Ring Gap suggestions

[Steel Heads 'R' Us]

I am using Perfect Circle Hellfire rings in a 355 SBC. I am using SRP forged pistons with 1/16, 3/16 ring stack. The motor will be 10.25:1 with lots of nitrous via a Big Shot Plate. Should I expect a ton of blowby out of a brand new motor? I have two breathers on the passenger side valve cover and it puffs some kind of light smoke out of both breathers like two little chimneys eventually causing some kind of liquid to drip out of them onto the header and creating a thick smoke that track officials don't like too well. What kind of ring gap should I be running for a street/strip engine like this on nitrous? Chris.

[91notch]

just curios how many passes you have on the motor, and have you done a leakdown test? doesnt sound like a end gap problem unless they were too tight and hurt it from that.

[81 olds]

if it leaks down good just go to your local sporting goods store and get some sweat bands and wrap them around your breathers . when they get soaked replace them we've done it and it helps

[Chris Uratchko]

As Kevin stated, the ring gap does not cause blow by unless maybe they butted ends, cracked, damaged... sounds like the cylinders could either be out of round, or the rings/cylinders are worn... or rings cracked.

I've seen a lot of cylinders that are not honed correctly, and you can always tell with the shiney spots under each stud.... cylinder being out of round right where it counts most.

[388Monte]

I would do a leakdown test for sure, ring gaps are not your problem. Like said above, either the rings butted and broke or the hone job has gone away. Does the plugs have oil on them after a pass?

[Steel Heads 'R' Us]

I've had this problem since the motor was built. But to answer your question it probably has 60 or 70 passes on it. The ring gaps are set are .024 top and .026 2nd. The plugs have always had oil on them after I let it warm up or after a full pass. I haven't done a leakdown test yet. As far as I know the block was honed with a torque plate, or was supposed to be... That's all I know about the honing.

[Rick Crawford]

Buy the Moroso breathers that they use on header scavanger setups. They have the hose connector on it and will drain back into the valve cover vs drip from the open element like you are running now. As long as you can deal with them not looking as pretty.

[Steel Heads 'R' Us]

I'd do that but the problem is I've got tubes welded onto the valve cover with female K&N's with clamps so I don't think I can mount the moroso breathers. I've had baffles welded in. I've rolled up a whole pad of Scotch-Brite and stuffed it in the tubes. I've done everything I know to do and nothing works and it's really an eyesore and as said the track officials aren't too fond of it either... I'm lost.

[Chris Uratchko]

It's definitely a blow by issue from the sound of it.... Put a vacuum pump on it if you can afford it.

[388Monte]

I've had this problem since the motor was built. But to answer your question it probably has 60 or 70 passes on it. The ring gaps are set are .024 top and .026 2nd. The plugs have always had oil on them after I let it warm up or after a full pass. I haven't done a leakdown test yet. As far as I know the block was honed with a torque plate, or was supposed to be... That's all I know about the honing.

I would honestly pull it apart and get it re-honed and put new rings in it. By the sounds of it, you have never gotten the motor to seal up. I can email you a sheet on the proper honing steps for that ring. What block is it? Bowtie, Factocy, Dart? Depending on which one of those will also effect how the cylinders need to be honed.

[mike gerlach]

Low tension oil ring? Too much oil in pan?

[Steel Heads 'R' Us]

It's a factory block, I've got one more test and tune and a race to make this year and I can pull it down and re-ring it and stuff. I'd love to be able to afford a vacuum pump and I might still try to squeeze one out before the race. I've had plans for one for some time now but just haven't been able to turn loose of the money. Which pump/pump kit should I look into? I've seen a few different brands but I don't know which one to go with. I'm gonna ask a stupid question. Would it make a difference if I switched the valve covers side to side? Does the smoking out the breathers have anything to do with the windage of the crank going to the passenger side? I mean I know that it can only get out through the lifter valley, heads, and then valve covers but I'm looking for anything at this point... The reason I don't switch them is because one of the tubes gets in the way of my wiper motor so I had to keep it on the passenger side... And yes they are low tension rings. About the oil in the pan, I don't know. I run a stock pan and pickup and stuff with the normal 5 quarts. All my clearances are loose so theres a little more oil up in the motor than normal but that's about it. I remember reading about a motor that Dan Fletcher used to run a few years back. It was a 350 with super loose clearances and he only ran 2 quarts of oil in it. By the time he'd reached the 1/8th mile mark the oil pressure would bottom out because all of the oil was up in the motor and there was none in the pan for the pickup tube to get. I don't know how long that motor lasted but I feel like I drive mine too much on the street to do something like that... Chris.

[strlegal]

Do you have to add oil to it very often? If so how much in how many miles?

[Steel Heads 'R' Us]

Never had to add oil at all...

[George Klass]

Touch base with Mark O on this, he invented the piston ring. Not many people realize this but Mark is Rocky Childs father.

[mike gerlach]

... And yes they are low tension rings. . I run a stock pan and pickup and stuff with the normal 5 quarts. .

Bingo...

[Steel Heads 'R' Us]

Ok.... Elaborate on your "Bingo". Are the low tension rings the cause of my problems or what?

[Bbarsh]

I've seen a lot of cylinders that are not honed correctly, and you can always tell with the shiney spots under each stud.... cylinder being out of round right where it counts most.

I used to run a 351w stock block and saw those spots around the studs,I thought it was because the studs pulled so close to the bore. Thanks for giving up that info,it's nice to know the true cause. I have since changed machinists so hopefully I will never see that again.

[Steel Heads 'R' Us]

I got to thinking back a little bit when I had my block rehoned and I remembered that Mondello's done the honing for me. I don't know for sure without tearing into the motor but with the reputation and skill at Mondello's I'm pretty sure it was done right. I'll make a note to pay close attention to that when we refresh it this winter though. Any suggestions on vacuum pumps? Are my low tension rings the culprit here or what?

[Robert1320]

I would put a Star Vaccum pump on it.
I am not a big fan of the low tension rings
especially without a pump.

[Chris Uratchko]

The vacuum pump should help some.... unless there is a mechanical failure.

If there is a failure in a ring, or cylinder wall.... the pump is just going to pull a bunch of oil out of the engine.