Oil leak down thru the pump into the sump. You are putting on some serious miles in a short time.

??
Alan

The oil in the tank is draining through the S hose That's why it's smoking on start up, it smokes more the longer it sits. The Rothsport valve will fix it, had the same thing in my 930.

with lower level in oil tank, barely registering on level gauge when at fully warmed up idle, it no longer smokes on startup or otherwise. No need for one-way valve and engine is sound. 1,5 quart used in 3000 miles, inluding one smallish leak. Runs well too, 3.2 SS with stock cams works great for smaller roads with good torque from early on

Good deal, that's a cheap fix.

did you check oil with the dipstick
 

hello
i am may be misreading but you say the oil level gauge when determing how much oil to put into the tank.
if you are not using the dipstick when the engine is at 180 or above then you may be over-filling it.
the gauge good for ascertaining if you have oil in the tank but I would not use it as a guide to how much oil to put into the engine.

Most of the CP Pistons come with 2.0 or 2.8 oil controls, all of which are a low tension which usually is about 7-10#. It's common to see oil consumption is the 1 quart per 1000 miles, however surface finish of the bores, crosshatch angles, etc. all have a direct correlation to oil consumption. We did a study of different manufacturers honing specs for nikasil a few years back and found you can drive a school bus through the wide ranges of honing specs.

To oversimplify things, the higher the RpK, the faster the rings will seat, but the higher the Rvk, the more oil the valleys will hold and more oil the engine will consume. Problem is it's damn near impossible to eyeball a bore. You have to test it with a profilometer. The crosshatch angle will also affect ring rotation speed. That's something we do with every bore/block to make sure it's in our specifications, which is different than OE or what others use for reconditioning.

Well said. A lot of old historic ideas are still considered today. Most came out of the Iron block days and still in current use due to uncoated Iron liners.

Nikasil is getting old tech now too. It doesn't need the surface finish as rough as iron as it wont wear down like iron does. The cross hatch can be less steep as well as the oil retention is not required as much as iron due to a lower friction CF. The rings will rotate but in these engines its not as critical as in Iron blocks. Its about controlling this movement in these engines and one way is to use a non common angle.


Piston design and the ring selection play as much if not greater part in the oil consumption. Ring land designs, Gas ports, Napier style rings, tension numbers all help here.

In difference to my respected colleague here, I do not subscribe to the fact that rings seat the same way in a Nikasil liner as they do in a iron block or liner. I don't agree that they will seat quicker with a higher surface finish number. Nikasil is extremely hard compared to iron. Wear out quicker? I guess the ring may seat better on its way to wearing out.


Charles know his stuff, so I'm open to other ideas and opinions.

Thanks for your reply Neil.

I should have been more specific on honing finishes. In my evaluation of various brands and platers, I found Ra finishes as low as 3 and some over 20 with Rvk, RpK, and Rk values all over the board.

Without getting into specifics for the component values that go into calculating surface finishes, an Ra over 10 is IMHO will result in shorter ring life. Anything over 14 and for sure it's going to burn oil and smoke. On the flip side, a finish of 3-4 will have very little oil consumption, but if the engine over-rich during break-in, the bores will glaze over. Over the years I've seen incorrectly finished cylinders wear rings out in no time like Neil mentioned above.

Running rings that are higher tension on Nikasil, even with proper finishes, will result in elevated oil consumption and smoking in no time as well, again because the rings wear out prematurely. There really isn't any reason for running tensions over 10# as long as everything is set up properly.

So many things go into setting things up properly. Only thing I can say for certain is that you have to check 100% of everything, regardless of manufacturer. In this day and age, you can't assume things are right, even from trusted sources, unless you have measured and quantified it yourself. We check 100% of everything.

Thanks for your continuing inputs guys. I continue to learn. Here is an article I found that deals with ring rotation. Humorous writing style, especially for an engineer. For example: "Staggering ring gaps when installing pistons is every bit as daft as having four tyres fitted and placing all the valves at "twelve o'clock". One trip to Tesco and they end up all over the place".

Ring rotation explains why some days I have zero smoke on startup, others, lots. Still, overall, unacceptable oil consumption so apart it will be once the season is over. Updates to follow.

Institution Of Diagnostic Engineers

I recently replaced ONE that was completely torn (Viton) from the previous build, as i think they used too mucho force (and think there are others torn as I still smell burning oil). Anyhow, when placing the new seal, I taped the top of the valve with any old tape and then inserted the seal, which worked great. When pressing the seal, I used (IICR) a 10mm socket and then tapped on it which worked great.

Excess oil consumption update
 

In preparation for the teardown of said oil burning engine, I had ordered 6 std rings sets for the 98 mm Carrillo pistons. And then, come time to fit them, a surprise. The oil rings were too wide for the land. I contacted Carrillo and Jerry said my 98 mm Carrillo pistons must have been a custom order with 2 mm oil control rings (their off the shelf 98 mm pistons sets are sized for 2.8 mm oil rings). I asked him if they had 2 mm rings sets and no was the answer. He referred me to two possibilities, Perfect Circle and a machine shop in Wichita KS. I called Perfect Circle and they were very helpful. Yes, they could supply a 2 mm oil ring but the pistons would need the ring land depth deepened to accommodate their ring. Keep in mind I already had 2.8 mm oil rings so now it was machining the pistons and buying Perfect Circle 2 mm oil rings. Plus, after some research, I wanted to use the 2.8 mm rings as apparently they would offer better oil control than the very delicate 2 mm rings.
On to Rebco Machine in Witchita. I explained the situation to Eric and he said no problem, he could cut the ring lands to the Carrillo spec and have them back to me in a week or so. So the pistons were shipped to him and they were ready in the specified time. I've got to say, Eric does amazing quality work at a very reasonable price. Each land measures exactly as per the Carrillo supplied spec. Based on my experience, I can highly recommend Rebco for any piston work you may need. His site is here:

https://www.rebco-machine.com

Attached, a rather poor hand held comparison of the 2 and 2.8 mm rings as well as a piston with the widened ring land.

/http://forums.pelicanparts.com/uploa...1550363605.jpg


http://forums.pelicanparts.com/uploa...1550363712.jpg

Did the wider expander solve the problem?

Good question Neil. As we have at least 6 more weeks of winter here (more like 8), I have lots of time to assemble carefully and double/triple check everything. Cylinder bores were re-conditioned as per US Chrome plus the input of the well informed people on this thread. Valve guides checked and new seals to be in place. I hope to be providing a positive report once our spring arrives.

Change the 2nd ring to a Napier style if you haven't already.

Yes, the new second rings are indeed Napier cut. And Neil, you piqued my interest on the 2.8 mm oil rings being just a wider expander so I checked the rails. The 2 mm sets have rails .012" thick, the 2.8 mm ones are .015" thick. So percentage wise, about 20% thicker but significant, I don't know.

Good.

The 2nd ring does a lot in controlling the oil too. Its probably a cast ring so be careful installing them.

I'm a big fan of 3 piece rings in these engines. I believe the separate oil rails work independently of each other somewhat and help control the oil when the pistons tip.

I am very pleased to report that my oil consumption for the first 500 miles has been negligible. Proper bore finish, new rings and valve guide seals seem to have done the trick.
I really appreciate the sound advice from everyone. Nice to have a completely dry and smoke free engine. I've been fine tuning the Megasquirt system to make sure A/F mixtures are staying out of the rich zone. I also added a knock sensor so timing can be quickly pulled back in the event of knock. And while you are in there was also in the form of an aluminum pressure plate, a new disc and a resurfaced flywheel.
Also, thanks to Craig (Cgarr) for the great job on reconditioning my rockers.
Now to get out and enjoy the driving part, winter was just too long.

http://forums.pelicanparts.com/uploa...1556237437.JPG

tell more about surface condition of the cylinders ? My engine still smells of burnt oil, even if it consumes little. 98 mm nickasil cylinders from EBS and CP pistons. No other issues

I wouldn't worry about it. I'd be annoyed but to fix it would be a big pain in the butt.

I 2nd the leak down just to make sure the valves are seating. You really should do a leak down after you get the heads on during the assembly. I did this on my 914 a long time ago to find the machine shop who installed the guides didn't cut the seats enough on the burned exhaust valve that caused me to do the rebuild in the first place.

Maybe you should have kept dino oil in the engine until you change the oil again (3000 or 5000?) Something like Castrol 4T motorcycle oil.