meadowbrook Posted June 5, 2020 Report Posted June 5, 2020 (edited) Hi all, so my 50 Dodge fractured #4 piston and so I pulled the head and pan and pushed out all 6 pistons. There is no scoring on the cylinders and the oil pressure has always been 45 to 50 psi at anything above idle and the rod bearings looked dark but no scuffing. So what are the opinions here on me buying new pistons and rings, honing the cylinders and with new rod bearings, reassembling everything? The engine has 80,000 miles. I’m not sure what fractured the piston, I think a ring broke as it was gone and some pieces are stuck to the piston. What would break a ring? Age? Is it advisable to replace valves or springs? Lap them? thanks, Pics attached Edited June 5, 2020 by meadowbrook Quote
Dodgeb4ya Posted June 5, 2020 Report Posted June 5, 2020 All I can say is WOW! Your engine must have had some blow by and not the smoothest running old flathead. It was high mileage engine and worn out...fatigue failure. These flatheads can run without failures even longer than 80,000 miles but that depends on how good the maintenance was and how hard it was driven over the years. It's common to see ring land failure/ and broken rings at higher mileage. That probably caused the broken skirt as pieces of the ring and or top ring land jammed the piston in the cylinder. Be sure that cylinder is not scored or out of round. MAX taper top to bottom of about .010 on an old flathead. Modern cars no way. 1 1 Quote
meadowbrook Posted June 5, 2020 Author Report Posted June 5, 2020 Funny part, it happened on the highway and the only symptom was occasional smoke and a random clicking sound on overrun. I didn’t even feel vibration or a loss of power. Quote
plymouthcranbrook Posted June 5, 2020 Report Posted June 5, 2020 6 hours ago, meadowbrook said: Funny part, it happened on the highway and the only symptom was occasional smoke and a random clicking sound on overrun. I didn’t even feel vibration or a loss of power. Designed to keep going in what we would call a primitive environment. Get you home if at all possible and then some. Quote
Plymouthy Adams Posted June 5, 2020 Report Posted June 5, 2020 a testament to just how tough these old engine truly are...... Quote
Los_Control Posted June 5, 2020 Report Posted June 5, 2020 Lucky you caught it before it destroyed the cylinder. You get a ATA-BOY! and a extra cookie. Back in the day it was common to take these old jalopies to the local gas station and have the mechanic do a ring or valve job, not always both. I question the need to replace all pistons .... probably the ring failed and broke the piston .... because you are replacing the rings one would hope it did not happen to another piston. You might sleep better if you replaced all of them .... myself I might pull a used piston out of a parts engine and slap her back together with hone and new rings. Certainly would be a good time to pull the valves and lap them, while you have it tore down. Then you may as well pull the engine and check the cam and the timing chain and then .... Kinda falls into the if not broke don't fix category. Either way you go is not wrong. Just up to you how much fun you want to have at one sitting. Quote
Tams50 Posted June 7, 2020 Report Posted June 7, 2020 No. I got lucky.Funny thing was, when I took the head off the broken valves were in the seats. Quote
Sniper Posted June 7, 2020 Report Posted June 7, 2020 Dang, with luck like that you ought to buy a lotto ticket. Quote
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