How to resurface an outboard motor without a machine shop or milling
ฝัง
- เผยแพร่เมื่อ 29 ส.ค. 2024
- This is an information only video I made for blocks and heads that are warped or pitted and an effective method to sand them down for a good seal within 1/1000ths of an inch. I recommend this on small motors 35 hp or smaller as it can become labor intensive. I do this for a hobby and as fun on small motors but on larger motors I bring them to a machine shop.
Thanks, Edgar. Turns out that I’ve got the same problem with the same motor. Good video. So no need to go beyond 120grit? I’m not planning on resurfacing the block itself. Just the head. I hope it will work out.
The 120 grit seemed to work best and leave an even mating surface. For added security finishing with 180 grit is suffice. My motor is still running after all these years with using 120 frit....the gasket will take care of the rest. What's more important is a flush and truly flat surface so find the thickest glass possible and use some spay adhesive on the back of the sandpaper to bond it to the glass and then slowly sand until you have an even sheen on the mating surface
1/2 or bigger Tempered glass works best. Then spray glue.
I agree a good thick sheet of tempered glass is best and I would recommend grinding paste-like the stuff used for lapping in valves( I saw one guy that attached a spark plug socket to the spark plug and then used the socket Extention that went into a drill so that he could spin the head on the glass using the paste and in 10 mins he had done a dam good job .... I know not all heads can be spun using this method but I would try to finish the job with the paste if I used the sandpaper method ) I am a spray-painter by trade and I know hand -pressure and not mixing up the direction equally uneven wear of the sandpaper blah blah can give you a bad outcome, plus you should know the specks on how much you can skim it down before you overdo it!
Good advice. Never hurts to have more insurance on the job. many year later and motor still fires up first turnover.
How do you know how much was removed?
Good question I am thinking he has no idea and is maybe just going for the minimal amount trying to just get the pitting out and flat as possible! A heavy grade of sandpaper will shave off the aluminum at a rapid rate and then the scratches left by that heavy sandpaper have to be removed by different grades of sandpapers until the surface has that polished look and that can mean if he used an ....... OMG, he used an 80 grit grade of paper !!!! ( i just rewound the vid to check) I thought he started with 180 grit !!! 80 is too coarse in my opinion! anyway if you start with say a 120 grit you need to use a 180 grit after that next to a 220 or 240 grit then a 360 grit next a 400 or a 450 ok you can see my point because the sandpaper continues like this, the higher the number the finer the paper it continues to 1,000, 1,500 2,000 up, until ultra-fine sandpaper! I would probably have probably started at 180 gone to 240,360 400, and then used valve lapping paste on a glass surface to finish because taking too much will fuck it! looking up the specks can tell you recommended tolerances etc but DIY this way you will never know where that is! I guess it depends if the head comes off a lawnmower or some high-performance motor like a 4 cylinder 1,000cc sports bike!
@@NINJUTSUguy I just saw your comment and your suggestion is overkill for a small boat motor like this. Almost 6 years and my 35hp is still running strong with full compression using 120 grit as my final sanding.