The state of my engine internals - need some feedback here!

[Julian Sudano]

1984 V65 SP 15k miles shown on odometer...

So in preparation for upgrading the heads on my bike, to a single valve spring system, I pulled the heads, cylinders and pistons yesterday.

I've posted pictures of both pistons which do show some ugly wear on the upper and lower (axis of thrust?) faces, and some damage from crap in the oil no doubt. The wrist pins look pretty bad too with concentric wear/overheating rings. The pins are a pretty close fit in the pistons, and slightly less so in the little ends. Excessive wear?

Is any of this worth saving/reusing? I know sadly, that wrist pins are as rare as hen's teeth and pistons slightly less so. I did test the compressions and got 120 L & 125 R and there were absolutely no carbon traces below the rings.

The heads show all but one valve leaking, so it was definitely time for a refresh up top!

The video shows some rock (thrust?) on the RHS con rod. Is this normal?? Tried to upload this, but to no avail. There is lateral movement (along the length of the crankshaft) which I'm not sure about. Is this because both con rods share a journal?

 

[Raven]

That does not look good considering the low miles. The pistons almost look like they are not getting enough oil. What do the bores look like?
I've never seen wear like that before. They look worn down rather than scratched or gouged like oil contamination.

 

[scottmastrocinque]

This is what I see...

The vertical lines in the skirt are caused by debris in the oil. They are scratch lines from debris being trapped in-between the skirt and the cylinder.

The V65 oil lubrication system utilizes a really old style cartridge filter, and as in early BMW's, I fear that people ran these filters way past the point of efficiency in removing particulates and this is a proximate cause of those vertical lines on your skirts.



As to the horizontal lines, piston skirt wear occurs because of the thrust loading that results from the inherent geometry of the crank mechanism as the engine fires. Peak combustion pressure occurs slightly after top dead center which causes the piston to thrust into the cylinder wall.

I think your skirt wear, although visually significant, it isn't horrible.

Your compression numbers before teardown were very good and are less than 5% difference between the two.

The gudgeon/wrist pins show typical wear marks from edge contact with the con-rod and the piston bosses. Again, I think the excessive marks are more a result of poor oil filtration and poor quality oil. I have said it a million times, "Oil is cheap. Engines are expensive."

If it were mine, I'd send the head to a machine shop for cleaning up and lapping of the valves back to a solid seal. I would flush the engine and reload with a premium synthetic oil of the correct weight.

As to your pistons and wrist pins, visual inspections are only so so and should never be relied upon for determination of suitability for re-installation. The factory service manual with dimensions and a micrometer is your best friend here.

 

[Julian Sudano]

Thnk

This is what I see...

The vertical lines in the skirt are caused by debris in the oil. They are scratch lines from debris being trapped in-between the skirt and the cylinder.

The V65 oil lubrication system utilizes a really old style cartridge filter, and as in early BMW's, I fear that people ran these filters way past the point of efficiency in removing particulates and this is a proximate cause of those vertical lines on your skirts.

View attachment 33701

As to the horizontal lines, piston skirt wear occurs because of the thrust loading that results from the inherent geometry of the crank mechanism as the engine fires. Peak combustion pressure occurs slightly after top dead center which causes the piston to thrust into the cylinder wall.

I think your skirt wear, although visually significant, it isn't horrible.

Your compression numbers before teardown were very good and are less than 5% difference between the two.

The gudgeon/wrist pins show typical wear marks from edge contact with the con-rod and the piston bosses. Again, I think the excessive marks are more a result of poor oil filtration and poor quality oil. I have said it a million times, "Oil is cheap. Engines are expensive."

If it were mine, I'd send the head to a machine shop for cleaning up and lapping of the valves back to a solid seal. I would flush the engine and reload with a premium synthetic oil of the correct weight.

As to your pistons and wrist pins, visual inspections are only so so and should never be relied upon for determination of suitability for re-installation. The factory service manual with dimensions and a micrometer is your best friend here.

Thanks for the feedback - most appreciated!

You say lapping - no need for cutting the seats?

I was able to polish out the worst of the scuffing on one of the pistons, with less than 15 seconds with a Scotchbrite and some lubricant.

I did measure LHS wrist pin and got a very even 19.998 mm which I though was not bad considering the diameter is supposed to be 20 mm. The fact that its supposed to be 20 mm suggests it never was given my measurements.

When I got the bike the oil was really nasty, so would tend to agree that the previous owners didn't really take care of her. I did drop the sump, and clean out the light sludge (not bad at all considering) and cleaned the mesh filter. I have since put about 4 changes of synthetic through the engine!

 

[Julian Sudano]

That does not look good considering the low miles. The pistons almost look like they are not getting enough oil. What do the bores look like?
I've never seen wear like that before. They look worn down rather than scratched or gouged like oil contamination.

The bores definitely have a glaze on them, but you can see a few hone marks here and there. Would you suggest having them honed?

 

[john zibell]

If you are going to install new rings, then using a bead hone to break up the glaze would be a good thing to do so new rings would seat. Since you have good compression before tear down it would be a toss up in my opinion.

 

[scottmastrocinque]

Thnk

Thanks for the feedback - most appreciated!

You say lapping - no need for cutting the seats?

I was able to polish out the worst of the scuffing on one of the pistons, with less than 15 seconds with a Scotchbrite and some lubricant.

I did measure LHS wrist pin and got a very even 19.998 mm which I though was not bad considering the diameter is supposed to be 20 mm. The fact that its supposed to be 20 mm suggests it never was given my measurements.

When I got the bike the oil was really nasty, so would tend to agree that the previous owners didn't really take care of her. I did drop the sump, and clean out the light sludge (not bad at all considering) and cleaned the mesh filter. I have since put about 4 changes of synthetic through the engine!

When I operated my workshop, I never told my engine machinist what I wanted. I paid for what he said it required. Machinist work is best left to a machinist.

So, my comment was meant in that context.

Did you replace the cartridge filter (H) from the diagram?

Happy New Year.

 

[Julian Sudano]

Point taken. Yes, I've replaced the filter every oil change.

How are you enjoying your V100S?

Happy New Year to you too!

 

[Paul Brice]

In case it helps here are pictures from 16k miles V65 florida as comparison....(replaced rings as they were corroded in solid after 18 years in wet air). Hopefully you can see the honing marks on bores to compare with yours - mine are good.

 

[scottmastrocinque]

Yes, those filters are really old style and poor performance filters. I never ran one more than 3,000 miles in any air cooled BMW twin that used them and in fact, I usually changed cartridge and oil every 2k miles on my old 1977 BMW R100RS that used that same type filter. Like I said…

Oil is cheap. Engines are expensive!

Unfortunately, I live in Northwest Ohio and it is a lovely 26 degrees outside with snow flurries, so the V100 sits patiently and waits.

I’m still putting things away in my workshop, trying to be ready before my electrician comes on the 19th. The 2 man team is upgrading my power services throughout my property and should be very busy for about 80 hours of work.

I have the 3 cases and the factory rear rack, crash bars, fog lights, radiator cover, dash USB, and a few other tidbits to get installed as soon as my lift stops being a sorting table and returns to being a motorcycle lift!

I will say that the limited time I got to spend on her, I loved her.

I think the great people at Mandello del Lario, knocked it out of the ballpark with this model. She is an awesome and incredible motorcycle for sure.

Yes, there are some teething issues people have experienced, but I have faith that my late year production 2023 will be just fine.

Thanks for asking!

 

[Julian Sudano]

I've been religiously changing the oil and filter every 1800 miles, as per the handbook's recommendation!

I was actually contemplating changing the rings, and having checked the pictures I took of the compression gauge, I see I was wrong and misread it - I have 115 and 110 psi. So new rings and honing would probably not be a bad thing and will certainly extend the life of the internals...

The V100 does look gorgeous, and from the numerous reviews I've read, it does sound like a fantastic machine! I'm sure you'll be inseparable come Spring! Enjoy!

Thanks again for you feedback too.

 

[Julian Sudano]

In case it helps here are pictures from 16k miles V65 florida as comparison....(replaced rings as they were corroded in solid after 18 years in wet air). Hopefully you can see the honing marks on bores to compare with yours - mine are good.View attachment 33714View attachment 33715View attachment 33716View attachment 33717View attachment 33718View attachment 33719

I need to take another look at my barrels, but yours seem to show considerably more honing marks than mine do. I'll take some pictures for your amusement - will make you feel better about your seized rings!