Top-End Reassembly

The cylinder bore scuffing after only 6000 miles looks alarming.  I don't want to start an oil thread, but I'd use some high ZDDP oil, not just Rotella.  Driven 40 would be good for break-in, run two batches, 400 miles each, then switch to some high ZDDP motorcycle oil, or something like, M1 15W-50, since it has a bunch of ZDDP.  

Nessism wrote:

The cylinder bore scuffing after only 6000 miles looks alarming.  I don't want to start an oil thread, but I'd use some high ZDDP oil, not just Rotella.  Driven 40 would be good for break-in, run two batches, 400 miles each, then switch to some high ZDDP motorcycle oil, or something like, M1 15W-50, since it has a bunch of ZDDP.  

Might be the scuffing looked worse than it actually was. 
Could barely catch a fingernail, and the glaze break hone job (I think) eliminated it.



I'm reluctant to upgrade before the motor shows a reduction of oil use.  
Likely will use Shell Rotella T6 until then.
~~~

Same head BTW...different valves


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daveo wrote:

Nessism wrote:

The cylinder bore scuffing after only 6000 miles looks alarming.  I don't want to start an oil thread, but I'd use some high ZDDP oil, not just Rotella.  Driven 40 would be good for break-in, run two batches, 400 miles each, then switch to some high ZDDP motorcycle oil, or something like, M1 15W-50, since it has a bunch of ZDDP.  

Might be the scuffing looked worse than it actually was. 
Could barely catch a fingernail, and the glaze break hone job (I think) eliminated it.

I'm reluctant to upgrade before the motor shows a reduction of oil use.  
Likely will use Shell Rotella T6 until then.
~~~

Same head BTW...different valves

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M1 15W-50 has 30% more ZDDP than Rotella T6 5W-40.  Even though the M1 is not certified MA2, frankly, neither is T6, even though they put it on the bottle as "meeting the spec of...".  That M1 is super popular with motorcycle guys, and it won't hurt your clutch.
Driven 40 is a dedicated break-in oil with even more ZDDP.  Not sure how much, but a LOT.  It's dedicated for breaking in engines, and avoiding cylinder wall and piston scuffing during early engine life.  

 

I belive the cylinder scuffage was directly related to the intake valve engagement with the piston pocket wall. 
That relationship must have persisted from initial startup, immediately after which Ed provided a comment regarding a concerning sound in the video repost below:

photos.app.goo.gl/hqf5yUMbpZrmWxkh6

I am thankful the issue was discovered and hopefully resolved.
~~~

I'll look into this too:


🙂
 

daveo wrote:

I belive the cylinder scuffage was directly related to the intake valve engagement with the piston pocket wall. 
That relationship must have persisted from initial startup, immediately after which Ed provided a comment regarding a concerning sound in the video repost below:

photos.app.goo.gl/hqf5yUMbpZrmWxkh6

I am thankful the issue was discovered and hopefully resolved.
~~~

I'll look into this too:

🙂


 

M1 4T is excellent oil.  A great choice.  Sorry to sound overbearing, I just feel strongly that Rotella isn't the best for your use case, given your extreme level of caring, and attention to detail.

And FWIW, I don't think the valve contact with the pistons caused that scuffing.  That contact only occurred at TDC, and the scuffing is all down the bore.

Nessism wrote:

And FWIW, I don't think the valve contact with the pistons caused that scuffing.  That contact only occurred at TDC, and the scuffing is all down the bore.



 

Analysis appreciated!

I visualize pistons rocking slightly when hit by the valves, and piston fragments sliding along the cylinder wall before dispersing in the oil.  Yikes



😱



Fragments observed in drained oil after initial 70 mile ride.  12/31/24

The original oem components were replaced with used APE VS900K .440 lift valve springs (oinkjohnson) and new SMW stainless steel valves.



The increased spring tension is quite noticeable when changing valve shims.

😵‍💫

🤪  Can't wait to ride again!

High valve spring tension increases wear of all parts involved.  Are you using high lift cams?  Are you sure the high spring tension is providing a functional benefit?  Sorry to be a downer, but there is a downside to high spring tension.  One of the nice things about 4 valve cylinder heads, is that the springs are quite light, and the valves live a long time.  

I've had Kibblewhite valve springs since 2014 and haven't noticed unuseual wear to the valves or seats. 

I think this is another "one of those things" where opinions will vary. The extra load is mainly on the chain and idlers but some guys will trade premature chain wear for the "peace of mind" that they are unlikely to experience "valve bounce" or displaced shims at high RPM. On the other hand there are those who tend to favour lighter springs and ultra-light titanium valves like Dresda (UK company that built racing Tritons) The thought process being that less internal resistance means more horsepower and sharper throttle response. No right/wrong answer for this one, just preferences (IMHO)

Nessism post=920674 userid=14026High valve spring tension increases wear of all parts involved.  Are you using high lift cams?  Are you sure the high spring tension is providing a functional benefit?  Sorry to be a downer, but there is a downside to high spring tension.  One of the nice things about 4 valve cylinder heads, is that the springs are quite light, and the valves live a long time.  

 

Adequate seated valve spring pressure will allow the valves to "self clean" carbon deposits and ensure a good face seal. Anything over 100 PSI is considered a high spring tension.

New stock KZ valves springs only test at 60-62 PSI seated pressure and may be the cause of all that carbon on those higher mileage cylinder heads. Most used KZ springs I have tested only come up between 50-55 PSI so these can't be relied on to seal at 10K RPM.

APE .440" valve springs test at 85-95 PSI right out of the box. Most cylinder head porting guys suggest installed height valve spring seat pressure for high performance street applications at about 80-90 PSI maximum. If you cycle a new out of the box aftermarket spring set to coil bind in a vice 10 times it usually removes about 2-5 PSI. You can tailor the installed height pressure with shims if required as long as they do not coil bind. If I find some spring sets give a higher pressure I put them on the exhaust side to better combat carbon buildup.

You can use aftermarket springs even with stock cams to be able to seal better. There is no downside to better self cleaning or sealing abilities as long as you don't exceed 90 PSI seated pressure. To be able to do this you need a valve spring pressure tester and some way to measure installed spring height.

Drag heads require about 110-120 PSI valve seat pressure to withstand higher compression's.