How much honing can a person do?

[KVF 700]

I burnt up a ring on my old 75hp johnson boat and need to replace the piston and rings, as well as hone the cylinder quite a bit to get out the scratches.

i understand it would be a lot easier and propper to bore out the cylinder, but i really dont have/want to spend the cash on this old pile of junk.

i am wondering how much a person could take off with a honing stone? would i be able to take off 10-20 thou? give me some ideas.

 

[AreWeThereYet]

I would say that would be too much,.. .001 to .003" MAX without having to put over size in, unless of course you can sleeve,. What are the options for your Mariner/Johnson motor?

 

[Garryese]

10-20 thou. is boring it out. But using a hone is going to take a long time and when your done the cylinder isn't likely to be round or straight.

 

[Polarblu]

i did a 350 chev 30 over with a ball hone.......... took allot of time and it was a piss poor job. Like previously stated 2-3 thou is huge. To put it into prespective 3 thou is the average thickness of a sheet of paper.............

 

[polarice]

I burnt up a ring on my old 75hp johnson boat and need to replace the piston and rings, as well as hone the cylinder quite a bit to get out the scratches.

i understand it would be a lot easier and propper to bore out the cylinder, but i really dont have/want to spend the cash on this old pile of junk.

i am wondering how much a person could take off with a honing stone? would i be able to take off 10-20 thou? give me some ideas.

you can do it that way ya might have it done for next year :d:d:d

 

[KVF 700]

Ok. Not really to many options besides boring it out or else by an entire new half of the engine since there are no sleeves and all 3 cylinders are connected. It does still have 85psi dry compression on that cyl compared to 105 on the other 2 so not sure how much I have to take off.

And yeah my plan was just to hone it smooth however long that takes then measure it and get an appropriate piston. Doing it this way would only cost 100 bucks for the piston and rings and can be done in chasis. Otherwise I have to pull the engine, take off flywheel which I already tried and couldn't and split the case etc etc.

 

[Riverjet]

Honing a cylinder is done for two reasons. 1. To create the final piston to cylinder clearance. 2. To provide a crosshatch pattern for the rings to seat to the cylinder walls. When you hone a cylinder too much, (beyond the specified piston clearance specs) you are asking for trouble.

 

[KVF 700]

Well I got the cyl cleaned out pretty decent. Guess I didn't have to take off as much as I thought. Only took off .005". Ordered a piston but the smallest over sized piston is .020" over so might end up using the stone a bit more. Standard would be much to small

Some before and after pics

 

[the_real_wild1]

Looks like the lines are horizontal in the picture??????????? You need the cross hatch pattern! It is to trap oil and lubricate the piston.

 

[overkill131313]

I did a 294 twin Rotax years ago with a flat stone (sun in hone or some thing like that)......I took out .020" and it came out perfect with no tapper or out of round.......I did lots of measuring because you can always take it off but putting it back on sucks lol.......it did not take long at all! then I used the ball hone to put the crosshatch pattern back in! I stopped about .030-.040 before finnal tolarance and finnished with the ball hone! it started big so in total I think it was .024 I took out to put a .030 over piston in.......do the math before you start to hone......well true it up first then figure out how much you need to take out to make the piston to cylinderl clearance be in the tight end! just my 2 cents but with the grade 5 math I had, it worked out! lol

 

[Modman]

So you are honing the bore with the motor still installed and the crank still in the block? Honing is a final polishing step for a motor, not a process designed to remove significant material. It can be done, but I seriously doubt the quality of the round and taper will be there at the end, especially using a hand drill, motor installed, with the crank still in it, even if other people tell you they did it once to a very small bore fan cooled motor, your application is entirely different. Boring a cylinder 20 thou should be done precisely, but that's just my opinion.

 

[gotboost]

not as much honing as we had to do on my buddys sprint boat hahah well that cost $9000:d all new power plant in her now

 

[heavy d]

owwwwwch

 

[CUSO]

YOu would be better off finding a good used jug on a boat forum and just go from there.

 

[gotboost]

YOu would be better off finding a good used jug on a boat forum and just go from there.

yeah we could of but we stuck a new zz4 chev crate motor and put a new fast efi on it and that engine rocks :d

 

[KVF 700]

YOu would be better off finding a good used jug on a boat forum and just go from there.

Yeah I know but all 3 jugs are connected, and are also the entire half of the engine.

Yes I understand this is not the right way to do it but it's not worth sinking 1000$ into a 1500$ boat that is 35 years old. It has been a complete Lemmon since my relatives bought it new. Never has been to great. I am only getting it running to hopefully sell. I mean it ran before I took it apart on only 2 cyl so hopefully my $100 patch job will work good enough for this purpose.

 

[CUSO]

Yeah I know but all 3 jugs are connected, and are also the entire half of the engine.

Yes I understand this is not the right way to do it but it's not worth sinking 1000$ into a 1500$ boat that is 35 years old. It has been a complete Lemmon since my relatives bought it new. Never has been to great. I am only getting it running to hopefully sell. I mean it ran before I took it apart on only 2 cyl so hopefully my $100 patch job will work good enough for this purpose.

Remind me not to buy any of your stuff...
I feel sorry for the young kid that is gonna buy his/her first boat and have it blow up.

 

[Modman]

Remind me not to buy any of your stuff...
I feel sorry for the young kid that is gonna buy his/her first boat and have it blow up.

X2 - if your intention is to "farmer fix" it, just to unload your shitty repair onto someone else, then I hope Karma comes back and bites you in the ass. Its ch!t like this that makes people distrust others when buying used.

Accept the fact that it is 35 yrs old, its only worth $250, so throw a match to it and sell the motor for scrap.

 

[imdoo'n]

with the hack job your doing, can't see it running long. either fix it right or don't fix it at all. snow and mud is usually not very forgiving of slime balls.


shheeet to bore the cyl may have cost $45, new piston $100 yes may karma bite your azz.

 

[KVF 700]

Ya after further investigation, I am selling it for parts now. Rest in peace, I am not a bad person.