SuzukiSavage.com - May have ruined engine.

Dave YaBB Moderator ModSquad Offline SuzukiSavage.com Rocks! Posts: 17867 Camp Springs, Kentucky Gender:	Re: May have ruined engine. Reply #90 - 04/24/20 at 04:08:48 youzguyz wrote on 04/20/20 at 13:36:13: MMRanch wrote on 04/20/20 at 12:56:48: Congratulations ........................... So , "How many cam-chains does it take to get to 200,000 miles" ??? I am on my 3rd one. The last two have been Lancer Nitrided Specials. Work fine, last a long time.
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Bokobob

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Re: May have ruined engine.
Reply #91 - 04/24/20 at 04:41:30

Good morning, Guys...Cool to see this thread turn into an "oil war" as someone remarked a few posts previously.

For the most and latest on OIL, there is this site which will tell you much more than you ever would likely ask:

https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=cfrm

I don't know how much of it relates to MCycles, but it is quite informative.

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Bob
84 and still riding
2009 S40 650, and Rebel 250
Gastonia, NC

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srinath

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Re: May have ruined engine.
Reply #92 - 04/24/20 at 06:44:56

Dave wrote on 04/23/20 at 18:37:58:

Youzguys ran the first 60,000 miles using Valvoline VR1 in 10-40 I believe, the next 100,000 miles was using Rotella T6 in 5W-40. At the 160,000 miles rebuild the only thing that was out of spec was the valve guides and valves. The cam and rockers were fine, the piston was fine, and even the rings were still in spec.

The engine went back together with new valve guides, valves and rings - all other parts were put back in and the engine just passed the 200,000 mile mark.

I really don't need any other proof that 10W-40 and/or 5W-40 works just fine.

Most rocker/cam failures on this bike are from using oil with low ZDDP levels (rocker failure) - or cam bearing failure caused by running too low of idle speed.

The bottom end probably could care less what oil is used, as roller bearings don't really need much oil to survive. The piston is somewhat similar and the piston/cylinder failures on this bike seem happen when folks run the engine out of oil.

Every now and then somebody trashes an engine when the top of the exhaust valve comes off the stem - I suspect running too big of valve clearance for too long may contribute to that failure or too lean of fuel mixture - but I really don't know for sure.

I am just going to keep running Rotellat T6 that is 5w-40.....and not worry about my oil doing a proper job.

I have had one of those highlighted in Magenta - that bike had a broken vacuum line sucking air.
Now Why did he switch to a lower viscosity oil after 60k.
Also the case we are talking about is one where the cam bearings are at the high end of the spec from having run without oil pressure for a while.
BTW that having too low of an idle causing damage is proof that pressure can get too low - but a higher viscosity oil isn't going to help there. A higher rpm idle would.

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Srinath.

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batman

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Re: May have ruined engine.
Reply #93 - 04/24/20 at 06:54:39

Dave , you're saying that valve failure might be caused by the valve clearance being set large ,this may cause the valves to be louder, and show some added wear on the top of the stems, but that wouldn't stop them from seating which they must do to prevent overheating. I think the it might be that they're set to tight, when the motor reaches temperature the valve stems expand and clearance is lost, they either don't have enough seat time or fail to fully seat ,and overheat.

Srinath, the move from 10w40 to 5w40 was made because it's viscosity is only half as thick when cold, therefore causing less wear at startup where most wear occurs, even for non-believers like yourself.

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Dave

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Re: May have ruined engine.
Reply #94 - 04/24/20 at 07:31:54

batman wrote on 04/24/20 at 06:54:39:

Dave , you're saying that valve failure might be caused by the valve clearance being set large ,this may cause the valves to be louder, and show some added wear on the top of the stems, but that wouldn't stop them from seating which they must do to prevent overheating. I think the it might be that they're set to tight, when the motor reaches temperature the valve stems expand and clearance is lost, they either don't have enough seat time or fail to fully seat ,and overheat.

Thank you for your responsible divergent point of view.

I have read that valve failure can occur if clearances are too large. The theory is that the cam lobe ramp lowers the valve gently onto the seat and allows a slow change in the velocity of the valve as it approaches the seat with normal valve clearances - however with excessive clearances the valve spring can push the valve onto the seat too quickly and allow excessive force......which is then transferred onto the valve stem.

Can't say for sure, as I don't have any experience with this issue and I have never had a valve come apart.

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batman Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 3806 osceola new york Gender:	Re: May have ruined engine. Reply #95 - 04/24/20 at 08:14:45 Dave, I see your point, the spring could make the valves bounce off seat and do damage to the seat and/ or valves . Either of our thoughts could be correct.
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srinath

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Re: May have ruined engine.
Reply #96 - 04/24/20 at 12:00:50

On this bike - the motor which I still have BTW the left exhaust valve broke because it was run for long time with the vacuum line broken at the carb.

Batman - Once again - the 5 isn't the issue - that 5 vs 10 is at cold starts and I would say yes 5 works just fine. The 40 with a loose cam bearing would be better served by 50 wt.

Seriously maybe I should have posted about a 10w50 or a 5w50 (which is easily available in castrol).
This argument is going nowhere because we have no way of measuring the pressure at the cam bearing. 50 will make more pressure right out of the pump. But it would lose more per length of flow before it gets to the cam bearing. Now even if it arrived at a slightly lower pressure at the cam bearing, it could protect it better. But we don't even have that information. The pressure at the cam bearing is what counts. The oil pump is well capable of 3X the pressure or more because when cold the pressures are over 20 and when hot, they barely break 10 psi.

Yea 10w50 vs 10w40 would have been less confusing IMHO. I didn't do that cos 10w50 is impossible to find.
And unlubricated doesn't always mean wear. It can be unlubricated and not making contact or have high temp and disappearing clearance and hence no wear is occuring.
Remember the plain bearings rarely wear themselves to a larger and larger and larger to where they're loose and don't work. Does happen, but that's in 100's of 1000 miles at what I'd call design life. They die when the clearance drops below 0 due to temperature, and swelling due to centrifugal force and at one point the spinning shaft makes contact with the bearing - hot fast moving metal onto hot metal taking a chunk of it with it. Its called galling. There ends your bearing in sudden death. The millions of cold dry starts may have prolonged this by wearing the bearing smoothly and gently increasing the clearance gently to the upper limit etc etc with still many 1000's of miles left - of course you can be like me and run a motor to 300K, have a mechanic pull everything apart and go - wow, this is perfectly worn, if not for your head gasket leak, you'd have got 100K more from the crank and bearings. It was a 97 F150 truck BTW.

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Srinath.

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justin_o_guy2

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Re: May have ruined engine.
Reply #97 - 04/24/20 at 12:12:45

Dave wrote on 04/24/20 at 07:31:54:

batman wrote on 04/24/20 at 06:54:39:

Dave , you're saying that valve failure might be caused by the valve clearance being set large ,this may cause the valves to be louder, and show some added wear on the top of the stems, but that wouldn't stop them from seating which they must do to prevent overheating. I think the it might be that they're set to tight, when the motor reaches temperature the valve stems expand and clearance is lost, they either don't have enough seat time or fail to fully seat ,and overheat.

Thank you for your responsible divergent point of view.

I have read that valve failure can occur if clearances are too large. The theory is that the cam lobe ramp lowers the valve gently onto the seat and allows a slow change in the velocity of the valve as it approaches the seat with normal valve clearances - however with excessive clearances the valve spring can push the valve onto the seat too quickly and allow excessive force......which is then transferred onto the valve stem.

Can't say for sure, as I don't have any experience with this issue and I have never had a valve come apart.

Whether that Is the cause or not, it's a mechanically sound argument to explain destructive forces. A look at a cam profile shows how the closure rate slows , makes sense.

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srinath

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Re: May have ruined engine.
Reply #98 - 04/24/20 at 14:52:45

justin_o_guy2 wrote on 04/24/20 at 12:12:45:

Dave wrote on 04/24/20 at 07:31:54:

batman wrote on 04/24/20 at 06:54:39:

Dave , you're saying that valve failure might be caused by the valve clearance being set large ,this may cause the valves to be louder, and show some added wear on the top of the stems, but that wouldn't stop them from seating which they must do to prevent overheating. I think the it might be that they're set to tight, when the motor reaches temperature the valve stems expand and clearance is lost, they either don't have enough seat time or fail to fully seat ,and overheat.

Thank you for your responsible divergent point of view.

I have read that valve failure can occur if clearances are too large. The theory is that the cam lobe ramp lowers the valve gently onto the seat and allows a slow change in the velocity of the valve as it approaches the seat with normal valve clearances - however with excessive clearances the valve spring can push the valve onto the seat too quickly and allow excessive force......which is then transferred onto the valve stem.

Can't say for sure, as I don't have any experience with this issue and I have never had a valve come apart.

Whether that Is the cause or not, it's a mechanically sound argument to explain destructive forces. A look at a cam profile shows how the closure rate slows , makes sense.

You're talking about those "comma" cams ? They have an aggressive open profile, but the back side of the comma is the closing side - not more aggressive than any other cam - the close side of the cam depends on the redline/limit rpm and the spring and valve's weight etc etc to prevent valve float. Even in cases of valve float, most of the damage occours when the cam is fully open where the valve gets hit by the piston or the opposing valve (like in a GS500)
Also the more likely valve to float is the intake. Its larger, heavier and the aggressive profile is more aggressive on the intake etc.
If the valve just breaks off, its a heat issue with likely a lean mix to be to blame.

Cool.
Srinath.

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