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pro's and con's of engine reringing trick

Discussion in 'The Hokey Ass Message Board' started by carcrazyjohn, Sep 18, 2010.

  1. carcrazyjohn
    Joined: Apr 16, 2008
    Posts: 4,844

    carcrazyjohn
    Member
    from trevose pa

    Many years ago a streetrodder friend of mine taught me to buy 10 over rings and file fit each ring ,All 4 any pro's or con's to this reringing trick Of course 2 rings are oil rings
     
  2. eddieb
    Joined: Apr 6, 2009
    Posts: 52

    eddieb
    Member
    from Sharon SC

    I guess you are talking about using them in a standard bore. (or near standard) It makes them out of round.
     
  3. rodknocker
    Joined: Jan 31, 2006
    Posts: 2,267

    rodknocker

    I'm assuming you're just replacing rings without doing any machining to the block.To me if I have an engine torn down that far I'd be taking it to the machine shop to make sure everything is good, no taper, or out of round.i think if you ignore these tasks and just replacing the rings with oversized ones, you may be writiing your engine off.
     
  4. What is the advantage of that? If the bore is out of spec then fix it. Like eddieb said... the ring when compressed will no longer be round.
     
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  5. carcrazyjohn
    Joined: Apr 16, 2008
    Posts: 4,844

    carcrazyjohn
    Member
    from trevose pa

    Im just curious .I only did one motor that way and its long gone .I usually just rering them with standard ,Im just wondering if any body else uses that trick ,
     
  6. dave lewis
    Joined: Dec 12, 2006
    Posts: 1,358

    dave lewis
    Member

    John, "race " rings only come in "file fit " size IE:.035 instead of .030 etc.
    And yes ED, they are slightly out of round when new..It takes a few minutes of run time for them to get round as they are made from very maleable material.
    Smokey Yunick liked to re-use the old rings (kept in the same cyl ) during a race engine refresh because the were already round !
    Dave
     
  7. Most performance engines we build we order a ring size of .005 larger then the bore size and file to fit and that depends on the piston style as well.
     
  8. phat rat
    Joined: Mar 18, 2001
    Posts: 4,383

    phat rat
    Member

    A ring is not made round. The O.D. becomes round when compressed. Depending on application there is a large flat area on either side of the gap. In the machining process the area at the end of the flat spot (away from the gap) is refered to as the rise. The rise also depending on application and size can run anywhere from .020 to over .125. If we assume the bore is correct then the gap would need about .031 filed off in order to fit. The expansion gap cut during the machining process can run from as low as .180 to over 1.100 again depending on application and type of ring
     
  9. Larry T
    Joined: Nov 24, 2004
    Posts: 7,680

    Larry T
    Member

    If you're talking about file to fit an engine that has a little wear, I don't think I'd do it. Most cylinders wear at a taper, larger at the top. If you file to fit at the top of the cylinder, then it's gonna be to tight at the bottom.
    Larry T
     
  10. squirrel
    Joined: Sep 23, 2004
    Posts: 46,390

    squirrel
    Member

    I'm too damn lazy to file rings to fit (unless checking the gap shows that they need it, or they're for pistons that you can't get "normal" rings for). And I'm not very good at filing the gap perfectly perpendicular anyways.

    How much do you think it's really gonna affect performance?
     
  11. Diavolo
    Joined: Apr 1, 2009
    Posts: 810

    Diavolo
    Member

    Never bothered file fitting them. I imagine there are some very small gains to be had by doing it but knowing me I wouldn't file them enough and they would get stuck. Sometimes I just don't get things right and I pay for it...
     
  12. Retro Jim
    Joined: May 27, 2007
    Posts: 3,860

    Retro Jim
    Member

    I rebuild Ford engines and I just use the ring that are already sized .
    If I am building a high HP drag race engine then I will file to fit . Other than that , I just use what comes out of the pack .
    I also buy good rings and not some cheap crap that you have no idea on who made them either !
    One question , did you have the block bored or just honed ? Standard stock rings work best in a honed block and chromemolly work best in a bored block .
    Just my opinion !

    Retro Jim
     
  13. eddieb
    Joined: Apr 6, 2009
    Posts: 52

    eddieb
    Member
    from Sharon SC

    They are round when they are compressed to the diameter they were made to fit in. Supposed to be anyway.
     
  14. This kind of sounds like an old rebuilder's trick that may have worked to a certain degree under certain conditions, like when you couldn't afford an overbore and a new set of pistons.

    Use a dingle-ball hone to deglaze the bores, maybe knurl the pistons and use .010" over rings with the end gaps file fitted. You ended up with slightly higher ring tension which helped seat the rings more quickly and reduce blow-by. If you had much taper you'd have make sure the end gaps weren't too tight or the rings would bind at the bottom of the bore.

    Not really a "racer" trick because you ended up with extra drag in the cylinders. But I could see it working to a degree in an older, slower turning, lower compression engine. Maybe kind of a "field fix" for a used car dealer years ago.

    Some of the old parts catalogs used to list "severe duty" ring sets for older engines. Always suspected that they were .010" O.S. rings with a little extra end gap clearance ground into them.
     
  15. Wheelie
    Joined: Nov 26, 2008
    Posts: 234

    Wheelie
    Member
    from Dallas

    I wouldn't call it a "trick" unless some poor bastard bought an engine that was reringed in this manner.
     
  16. matt 3083
    Joined: Sep 23, 2005
    Posts: 137

    matt 3083
    Member
    from Tucson, Az

    Sounds like something we did back in the 1950's - 60's and earlier.
    First it was important to be too poor to go to a machine shop to get
    things done right. Second it was sort of important to not have any really
    deep vertical cylinder grooves. A good job would involve removing the
    ridge at the top of the cylinder. Clean the pistons, put on the rings,
    insert into bore, connect to crank with new bearings, put on head gasket with silver paint, torque the head(s). Start it. You're done. If you did it right and
    the gods are on your side the engine should run about 80 to 90k before
    you need to do it again. Run the engine real hard and your mileage will
    vary. Do it right and go to a machine shop and get good parts and
    put it together right and mine always went about 250k plus. Again
    run it real hard your mileage will vary.
    My guess is that a lot you "old timers" like me did it something like this.
    Yes we did know that there was a better way, we just couldn't afford it.
    Matt
     
  17. About 16 hp at 7500 rpm, in one SBC test we did some years ago.

    In most mild street engines, as long as the ring ends don't butt together, the avg. guy won't notice any difference. Rpm, piston-to-wall clearance, volumetric efficiency, crankcase pressure, and a whole slew of other things affect it anyway.

    With a good aftermarket vacuum pump that 16 hp would have been closer to 22-23 or more.

    Back-to-back ring tests are fun. :rolleyes:
     
  18. Rickybop
    Joined: May 23, 2008
    Posts: 6,511

    Rickybop
    Member
    from Michigan

    Even though I didn't start this thread, I have to say "thankyou" to you guys that gave reasonable answers, instead of "WTF...do it right"...or something to that effect.

    The fact is, John is a friend of mine here, and I know that he started this thread for my benefit. We talk all the time, and he knows exactly what I'm trying to do...a basic refresh of a '54 261 Chevy six. Yes, I'm too poor right now to have it bored and install new pistons. I wouldn't try this if the engine in question was overly worn, but this one seems like a likely canidate. So I cut the ridges with a ridge-reamer, and honed the cylinders. Gonna install new rings. Crossing my fingers.

    Some of you may have seen my recent thread, "[​IMG] Bought a f'ed-up 261 six...experienced engine-builders, help me think about this." In the thread, I explained how I bought this engine, and was told it didn't burn oil. It smoked like a fiend, and had low compression in two cylinders. Naturally, I was worried, and a little upset. But during disassembly, I learned more about this engine's condition. Check out the thread if you're curious. Thanks again to all who posted...even the guys who are eager to spend my money...that I don't have. :)
     
  19. hotcoupe
    Joined: Oct 3, 2007
    Posts: 480

    hotcoupe
    Member

    when you finish the work on this engine, please post the results.
    thanx.
     
  20. mustangGTS
    Joined: Sep 18, 2010
    Posts: 28

    mustangGTS
    Member

    File fit rings show a little bit of a horsepower gain, but the big reason is with blower/turbo/nitrous applications, you can set it "right for your application". Also some naturally aspirated applications that use a high silicone casting, can run tighter gaps due to less material growth at temp.
     
  21. I've always used .005 over file-to-fit rings on my engines, but I've also filed a shit-load of rings and I'm proficient at it.

    It is somewhat of a real pain in the ass if you don't have a real ring-filer . . . which I don't, but I do it anyways. Also, you better understand the correct gaps for your application and take your time. I just filed a set about 2 weeks ago (SBF 302) - took me about a hour to do all 16 rings.

    As another said, in many 'race' ring packages, that is how ALL of them come -- so it is a very common thing to do in new engine builds as well.
     
  22. This is the real logic and motivation behind making this kind of a repair. This isn't about getting the last couple horsepower out of a racing engine, it's about getting a few more years of daily use out of an old tired engine. This is from a mindset where a car wasn't so much a hobby as a valued mode of transportation. And when you didn't have the cash and a ready supply of easy to get parts, some people learned to be creative. Piston skirts and valve guides got knurled. High tension piston rings got installed. Rod journals got turned with the crank in the block and the engine still in the car.

    This is all from an era when many cars needed valve grinds, bearings or rerings at 50,000 miles. Modern engines, for all their damnable complexity, are just built that much better. But for the most part I don't think they'd tolerate most of these kinds of "creative" repairs. Besides, most of them will go 150,000+ miles without major repairs and by that time the rest of the car is prety well shot. So, as a rule, you just replace the whole car instead of repairing the engine. Simple economics, really.

    But an old Chevy stovebolt or a Dodge flathead would be a perfect candidate for some of these low-buck repairs. Just keep in mind that some of these tricks may have already been applied once or twice to these old engines. And you may have no choice but to scrimp and save up some cash to do the job the "right" way. :rolleyes:
     
  23. 51pontiac
    Joined: Jun 12, 2009
    Posts: 136

    51pontiac
    Member
    from Alberta

    Did the exact thing several times in the past - not enough money to rebuild. Didn't expect perfection but was always happpy with the results, especially the extra 70,000+ miles on a 250 chev six. My dad taught me how since that was how they had to do it on the farm (again, no money). As long as the bores are reasonably good, it will work. Honing properly is important. It is just an inexpensive way to extend the life of an engine.
     
    Last edited: Sep 25, 2010
  24. Rickybop
    Joined: May 23, 2008
    Posts: 6,511

    Rickybop
    Member
    from Michigan

    Yes...did it before on a 235 Chevy six, and I was happy with the results...worked out very good. Hone, rings, valve-job and bearings. A little exhaust-smoke on first startup, but after a bit, the rings settled in, and that engine ran excellent, with no smoke.
     
  25. phat rat
    Joined: Mar 18, 2001
    Posts: 4,383

    phat rat
    Member

    Back when, many an engine was rebuilt in the car. Thin wallets encourage ingenuity and a spirit of can do. As someone said earlier 50-70,000 mi and most cars back then needed a rebuild. It was a rare motor that made a 100,000+ without being rebuilt
     

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