New Piston Rings, Matching, and Cleaning

so i did all of the above along with new gaskets (didn't even have a head gasket and the exhaust was almost completely blocked by carbon) this is the first time this ped had been taken care of since it was made

now that everything is together and i loobed up the cylinder and piston with some oil and it is making a sort of sandy scraping / sharp slirpping noise a straw makes when you're drink is all gone when i turn the magneto wheel to turn the piston...

it's coming out of the intake manifold and i took the head off to take a look and listen and the noise stops and i dont see nothin...

when i put everything on including spark, except the carb and cover the manifold with my finger there is resistance to me turning the piston at that point...

this is my first ped and i don't wanna start it up and ruin all my money and work can someone just tell me im overreacting/ give me a scapegoat for all my rage and disappointment when i seize the engine

Re: New Piston Rings, Matching, and Cleaning

it could just be the noise from it sucking air through, it is essentially an air pump..does it stop when you take out the spark plug?

Re: New Piston Rings, Matching, and Cleaning

no it still makes the noise with the plug out not with the head off though

Re: New Piston Rings, Matching, and Cleaning

*it doesn't make noise with the head off

Re: New Piston Rings, Matching, and Cleaning

Align the piston on the wrist pin so it is centered.

Then torque head dowm.

Re: New Piston Rings, Matching, and Cleaning

im sure the wrist pin is in the center of the piston what do you mean torque the head down do you think it's too tight or too loose cuz either way it's still making this noise is there any reason you think these are the cause/ problem? explain more

Re: New Piston Rings, Matching, and Cleaning

plus even if the wrist pin wasn't centered there is still room for the piston to slide back and forth on the bearing so this shouldn't really make to much of a difference unless i was horribly off and a pin was sticking out or something

Re: New Piston Rings, Matching, and Cleaning

strange, id double check my wrist pin clips and ring/pin alignment etc, other than that it's hard to say w/o being there ur gonna have to use your ears. maybe a vid?

Re: New Piston Rings, Matching, and Cleaning

Cold Trailer GARzan Justin /

The 'slurping' noise is the piston sucking air in the intake/blowing through the transfers like normal, just with more liquid in there than normal because you lubed it before installation. I noticed this same thing on my MK80 after I built it.

Re: New Piston Rings, Matching, and Cleaning

what do you fellas mean by wrist pin alignment? because it's the same amount into the piston on both sides with the clips in both their grooves. also is there supposed to be resistance at a certain point when i move the piston with only the intake manifold open.. there seems to be more than before i cleaned it but then again that could be a good thing since the exhaust was almost clogged before i cleaned it

Re: New Piston Rings, Matching, and Cleaning

You're fine. Put your carb on and run it. The noise, the suction, and the resistance you are feeling are the results of your motor functioning correctly.

When you rotate the flywheel by hand, the piston compresses the air ('cause you've got no carb on it) in the cylinder head. Because you're not running it, you have no spark or explosion to push the piston back down, so there's resistance when you get to Top Dead Center.

When the piston moves upward, it creates (sort of) suction in the cases, which is why your fingers get sucked if you put them over the intake and rotate the flywheel. This is what normally draws fuel/air mixture into your cases which will then be shot through the transfers.

When you rotate the flywheel with no sparkplug in (and no carb on), you're compressing air in the cylinder head quicker than the air can whoosh out of the sparkplug hole, but it IS whooshing out of the sparkplug hole, and that should be what's making that sound.

Re: New Piston Rings, Matching, and Cleaning

thanks for the reassurance im just really paranoid cuz i don't wanna ruin my cylinder im just thrown off by the insane increase of resistance after cleaning everything and the crackling ill just try n start it up as soon as i can get it out of my room and into the fucking 2feet of snow outside

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