icantlearn

Ah ok. I thought you want a film of oil to coat the walls as lube. Obviously not enough to produce smoke but enough to keep everything moving.

As far as the car smoking only at idle, I have no idea. I would think if the rings were bad it would smoke more in RPM than at idle. So, I'm stumped.

codrus

AIUI, the oil control rings are supposed to leave a certain amount of oil in the cross-hatching to lube the compression rings, thus even a brand-new, "perfect" condition motor still burns a teeny tiny bit of oil. If the oil rings don't seal properly, they leave a lot more.

--Ian

icantlearn

But it would do it all the time if it was the oil rings, not just idling.

cal_len1

It's a bit of a balancing act, you need enough of a film of oil to keep metal on metal contact (rings to cylinder bore) to a minimum, but if you leave too much it will lead to excess oil consumption. Essentially, this is done with picking a correct cylinder bore surface finish, the correct tension of the rings (how hard the rings push against the bore), and how round the bore is. Generally, if the rings are not working very well, it will be worse at higher speeds.

Note. 2nd rings scrape oil too...

cal_len1

A new motor will always burn a little oil, because combustion always evaporates some of it. That's why you can never have motor that has no oil consumption.

codrus

IIRC, it does it when idling after running hard. That might just mean that it does it whenever it's been running hard, but at above idle the smoke is diluted in the much larger volume of exhaust gas, so you can't see it.

--Ian

aidandj

iTrader: (5)

It smokes like crazy. There is no way you wouldn't see it when driving hard.

icantlearn

But thats assuming that the same amount of oil is getting by. The higher the RMP/load, the more oil would get by. So you should still see it. Right?

Edit: thats for Ian.

cal_len1

It may be less visible, as when everything gets hotter, you get a more complete burn of the oil in the combustion chamber, exhaust ports, etc.

Edit. Now that I think about it, if your oil ring wasn't sealing it's flanks well enough against the piston when you are pulling vacuum, you could be pulling oil up into the combustion chamber, but not see it when making close to atmospheric intake manifold pressure.

aidandj

iTrader: (5)

Doubtful. I had someone drive behind me on the track and saw absolutely nothing other than a few very small puffs during shifts.

And remember, its hard driving, then cool down. Then idle. Then wait a few minutes, then smoke.

codrus

Maybe, maybe not. On a 250-ish rwhp car, gas flow at idle is like 1% of what it is at max power, so even if the oil leak goes up with RPM it's not going to go up as fast as the diluting gas flow does. This isn't a case of blowby pressurizing the crankcase and pumping oil out through the PCV.

Also, as cal_len says, romping on it means more heat, which changes the way stuff burns.

Another wild hypothesis: heat changes the geometry of the the oil control ring, spacer, piston, and cylinder. Running hard builds up heat in certain parts, then when it idles the heat transfers to other parts, changling that geometry.

--Ian

icantlearn

Aidan, I have a question for you. If you were do do this over again, would you have just bought a TSE Longblock?

aidandj

iTrader: (5)

Of course not. But I'm weird like that.

icantlearn

reasoning?

aidandj

iTrader: (5)

I like learning new skills and gaining experiences more than I like swiping my credit card.

Also there's no guarantee it's the long blocks fault.

icantlearn

I can see where you are coming from.

aidandj

iTrader: (5)

Also a TSE long lock would have come with supertech seals and a shitty boundary FMS.

Both of which he has since changed. (I believe)

codrus

When thinking about buying vs building, here's a couple of things to consider.

- usually building is cheaper but takes longer. Are you more sensitive to time or to money?

- do you find building (and learning how to build) to be fun and rewarding in its own right, or is it simply a means to and end (having a fast track car)? Put another way, if you have limited amounts of car-related free time, do you want to spend a good chunk of it building the car, or would you rather maximize the amount of time you spend driving the car?

Everyone has to find their own balance on these scales. Aidan's seems to be pretty far on the cheap/building side of things. I'm actually kind of surprised he hasn't started a Locost frame yet.

--Ian

aidandj

iTrader: (5)

For me the satisfaction of a track day is not a fast lap time. But putting my hours and hours and hours of hard work to the test. If it holds up then I did things right. Otherwise, learn from mistakes and redo.

I'm not in this to make the fastest most reliable car around. I'm in this to learn new skills, expand my knowledge, and have fun along the way.

Sure, this last set of issues has been frustrating. But in the end it will mean more to me than if I had just bought a car and gone driving.

Drove the car more yesterday. And my god its good. It pulls so hard and so linear.

Got a possible line on some 800/500 springs, and some 225 R7s. Next planned event is the packwood tour, for my first shot at "real" autocross.

patsmx5

iTrader: (16)

All of this.

Besides, many of the people offering solutions for those who want to write a check, are ones who went down this path and learned for themselves what works, and how to build things.