yeah that sounds like what i recall hearing
cool no need to resleeve then i would guess except that one eshaust does look pretty fubar
Broken piston
- Thread starter SJet
- Start date
yeah that sounds like what i recall hearing
cool no need to resleeve then i would guess except that one eshaust does look pretty fubar
D-Roc
I forgot!
- Location
- Dirty River Rider
FUBAR!!! :headbang:
I said you might want to resleeve because of that big chunk missing from the top of the port. It seems like the exh port timing would be way too high in one cyl if you try to clean that up. Drop a sleeve in, match it up to the cast and start running 93 octane fuel after you make sure the main jetting is right.
right less headaches than trying to make it go again
Kaveman
Born in USA(not Kenya)
- Location
- texas but soon tejas
What do the sides of the piston look like? Does it show signs of a "4 corner seizure"? Was this the front or rear cylinder? Did you do a leak down test BEFORE tear down?
- Location
- Strathroy Ontario Canada
That chunk at the top of the port was machined in, it is on both sides.
- Location
- Strathroy Ontario Canada
There is heavy scuffing from the center of the intake side all the way to the wrist pin. Some very light scuffing on the two conrners of the exhaust side. The one corner has no scuffing.
This was the front cyl. No I didn't do a leak down test.
Why was that chuck machined in. Looks like it would cause a hotspot on the piston.
Those "chunks" are missing on purpose...it's part of the porting.
To allow for easier starting in what is supposed to be a high compression cyl
From the fuzzy pictures it looked like it was an off center broken off part of the cyl. I have seen some port jobs with that indention machined into the exh before. Guess I should pay better attention next time. So nevermind to all my previous comments.. Bore it, hone it, and chamfer the hell outta it. I would still change over to 93 octane since you are running advanced timing to keep the EGT down and you should be safe. A couple of dollars more per tank is cheaper than a new top end.
- Location
- Strathroy Ontario Canada
Sorry for the crappy pics. I have a crappy camera. So, do I want to put roughly a 1/16 x 45 degree chamfer?
I was running 93 and someone told me it would run better on 87 because of the low compression???
I will be going back to my 93.
Kaveman
Born in USA(not Kenya)
- Location
- texas but soon tejas
Do yourself a favor. Change the crank seals. Also always do a leakdown test before tear down and after any internal parts, seals or gaskets are replaced. Do this test after reassembly before you put the coupler, stator or flywheel on the engine and with it removed from the hull. This may be a few minutes of extra work but WELL worth it. You should be able to spot the leak (if there is one) with Windex or something similar. Don't forget to spray the pulse line, spark plugs, crankcase mating surface, intake gasket area, exhaust gasket area, crank seals, cylinder to crankcase mating surface and all the fittings and hoses of the leakdown tester. If you cannot find a definite leak, plug all but one of the water jacket nipples. Spray the open one to see if you have a head gasket leak or crack in a cylinder or head. Also, if this is a ported case engine, spray the entire inside of the flywheel area. If it is a stroker be sure to spray the entire bottom of the cases. Be VERY THOROUGH with your testing, it will save you alot of money and time in the not so long run.
SUPERTUNE
Race Gas Rules
- Location
- Clearwater Fl.
You need to completly teardown this engine and inspect the crankshaft for any bearing failure!!! (this is what crank failure looks like)
I like to use Wiseco pistons when running .006 piston clearance, ProX pistons need to stay closer to .005. (but I don't think this is your problem)
I like to use Wiseco pistons when running .006 piston clearance, ProX pistons need to stay closer to .005. (but I don't think this is your problem)