How long will it take for new rings to break in

[redoakroach]

I've installed new liners and pistons in my tractor and the compression is low, 150psi. It's even across all four cylinders and will come up to 165 psi if I put oil in the cylinder. There is 8 - 10 pounds pull with a .0015 shim between the piston and sleeve. I have about 1 hour run time at this point. This is the 5th engine I've done and the first time I've had a problem. Should I be thinking about pulling it back down and honing the cylinders a little or just wait to see what happens after a couple hours of run time?
Larry

 

[Dieseltech]

Helps if you can load the engine, like a PTO dyno. Needs more than 1 hour..

 

[Welding man]

Did you let it sit and idle for an extended time after rebuild? If you did,you glazed the cylinders. Do not idle a newly rebuilt engine. Did you put the head back to factory specs and are the valves adjusted correctly? If you can't get it to a dyno, put it to work, hard work,plowing ,discing or some means to load the engine. It may still survive.

 

[David G]

I put mine on Dyno for several hours right away.

 

[JIM MN]

With the John Deere overhaul, you had a procedure to go threw to break-in that four or six cylinder engine.. Used a break-in oil. Put on a PTO dyno, get up to temperature, varied load at different speeds for an hour or so.. Then retorqued head bolts.. Finished up pulling for four hours on dyno at 3/4 load.. Sent home, don't overload the tractor and do not let idle... At 100 hours drain engine oil, new filter, good to go...

 

[Southern Ray]

Many years ago guys around here would dust in some Bon Ami into the carburetor intake while the engine was running.
They claimed it helped set the rings. I don't know how much it took, and I would definitely get a second opinion before trying it.

 

[David G]

I would make tearing it down the last resort.

Put it on a plow for a day, or any other heavy tillage.

I have a dyno, where you located?

 

[47fivewindow]

I have seen the Bon Ami treatment done on a new rebuild by one of the best. I was horrified but it seemed to work. The second trip to the dyno was a success. I don't know how long the engine lasted after it left. Just sayin, not recommending.

 

[SVcummins]

Dump the oil you have and put break in oil in the engine and run it hard

Break in oil

 

[rustred]

What tractor? To seat the rings you need the engine at operating temp. Then work it. Vary the rpm and don’t lug it too much for the first while like an hr or 2. But if the cyl’d ar glazed you need to run it a bit hotter by even covering the rad and pull it hard. This pushes the rings out into the cyl’s. You can also sniff some bon amie into the intake while working it. A couple tablespoon fulls. Also. How much run time is on this engine? Glazed cyl’s will cause oil use. U have no mention of that.

 

[rustred]

Ok I see 1 hr run time. Well that’s nothing to speak of. Give it 50 hrs.

 

[Steve@Advance]

That it has new liners, they would have had a nice factory hone,so no need to rehone.

Did you retorque the head and run the valve clearance afterward? If not, that would be a good place to start.

Then give it a chance, put some hours on it, it should seat.

The Bonami down the intake was a desperate attempt by I think Dodge back in the 50's that got in trouble for sending out a bunch of smoking engines that were out of spec on the bore. I would highly discourage it!

 

[redoakroach]

Thanks for all the replies. I don't have a dyno or a plow to put on the tractor. I did put a big load of wood in the firewood trailer to give the tractor some work. I drove the tractor around another hour yesterday and pulled the plugs. The cylinders are not glazed, but it looks like I'm getting some coolant leaking into the cylinders. I'll torque the head bolts again and see what happens. It may just be that the head gasket failed to seal up good. Once it snows I can put the blower on the tractor, that heats it up pretty good.
David G - Thanks for the offer on the dyno but I think Red Oak Michigan is long way from you.
Larry

 

[DIM]

I had the motor in my truck rebuilt by a guy that builds up hot rod engines. He told me to push it and do not run at a steady speed. That puts extra fuel in and wash the cylinder dry and they wear in faster. I did that and had no problems. Had over 100,000 on engine when I sold truck and still did not use oil.

 

[rrlund]

My son has an engine machine shop. A guy who I went to high school with had an engine built at another shop. It was burning oil like there's no tomorrow. He was talking to my son about it at a wedding reception. My son told him he'd stop and look at it. The shop that built it, put synthetic oil in it. My son drained it out and put a break in oil in it. We had a high school reunion a few months later and I asked him if Jon fixed it. He said he told him to take it out and run the crap out of it with that break in oil. He said it was coming around in pretty good shape.

I don't know where Red Oak is, but if you're within a reasonable distance of Sheridan Michigan, he has a dyno and can take a look at it for you. Apex Competition Engines if you want to look it up.

 

[Indiana Ken]

Perhaps I missed something, could there be a problem other than a faulty ring seal? First, what is the compression supposed to be for this engine? Certainly, 150/165 is low for a diesel but not for many gasoline engines. It is interesting to me that all cylinders increase by 15 psi with the addition of oil. Is the increase due to the oil sealing the leak or due to displacement of combustion chamber volume? You did not mention that the engine uses oil which I would suspect if the ring seal is faulty. Performing a leak down test would allow you to verify the valves are sealing and the rings are leaking. Could you have been provided the wrong pistons (lower dome height) resulting in a lower compression pressure than expected?

Just asking questions, not meant as criticism.

 

[bc]

So how is break in oil different from regular oil? Just wondering.
Maybe non-detergent or extra detergent?

I'm hoping my 2606 engine will get back from its rebuild one of these days. Can't plow with it and probably won't get the hoe put on for a while so the best I can do is run it up and down the road for a while. I bot some 15w40 oil to put in it, regular and not synthetic. Thanks.

 

[redoakroach]

The engine is a 172 cubic inch gasoline engine in a ford tractor. It has flat top pistons. The manual states that the compression should be 210 psi. I don't expect that because I'm not at sea level and the engine doesn't crank at 1000 rpm. Just driving the tractor around here is improving the performance at this time.
Thanks.

 

[WayneIA]

150 psi across the board on a 172 Ford gas engine I would not consider a problem, or did I miss something?

 

[jacksun65]

Warm the engine up hook it up to your pickup and have someone ride the brakes while you tow it.

 

[MikeJM]

By chance are you running the compression check with the throttle wide open? Hows your cranking speed? It makes a big difference.

 

[showcrop]

50 is perfectly good for a 172 gas.

 

[marloweg]

when i built stock car engines it was balls to the wall out of the box over 10 years never had one bad one