- Location
- North Carolina
Dent in top of Piston?
- Thread starter Blaster94
- Start date
- Location
- North Carolina
I'm not planning on running it that way. I hope new pistons/rings/top end bearings will suffice.
Boris
The Good Old Days
- Location
- The surf-less coast
That will fix the damage but not solve the problem.
- Location
- North Carolina
Would running too low of an octane cause this?
#ZERO
Beach Bum
- Location
- Florida - U.S.A.
It depends on your compression etc.
It looks too lean and you might want to check your ignition timing and install a colder heat range plug.
Q
QuickMick
Guest
Yes it can. Old gas will do this same thing. How old was the gas in the ski?
- Location
- North Carolina
I bought the ski like this. I stripped the entire ski but left the crankcase, cylinders, head and manifolds in place in the hull. I had it painted and decided to take the head( a twist billet head BTW) off and look at the cylinders. This is what I found. The front cylinder is very clean, very little carbon. The back cylinder is as the picture shows. The cylinder walls look perfect. The dome in the head above this piston has a small chip in the o-ring area outside the combustion chamber. I am sure that detonation is the cause of the dent and that this engine was close to having a very expensive repair bill. I just finished rebuilding the carbs. I can't remember what the compression was before I took it all apart. I did not write it down but I remember thinking it was high enough that it needed race gas and not just straight 93.(Previous owner ran 93 in it) Good thing is I found out about it now while it is a relatively cheap repair job.
- Location
- Southern CT
What do you guys think of the piston wash in the pic? Or is that not valid since it could be lean at high rpm and correct mixture down low?
DAG
Yes, my balls tickled from that landing
- Location
- Charlotte, NC
what plugs you running?
- Location
- North Carolina
B8ES on the plugs.
Just yanked the jugs off. A very light scoring in that cylinder hole. A light honing should fix. The rods seem to be good. The lower end is good and clean. Oddly enough there is not any distortion on the bottomside of that piston. I'd expect there to be a bulge or something. Just a little carbon build up. The top ring was stuck in it's groove. A lot of carbon build up in the ringland area.
Just yanked the jugs off. A very light scoring in that cylinder hole. A light honing should fix. The rods seem to be good. The lower end is good and clean. Oddly enough there is not any distortion on the bottomside of that piston. I'd expect there to be a bulge or something. Just a little carbon build up. The top ring was stuck in it's groove. A lot of carbon build up in the ringland area.
showmepro1200
ISJWTA Member #007
- Location
- Jefferson City, Missouri
Based on you saying you expected to see a bulge, I have to comment - you do know that the "dent" in the top of the piston is literally the aluminum of the piston top eaten away by the detonation, right? If it had gone much longer you would have had a nice hole and total loss of compression in that cylinder. I'm not trying to sound like I know anything ( I don't ha ha) but felt the need to clarify here.
- Location
- North Carolina
Yeah, I just expected the under neath to show some sign of damage. I cleaned the piston up with some motor decarb spray and the dent is just where the aluminum has been eaten away.
id check your plugs. detonation looks different. Looks to me like your running REALLY hot. i had a dirt bike that did this all the time, i put in colder plugs and it ran mint for years.
- Location
- Reno,NV
reconsider the compression and running race gas....what compression did you have ?
Make sure the carburator ( dual carbs ) is jetted,screws everything identical to the other one, make sure pump is delivering...
Make sure the carburator ( dual carbs ) is jetted,screws everything identical to the other one, make sure pump is delivering...
cmeripper26
Ripper26
- Location
- Connecticut
Are you running an aftermarket ignition. Depending on the timing curve programmed, you could be burning a whole right into the piston surface. An ignition setting alone can cause this. I run an Advent T3 and always run one timing curve less than the motor is set for because of this as a possible prob. Other than that everyone else is right to, that is one lean running engine! Good luck with the fix.
- Location
- Maumee, Ohio
that wont fix the problem though but it would be better then something