04 185 SC LTD Exhaust valve catastrophic fail

[mnjoker1]

Last weekend I thought I heard a rotation or slight grinding noise before I put the ski away, and figured it was down in the pump area. I took one last spin to see if I could figure it out. I did! exhaust valve broke and dropped into cylinder. Bad news! I did some reading and these older skis had hollow valve stems. When I found this ski, it had sat for a number of years. From what I gathered there may have been some rust on the valve stem and the heat may have helped push the valve to its breaking point. Does this sound like the correct theory why I killed the head.
I am looking for suggestions on the best cheapest route to put this back together. I have completely torn it down and going to use the head off an 04 215 engine I have. While I am in there and keeping this project as a budget build, what is most important? any input is appreciated

Must do;
valves intake and exhaust
Complete gasket set
timing chain and guides
thrust washers for crank and balancer
spark plug tubes
new bolts head, cam and crank
1 piston and all rings (3 sets)
motor mounts

Should I replace:
Valve springs while apart
inspect oil pumps if not obvious damage

 

[ski-d00]

I don't usually replace valve springs but I usually do replace the main crank bearings since they are inexpensive and will really tighten the motor back up.

If the oil pumps only have light minor scoring, I leave those alone as well. I would have a machine shop check your valves and lap them in if they are not perfect.

You should check your cylinder wall closely and even magnaflux it you have any doubts. Many times after it drops a valve the cylinder will microcrack and need resleeved.

Understand working on a budget but it's pretty expensive to do it twice so you should do it right the first time.

 

[mnjoker1]

Yep, good tip. Any suggestion on the brand of valves should I shop for. Saw some cheap ones on E-bay and SBT seems to be on the high end?

 

[Digdog]

Check the magneto for debris caught inside, you'll need new bolts but it's worth it, usually it's full of magnetic particle paste that needs to be cleaned.
Forged pistons ? not budget friendly but an option, looks like 2 pistons might be collapsed.
Get a shop manual to reassemble , you need it, electronic downloads are available , follow it exactly.
You'll need an engine alignment tool, or rent one. You should have a crank shaft and cam shaft locking tools
Find out where all that scum above the compression ring of the pistons came from , might be the cause of the valve failure, it looks like the top ring is stuck in the groove on two pistons.
You will need a torque angle gauge , I made one using a piece of rubber tube with a pin through it and slipped onto the socket , print a wheel on the net, actually was more accurate.
I know you want to do a less expensive reassembly , but check into SBT engines for a short block , the price includes a full gasket set.
Possibly replace the starter bendix , not cheap but you're already in there and they do fail.

 

[mnjoker1]

I found a 2011 head that is in perfect condition. I just posted what to do with the newer PCV system is rather than the cap on mine . Is it usable or do I stick to the original in the valve cover.

I cleaned the magneto and it was pretty free from debris
I have all new rings and 1 piston, others cleaned up nice.
replacing the oil pumps, timing chain, bearings and thrust spacers, all important bolts and the bendix.

Not cheap but hopefully it will work out!
Re assembly this weekend.

 

[ski-d00]

You can't just use the 2011 head on your 2004. Your block has an oil jet in it that has to be removed.

You can't change the TOPS unless you drill a hole in the block above the CB shaft and change the electronics.

 

[mnjoker1]

oh no!! Can it be used or just keep it simple and get the rebuilt for an 04?