When I went to install the rings, I noticed that the top compression ring was beveled on the inside edge. Is the bevel supposed to face down? There is no dot. Has anyone ever used these rings?

 

i'd ask the maker how it installs if there were no instructions or referance for the bevel. must be a pretty hot engine to use gapless rings.

 

The rings in my other 305 have the bevel facing up.

 

thanks, I asked the guy that sold them, and he said the bevel faces up. I don't know what you meant by the motor being hot, but a couple of cylinders had taper greater than .005, that's why I went with gapless second ring.

 

Sounds like you need a bore.

 

reason i said you must have a wild engine is because ZGRs are for competition engines, not run of the mill engines you'd see in a daily driver.

 

A gapless ring will not give a power advantage on a used cylinder.

If you want to rebuild a motor with non bored cylinders and reuse the pistons, Hastings makes a piston ring especially suited for this. You must hone the cylinder bores thou to remove the glaze/ polish so the new rings will seat.

You're wasting your time with gapless rings on this motor.

When a piston ring is in the cylinder the gap is very small.
the gap space actually seen by the combustion gas pressure is even smaller especially when the moter is at WOT because the ring heats up and expands.

The quality if the ring seal against the cylinder wall has much more to do with how well the cylinder will seal while running.

 

I didn't know this. I heard of the hastings rings, but never looked into it. Someone I talked to, at a machine shop I used to deal with told me to go this way. I'm happy I spent only $90, instead of the total seal $180 rings. I hope the rings aren't garbage. I already honed the cylinders,and installed all the pistons, so I can't get a refund. Are they just regular hastings rings? thanks for the info

 

Hastings has a "Rebuilder ring" that is designed for those on a budget that just want to hone 'er and put in new rings.
There is nothing fancy about this ring but it works.

 

Check this out:
http://www.carcraft.com/techarticles/77899/

The following statement is from one of the pics included in the above tech article.

Total Seal’s patented gapless rings generate ultra-low leakdown numbers. The design incorporates a two-part interlocking ring that closes off the gap to enhance overall sealing—yet as the ring wears, the gaps stay sealed. The latest competition versions put the gapless ring in the top groove.

Here's another informative article:
http://www.aa1car.com/library/2003/eb90329.htm

Check out the quote from the above article:

A lot of the cutting edge ring and piston technology that’s being used in racing today will eventually find its way into production engines. The piston and ring sets that are found in many production engines today were considered racing parts less than a decade ago, so it’s logical to assume such things as "gapless" rings and exotic coatings may be in OEM engines before long.

Keith Jones of Total Seal Piston Rings says eliminating the end gaps in the compression rings can improve horsepower by as much as 10 percent depending on the application. "Our gapless rings have been very popular with racers, but we also have conventional rings, too, and offer both types with various coatings."

I think this warrants a better rap for gapless rings than what they've received in the past. Just my

 

would there really be any problem with using gapless rings though?

if anything I would think it would help out a little bit with reliability though as far as oil being less prone to getting blowgas in them.

though as far as power gains I donno.

 

those are some interesting articles on rings. thanks for the replys
rx7speed when are you going to drop a 350 with a 10 bolt rear in your rexie?

 

prolly not anytime soon. need to fix her and can't even afford to do that right now. plus I'm hoping to get at least 250k out of the motor. when she blows the motor though and I have enough money maybe. but I woudl rather do it to a first gen rx7... they are a lot lighter and come with a solid rear end. much better for launching

 

Just the cost, I guess.

 

I give rx7s credit, even though I haven't heard to many good things. Someone I went to school with had a first gen running low 11s all motor, coming out of the hole at like 10 grand. I wish I still had the video, it's pretty funny to watch because the front end bounces a lot. He modified the shocks but did something wrong.

 

Seems to me this topic is right up there with "the chicken or the egg", or "Tastes Great. Less filling." (The old guys will know that one )

Other tests have shown that having a larger gap in the second ring (apposed to running a smaller gap than the top ring) also increases power and efficiency by the higher pressures under the top ring forcing it to seal better against the cylinder wall.

 

Total Seal and most other gapless plug manufacturers do exactly as stated above. The second ring is there to help the top ring seal and help scrape oil for oil control. Most N.H.R.A. & I.H.R.A. drag racers remove the second ring for less drag since they rebuild the motors in between rounds, oil control isn't very big on their list,lol.

 

now I'm confused. always thought lower pressure would help.


least that was my thinking after seeing vacuum pumps for the crank case.
always heard that the pvc with it venting the crank would increase ring sealing also

 

I'd guess a larger gap in the second ring would be allowing more crankcase vacuum below the top ring, which would increase the difference in pressure above and below the top ring and allow slightly better sealing? If that were true though I'd wonder why there's a second ring at all.

 

If the pistons/cylinders/rings are not doing their job (sealing), you have a problem called "Blow-by". Blow-by occurs when hot combustion gasses leak past the rings and into the crankcase. Besides the obvious loss of power and efficiency, many people aren't aware of another consequence, which is the damage caused by hot exhaust and flames into the crankcase! You are literally heating your engine's oil with a blowtorch. Yet another complication is the contamination of the lubricating oil with exhaust and gasoline. Based on these negative side affects alone, blow-by should be avoided - the added incentive of increased engine power will be a bonus!

Obvious signs of blow-by are carbon build up (nasty hard, black chunky stuff) and/or heat discoloration on the piston land (between the top and second ring). Bad cases of blow-by will even discolor the piston skirt to a black/brown color.

Let me explain even further, so you'll be totally convinced. Ideally, as the piston is beginning to move upwards on it's compression stroke, the air/fuel mixture is compressed above the piston and rings. The rings are sitting on the bottom of the ring lands as the piston drags them upwards. As the pressure increases, the rings (especially the top one) are pushed downwards even more against the ring land. The combustion pressure spreads across the upper ring surface and down behind the ring, and forces the ring out against the cylinder wall. The radial pressure of the ring tension is only used to START the sealing process, and cylinder pressure is what really pushes the ring outwards against the cylinder wall. For this to occur, the ring gap and piston to ring contact surface must be perfect.

There are multiple problems that can result when the piston and ring mating areas are ignored. Excessive clearance between the backside of the ring and the ring groove in the piston results in pressure building too slowly behind the ring, and leakage occurs because the ring is not being pushed out against the cylinder. This gap should be as small as possible.

Also, if the ring is not sealed against the bottom of the ring land, the pressure will leak past this area. Once the ring is leaking, the hot gasses from the chamber are like a torch to the metal surface of the piston land and the ring itself. This excessive temperature bakes the oil in that area and turns it to carbon, which reduces ring clearance to nothing and grabs the ring solid. Can you say, "ring replacement"? You don't want to have to replace those on a regular basis! Although there is a second ring, it is primarily an oil scraper ring, not a compression ring, and if the top one leaks for any reason, your engine loses power.

 

very well written, now I understand fully

 

I use Total Seal gapless rings on my 400, and I have no complaints so far. The top ring is standard with a gapless 2nd ring and standard oil control rings.

I noticed a slight improvement in vacuum, and ALOT less blowby using these rings. But as stated above, if your cylinders are not properly prepared, any ring would be useless.