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[ghost183]

im at a loss here, the motor has 3200 miles on the stage 4  which included a mild porting, you can obviously see the valve guides have been busted since the install cause it has the same amount of carbon buildup due to the tune being out of whack, but what would cause this? bad install job? bad manhandling? no way it came back from porting with busted valve guides!!!!!

im just glad the exhaust valve guides broke and not the intake. pistons are spotless, but BOTH exhaust  guides??

i came across this while looking at the exhaust flange gasket since i had the pipes off for something unrelated.. saw the damage clear as day from the exhaust hole

the only way i see this happenning is piston/valve contact, but when? valves are straight and seating, obviously i have the heads on the bench now and waiting for the new parts...
[/size]
[/size]on the note.. any suggestions on guide installation? im old school, heat the head to 400+, freeze the guide overnight, bath guide in oil and tap in.. any other suggestions?

[ghost183]

other head

[ghost183]

pistons

[johnsachs]

Hard to tell.
Shiny line on the back of the valve pocket? Did you size the id of the guides after install?

[Phreakyz]

Too lean, detonation and heat?

[ghost183]

Hard to tell.
Shiny line on the back of the valve pocket? Did you size the id of the guides after install?

Hey john.. 
   thanks for chiming in, the heads came back complete after the porting, and were installed by the dealer during the stage 3 kit install, i never looked in there to see if they were new.. who would??? everything else was new,, anyway..


after googling the only feasable explanation is they were damaged during install, cracked or fractured somehow, and seperated during its initial few heat cycles


im considering myself lucky considering it couldve been the intake and this couldve cost me a new top end


Phreakyz:


thanks for your input too brother.. but not a chance.. the motor has been running rich ever since the install, but mostly due to inproper map, the bikes needs to go to a dyno that i never got around to doing.. and has been burning 100 octane since cause its readily available to me 

[prodrag1320]

9de be pulling the heads off & checking the valves.only way ive ever seen guides crack is with bent valves,either bent on intall (not letting lifters bleed down) or not enough piston to valve clearance or valve to valve clearance.as far as guide replacement,if your planning on doing it yourself,remember that guides must be sized (honing is the preferred method) and seats must be cut

[ltank]

I recently had a Beehive spring fail causing a bent valve hitting the piston and the bent valve broke the guide. Make sure the head is not cracked. Heat head to 400 degrees the press out the bad guide. Then inspect the hole. Check head bore from valve guide is straight. The new guide need to be .002 to
003 interference fit. Heat head to 400 and press in new guide to correct height. The new guide will most likely be in a different position. The old valve seat will need to be cut and new surface prepared.

[ltank]

What puzzles me is that both exhaust valves broke.
Did the valves hit each other? I missed something  somewhere.

[trippy]

100% agree with this

"Too lean, detonation and heat!"

High Compression, high heat, detonation and carbonation of the exhaust guides, causes them to crumble!!

You can get special valve guides and valves to stop that.

[prodrag1320]

100% agree with this

"Too lean, detonation and heat!"

High Compression, high heat, detonation and carbonation of the exhaust guides, causes them to crumble!!

You can get special valve guides and valves to stop that.

has nothing to do with heat,detionation or being too lean.

[HD Street Performance]

A little shy giving internet diagnosis any longer. Have to see all the parts to be sure what happened plus get the full story with an interview of the owner. The first head picture has a broken head guide boss besides needing a new guide and valve (likely).
The reason for the problem would be revealed with a close look and measurements.

[MCE]

When you replace the guides, a valve job will be needed (on the EX side anyway). You also need to check
clearances on valve to valve as well as valve to piston. Chances are the EX valves are bent as well.

2 cents.

[MCE]

Too lean, detonation and heat?

The piston is black, (It's likely rich). Piston should look light-medium brown. Most likely, the EX
valves hit the pistons.

You're lucky it wasn't the intake guides. That would have trashed your cylinders, combustion
chambers and pistons.

I would also check the intake valves, make sure they're not bent too.

[MCE]

Are they stock size valves? If they're oversize, the reliefs in the piston may not be big enough.
You need a Trock fixture to check V-V clearances at overlap TDC.

[ghost183]

thanks for all your insight fellas..


i spent the better part of this week on this issue..  talking to people, harley svc techs, google, and measuring clearances, checking timing, you name it.. i probably did it. 

the mechanic at the dealer made a note in my svc history of the compression readings after the install which sparked me to talk to other dealers..  and do some diagnosing and figured 2 things out for sure....

1) that i made a good decision and dont go to the dealer anymore..


2) initial compression readings were 226 rear, 218 front, which is extremely high for a stage 3 kit, 10.5 compression..


as of wednesday that just passed, the initial mechanic doesnt work there anymore, but the current mechanic still stated its normal till after breaking.. so ok..


but heres the kicker, after the initial install, and for 1200 or so miles i use to have an abrupt and violent compression kickback, no metal to metal noise.. but it was bad enough that i did want to start the motor in fear of breaking the starter clutch(gear) apart or burning out the starter.. i mean really bad blow out thru the intake too.. and dealer still stated its nrmal till after breakin..

at that 1000-1200 mile point, i had learned my way around the tuner well, so i went into the tuner and reduced starting fuel pulse and it became normal.. 

but...

somewhere along during that initial 1200 miles or so one of those kickbacks happened at just the right time, causing just enough slack on the timing chain and i had piston/valve contact


i didnt catch it till i rolled the valves on glass and they ever so slightly kinda favored rolling to one side..  so ok,, im blind as sh*t so i clamped them individually in my lathe and spun the valves at 1000 rpm. and man o man did the bend show up at that rpm

btw..
  that clear line on the pistons valve pocket, isnt clean metal.. camera picked up the flashlight,  flash or something, who knows.. its not there normally..


on another note..
  the guide installation..

the heads have been checked and pasted with flying colors, no issues except for VERY slight indication of out of round contact on the valve seats that have already been lapped out using another valve

based on some statements from you guys about this..

the busted guides have been measured for location (micrometer) and pressed out and the sleeves are spotless, clean, no scars, so im thinking giving them a polish hone, re-install another set of OEM valve guides by heating the head, freezing the guide, and pressing in to match the original location, is this not a good idea?

[trippy]

Just thought you might be interested in reading this,

http://cylinderheadshop.com/valves-guides-for-harleys/

Just a thought,

Good luck getting it sorted, as said earlier, lucky its the Exhaust and not the inlet!!

[prodrag1320]

thanks for all your insight fellas..


i spent the better part of this week on this issue..  talking to people, harley svc techs, google, and measuring clearances, checking timing, you name it.. i probably did it. 

the mechanic at the dealer made a note in my svc history of the compression readings after the install which sparked me to talk to other dealers..  and do some diagnosing and figured 2 things out for sure....

1) that i made a good decision and dont go to the dealer anymore..


2) initial compression readings were 226 rear, 218 front, which is extremely high for a stage 3 kit, 10.5 compression..


as of wednesday that just passed, the initial mechanic doesnt work there anymore, but the current mechanic still stated its normal till after breaking.. so ok..


but heres the kicker, after the initial install, and for 1200 or so miles i use to have an abrupt and violent compression kickback, no metal to metal noise.. but it was bad enough that i did want to start the motor in fear of breaking the starter clutch(gear) apart or burning out the starter.. i mean really bad blow out thru the intake too.. and dealer still stated its nrmal till after breakin..

at that 1000-1200 mile point, i had learned my way around the tuner well, so i went into the tuner and reduced starting fuel pulse and it became normal.. 

but...

somewhere along during that initial 1200 miles or so one of those kickbacks happened at just the right time, causing just enough slack on the timing chain and i had piston/valve contact


i didnt catch it till i rolled the valves on glass and they ever so slightly kinda favored rolling to one side..  so ok,, im blind as sh*t so i clamped them individually in my lathe and spun the valves at 1000 rpm. and man o man did the bend show up at that rpm

btw..
  that clear line on the pistons valve pocket, isnt clean metal.. camera picked up the flashlight,  flash or something, who knows.. its not there normally..


on another note..
  the guide installation..

the heads have been checked and pasted with flying colors, no issues except for VERY slight indication of out of round contact on the valve seats that have already been lapped out using another valve

based on some statements from you guys about this..

the busted guides have been measured for location (micrometer) and pressed out and the sleeves are spotless, clean, no scars, so im thinking giving them a polish hone, re-install another set of OEM valve guides by heating the head, freezing the guide, and pressing in to match the original location, is this not a good idea?

you do know you have to use a oversize guide,.001 at least.as far as heating the head & cooling the guide,this is the method to press guides in but you`ll never get it in the exact location so seat work isnt needed.also if your clearances were so tight that "slack" in the cam chains cuase contact,it would have happened anyway

[HD Street Performance]

Again no way of knowing the real root cause, we have a small bit of data.
220+ cranking compression is not normal on any harley stage twin cam build unless it was sampled with collapsed lifters before the first start. The only OEM or Screaming Eagle build I can recall that will crank that with compression releases disconnected is the SE CVO 110 stock. The rings are the only "break in" item and with the hone pattern HD uses it happens fast or not at all when the fuel and timing are not reasonably close on first start or if the tech takes the bike for a ride it like you stole it shake down run. Compression goes up after the rings seat.

The forensics are not important at this point. You need to get this fixed and the internet isn't going to aid you unless you want to use the talking points to argue with the dealer. I recommend you pull the plug and get to an independant shop that has a good reputation for quality and can take a build such as this, turn key, including and especially important the tune.

[MCE]

You'll need a valve job on the EX after putting guides in it. They're never exactly the same for whatever reason.
I would look at the piston reliefs very closely too. If the valves are oversize, the reliefs may not be large enough.
It's usually the intakes for that though.

Just food for thought.