Topic: Gapless rings

[Nic]

I'm having my 750 rebored and the machine shop that I spoke to reckons only a fool would use the old style rings. I haven't read anything here about total seal gapless rings. I love the sound of them but not sure I can get them for the 1st oversize Cyclex cast pistons. Anyone using these rings?

[krusty]

I'm having my 750 rebored and the machine shop that I spoke to reckons only a fool would use the old style rings. I haven't read anything here about total seal gapless rings. I love the sound of them but not sure I can get them for the 1st oversize Cyclex cast pistons. Anyone using these rings?

When I first read that I thought somebody must have been havin' a lend of ya so I went and Googled gapless rings cos I'd never heard of them. Well bugger me, there they were. Looking forward to responses on this one. Mmmmm, very interesting.

[dave500]

only for the "frequent rebuilder" a few million 308s and souped up 202s seem to do well enough with out them?

[trueblue]

True seal rings (gapless) are usually only recommended if you are using a high static compression ratio, over 12:1, or are running high boost pressure, in excess of 15psi.  Sounds like your machinist is a wanker, they are still using conventional rings in nearly every engine in production.  The improvement in sealing you get when using true seal rings in a standard engine is not justified by the expense.  Conventional rings are more than adequate for the job.

[dave500]

dont talk #$%* #$%*,,i want gap less,unlike my teeth!

[Nic]

Yeah, I can appreciate the absence of blow by though but I'd never heard of em before either, I'm pretty sure I'll just go with the tried n true. It's gonna be stock engine with a bit of head work and the CycleX #41 cam,  I reckon it'll out live me. Thanks for the replies. Gapless teeth, yep, some whitening wouldn't go astray either, lease I still got most of em

[dave500]

the normal rings will be fine!

[NitroHunter]

Nic I ran total seal 2nd rings in a big-bore SOHC turbo and had no problems, but it still had 4% leakdown. But a standard ring was just fine too and truthfully I found no documentable performance advantage.
FYI We also ran total seal rings in our Top Fuel car for several years back in the 90s, the thought was to minimize fuel dilution (washing the oil off the skirts) but with the advent of better piston coatings the scuffing cut way down, nowdays the norm is a standard 2nd ring just make sure it has enough gap or bad karma happens. It's a heat thing.
My .02 There is way more power to be found in other areas of a motor build than worrying about a small amount of ring blow-by. Concentrate on the basics like a zero deck piston height, and a PROPER valve job ie. open intake valve seat to 90% valve diameter with matching pocket work... your machinest can guide you there.
That all being said, if you want them, use them. 

[Nic]

Nic I ran total seal 2nd rings in a big-bore SOHC turbo and had no problems, but it still had 4% leakdown. But a standard ring was just fine too and truthfully I found no documentable performance advantage.
FYI We also ran total seal rings in our Top Fuel car for several years back in the 90s, the thought was to minimize fuel dilution (washing the oil off the skirts) but with the advent of better piston coatings the scuffing cut way down, nowdays the norm is a standard 2nd ring just make sure it has enough gap or bad karma happens. It's a heat thing.
My .02 There is way more power to be found in other areas of a motor build than worrying about a small amount of ring blow-by. Concentrate on the basics like a zero deck piston height, and a PROPER valve job ie. open intake valve seat to 90% valve diameter with matching pocket work... your machinest can guide you there.
That all being said, if you want them, use them. 

Thanks Nitro, I have a friend who is a mech engineer who goes on and on about how the less blowby is so good for your oil. Not thinking about extra power but the extra reliability. Anyway, this project is bleeding me dry or has already done so actually and any money saved is good money, I never really thought I needed the gapless but thought I'd ask here for any exp. Happy to go with std rings for sure. Thanks again.

[lucky]

This is what happens when car people work on your motorcycle.

[dave500]

most guys change the oil in these old air cooleds more than regularly any way?

[KB02]

When I built up my SOHC 750 with the Cycle-X 850 kit, I broke a second ring on one of the cylinders. Cycle-X wasn't able to supply a new set of rings () so that put me on the search for something that would work. I ended getting a set of gapless rings from Total Seal that were the right dimensions (I've got the part number is my build thread somewhere...).

So, YES, there are (or at least is ONE) SOHC's running gapless rings. Granted, I've been fighting carb (and $) issues to get it running right, but It's been running, it ran great!