850 Cylinder wear

L.A.B. said:

MS850 said:

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:!:
http://garage.grumpysperformance.com/in ... info.2795/

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I have never heard that one. Obviously Hastings hasn't either as their picture shows the ends pointing toward the top of the piston. Jim

Probably had a brain fart that day installing the pistons, The guy that bored the cylinder and head work gapped the rings and installed them on the piston. Not blaming him cause I put the engine together.

MS850 said:

Any ideas why both cylinders look like this, the vertical marks. Has Emgo pistons and Hastings rings, about 2000 miles on motor. Head was removed because of stud pulled on re-torque, (has inserts now).

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The wear patterns shown in your first image are certainly due to variations in pressure the expander or expander rails are exerting on the cylinder. It is clear from the image that the wear pattern ends just at the witness mark from the top expander rail, and appears to occur uniformly between the top and bottom expander rails.

Was the engine using any oil? I ask because the limited view provided by the pictures suggest a damp look on the cylinder deck and piston sides, so just wondering.

I’d be tempted to pop a piston out, fit it with rings, and on the bench assemble into the bore and move it to see what it feels like and qualitatively or quantitatively (with a scale) assess the amount of drag that is occurring. Something seems out of whack there.

Also have a question about the 2nd ring, as your piston image shows the 2nd ring appearing to be worn full height, i.e., contacting the bore from the ring top to the bottom. 2nd rings often have a tapered face to enhance scraping, and at 2,000 mi I’d expect maybe the bottom 10-30% of the ring to show wear due to bore contact and the top 2/3 or more of the ring to be virgin. If your 2nd ring did in fact have a tapered face it would appear to be worn excessively for having only 2000 mi on it.

Did you order another set of Hastings rings or have you seen enough of their product and are ready to try a different design/brand?

Regarding the ring gap spacing, there are myriad suggestions/opinions on the topic. Here is JE’s $0.02 on the subject.

comnoz said:

I have never heard that one. Obviously Hastings hasn't either as their picture shows the ends pointing toward the top of the piston. Jim

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https://www.hastingsmfg.com/Master_Cata ... er2012.pdf

WZ507 said:

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Was the engine using any oil? I ask because the limited view provided by the pictures suggest a damp look on the cylinder deck and piston sides, so just wondering.

I’d be tempted to pop a piston out, fit it with rings, and on the bench assemble into the bore and move it to see what it feels like and qualitatively or quantitatively (with a scale) assess the amount of drag that is occurring. Something seems out of whack there.


Regarding the ring gap spacing, there are myriad suggestions/opinions on the topic. Here is JE’s $0.02 on the subject.

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Thanks for input, no it wasnt using oil. When rings arrive Ill be putting into the bore on the table to see how it all fits.

Do the oil ring rails have "shiny spots" (magnifying glass)? Or evenly polished? A final grinding step COULD have been accidentally skipped....

It does happen. Recently I was in a precision bearing manufacturing shop, three pallets of bearings sitting there, rejected from a well know turbine engine manufacturer. Seems they somehow got a final grind step missed, they only showed up when assembled and engine test run. Both (engine) competitors HEARD of it, sent their bearings back just because. :shock:

concours said:

Do the oil ring rails have "shiny spots" (magnifying glass)? Or evenly polished? A final grinding step COULD have been accidentally skipped....

It does happen. Recently I was in a precision bearing manufacturing shop, three pallets of bearings sitting there, rejected from a well know turbine engine manufacturer. Seems they somehow got a final grind step missed, they only showed up when assembled and engine test run. Both (engine) competitors HEARD of it, sent there bearings back just because. :shock:

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I looked at the oil ring expander under a magnifying glass, I didnt see wear, no shinny spots. Thats true mistakes happen.

Hone finish looks to coarse, if you look closely at the first picture the scuff marks go right to the top of the bore, it's only the discolouration that stops at the oil ring, the rings appear well run in for the amount the bores seem to have polished up, you should still have the rings that come with the JCC PISTONS fit them in and carry on, you have pre finished the bores with the first set

Hi,

the signs at the cylinder are not normal and they seem to be caused by the oil expander ring. After this milage you should see nearly nothing. I can't tell you what exactly the problem is, but I would go with other oil rings just for my peace of mind.

Edit: Maybe still meaningful to measure the play between piston and cylinder.

Ralf

MS850 said:

concours said:

Do the oil ring rails have "shiny spots" (magnifying glass)? Or evenly polished? A final grinding step COULD have been accidentally skipped....

It does happen. Recently I was in a precision bearing manufacturing shop, three pallets of bearings sitting there, rejected from a well know turbine engine manufacturer. Seems they somehow got a final grind step missed, they only showed up when assembled and engine test run. Both (engine) competitors HEARD of it, sent there bearings back just because. :shock:

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I looked at the oil ring expander under a magnifying glass, I didnt see wear, no shinny spots.

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Possibly the oil ring spacer is of a much harder material than the cylinder wall?

I think you can see from the illustrations that the spacer's function is to hold the oil scrapers in place vertically and to contribute nothing to the axial tension of the scrapers. A better design has a turned-up rear face that keeps the spacer inside the outer perimeter of the scrapers where the type you have would allow it to float outward and contact the cylinder wall, resulting in the marks shown in the first photo. Could it possibly require a trimming of the ends? The total circumference of the spacer determines the diameter in situ and contact tension with the cylinder wall.

Here is a good question. Apart from the pulled head stud, why did you pull the barrel off etc. If it want using oil, compressions were good??????


Why. Why Why.

maybe because there are tooooo many theorists on this site.


Have you too much time and too much money burning a hole in your pocket.


Sorry to be blunt.


Dereck

Dances with Shrapnel said:

Did you clip and shorten the oil ring expander upon initial install of the Pistons and rings? The butting of the expander ends does not look right and could be binding the rails, thus causing scuffing.

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Exactly.

kerinorton said:

Here is a good question. Apart from the pulled head stud, why did you pull the barrel off etc. If it want using oil, compressions were good??????


Why. Why Why.

maybe because there are tooooo many theorists on this site.


Have you too much time and too much money burning a hole in your pocket.


Sorry to be blunt.


Dereck

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Is it really a large expenditure of time and money to pull the barrels once the head is off? I know base gaskets are inordinately expensive and the base nuts take FOREVER to remove. :roll:

Sorry to be sarcastic, but the OP had questions and this IS a forum and not Dear Abby's column.

geeze I think we have had this conversation before. IT IS NOT A SPACER it is called an EXPANDER for a reason. nobody makes a 3 piece oil ring like you describe where it is JUST a spacer.

Danno said:

I think you can see from the illustrations that the spacer's function is to hold the oil scrapers in place vertically and to contribute nothing to the axial tension of the scrapers. A better design has a turned-up rear face that keeps the spacer inside the outer perimeter of the scrapers where the type you have would allow it to float outward and contact the cylinder wall, resulting in the marks shown in the first photo. Could it possibly require a trimming of the ends? The total circumference of the spacer determines the diameter in situ and contact tension with the cylinder wall.

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bill said:

geeze I think we have had this conversation before. IT IS NOT A SPACER it is called an EXPANDER for a reason. nobody makes a 3 piece oil ring like you describe where it is JUST a spacer.

Danno said:

I think you can see from the illustrations that the spacer's function is to hold the oil scrapers in place vertically and to contribute nothing to the axial tension of the scrapers. A better design has a turned-up rear face that keeps the spacer inside the outer perimeter of the scrapers where the type you have would allow it to float outward and contact the cylinder wall, resulting in the marks shown in the first photo. Could it possibly require a trimming of the ends? The total circumference of the spacer determines the diameter in situ and contact tension with the cylinder wall.

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Maybe I should dig one out of my bonepile and send it to you. The spacer can exert no outward pressure on the scrapers if it only contacts their flat sides and not the inner edge. If you can explain how it could with no contact to the inner perimeter of the scrapers...well, you can't. It's impossible and I don't care what you call it. It expands the assembly vertically and acts as the lower (to the upper scraper) and upper (to the lower scraper) ring lands would .

Please look at the part itself in the hands of the OP and tell me how it could be otherwise. You can't.

For Bill; 750 Norton Hepolite 3-piece oil ring spacer. Should I mail it to you so you can examine it more closely?

I would never recommend clipping an expander of an oil control ring set. Furthermore, the expander shown above as well as the OP's expander clearly show the little tabs on the inside circumference which hook behind the inside circumference of the upper and lower oil control rail. The expander also acts as a spacer.

Danno said:

Dances with Shrapnel said:

Did you clip and shorten the oil ring expander upon initial install of the Pistons and rings? The butting of the expander ends does not look right and could be binding the rails, thus causing scuffing.

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Exactly.

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No I didn't.

Keep up the conversations, no hard feelings but the ebb and flow is entertaining.
That's what i like about this forum, there's a lot of strong opinions.

You do not want to shorten the expander. It is there to supply the tension that keeps the oil ring rails against the cylinder wall. Jim