It looks like the rings on my number one cylinder of my 1964 401 have given up the ghost. The cylinder looks fine. All the other cylinders are with in spec pressure wise. I don't have the time or money to rebuild the engine and plan to re-ring the one piston and be on my way until I have the time to refresh the engine. Any idea where I can get a set of rings for one piston in standard bore?
Ebay and many suppliers have a p/n for one ring only, but often those are high end rings. They sell them listed for bore size rather than application. A whole set of rebuilder type rings is $25-35 anyways. I'd be far more cautious as to why the failure and what other damage has happened. Rings don't fail without a really good reason. Is the ring broken? If so it is likely that your piston is junk, too. Overheat to the point of butting and breaking or a broken new ring from hitting the ridge of an old cylinder means impending failure on the next. Both usually mean the ring groove has experienced enough trauma to relegate that piston to the junk pile. Did it wear out badly? What's stopping the next one from failing? Are you willing to risk more wreckage? More info would be helpful. Recent rebuild? Just noticed you are in MI. There should be zillions floating around.
The car didn't run for 20 years, then I drove it home nearly 3000 miles last week. It had 150 psi when I left Seattle, all was well until a couple days ago when I started seeing a ton of blow by. Didn't burn any oil in that 3000 miles. The engine has I would guess has 120,000 miles on it maybe 220k (it is the original engine) best I can guess it fatigued. I have a good used piston lined up. Just need rings. Clearly I will root cause the failure the best I can, but it doesn't look very traumatic so far, the cylinder wall appears to be fine. I plan to rebuild the engine this winter, I just do not have the extra time/money to go through the engine now since I am remodeling my kitchen for my wife. I can have the engine out, rings replaced and back in the car in a day. So I either put a day of work into it and like $50 and enjoy the car for the rest of the summer or I park it and hear about how it doesn't run until the winter. Really I just need a source for a single piston's worth of rings. All I can find are sets which either seem way too cheap ( I would rather use a used oem part than that stuff) or sets that seem like they are good quality but more than I want to spend right now.
Forgot that was you that put the head on and drove it back, lol. Knowing what happened now, the ring was likely just stuck to the aluminum ring land and couldn't move with expansion (?), or that piston had been previously overheated. I don't think I've ever seen a 'too cheap' ring set to be put into a no $$ or parts repair job that would get torn back down in 6 mos. The cheap rebuilder ones are OEM quality already. Glad you want to enjoy your Buick
That would be great of you could find something. My buddy Don is looking through his stuff but is only finding 425 stuff. I may need a piston too if you stumble on one. Engine comes out tomorrow so I should have a good idea of what I need for sure after that.
Yeah, I took a look at that. I also noticed that my freeze plugs have been replaced with rubber at some point (at least 20 years ago) so I want to swap those out at the same time. Plus it doesn't take much to pull this engine compared to modern stuff.
I pull the engines and get them on a stand. It seems I most always find something else that needs attention. Good luck
Piston rings for a 401 are the same p/n as the rings for a BBB 430. You might be able to find those "cheaper" if someone doesn't think you're working on an antique.
Last night I pulled the engine and checked things out. I found a bunch of what looks like masking tape in the oil pan. One broken compression ring. Nothing else seems damaged.
When I left Seattle: 150 PSI When I first tested back home: 50 PSI After I pressurized the cylinder to see where it was leaking: 0 PSI
I see quite a few like that from overheating at an earlier point in it's life. It's respective groove is usually wider from trying to bind in the cylinder. I have a 425 and a 401 core that have many of their pistons exactly like that. They tend to break across from the gap. I wonder if it was assembled with masking tape around the piston to 'fix' any slap? Surprised it didn't have sawdust packed into the oil pan to insulate any knocking You sure everything is just fine? I'd set it aside and go through it right, maybe swap in a runner. Then you won't blow this one up.
I took another look at the piston today and one of the ring lands fell out! Cylinder still looks fine. Looks like I will be needing a piston too. Hopefully Roberta can come through for me tomorrow. Looking at the top ring I think it has been broken for a while and I'm guessing the ring land just gave out from all the load being on the lower compression ring.
If it was caused by overheating to the point the rings were butting and attempting to slow up the engine, the 2nd land could have been damaged at the same time, too. I've seen them go thousands of miles like that, with the pieces hanging on. Definitely contributed by sitting for 20 years and seizing. I can picture a scenario in which the last time it was driven was when they ran it until it nearly locked up. It probably 'just didn't run the same' afterwards. Lots of other reasons they break. The ring width still tells a tale here. Some of the ones I've seen have cylinders that visually look just fine, but aren't. They can be quite a bit out of round. Might want to get a bore gauge to it.
Yes. That valve was bad due to corrosion on the stem. Maybe water got in there. Maybe I should take a look at the rod too.
Roberta graciously gave me some good used pistons and rods so I have the parts needed to put my engine back together. So first I ridge reamed the cylinder I was working on. And then I honed it a bit to give the piston rings the surface they need to break in. Then I installed the replacement piston and rod assembly. The engine is back in now. I just need to install the accessories and I should be good to go.
Roberta graciously gave me some good used pistons and rods so I have the parts needed to put my engine back together. So first I ridge reamed the cylinder I was working on. And then I honed it a bit to give the piston rings the surface they need to break in. Then I installed the replacement piston and rod assembly. The engine is back in now. I just need to install the accessories and I should be good to go.
