Piston Ring Breakin

[wsa111]

Has anybody heard of an old method to seat the piston rings to the cylinder wall??

I talked to an old timer who still builds engines & he said if the rings are slow to seat in to sprinkle Bon-Ami cleanser into the intake in a very small dosage to let the abrasive characteristics of the cleanser abrasive let the rings seat faster with the cylinder bore.

Since only a small dose is ingested it will let the rings wear enough to mate with the cylinder walls & will not cause piston or cylinder wall scoring.

Any thoughts or comments from past experience or here-say. William

 

[MustangSix]

It's an old trick that works in some cases. It might be useful with cast iron or chrome rings on the usual 400-grit cross hatch. Sometimes those rings are reluctant to wear in.

But moly-faced rings should never be treated to this type of "help". Given a 600 to 800 grit finish on the bore, a moly ring will seat almost immediately and improve even more over time. There is practically no break in required. Adding BonAmi or any other thing will probably destroy the moly face and make the break in period longer.

 

[Anonymous]

There is NO SUBSTITUTE
for a properly machined block with correspondingly correct bore finish.
Period.

 

[Stubby]

There is NO SUBSTITUTE
for a properly machined block with correspondingly correct bore finish.
Period.

Well said Linc. A well preped block is the key.

 

[Lazy JW]

There is NO SUBSTITUTE
for a properly machined block with correspondingly correct bore finish.
Period.

Well said Linc. A well preped block is the key.

Yup. A textbook answer to a textbook situation. But I have seen numerous things in my misspent life that didn't always go according to plan, you know, that mice-and-men phenomonen. And not all of us have unlimited budgets. So, if you're in Siberia helping rebuild a Trabant-two-stroke don't be too surprised if some Russian peasant farmer throws in some BonAmi powder. And don't act too surprised when it works But then, you already know that now.
Joe

 

[Stubby]

I have spent a lifetime arround engines and I have seen alot. BonAmi and other types of abraisives, run it without water to build heat , find a long downhill strech and shut the engine off and let the engine slow the car down, supposedly to put heat in the rings. I would put more stock in the BonAmi than the others.

The main problem I have seen is too much oil in the cylinders from things like cheap chrome valve covers without baffles. Major amounts of oil sucked in thru the PCV valve, mixed fairly well with gas in the intake and very little smoke and misterious oil consumption. Once the engine runs like this for awhile during the critical breakin period the rings don't want to seal.

The second most common thing is improperly finished cylinders for the type of rings. If your machinest tries to talk you into plain cast rings he probably has had problems with his method, whether he wants to admit it or not.

The third most common thing would be cylinder distortion. Some engines are more prone to this problem than others.

I would be very careful about any abraisive in an engine. The cylinders can tolerate more than the bearings. If the rings aren't sealing, some of everything thats going into the cylinders is also going into the crankcase

 

[wsa111]

Thanks, guys the engine in question is owned by a friend of mine.

To make a long story short, he installed a rebuilt carburator on a fresh short block & heads with all teflon spring loaded valve seals.

The carburetor had a blown power valve & I think washed down the cylinder walls & the rings did not seat properly.

Today we ran some bon-ami through the engine. Immediatelly changed oil then proceded to drive it a 100 miles. Before this the engine used 1/4 QT. in a 150 miles of driving.

After the dose of bon-ami there was no change in the oil level after the 100 mile drive.

All the previous machine work was done by a local reputable machine shop using speed-pro moly rings.

This is a scary thing to do, but this time it worked.

As stubby stated strange things happen when an engine is first fired up & driven with cylinder finish or in this case cylinder washdown.

I will monitor this engine to see if this bandaid works or to tear the engine down again, rehone-re-ring & start over, so far so good. William

 

[Stubby]

I am glad to hear the good news. Let us know how it turns out in the long run. My first response is always on the conservative side. I might be inclined to try it on my engine for the education but, I would be afraid to advise someone else to do it on there engine.

How much did you use? What rpm? What proceedure? Need input!!!!

 

[wsa111]

Gary, this was strickly a long shot, really had nothing to lose. As I told my friend are you sure the second ring which is a scraper was installed the correct way & he said yes.

First we pulled the rebuilt 500-4412 off the engine & I had an extra 350-7448 so we installed that carb.

When the carb was off I put about 1 teaspoon of bon-ami in the intake plemum, reinstalled the 350, then fired the engine up, by the way the engine was already up to close to running temperature, brought the engine up to 3500 RPM'S then proceded to put a tablespoon more into the venturi area, of course some spilled on the air bleeds so proceded to flush the area with carb cleaner.

Then changed oil & filter.

Then took the car out for a test drive & drove it like we stole it.

Will just have to monitor the results further.

At the dealership we used to have a boreoscope to examine valve guide desposits & cylinder condition, but that was stolen.

I would love to look at the cylinders after this dose of bon-ami.

The worse seneraro is to pull the engine, & either rehone & re-ring or rebore.

Hope this bandaid fixed the problem. I agree with you & Linc that proper cylinder wall honing should have prevented this situation, but when he installed a carb with an unknown history anything can happen, especiality during the critical break-in period.

By the way synthetic oil was not put in for the initial breakin.

I know this is another topic do you thing corvette's,vipers & other manufacturers really install full synthetic oil at the factory or do they just put regular mineral oil in for brakin??? Then at the first oil change install the synthetic, or is technology so advanced that these engines are already broken in at the factory then shipped to the dealers with full synthetic in the crankcase??

Would love to know. William

 

[Stubby]

Gary, this was strickly a long shot, really had nothing to lose. As I told my friend are you sure the second ring which is a scraper was installed the correct way & he said yes.

I had a customer who installed all eight second rings upside down on a 454 and it was wild. When it idled it was hardly noticable. As the rpms increased the smoke increased. It would fog the shop in seconds. It deffinatly sounds like the carb bit him.

I know this is another topic do you thing corvette's,vipers & other manufacturers really install full synthetic oil at the factory or do they just put regular mineral oil in for brakin??? Then at the first oil change install the synthetic, or is technology so advanced that these engines are already broken in at the factory then shipped to the dealers with full synthetic in the crankcase??

I think they might use a run in machine. Some of the larger rebuilders use them. Basicly it uses a large electric motor to spin the engine up to a desired rpm and they can monitor oil pressure, temp, vibration, and any other pertinent information. Then they can change the oil and inspect for anything abnormal. It is kinda like dynoing a motor without the hassle of fuel, ignition, and noise. This is just a guess but it seems like the most cost effective solution and best way to avoid problems.

 

[wsa111]

Will monitor the results????? Worst that can be happen is tear the engine & start from scratch. William

 

[Lazy JW]

I have been an advocate of using BonAmi powder for quite some time. Please don't misunderstand, I don't recommend it for general use by everyone in all situations. But there are times when it can be a viable option. Caterpillar used to suggest it as a break-in aid in their engines, I have a genuine Caterpillar repair manual that details how to use it IF AN ENGINE DOESN'T BREAK IN NORMALLY! They even had an official part number. A couple of years ago I needed to rebuild a VW engine, but I was broke. I scrounged used parts from THREE different engines and built one. Yup, it has mis-matched pistons, rods, and cylinders from at least three engines. And you don't re-bore those jugs either. Naturally, it burned oil at the start. It required two separate doses of BonAmi, but now it runs fine, normal oil consumption and good compression. And don't get too worried about changing the oil, VW's don't even have a filter.

Proper BonAmi treatment is first warm up the engine, remove the air cleaner, run it at high idle, and hold a teaspoon full of powder near the intake, letting the air flow pull it in a little at a time. 4-5 teaspoons full should do the trick. Then put the air cleaner on and take it out and drive it HARD!. Then change the oil if you like.
Joe

 

[Stubby]

Thanks Joe, you have shed some light on one of those mythical repairs.

 

[wsa111]

Joe, that was a great reply. I was very reluctant to even post the subject.

I had no idea caterpiller being such a major manufacturer would even suggest such a field fix. Looks like I put my hand into a bees nest & did not get stung.

A word to the wise, when you have a fresh engine do not install a carburetor without running it previousy on an engine or have it checked by a professional. I should have checked my friends carb before he installed it, but I think he put on an ebay bargin. Some bargin the price of failure is very costly. I pulled his bargin 4412 apart & the power valve was blown, the carb was an old unit before holley put in power valve backfire protection & it had 75 jets in it. I went through this carb & put in 71 jets, a new power valve & installed the backfire protection kit in the carburetor base. For the present I told him to leave the 350-7448 carb of mine on there to make sure the rings seat in with the smaller carb to not wash the cylinder walls further.

He has driven the car over 200 miles & the oil level has not changed.

Miracles happen. William

 

[Anonymous]

This was a very common remedy for the Chevy mouse motor of the mid 50's. The early 265's and 283's were prone to bad ring seating and Bon-ami and Comet cleansers helped get the oil off the cyl. walls and remove the glase that had formed. But this ain't the 50's any more. another interesting trick was the use of a piece pf leather belt for a rod bearing in old chevy 6's that came with babbit bearings. On an occasional use farm truck the leather 'bearing' might last 3-4 years and didn't even require a trip to town for parts.