addition to previous post 235hp 2.6GT

[Jvdm]

OMC forever was helping me nicely with previous post, there is something I like to add to that same engine , can somebody please tell me what could cause the piston to score the headgasket like this.

[omcforever]

Blown head gasket between cylinders/burnt sealing ring. Check cylinder head for straightness and defects in sealing surface. Have a shop check heads or you can use a straight edge. Then have just enough milled off(just a few thousandths usually). Don't go crazy because it will raise compression and that already is a high compression motor. Check block sealing surfaces at top of cylinders also. Use proper head gasket for 2.6 motor, torque in steps/increments and proper torque pattern per the manual to the value of 20-22 foot pounds and run thru 1 heat/run cycle and then re-torque. Insure cooling system is good(good thermostats and good water pump and good internal block defectors.) Also replace the cylinder head covers gaskets(on top of heads) and torque to 60-84 inch pounds. Also insure head bolts are 100% clean and run a thread chaser down threads in the block. Coat each bolt with a thin film of oil to get precise torque.

[omcforever]

Also insure top of cylinder liner in the block has no gaps/cracks on top where the gasket ring seals.

Torque sequence/pattern---
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[Jvdm]

Thanks again, appreciate ,good to see you back on the board

[omcforever]

I would also run a straight edge across the top of the block where the head bolts on. Lots of these motors where ran with out thermostats and that can cause all kinds of issues as well

[316jughead]

I can't tell from the picture, how bad is that head damaged? I took .020 off of those heads and only raised the compression 5 t0 6 pounds on the same motor as yours. I would like omcforever said, only take off just enough to get them straight. We had better gas back then. My 2.6 had no bottom end power I had to prop down to get my Skeeter Starfire 175 out of the hole and watch out for over rev. OMC said to double oil that motor also. I did have a racing connection with OMC, from him I learned I could run to 7000 or more RPM. I did that with no problems, but not for long runs. I sold that motor and I don't know what ever happened to it. It just wasn't a motor for me.

[omcforever]

I can't tell from the picture, how bad is that head damaged? I took .020 off of those heads and only raised the compression 5 t0 6 pounds on the same motor as yours. I would like omcforever said, only take off just enough to get them straight. We had better gas back then. My 2.6 had no bottom end power I had to prop down to get my Skeeter Starfire 175 out of the hole and watch out for over rev. OMC said to double oil that motor also. I did have a racing connection with OMC, from him I learned I could run to 7000 or more RPM. I did that with no problems, but not for long runs. I sold that motor and I don't know what ever happened to it. It just wasn't a motor for me.

Yep, def don't like cheap gas and love more oil. Have to insure timing is spot on( I reduce max timing on some of my old crossflows with tight heads 2 degrees just to be safe with todays cheap gas). Those old crossflows had some weird harmonics above 6000 rpm. The 2.6 made some great top end power and could rev way up there with 1 3/8 carbs, aggressive port timing, and Like Jerry said, just don't do it for long. Hang that motor on the back of a short, light speed boat and you have one bad azz fast ride.

[Jvdm]

Thankyou gentlemen I will keep you updated