It is amazing how many strokes these things operate for. Blows my mind if you do the math!
@Ceemysix
Жыл бұрын
Keeping fines out of th engine helps in piston wear, as well as running quality oil.
@EcSsAwS
Жыл бұрын
Walmart supertec oil for me. Over 2 decades so far I send saws to people to be built (like Boedy) and they have NOTHING to say about the oil and mixture I run
@thetwostrokerebuilder
Жыл бұрын
Piston slap is from worn intake skirt caused from dirt, lack of oil or just plain old wore out. Check clearence with feeler gauge and you'll know if worn out
@chainsawcanuck
Жыл бұрын
I have a few older saws that have slap, one day I'm gonna take the piston out of one of them and knurl it, then machine it back down to correct diameter if need be
@z1berzerker
9 ай бұрын
The intake side of the piston is cooler, it is the last part of the piston to expand... it tends to exacerbate what you are talking about further
@aaronpowell4885
Жыл бұрын
Still love the cutaway! Hopefully we'll get to see inside the 625ll
@eurokid83
Жыл бұрын
Piston slap is caused by excessive clearance in the bore. It’s not exclusive to the intake side of the piston. When you take that 625 apart what you’ll most likely find is the piston is just worn out. The skirt on intake and exhaust side will be smooth with no visible tool (machine) marks. Either that or someone installed the wrong grade piston in that saw at some point. If you look on the top of the cylinder (and top of piston) there will be either an A, B, C, or possibly a D. Say you have a C cylinder. You should also have a C piston. For example If you have a C cylinder and A piston the clearance will be out of tolerance which will result in piston slap.
@novicelumberjack
Жыл бұрын
Sure, anything can happen. And if left to slap long enough, the exhaust side will wear too. But...all things as they should be, over time it is the intake side that gets the wear to cause the slap. That is where the majority of the force goes. Right into the intake side cylinder wall. I have taken it apart already. The damage is very clearly to the intake side.
@eurokid83
Жыл бұрын
@@novicelumberjack if the saw has been ingesting fines, yes the intake side will wear faster than exhaust. I work on small engines for a living, that’s the only time I’ve seen excessive wear on the intake side of a piston in a chainsaw. That era of jred and husky saws are known for ingesting fines.
@novicelumberjack
Жыл бұрын
@@eurokid83 I understand that you know what you're talking about and you are not at all wrong. I think you just have never stopped to actually look at the deeper issue. If your saw is ingesting fines, do those fines not make it to the exhaust side as well? Of course they do. They also make it into the crank bearings as well as up to the top of the piston and into the ring. They don't just hit the intake side of the piston and cylinder and stop there. If they did, your crankcase would have years worth of built up sludge just sitting in the bottom of it. They travel all throughout your crankcase and ultimately out through your exhaust. Wouldn't you agree? If so, then you have to stop and ask yourself why they are only or at least MOSTLY only effecting the intake side of the piston and directly underneath the intake opening of the cylinder. It is because there are hundreds of pounds of pressure pushing your piston skirt up against that area specifically, grinding any debris into the piston and cylinder wall every time combustion takes place. Seriously, consider what I am saying...because it is correct. This is your thrust side and it happens on all engines with a traditional reciprocating engine setup. Motorcycles, lawn mowers, automobiles, diesels...everything. It is compounded in the world of small engines because of the dirty environment they operate in, but it happens with every traditional reciprocating engine.
@eurokid83
Жыл бұрын
@@novicelumberjack you’ve made some good points and I’m in agreement with you for the most part. On the many saws I’ve taken apart with clear signs of particulate ingestion, I just don’t see significant wear anywhere else but the intake side of the piston. There are exceptions to this of course depending on how bad the particulate ingestion is, size/quantity of fines getting through, etc. I think we can agree ANYTHING getting past the air filter isn’t good and certainly not going to help the piston slap issue.
@MrJeepfreak1972
Жыл бұрын
@@novicelumberjack If you ever get the opportunity to dig ito a warn out concrete saw that has ingested concrete dust you will often find the intake skirt worn badly as well as the plating off the cylinder wall. Concrete dust, being very abrasive, really shows where the majority of wear occurs from particulate ingesting.
@Witschor
Жыл бұрын
i got 2 videos on my Channel about piston Rattle.before and after Piston change , wear headphones to hear it better .Solo 644 and the 562 Video is showing it.
@terricoon9029
Жыл бұрын
Let me know when that 670 shows please should be soon and look at the piston if you have the time just curious nerves took it apart thanks
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