Two years ago I went through a 1914 engine for a friend, keeping the 1950's aluminum pistons. The valve guides were reamed for oversized stems and the cylinder walls professionally honed. Rings and piston went into #4 cylinder fine, so I'm sure no ring was broken. The engine runs strong.
Problem: Someone following the "T" last week reported periodic puffs of smoke coming out of the tail pipe, presumably between shifts. I pulled the plugs today and found that #4 is a little crusty and slightly oily. The other spark plugs were normal. So, the problem lies in #4 cylinder. There's probably only about 200-300 miles on the engine, as the car is just driven around town on errands and on short pleasure jaunts.
My question is, if everything is o.k. in #4 and the rings just haven't seated yet, what can I do to "encourage" their seating? I read once that pouring a little Boraxo into the offending cylinder helped scuff the cylinder walls up enough to help the rings seat. I kinda don't like that idea, so I am soliciting other suggestions to help make the rings in this cylinder seat. Barring no success with suggestions, I guess I'll have to remove the piston and rod to install new rings and/or re-hone the cylinder wall.
Anybody been through this before?
Thanks in advance.
If you are sure it was assembled properly, I would run it and see what happens. If the cylinder walls are in good shape the rings should eventually seat.
A leak down test would give you an indication of any serious compression leaks.
If the piston has a expansion split in it and was installed backwards it can cause smoke.
Don't ask how I know that.
I'm with Don.......that engine will NEVER break in if it never gets the snot beat out of it.
Tooling around at 25 mph for 3 miles isn't going to do it to it.
When you reuse existing pistons with new rings, it takes a while for the rings to seat, that's been my experience, anyway. 200-300 miles in two years is not a good way to break in rings in any situation. Its also been my experience that if a rebuilt engine sits for a long period before being run, the rings may need to be replaced.
My suggestions. Take the car for a half dozen long runs and see if the problem goes away. It probably will. If not, consider installing new rings.
Now my turn... I hsve seen a problem like this before. and ingesting a little bo-nami cleanser in the intake can help.. it will not scratch anything but will clean any glaze there may be off. But also.. get it out and run it.. not just small trips.
Don't know about dumping any thing in there. Don't see how it'll get to anything but the tail pipe. Take a compression test. See what you've actually got going on in there. I honestly believe that they may not have seated yet and running & time are the easiest answer.
My engine is just starting to really break in at 1700 miles.
Honing technology today is somewhat different from the early days as is stone design and application methods. Ring design has advanced considerably so much that "seating in" is practically eliminated. Ring manufacturers can differ some take the corners off the rings an some taper the rings for a better scraping effect if by chance the oil ring is in upside down oil could slip past and cause your puffing. A leak down test is the best method to determine the cause.
Marshall, you didn't say what break-in method was used to seat the rings.
Hastings will tell you to avoid long idling after assembly and to take it out and go thru a sequence of short Full throttle and closed throttle runs to seat the rings. The rings should seat properly on a new engine rebuild in a very short time. Avoid driving a constant rpm for several miles.
You said the cyls were honed by a pro and your assembly was ok.
Here's another thought... Since you didn't mention what the cyl to piston clearance was with the used pistons it could very well be that you are just starting to see signs of some excessive clearance issues as the engine starts to wear in.
One thing you might consider if you pull the pistons is to check the ring gap on the oil ring. If its too much and you don't want to rebore you can order the next size larger ring set and grind the ring gap back to the correct tolerance and that may solve your oil burning issues at that point.
First rethink your break in procedure.
I once rebuilt a 200 C.I. Ford 6 that used a little oil for almost 10,000 miles.
Bon-Ami needs to be put in the chamber as the engine idles with the spark plug out.
Just put in a little at a time.
I have taken engines apart that were just choked with Bon-Ami in the rings and it still pumped oil.
I'd run it some more and then if it still smokes I'd pull the piston and maybe get another set of rings.
Never put the ring gap above the end of the piston pin.
Put the lower (no.2) compression ring opposite the top oil ring gap. put the top compression ring gap on the other side, but not directly above the oil ring gap.
.015 to .020" ring gap for the top ring, less for the lower rings and at least .010 for the oil ring. Up to .020 is ok but any more and I'd get the next oversized rings.
Several things could be the cause of your problem. Just putting in new rings will not fix out of round or tapered cylinders. It will also not fix scored cylinders. If the cylinders are in otherwise good condition, they should be honed first before the rings are installed. The old carbon should be cleaned from the piston grooves.
The end gaps on the rings should be staggered around the piston and preferably not be in line with the wrist pin. The ring gap should be correct and the rings installed in the correct position in the correct groove.
Subsequent to the installation the following could cause a problem. Overheating causing the engine to seize or nearly seize could score the cylinder walls or cause rings to lose temper. With only 200 or 300 miles on the engine in 2 years, if the coolant was left in the engine during the 2 years, it is also possible that a very small leak could cause water to leak into the cylinder and rest on top of the rings. This would cause rust grooves in the cylinder walls which would cause some oil to leak into it.
My recommendation would be to take your car on one of the club's week long tours such as the National Tour in America's Finest City in July. Driving it constantly at reasonable speeds occasionally reving it up a bit and then immediately slowing down, will seat the rings as best as they can be seated. Preferably this should have been done soon after the rings were installed, but later is better than never.
Thanks to everyone for your opinions. I'll have my friend continue driving the car for a while longer to see if the rings in #4 finally seat. I'll ask him to vary his speeds more, especially on the open road between towns here in southeastern Iowa. Maybe we can avoid re-ringing the cylinder?
Didn't see any reference to this in the posts, but what kind of oil are you using for break-in?
Straight 30w, detergent. The other three cylinders seem to have seated well, so I can't believe the oil is the problem for #4 rings not seating yet. Maybe some more driving at varied speeds will help. I am sure there can't be more than 250-300 miles on the engine so far.
Thanks again, everyone!
As long as it is not "Energy Conserving" oil, you should be fine for break in.