piston rings not sealing, why?

[Lynn]

Hate when things like this go wrong.
When you say "cast iron as per the SI rebuild kit I purchased" I assume you mean a chrome plated top ring, is that correct?

If so, yes traditional engine building requires a rougher final hone to facilitate break in. It may be possible to get them to seat at this time, but ANYTHING you try, other than Mike's suggestion or disassembling the engine carries at least some risk.

Going to disagree with Mike, but just a little. I agree with him 100% that pressure aids piston break in, but disagree that it is the ONLY thing that can. The other is increased friction, and therein lies the risk.

Least riskiest is to richen the mixture enough temporarily so that some fuel is getting on the walls. The increased friction will aid the seat between wall and ring. The risk? You over do it and score a cyl. Ouch.

Other methods have been suggested over the years, but nothing I would car to try. Even saw a guy dump Comet household cleanser down the carb while it was running to act as an abrasive to aid sealing. That engine ended up coming out.

I can tell you exactly what I would do after 13,000 miles. Number 1, try just what Mike posted above. Can't hurt a thing to try. If it works, great. Only thing I would do different is to pump the gas a few times right before you start the hard load driving for 15 seconds or so.

I would not try honing cylinders with the respective pistons at bottome dead center. No disrespect, but seems like a great way to leave some abrasive material behind. Again, you would risk scoring a cyl. Besides, it you are taking it that far apart, why not just go all the way and fix it correctly.

If Mike's plan doesn't work, take out the engine and disassemble.

Problem with additional honing is that you will be removing some metal, and I don't know how tight you are on tolerances, but you don't need to make things too loose. Did you save an old piston? If so, you can hand lap the rings to each cylinder. It will take several hours, and a lot of patience. I built a BMW turbo motor years ago. I had chrome plated top rings, but asked the machinest to put the slickest hone he could on the cyl. He asked to see my rings. I knew he wanted to see if they were chrome. I didn't have them with me, but admitted to him they were chrome. He told me he could do a 600 or 700 (can't remember) final hone, but also told me the rings would "never" seat, and it would always burn oil. I told him he was off the hook, and to put the smoothest final finish he could. Almost looked like a mirror. After file fitting each ring, I carefully laid out every part, and using an old piston, hand lapped each ring (just the two uppers... no need to do the oil ring) using a diamond lapping compound.

That engine never used a drop of oil (at least not measurable on the stick between changes). It died from owner abuse from other causes after about 150k miles of very hard driving, but never used oil. BTW, the guilty party (abuser) shall remain me.

Of course, if you buy another set of rings, and hone the cylinders accordingly, you may be just fine. Just telling you what I would do.

[JoeHall]

My guess, as to why the builder used a 400 grit hone: Probably has not installed a set of cast rings in decades; only installs moly rings, in the brand 'x' motors, which are his bread and butter. Did not bother to go buy the correct hone, instead just grabbed the one he always uses for molys.

As for the leak down noise (gurgling/hissing sound), when shut down and one piston lands near TDC on the compression stroke, or when turning the motor by hand, they ALL do that. Never had one that did not. I must be misunderstanding something here.

[GrumpyOne]

Hi Guys I need some help with a Studebaker engine that was rebuilt by a very reputable race engine guy from my area. Some back ground on the engine. It is a 61 289 that was bored 30 over and assembled with all new internals from a kit from Si. After 13000 miles it is still using a lot of oil approx. 1 qt. to 500 miles. Yesterday the fellow that built the came over and we did a leak down test. We got readings 21% to 33% leakage on most cylinders and we could hear the air blowing in to the oil pan, not good. The machine shop that did the machining did a fine cut on the hone job because they are use to using molly piston rings. We used cast iron as per the SI rebuild kit I purchased. The engine builder thinks the honing should have been a much courser cut as to help the cast rings seat better and faster. Has anyone else had this problem. Also the machine shop said this block was extremely hard, a very good casting . Also does anyone know where I could buy a set of molly piston rings. I hate doing things twice. I follow the forum sometimes when I have time. You guys know your Studes, I*m always impressed with the collective knowledge out there. Thanks in advance for any help.

I installed a set of moly rings in the Power Hawk back in 1971, did not hone at all and it took 15K for the rings to seat. Now 31K later it still runs like a new engine with very little oil consumption. I'm not a big fan of honing anything by removing material...

[JoeHall]

I installed a set of moly rings in the Power Hawk back in 1971, did not hone at all and it took 15K for the rings to seat. Now 31K later it still runs like a new engine with very little oil consumption. I'm not a big fan of honing anything by removing material...

There are hones designed to remove material, and there are hones designed to break the glaze, and scratch the surface, e.g. a ball hone. To remove even .0005" of cylinder material with a ball hone would require about 1000 passes back and forth with the hone. Usually, a few dozen passes are all that is necessary. As long as the correct type hone is used, there is NO PROBLEM with increasing piston to cylinder clearance, when breaking the glaze for new rings.

[altair]

The art of honing cylinders has technically advanced substantially in the last 20 years. Hones are very different than the three bladed types and the methods of application have also advanced. I have spoken at great length with a local machinist and he demonstrated the use of a modern hone. It is fitted into a permanent jig vertical to the cylinders and actuated up and down by hand with lubrication. The stones are of a special design and not typical. The intent of the finish is to eliminate any scratches and create a near polished finish. Rings are designed with sharp edges removed. When this form of honing is performed there is no break-in procedure. I have a friend that builds race engines and is very competitive and a consistent winner, however I would not let him near my engines. His ring clearances and ring gaps are double of that used on a street car. He can do 150 mph in the 1/4 on the weekend for 8 or 9 seconds and then the car sits in the garage the rest of the time, but a consistent winner.

[JoeHall]

The art of honing cylinders has technically advanced substantially in the last 20 years. Hones are very different than the three bladed types and the methods of application have also advanced. I have spoken at great length with a local machinist and he demonstrated the use of a modern hone. It is fitted into a permanent jig vertical to the cylinders and actuated up and down by hand with lubrication. The stones are of a special design and not typical. The intent of the finish is to eliminate any scratches and create a near polished finish. Rings are designed with sharp edges removed. When this form of honing is performed there is no break-in procedure. I have a friend that builds race engines and is very competitive and a consistent winner, however I would not let him near my engines. His ring clearances and ring gaps are double of that used on a street car. He can do 150 mph in the 1/4 on the weekend for 8 or 9 seconds and then the car sits in the garage the rest of the time, but a consistent winner.

Hand lapping of rings to use 600-700 grit hones, polishing of race car cylinders, honing procedures for a Ferrari or space shuttle motors, etc.; all apples to oranges, regarding the OP's problem and technology in a Stude motor.

As for concerns of leaving abrasive material behind, if running a ball hone down the cylinder with piston at the bottom: anyone who does not understand the importance of cleanliness, nor can figure out how to clean up after the operation, probably should not be trying to do anything inside the motor. JMHO

[Dan Timberlake]

" We got readings 21% to 33% leakage on most cylinders ". Got info on all 8 ?
Installing rings upside down can cause oil control problems, but I don't >>think<< that would cause such miserable leak-down readings.

Did you receive the engine from the builder as a sealed assembly, or did he install it in the car for you to drive home?
Are there any eye witness accounts of how the engine was started and how it ran initially ?

I'd expect iron or moly rings to seat fine on just about any decent honed finish.
I have limited experience with chrome faced compression rings, and never had any trouble, but there are certainly lots of horror stories floating around.
I'm a proponent of break-in that uses brief ( like 3 seconds) periods of mid rpm heavy throttle, each followed by several minutes of gentle running.

If poor cylinder prep before assembly left honing grit behind, then irreparable damage can be done to the rings (and cylinders) very quickly.
According to pages 92-83 on the link below there are other ways to cause similar problems.

http://mam.kspg.com/mc/epaper?guid=14c0122387e59c2c

Plenty of scary pictures here - page 39 may prove to be significant.

http://buy.engineparts.com/publications/DistressGuide.pdf

In any case it sounds like some internal investigation is going to be needed.

Maybe start with a peak at the cylinder walls' condition thru the spark plug holes via bore scope ?

[Endl98]

Oddly enough. One of my new auto techs I just hired , was a gm tech for 6 years. The 5.3 L with cylinder deactivation uses a lot of oil on those 4 cylinders as time goes by. The lack of compression on the rings causes them to glaze over. Gm has the techs install new rings and they don't even hone the cylinders. They just drop in a new set or rings .

[swvalcon]

A cylinder that miss fires is known to suck oil. You would think GM would be smart enough to know that.

[Hawkowner]

I have seen many sets of rings installed in a 454 that used more oil after ring job than before because the expanders on

the oil rings was over lapped and not butted at the ends. Do not know the style of oil rings used but this is food for thought . For seating rings in the old days the old timers used to run some Bon Amma scouring powder through carb.

[TWChamp]

"If poor cylinder prep before assembly left honing grit behind, then irreparable damage can be done to the rings (and cylinders) very quickly.
According to pages 92-83 on the link below there are other ways to cause similar problems."

Dan is right about the importance of removing all the grit from honing. In the 80's I hot tanked an Olds V8 for a customer. He bought the rings from the shop where I worked and he honed and assembled the engine. He came back a week later complaining about oil consumption, so we sent the rings to the lab for analysis. The report came back that the honing grit was not properly cleaned out. Sure didn't take long to destroy that set of new rings.

BTW, that customer also showed me how he polished the tops of the pistons to a mirror finish before he assembled the engine. It looked very impressive, but when he brought them back in a week later, they were covered with carbon just the same as if he never polished them.

When I hone a cylinder I like to use a syphon sprayer with gas to wash out the cylinders and block, then brush oil on the cylinders, let it set for several minutes, then wipe it off with a clean paper towel. I then repeat this as many times as needed until the paper towels come out clean.

[Bill A]

The reality is after an overhaul if the darned thing has a consumption issue it is easy to verify that fact and the very next thing you do is take it back apart and figure out what went wrong. there is no mystery or goblins, either it was right or not and it doesn't take days or weeks to discover the outcome. I spent way too many years working heavy lind building engines and drive it for 30 minutes and you know but running it for 30 minutes and listen and you already know.

[doofus]

Pull it out and tear it down and you will have your answer. Luck Doofus

[JoeHall]

"If poor cylinder prep before assembly left honing grit behind, then irreparable damage can be done to the rings (and cylinders) very quickly.
According to pages 92-83 on the link below there are other ways to cause similar problems."

Dan is right about the importance of removing all the grit from honing. In the 80's I hot tanked an Olds V8 for a customer. He bought the rings from the shop where I worked and he honed and assembled the engine. He came back a week later complaining about oil consumption, so we sent the rings to the lab for analysis. The report came back that the honing grit was not properly cleaned out. Sure didn't take long to destroy that set of new rings.

BTW, that customer also showed me how he polished the tops of the pistons to a mirror finish before he assembled the engine. It looked very impressive, but when he brought them back in a week later, they were covered with carbon just the same as if he never polished them.

When I hone a cylinder I like to use a syphon sprayer with gas to wash out the cylinders and block, then brush oil on the cylinders, let it set for several minutes, then wipe it off with a clean paper towel. I then repeat this as many times as needed until the paper towels come out clean.

For rebuild, I like to wash the bare block with soap and water, with particular attention to scrubbing the cylinders real good. Then when the block is dry, use a towel dipped in ATF to wipe the cylinders down. Then upon assembly, with ring compressor in place, dip each piston upside down into a coffee can of ATF, turn it sideways to stop most of the dripping, then slip it into the hole.
But if not tearing it completely down, and using field expedient measures, as discussed above, I just try to be creative in keeping everything as clean as possible.