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Valve Seat Pitting, Opinions Please

Started by guppymech, December 19, 2019, 03:40:41 PM

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guppymech

December 19, 2019, 03:40:41 PM Last Edit: December 19, 2019, 03:45:34 PM by guppymech
 Sorry for being high maintenance but I have questions.
  I have the heads off my '84 FXE and removed the valves to have a look.  The heads had a valve job 5k miles ago and I'm surprised to see that the seats are pitted, especially the exhaust seats. I filled the ports with solvent and the seats don't leak.  The guides have no wear.  The pics below are how they look now and the 2nd pic is from before the engine's first valve job at 25k miles.  In '84 I'd have thought the MoCo had the lead free valve seat thing down pat but these heads don't look like it.  I had a '80 BMW R100 that had no seat wear at 40K, is this wear typical?

Heads now, 30k miles


Heads 25k miles
'84 FXE, '02 883R

Ohio HD

Not the expert on heads, but I have done my share of valve resurfacing and seat cutting.

For one it looks like there was a lot of carbon for 5,000 miles, did you clean a bunch from the combustion chamber? Carbon will cause seat pitting. The valve seats appear to be cut pretty wide in my opinion, and the intake is seating pretty high on the valve.

A good interference cut should give much narrower valve to seat contact, 45° valve, 46° seat lessens the possibility of pitting on those OEM seats. More modern materials and harder seats and then 45° on valve and seat are good. But the looseness of Shovels valve guides makes an interference fit a benefit.

Just by the width of the seat mark on the valves, the seat and valves appears to be the same angle.

guppymech

December 19, 2019, 05:38:12 PM #2 Last Edit: December 19, 2019, 06:53:15 PM by guppymech
There was some carbon, I wouldn't call it excessive though.  The carb is a Super E jetted .0295/72 with accel pump at 1 turn out in summer, 1.5 fall and spring.  I turn the enrichener off as soon a possible.  The bike gets 42-46 mpg around town and aroundr 50 on the hwy.  Your thoughts on valve job angles sound reasonable.

*EDIT* maybe I'll revisit the intermediate jet size this spring, I have a .028 I can try.
'84 FXE, '02 883R

Ohio HD

That and check the 0.072 as well. It could be good, but I bet at mid RPM it's pulling fuel from the main. I ran an 0.072 main and 0.0295 in an 86" motor with an aggressive cam and free flowing exhaust. It's easy to over jet a Shovel with an S&S carb. Most stock inch motors ended up with an 0.068 main or an 0.070.

Don D

What you see is common. These are probably original seats. Replacing the seats with modern materials, seats from AV&V or Kibblewhite for example, will eliminate the issue. If reground it will likely go the same distance and present the same way. I have always seen the worst of them when there is no valve seal or poor seals used and/or signs of oil in the combustion.

Racepres

Quote from: Ohio HD on December 19, 2019, 05:10:45 PM
Not the expert on heads, but I have done my share of valve resurfacing and seat cutting.

For one it looks like there was a lot of carbon for 5,000 miles, did you clean a bunch from the combustion chamber? Carbon will cause seat pitting. The valve seats appear to be cut pretty wide in my opinion, and the intake is seating pretty high on the valve.

A good interference cut should give much narrower valve to seat contact, 45° valve, 46° seat lessens the possibility of pitting on those OEM seats. More modern materials and harder seats and then 45° on valve and seat are good. But the looseness of Shovels valve guides makes an interference fit a benefit.

Just by the width of the seat mark on the valves, the seat and valves appears to be the same angle.

My Thoughts Exactly... Except I do Not believe we ever needed "new seats"...  oddly...I never got any... But, Only had my '82 since New!!!

Don D

Quote from: Ohio HD on December 19, 2019, 05:10:45 PM
Not the expert on heads, but I have done my share of valve resurfacing and seat cutting.

For one it looks like there was a lot of carbon for 5,000 miles, did you clean a bunch from the combustion chamber? Carbon will cause seat pitting. The valve seats appear to be cut pretty wide in my opinion, and the intake is seating pretty high on the valve.

A good interference cut should give much narrower valve to seat contact, 45° valve, 46° seat lessens the possibility of pitting on those OEM seats. More modern materials and harder seats and then 45° on valve and seat are good. But the looseness of Shovels valve guides makes an interference fit a benefit.

Just by the width of the seat mark on the valves, the seat and valves appears to be the same angle.

Agreed, I no longer use the interference angles but change the guides and improve the guide fit which is possible by using modern bronze manganese guides

guppymech

What would be a ballpark cost of a head rebuild including replacing the seats?  Would getting some replacement heads from S&S be a better option?  The bike will only ever be a stockish cruiser.
'84 FXE, '02 883R

Don D

Your heads appear to be in good condition. With seats and guides the cost would be half or less compared to S&S, depending on what parts can be reused.

Racepres

I guess I don't understand replacing those heads... or even the seats!!!
I have seen seats much more sunken than that, unless the photo is such that I cannot actually see the seat depth..
Wouldn't take me long to reface those Valves, do an interference [45 and 46 angle Valve job... with narrower seats..
And be Riding Tomorrow!!!!
Assuming the guides are OK...

Ohio HD

December 20, 2019, 08:00:48 AM #10 Last Edit: December 20, 2019, 09:00:35 AM by Ohio HD
My point to the looseness of Shovel guides, is that since they're 0.375" nominal valve stems, they should be setup with more clearance than an Evo / TC with a nominal 0.312" or a later TC with a nominal 7mm stem.

guppymech

Quote from: Racepres on December 20, 2019, 07:33:49 AM
I guess I don't understand replacing those heads... or even the seats!!!
I have seen seats much more sunken than that, unless the photo is such that I cannot actually see the seat depth..
Wouldn't take me long to reface those Valves, do an interference [45 and 46 angle Valve job... with narrower seats..
And be Riding Tomorrow!!!!
Assuming the guides are OK...

It's not that the seats are sunken, it's that they're pitting.  The pitting was so bad on the front exhaust seat that at 25k miles the cylinder lost compression.  I'm just surprised to see the pitting coming back only 5k after a valve job.   
'84 FXE, '02 883R

Hybredhog

   I don't know your altitude, but here at 4000ft. I start with 28/ 66 S&S jets in a 80" shovel, so carbon and/or the funky foam A/C can be passing a lot of crap though. '84's I believe had "harder" seats than earlier, & I don't recall hearing about what kind of lifters you may be using, if its solids, they may be harder on the valve train.
   From what you've said in the other cam post, your protrusion specs are decent, so I'd just re-cut what you have & give it another shot, being more diligent about jetting.
'01 FXDXT, '99 FXDL/XRD, '76 FLH

wfolarry

That's not pitting that's carbon flakes hammered into the seats.
Looks like it's pushing oil.
Freshen up the top end & have the heads checked out. You don't need new seats.

Don D


guppymech

Thanks All for the info and have a Happy Holidays!

Tom
'84 FXE, '02 883R

Hillside Motorcycle

Absolutely do not not need new valve seats whatsoever.
Perform a good multi-angle valve job, check guide to stem fitment, replace needed parts.
We do that work in our Winnona-VanNorman PH 2000 seat/guide machine using Serdi/Mondello seat-form cutters over solid carbide pilots.
I'd look at the spring pressure as well.
OE shovel springs are like bubble gum.
Otto Knowbetter sez, "Even a fish wouldn't get caught if he kept his mouth shut"

Burnout

I have also seen many bikes with solid lifters and someone has set the valves when hot.   :oops:
They don't call me Ironhead Rick just because I'm "hard headed"

rigidthumper

Quote from: Burnout on December 26, 2019, 04:17:10 PM
I have also seen many bikes with solid lifters and someone has set the valves when hot.   :oops:
That can make em easy kicking (and hard starting)  :)
Ignorance is bliss, and accuracy expensive. How much of either can you afford?

Burnout

They don't call me Ironhead Rick just because I'm "hard headed"

Don D

December 30, 2019, 01:36:01 PM #20 Last Edit: December 31, 2019, 05:59:14 AM by Coyote
Replaced guides, Rowe, and did a valve job. The exhausts were pitted bad. Reused the OEM valves and used a Kibblewhite spring set and seals. Took only .015" cut to clean the seats .003 off the valves and did it on the Serdi 100 and Sunnen VR6500.

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Hillside Motorcycle

One thing that some overlook is the Shovel head usually has a low spot under the exhaust port, from the casting taking it's final shape, caused by heat.
We manufactured a fixture almost 30 years ago, to mount the head in place, and re-surface to establish a precision gasket sealing surface.
At that time, we also re-surface the face of the exhaust ports in another fixture, as well. :smile:
Otto Knowbetter sez, "Even a fish wouldn't get caught if he kept his mouth shut"

Burnout

They don't call me Ironhead Rick just because I'm "hard headed"

Hillside Motorcycle

We have our Winonna-VanNorman PH2000, on a full-floating air table, along with a complete New Way system, and both Sioux and Black & Decker stone systems in order to cover all bases of our full time, for a living, 6 day a week cylinder head section, of our shop. :smile:
Otto Knowbetter sez, "Even a fish wouldn't get caught if he kept his mouth shut"

Buglet


Don D

January 03, 2020, 06:42:57 AM #25 Last Edit: January 03, 2020, 06:50:39 AM by HD Street Performance
Certainly superior to an old drill press machine but out of the reach of most shops. Probably 60K or so for a Newen which is not to be confused with "Neway" which are hand driven cutters with flimsy pilots. I have all the old stuff and haven't busted them out for so many years I lost count.

Racepres

Quote from: BUGLET on January 03, 2020, 05:27:14 AM
  I though NEWEN was they way to go.
Neway
and Only for cookie cutter production... While I am Positive that a "round" seat like a "machine" can produce is the Pinnacle... Stones are extremely Flexible...And if you only do limited numbers... well... they suit me just fine

cheech

Quote from: Racepres on January 03, 2020, 07:18:26 AM
Quote from: BUGLET on January 03, 2020, 05:27:14 AM
  I though NEWEN was they way to go.
Neway
and Only for cookie cutter production... While I am Positive that a "round" seat like a "machine" can produce is the Pinnacle... Stones are extremely Flexible...And if you only do limited numbers... well... they suit me just fine

He meant Newen I'm sure. WAY different than Neway. https://www.newen.com/

Racepres

Quote from: cheech on January 03, 2020, 03:50:48 PM
Quote from: Racepres on January 03, 2020, 07:18:26 AM
Quote from: BUGLET on January 03, 2020, 05:27:14 AM
  I though NEWEN was they way to go.
Neway
and Only for cookie cutter production... While I am Positive that a "round" seat like a "machine" can produce is the Pinnacle... Stones are extremely Flexible...And if you only do limited numbers... well... they suit me just fine

He meant Newen I'm sure. WAY different than Neway. https://www.newen.com/

Hmmm.... Looks like cutting angles on uninstalled seats to me... Nah.....

Hillside Motorcycle

Otto Knowbetter sez, "Even a fish wouldn't get caught if he kept his mouth shut"

cheech

Quote from: Racepres on January 04, 2020, 05:44:28 AM
Quote from: cheech on January 03, 2020, 03:50:48 PM
Quote from: Racepres on January 03, 2020, 07:18:26 AM
Quote from: BUGLET on January 03, 2020, 05:27:14 AM
  I though NEWEN was they way to go.
Neway
and Only for cookie cutter production... While I am Positive that a "round" seat like a "machine" can produce is the Pinnacle... Stones are extremely Flexible...And if you only do limited numbers... well... they suit me just fine

He meant Newen I'm sure. WAY different than Neway. https://www.newen.com/

Hmmm.... Looks like cutting angles on uninstalled seats to me... Nah.....

They are redoing their website. So incomplete. But no they aren't for cutting uninstalled seats. A single point cnc controlled seat and guide machine. Supposedly "Nascar" type  technology so to speak. $60K and up or so what I heard.
I don't know if any of the machinist on this site use them or not. If so or if they know more hopefully they can disprove or prove if they have any merits.