaced belt
3rd trip 11 miles Right side blew. replaced on trail and back home i went
So...

replace the heads, possible warps?
Is my issue something else? Ignition Timing? i hear its non-adjustable. is this true?
How do you check it?
Lean?
Burn it to the ground? Trade it in? sell the problem to the next guy? (JK - im to honest for that)
Id really like to figure it out for my own piece of mind
Any help would be great.

**RJ Gleason** · 03-23-2008, 04:29 AM

Can you show us some good pics of the piston, cyl, heads, and plugs?
Seeing what they look like might help us pinpoint the problem.

Wirthy1 · 03-23-2008, 07:47 AM

Quote:

Originally Posted by RJ Gleason

Can you show us some good pics of the piston, cyl, heads, and plugs?
Seeing what they look like might help us pinpoint the problem.

I will try and get Some pictures up this afternoon, when all my easter stuff is done.
The pistons are still in the jugs but the heads are off. I did take the exhaust off and had a look in threw the exhaust ports for scoring. its a hard agnle to look at. I didnt see any Vertical scoring but was able to see the Horizontal machine marks in the piston (im asuming is normal) nice and even.

Wirthy1 · 03-23-2008, 08:06 PM

Quote:

Originally Posted by RJ Gleason

Can you show us some good pics of the piston, cyl, heads, and plugs?
Seeing what they look like might help us pinpoint the problem.

got some pictures here, hope they help

**smallengineguy** · 03-23-2008, 08:09 PM

Are the O-rings getting pinched when you install them? It looks like the left one in the pic got pinched and there is a sliver coming off of it.

Wirthy1 · 03-23-2008, 08:35 PM

Quote:

Originally Posted by smallengineguy

Are the O-rings getting pinched when you install them? It looks like the left one in the pic got pinched and there is a sliver coming off of it.

I'm not sure, there is a deep machined groove that it sits into and im torquing the head in a criss-cross pattern. I think the sliver is the begining of it blowing out. I could understand One gasket being pinched by mistake but all 4 that ive done. i hope it isnt that. I have cleaned the mateing surfaces with carb and choke cleaner and a soft cloth. I also used a carbon scraper to gently remove the carbon from the 1st time i took em apart.

**RJ Gleason** · 03-24-2008, 08:10 AM

Make sure that the grooves for the O-rings are very clean and smooth.
Try each to be sure that they fit comfortably in place. (if a bit small, warm it up and if a bit large , cool it to shrink by putting it in the freezer for a few min.)
Apply some grease to the ring before installation and reassemble.