What is this hole or pin? Top edge of sleeve at gasket surface- 2.5 150 2001

[CircleHook]

Tore down this 2.5 150 2001 O-ring engine to replace scuffed piston or 2- overheat damage. I spotted 2 of the holes or pins ? What is this?

Also odd scuffing 180^ apart- on 2 pistons- one side lines up with relief port- opposite side has no relief port- but has same scuff mark. Looks like somebody "de-burred" the ports as there are visible grinding marks in ports- Any idea on 180^ scuffs

[outasite]

Looks like sleeves have been "pinned",to keep them from rotating.

[CircleHook]

Is pinning standard practice? Any ideas on scuffs at 180^ apart?

[outasite]

The preferred method would be an oversize sleeve.Pinning can work, but is marginial at best.A sleeve that is not super tight in the bore will not transfer heat properly,allowing the sleeve to "grow"at the hot spot and scuff the piston.

[CircleHook]

The preferred method would be an oversize sleeve.Pinning can work, but is marginial at best.A sleeve that is not super tight in the bore will not transfer heat properly,allowing the sleeve to "grow"at the hot spot and scuff the piston.

The scuff mark opposite the exhaust relief port is in line with a narrow section of sleeve between 2 ports - so your note that the hot spot would grow makes sense since the narrow section would be likely to heat up- I suppose it could have pushed the opposite side tight at relief port and scuffed it on opposite side.

[outasite]

I cant tell from your picture for sure,but does any of the pin overlap into the sleeve? I have also seen them installed at a slight angle,so just the bottom portion of the pin is in the sleeve wall.Be very carefull if you ever pull those,the pin can wedge and break the holder

[hsbob]

think about using a o-ring head gasket system. one sorce is jays.

[CircleHook]

This is a 2001- which is o-ring heads- cleaned up real nice- parts ordered this morning-

[TEXAS20225]

dont waste your time with that type of rigging its just a cheap way to try and get back on the water, oversize sleeve is right way with new pistons by the way if there is not enough upset difference in one hole it most likely is in all six holes it was mis machine from factory ive rebuilt them before with 6 new sleeves

[tlwjkw]

its jus a "southern engineered" screw up ta try and fix a rotating and/or up n down moving sleeve screw up!.. gripes my but seein' junk like that!

is "southern" racist?

[CircleHook]

dont waste your time with that type of rigging its just a cheap way to try and get back on the water, oversize sleeve is right way with new pistons by the way if there is not enough upset difference in one hole it most likely is in all six holes it was mis machine from factory ive rebuilt them before with 6 new sleeves

Well shoot the messenger and scuttle the ship-

what harm in trying to make it run? It won't cost much- good practice and learning experience.

Oh - question - what is meant does this mean ? " if there is not enough upset difference in one hole it most likely is in all six holes "

[mn808gade]

ar'nt thoes cracks in alum just left of the pen point?-th

[CircleHook]

ar'nt thoes cracks in alum just left of the pen point?-th

-

Naw- nothing there once cleaned up-

[TEXAS20225]

upset is what is called the difference in od of register and id of sleeve if its not at least 31/2 thousandths bigger(that would be the sleeve end of it) it will spin when it gets hot you must be very young or very energetic ive rebuilt 100's of v6 merc motors and i dont care anything about cheap skating a project just for the sake of hearing it run for a 1/2 hour my labor is worth something but i sell mine with a warranty so i care about the customers experience with my rebuild job

[TEXAS20225]

i would hope that you knew that these sleeves are installed in a hot block 425 degrees + they then shrink down as it cools off to hold the sleeve in place without a "pin"