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I've read conflicting information on this. But I do know that in 2 cycle engines, the piston have a locating pin so the ring(s) cannot rotate, and avoid getting a gap edge hung up on the port inside the bore. I raced go-karts for about 5 years, and went through about 4 engines - all 2 cycle.I don't know if 4 cylinder pistons have locating pins for rings as standard design or they are in specific applications. Or if they don't have them and it does not matter that the rings rotate... or NOT.Gnarls.
I was told once that the 2nd ring has the wrong spec in FSM... Take that with a grain of salt. But when I assembled my engine one of the rings was tighter than the specs but was considered normal...
We need more info!Get to testing!Assuming and guessing time has passed.Chop chop!Park it in the garage and pull all the plugs. Take note of the cylinder that each plug came from.Take pictures and post for us. We will need hi resolution close up shots.Waiting!
Rebuilding from scratch makes no sense if you find a cause of the problem and the primary goal is a running engine. You could get a professional rebuild and have a random failure even then.
I saw on the chat you said you used royal purple for break-in. Was it the royal purple specifically made for break in or did you use regular royal purple synthetic oil?
I don't believe in all the "break in" hype. Sure u want to cruise your engine 2k for 20 minutes to beat in the cam, test drive and do compression brakeing to push rings in to cylinder wall and change out the oil. But other than that it's either built right or not at all. Let's see pictures of all your plugs. Take your oil cap off and put your hand over it to seal, what kind of pressure is there... No more talking, more doing
So when a new car is purchased does it have 500 hidden miles of engine break in with crazy oils? Break in is not the concern, these are not the droids you are looking for...
Back all Your rocker arms way off (way loose) and do the compression test again.
Poor Gnarls, I wish u were closer, I'd love to help u out. When u adjust your valves, do u follow the FSM on engine position? I strongly recommend you disregard it and adjust each rocker arm with the peak of the cam lobe 180 degrees from the contact pad of the rocker. Aftermarket cams are regrinds with different clocking (duration ect) and typically will throw off your valve adjustments...
Are you saying that the valve adjustment could be his issue?
Strange how spark plug 1 and 4 look the same, and not much different to 2 & 3, from what I can see from my laptop screen. And not that bad for that oil comsuption. Do you have a lot of blowby from the pcv vent on the valve cover? With the fact that the wet compression test showed only a 4 psi difference in cyl num 1, my uneducated guess is that the issue is in the head not the rings. And I think bestgen meant leak down test.
Not quite. Right now I see 2 different issues, oil consumption and low compression. If they are to be hand in hand it's best if he proves all he can through testing/elimination cause next step sounds like tear down. I'm just trying to give my best recommendation, assisting diagnosis of a vehicle online is alot like holding your phone to an engine and asking your friend if he can tell u what's wrong, lol.
Hey G,I can't see any smoke, no blow-by. After driving, engine hot, when I pull the oil dip stick I can hear pressure releasing, so I know there is air pressure in the crankcase and oil pan. I think the amount of air pressure is not normal. I don't see or hear any excessive blow by out the PVC valve, tubing, or rocker cover gasket.The tail pipe is black, and not a grayish color, so I see there is probably excessive carbon in the exhaust.Yes, I am puzzled by the clean plugs. I would think I'd see more carbon build up, and even pre-fouling. They are absolutely clean! Just a very tiny look into number 1 cylinder through the spark plug hole looks like the top of the piston is carbon'd up... I don't know if it is excessive or normal. Only an complete engine tear-down and inspection will give me the answers. Gnarls.
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