Burning oil after the rebuild

brawlins · 02-15-2004, 06:31 PM

I took it pretty easy for about 500 miles after my engine rebuild. (The rebuild was done by my mechanic.)

After that, I've been revving it through the entire range of RPM's. The car performance seems to be very good.

Anyway, I'm burning a pretty good amount of oil. (I don't have the exact count, but I know I've put in a couple of quarts of oil in just a few hundred miles.)

My mechanic says not to worry. He says he put tiny grooves in the cylinder walls (4/1000 of an inch) and he used stainless steel rings. He says those rings may take a while to completely seat against the cylinder walls, and oil could be slipping past. Or, it could just be burning a lot of oil.

Any thoughts???

(By the way, I am gaining mechanical ability. I am working with a friend to rebuild the engine in his car, and am learning along the way. My father never stuck his nose under the hood of a car, so I'm learning late.)

- Bill

Zeke · 02-15-2004, 06:45 PM

Some rings take longer than others to break in. At this point, you need to put some load on those rings, like a nice long acceleration in 5th from about 70 to over a 100. And let it decelerate back down and do it again a couple of times. Don't get a ticket. Be careful.

A hill would be good too, but I guess GA is pretty flat. At least the parts I was in were.

serval · 02-15-2004, 06:49 PM

Does your car run hotter than before? Your mechanic is right about rings having to seat against the cylinder walls, but 500 miles seems more than enough for this to happen. Do the tiny grooves he's referring to have anything to do with honing the cylinders? At any rate, it should stop pretty soon or I would be concerned about overheating. Check out Wayne's book on engine rebuilding. It is the most thorough book I have ever seen on the subject. Let us know what happens; hope it will all be ok.

Anton

brawlins · 02-16-2004, 03:28 AM

Yes, he said that he "honed" the cylinder walls.

And the car has not been close to overheating, though it is still winter here.

RoninLB · 02-16-2004, 03:35 AM

maybe install 30w non-detergent oil and start reseating rings following Zeke's recommendations, maybe using 3rd and 4th gear from 3k to 5k rpms constantly till it's over..

Wayne 962 · Wayne 962's Garage

Make sure the car is running lean, not rich. Too much fuel in the combustion chamber can prevent the rings from seating...

-Wayne

brawlins · 02-16-2004, 05:52 AM

Thanks!
Question: Can too-low RPM's cause ring damage on a new rebuild?
ie - idling at 400RPM? I had an ignition problem recently (now corrected).

Superman · 02-16-2004, 06:11 AM

Tons of questions. What kind of cylinders? New? Low RPM should not be a problem, but if there were ignition problems, then maybe. New rings ( or old rings for that matter) do not like detonation.

I wonder if you could squirt some non-abrasive solvent into the cylinders just to get the walls clean. The rings and the cylinder walls need to get friendly, and they won't want to do that if there is too much lubrication there. The accelerate/decelerate advice is good. Definitely do that. Be mean to those rings.

brawlins · 02-16-2004, 07:20 AM

cylinders were the original ones.
the rings are stainless steel.

Doug Zielke · 02-16-2004, 07:24 AM

Shocking news.....
You have approximately 50 miles to get the rings to seat properly!

If, during the first critical miles, you baby the motor, idle it a lot, drive it around in slow traffic, etc., the rings may never seat to their optimum.

sammyg2 · 02-16-2004, 07:38 AM

4/1000ths of an inch? I hope that isn't correct. If it is they are about 10 times too deep.

Were your cylinders alusil or nikasil? makes a difference.
It would also help to know a little more about those stainless steel rings. Ask him what brand they are.
If they are anything like total seal rings they have a different assembly procedure. It is necessary to assemble them completely dry so that they have little or no lubrication on start up. Scary, but that's what it takes. Don't ask me how I know.

Rings should seat quickly like they already said, I'm one of those who believe you don't baby it but break it in like you plan to drive it.
In order for rings to seat correctly they have to wear against the cylinder walls and stay nearly perfectly square to it. If you take it too easy they will not end up square to the bore but can end up slightly rounded due to rocking in the seat under light load and too much lubrication, hense the oil useage. If they wear this way you may never get them to seat right. Either deal with it or replace them. The best way to prevent this was described by Zeke.

Zeke · 02-16-2004, 07:49 AM

Quote:

Originally posted by sammyg2
4/1000ths of an inch? I hope that isn't correct. If it is they are about 10 times too deep.

If they are anything like total seal rings they have a different assembly procedure. It is necessary to assemble them completely dry so that they have little or no lubrication on start up. Scary, but that's what it takes. Don't ask me how I know.

Not very many people believe this, Sammy. But I just finsished the assembly of a Type4 motor for my 914 and the rings are dry. That's a lot of scraping in the first few seconds, but it goes a long way in getting the rings to seat according to many VW racers.

But, we don't know at this point whether he has Nikasil or what. His rebuild may be all wrong. How long was that debate on the engine building forum about rings and nickies? It was quite an offering of theories.

Doug Zielke · 02-16-2004, 07:58 AM

Quote:

Originally posted by Zeke
Not very many people believe this, Sammy. But I just finsished the assembly of a Type4 motor for my 914 and the rings are dry. That's a lot of scraping in the first few seconds, but it goes a long way in getting the rings to seat according to many VW racers.

Right on the money, Zeke!

Most of my rebuilding experience is with (air-cooled) m/c engines.
I always take the time to wipe all the assembly oil off the bores, before the heads go on. The rings are thus essentially dry for the initial start-up.

I used the same technique on my 3.0 rebuild. No oil burning and excellent compression!

fintstone · fintstone's Garage

My engine builder had me run my car hard after rebuild. In fact, installed it, warmed it up and adjusted the CIS, dropped it off the lift. We hopped in and he buried the tach needle in multiple burnouts to @ 100 mph at full throttle then hard braked to a stop each time...followed by another burnout. Then he sent me out to drive it...hard as possible, considering traffic, about 100 miles. Sorta stop and go...but where you could easily get up to high speed between stops. I have over 1000 miles on the rebuild and have not had to add any oil. And the car really performs well. Not quite like when in CA, because of the altitude here...but very strong. I have followed my builder's advice...after all...he warrantied it. I warm it up then run it really hard...typically at WOT, always shifting above 4500 rpm and usually between 6500-7500 with no problems.

serval · 02-17-2004, 03:54 AM

Bill, let us know how it turns out. Methinks, there's a happy medium between running your engine hard (almost dry) of the bat and babying it. Do you see any soot deposits (oily residue) in the exhaust? Take out one sparkplug and inspect it. It should have a nice clean burn ash look to it. If it is oily and black consider cleaning it. I agree with sammyg2, 4/1000 seems a bit deep for honing. You cannot damage the rings driving at low rpm, but you may prevent seating by hampering expansion and reducing the thermal cycle. What does you mechanic say?

Anton

dickster · 02-17-2004, 04:31 AM

i think theres a trade off with having power or long engine life, depending on how you run in.

i have heard for max power give it loads of rpm when built - just dont expect it to last.........

Superman · 02-17-2004, 06:48 AM

I don't believe that, Dickster. Seated is seated. Makes more power AND lasts longer, as far as I know.

AH HAH!!! I've admitted to starting my rebuild (re-ringed Alusils) with virtually no oil on the cylinder walls, and now Doug confesses. Great minds.....

You see, the ring lands on my pistons were as tight as a ....... well let's just say they were plenty snug. This means they will keep the rings held tight for the startup-break-in violence. With unlubricated cylinder walls, your next enemy becomes ring breakage. but if the pistons hold the rings tightly, they're much less likely to break.

jabb · 02-17-2004, 10:58 AM

my 3.0 rebuild rings went in dry light oil on the cylinder skirt

brawlins · 02-17-2004, 01:13 PM

I took the car to my wrench today.
I should hear something back later in the week. I think I may have some fuel/mixture problems also.
- Bill

brawlins · 02-17-2004, 01:25 PM

I should add I took Zeke's advice and took her north up I-85 at mid-afternoon and let her rip up to about 115mph, about 5000 RPM's. It was fun blowing by some other cars.
A Toyota Solara wannabe tried to keep up with me for a little while.