Posted By: moparniac
Cylinder damage ??? - 02/28/09 09:09 PM
Please see the discolored are in the #7 cylinder..... ??? with my finger i can feel the slightest of groove in the discolored area..... what is this from... how big of an issue is it....
Posted By: dthemi
Re: Cylinder damage ??? - 02/28/09 09:12 PM
Hard to say with out being there, but it looks like it sat with some fuel and or water in the bore for a while. Like a leaky gasket that sat all winter, and then cleaned its self up running. Nothing to worry about that low in the bore, Not much going on down there as far as power loss. It would be worse if it were near the top. I see fuel staining in the walls on just about all motors that sit over the winter.
Posted By: blownzoom440
Re: Cylinder damage ??? - 02/28/09 09:21 PM
i would think there would be some grooves if it had been rust.would you want to pull the piston to inspect the skirt?,rings?being at the bottom of the bore unless you want to hone/bore it i dont know if i would touch it.is it a street engine?
Posted By: Bob_Coomer
Re: Cylinder damage ??? - 02/28/09 09:31 PM
Looks like you may be able too.
Take a ring, and do some measuring around the bore, above, and on top of the colored portion. Use a feeler gauge to check for taper etc. See what you can come up with. If it doesn't show much of anything don't be too concerned about it.
Posted By: dthemi
Re: Cylinder damage ??? - 02/28/09 10:06 PM
Just for thought, the #7 and #8 cylinders are at the bottom of the slope the engine sits on in the car, so any fuel leaking out of the carb, water, or just condensation would run down to those cylinders before any of the others. the stain its self is in the form of a puddle as it would sit in the car. Fuel stains look just like that. I'm not there, so I can't say, but it stands to reason.
Posted By: emarine01
Re: Cylinder damage ??? - 02/28/09 10:30 PM
We often get markings like yours , what ever intake valve was open after heavy engine washing from mud racing , it only takes a couple of weeks with out running engine to leave marks, the fact that yours is so low in the bore it should not hurt much.
Posted By: Stroker Scamp
Re: Cylinder damage ??? - 02/28/09 10:50 PM
ive got em too, fuel staining the cyl,
Posted By: Anonymous
Re: Cylinder damage ??? - 02/28/09 11:28 PM
it could be just a stain, but i've also seen marks like that from excessive piston/ wall clearance. check it for size with a bore gauge compared to the rest of the cylinder. i bet you find it's a big wear spot from the piston rocking in the bore when the crank/ rod piston comes around from BDC
that area is large enough that it would take over a pint of liquid to spread out that far. that would be enough to hydrolock the motor.
Posted By: dthemi
Re: Cylinder damage ??? - 02/28/09 11:40 PM
Hey Dram, look at it again, it wouldn't take a shot glass full to do that. Not trying to start an argument over a cylinder wall, but the stain area is only about 3/8-1/2" in the center tapering off to nothing on the sides making it no more than anout 3.5" long. A pint would cover the piston. Also if it's rock, it would be on the top on that side, not the bottom.
Posted By: Anonymous
Re: Cylinder damage ??? - 02/28/09 11:49 PM
DT, you might be right, but i'd still measure it.
it's on the minor thrust side. i've seen wear like that before. the loose fit will allow the skirt to push on the major thrust side but the top of the piston will rock and try to dig into the minor thrust side. just another option to explore. it's just a picture so it needs the finger test
Posted By: moparniac
Re: Cylinder damage ??? - 02/28/09 11:50 PM
the diclored portion is still smoothe but the grooved area is ever so light running parralel across the center of the discolored area..... the grooved area is probally thinner thatn the thickness of a ring
the discolored area is not sunk or anything....
Posted By: B G Racing
Re: Cylinder damage ??? - 03/01/09 12:23 AM
Typical fuel or condensation stains,more well known as hydrocarbon contamination staining.Usually found in engines that have been run for short amounts of time and not brought to normal operating temp and allowed to set for long periods of time.It is best to bring an engine to temperature,fog the system with a top oil and seal the cylinders for long term storage.It is also advisable to cap the hedders or stuff cloth soaked with WD-40 or similar moisture repellent lube in the collecters of an engine notstored in a controlled enviroment.It is also advisable to remove the rockers to close all the valves to help seal off the cylinders during long storage periods.Even if your car is in a heated garage it is wise to rotate the engine once in a while.
