Changing Piston Rings in Car

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70sublime340

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Call me crazy but has anyone changed their rings without pulling the engine? I'm just not setup to yank a motor at the moment and its bailing smoke. Changed stem seals with no change. Dry compression test shows about 80-90psi, while wet is north of 140psi. Also when using a compressor to put air into the cylinders they will not hold anything. It goes straight to the crank case. Worse part is this engine has less than 2k on it. Obviously the guy who built it didn't do something right. So any input on changing the rings without yanking he engine is appreciated. I also have an extra set of hands to get under the car and guide the rods into the crank. Thanks!!!
 
What are the chances you have a leaking fuel pump and the oil is diluted?
 
You can do it with great results. It's called an in frame. Over the road trucks have it done all the time.
 
we do in frame overhauls at work,but diesels have liners that we change,you can do it in car,just have to hone cylinders but have to check your ring gap
 
You could do it, but until you figure out what happened you may get the same 2000 mile results.
 
67Dart273 said:
What are the chances you have a leaking fuel pump and the oil is diluted?
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Yeah, was thinking fuel washed. Pig rich. Smell the oil. In all honesty it would take me less time to jerk the engine and do it on a stand then do it bent over a fender over /under rigormorol. Easier to keep clean.
 
GeorgeH said:
Yeah, was thinking fuel washed. Pig rich. Smell the oil. In all honesty it would take me less time to jerk the engine and do it on a stand then do it bent over a fender over /under rigormorol. Easier to keep clean.
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Ugh... Pull it if at all possible... You take more time,you get a better product...
 
It can be done but as mentioned keeping things clean is a real problem. Normally it would take 2 people, one below and one above when it comes time to install the pistons again. Some of the problems are as follows, removing and reinstalling the crank. You have to do it because you will never keep it clean when you hone the cylinders which you have to do. When you install the pistons you have to make sure you don't scar the crank with the rod bolts. Sounds easy until you try and get your fingers in there to guide the rod. Good luck if you try it, but I would figure out a way to remove the block.

Jack
 
My veteran mechanic friend said it was a normal day to have a V8 in car torn down, heads and valves ground, block honed with new rings, with help from another mechanic for pistons in and out, all reassembled, running and out the door by 5:00.

This is what was normal and expected from a good auto mechanic.
 
Use rubber hose over the rod bolts to guide them to their places on the crank. You can also place an old piece of bicycle inner tube over the journal to protect it as the rod comes down. Dry hone the bores with a ball hone just enough to break the glaze, and be sure to cross hatch the pattern. Make sure you have enough clean rags to wipe things down well. Throw a quart of automatic transmission fluid in the start-up oil and change the oil and filter after the first 20 minutes. Then again in 100 miles.
 
Been done hundreds of thousands of times in the past and will continue to be done in the future in the name of low buck, no money, doing what you can with what you've got.

As stated, keeping clean is most important and also hard to do; a lot of aerosol solvents come into play here.

If you can lay your hands on one, I would suggest a dingle-ball hone, 30 seconds a hole, not nearly as messy as a 3 stone glaze breaker. Use a simple cast iron top ring set, they are not fussy to wall finish and will bite and seal.

Use 2 pieces of 3/8 gas hose to cover the rod bolts so you don't kick the crank. Make one longer than the other so you can steer the rod down over the journal by yourself.

Remember piston orientation.

Good luck!
 
doing it is not a big problem. Done it many times on varies cars & trucks Just be sure that is the problem. We had a Ranger (4 cyl) in our shop once that had no compression. It also had been rebult by who knows. Checked T belt and everything else we could think of. Finaly tore it down to find out who knows didn't put rings in it. Not saying that is your problem you have compression, but be sure to look for somthing in human err.
 
Done it on one cylinder but not all 8. With both heads coming off, out of car would seem easier. The K-member and steering linkage are going to make life pretty hard on this project in-car, and you will need a hoist anyway if you want to drop that out of the way.
 
it can be done. a gain of 50 -60 psi when wet seems extreme to me.
 
No need to remove the crank if all you're doing is rings. I've done it a few times...once on my current Dart. Yes, PITA, but if you can't pull the engine, it can be done "in frame". You will have to jack-up the engine to get the pan out, and possibly remove some of the steering linkage/exhaust for access as well.

Good luck!
 
In car overhauls were the norm "back in the day"..,

340 Dart Flat rate is 25.5 hrs for in car vs 36 hrs. for an out of car,, out of car is done if the crank needed work.. Head work, valve grind is extra.. 4 hrs. (actually doing the valves and seats)..
 
inertia said:
In car overhauls were the norm "back in the day"..,

340 Dart Flat rate was 25.5 hrs for in car vs 36 hrs. for an out of car,, out of car was done if the crank needed work..
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There even used to be portable boring bars to bore cylinders. Of course this was mostly inline 6 whangers

BoreBar-OldLit.jpg


MachineShop-03.jpg
 
Thanks for the input, I realize it's a lot more of a pita in frame...but my current situation just isn't optimum for yanking the motor. I've changed many pan gaskets on a bodies in the car so that's not a big problem. And I do have another set of hands. It's not imperative to be finished over night either. The car is in my garage, but I don't have a cherry picker, nor the space to have an engine on a stand for a couple weeks...therefore being able to pull the heads is much more suitable for me. Also with these damn spool mounts trying to get the motor/trans back together in the car and get the mounts back in the k member at the same time is a NIGHTMARE!! At one point the car did run pig rich but I have solved that issue. What leads me to rings is the fact that a dry test shows 80-90psi and wet is over 140psi (and 140psi I find to be adequate on a stock comp cast piston .030 360). I felt a gain of 50-60psi wet was extreme, but dry was extremely low. When I got ahold of this car it had no pcv system nor breathers for maybe 2-400 miles...maybe that hurt it? And for all I know the cat that assembled it didn't do it right. However I have proof that the cylinders were freshly punched with new Pistons. Maybe the rings weren't staggered??? But before I rip into it, does anyone have any recommendations to 100% ascertain the rings are shot? And if so, what rings do you guys recommend I run? I've always done hot street motors with high end rings but, nothing stock.And I plan on a ball hone to knock the glaze off. I figure 320 should do it. Also if any of you would rather speak in person as opposed to typing feel free to Pm your phone number and I would happily give you a ring to chat about it. Thanks in advance!
 
If you have compressed air, you could do a cylinder leak down test. That is about as definitive a proof sealing ( rings, valves, head gaskets ) as you can get.
 
^^^ This..... he already says the cylinders won't hold compressed air; but that is a subjective check without an actual leakdown gague. I would want to visually see the ring and bore conditions with this low a compression, and measure the bores. Hard to say what went wrong; ring stagger and no PCV would not seem likely at all. Either the rings are ruined (wrong gap and they seized for a moment, or re-used pistons with worn grooves, or upside down, or busted lands/rings due to detonation), or the bore surface is ruined. Or they did not bore it and there is a lot of taper and wear in the bores. I had the same level of compression as you have on #1 cylinder of a /6.... needed to bore it out to .040" !

As for stock rings, Hastings makes some good rings with a moly faced top ring. They have grit recommendations in this link:
https://www.hastingsmfg.com/ServiceTips/cylinder_bore_refinishing.htm
 
OK so totally off the frecken wall, and maybe a guy that runs mopars and ferds and visits this site can shed some incite. But I can remember from a moderate time ago (ok, long ago) that it was told (maybe a wise tale) that some certain ferd block were so hard that they wouldn't always seat rings on a rebuild. So they use an amount comet or bonami in the cylinder to help seat rings. In a far stretch of the imagination I can see it. Kind of like lapping valves in. If your in such a predicament might it be an option to try? I know I wouldn't but hey...........


Anybody???? I would think your just after the diatoms to do a little light scratching.
 
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