Tips on looking at carbon/oil build up on exhaust valve ports?

[aw614]

Got cylinder 4 pulled here is what it looked like

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IMG_20220315_183212.jpg (2.89 MiB) Viewed 919 times

Will be checking the rest later on,

[DC231]

O wow very nice!! Let us know how you plan to proceed or if you need some recommendations.

[shuttlepilot]

WOW, did that section of the piston vaporize? It is not obvious how all that material made its way out.

[aw614]

WOW, did that section of the piston vaporize? It is not obvious how all that material made its way out.

When I took the piston out, it was like a bunch of little metal rectangular bricks just fell out of the piston like it was barely holding on.

I do think some made it into the oil pickup as there was some thing rattling in it, will need to check that

Oddly enough the cylinder walls are still smooth and nothing catches on my finger.

O wow very nice!! Let us know how you plan to proceed or if you need some recommendations.

I am waiting on another block that I had sent out but thinking of keeping it as a spare. Based on what you mentioned earlier what Dealerships do, I am considering just buying the NPR 81.5mm JDM ITR pistons and reringing it/using a flex-a-hone on it.

[DC231]

WOW, did that section of the piston vaporize? It is not obvious how all that material made its way out.

When I took the piston out, it was like a bunch of little metal rectangular bricks just fell out of the piston like it was barely holding on.

I do think some made it into the oil pickup as there was some thing rattling in it, will need to check that

Oddly enough the cylinder walls are still smooth and nothing catches on my finger.

O wow very nice!! Let us know how you plan to proceed or if you need some recommendations.

I am waiting on another block that I had sent out but thinking of keeping it as a spare. Based on what you mentioned earlier what Dealerships do, I am considering just buying the NPR 81.5mm JDM ITR pistons and reringing it/using a flex-a-hone on it.

You could do that but don't expect more than about 30-50 thousand Miles if that and you will most likely still have oil consumption issues.. I'm thinking the problem lies with botched machine work in the first place.. you would essentially still be using the same botched machine work plus allowing even more clearance by using a flex a hone and not to mention will never get the correct 60° angle crosshatching for proper ring seal. The reason the dealership can do it successfully is because of the high quality of machine work that was initially done by Honda where they are measuring down to 1 ten thousandth of an inch. Not 1 thousandth which is .001 we're talking .0001. These numbers can only be done with certain quality machines and most machine shops just simply don't have these quality machines because of their cost.

If you want it to be reliable for years to come then at minimum you need to have the cylinders checked for out of roundness and tapered bore. If the bore ain't straight then it needs to go to 82mm which is the max without sleeving. If they are straight then you need the exact size of the bore to a thousandth and the max piston diameter at the skirt and calculate your piston to wall clearance and if it's within spec(very highly unlikely in my opinion) then you could re-ring it.. I would just go straight to 82mm and make sure you get the Pistons first and take them and the block to a GOOD HIGH QUALITY MACHINE SHOP. Tell them you want the tightest clearances allowable and the tightest ring gaps allowable and you'll have an engine that's fresh and will last for years if it's assembled correctly. I'm in Jacksonville if you wanna send it to me I can take care of it for you

[aw614]

I don't think it was botched machine work and more like install error with the piston ring gap and piston ring orientation. I kind of held this part back b/c I don't want to throw my friend under the bus in my build thread and on here. But when he assembled my motor originally, he did set the ring gaps larger than I wanted and didn't follow the service manual for the ring orientation. I didn't agree with it back in 2017 during the assembly as something didn't sit right with me having it that wide, but went in with it because I also wasn't sure about what the ring gap to set it to and the person we also asked advice for at the time mentioned the wider gap was fine.

The gap in my opinion and my gut feeling felt like they would have been fine for a turbo motor but not an NA motor.

If I had known about you've built motors, I would have sent the spare block I had last summer that I am still waiting on to you,
with Jacksonville being close. That motor though is being built the right way from the progress I have seen, just the delays.

[DC231]

I don't think it was botched machine work and more like install error with the piston ring gap and piston ring orientation. I kind of held this part back b/c I don't want to throw my friend under the bus in my build thread and on here. But when he assembled my motor originally, he did set the ring gaps larger than I wanted and didn't follow the service manual for the ring orientation. I didn't agree with it back in 2017 during the assembly as something didn't sit right with me having it that wide, but went in with it because I also wasn't sure about what the ring gap to set it to and the person we also asked advice for at the time mentioned the wider gap was fine.

The gap in my opinion and my gut feeling felt like they would have been fine for a turbo motor but not an NA motor.

If I had known about you've built motors, I would have sent the spare block I had last summer that I am still waiting on to you,
with Jacksonville being close. That motor though is being built the right way from the progress I have seen, just the delays.

In my opinion the most important thing to do when clocking rings is to not put any gaps at a thrust point and to position the gaps as to where it's the most resistant path through the gaps to the combustion chamber. I followed Wiseco installation technique with my current build using their pistons and rings. If the cylinder walls look good and everything then there's no need to flex hone it if you think it wasn't caused by machine work. Maybe you could buy 1 individual piston and use the original 3 in their original cylinders? Tight ring gaps is what you want NA bro hands down.. loose gaps let your cylinder pressure go right into the crankcase.