broken piece off of dome !

[Jaystre]

broke a small piece of the inner lip that holds the o-ring in place ,just above the exhaust port about 1/2 wide . what couldve cause this?

 

[trickedcarbine]

Few things could cause it. Do you have a pic of it? Other wise I could only speculate that it was due to clearances/tolerances being over looked. Maybe assembly error? Detonation? Have to see it to have a real idea though.

[DUSTY05]

Mine did the exact same thing.. both domes but mine were small chips

[n2otoofast4u]

What bore? Sometimes when you get a larger bore the material between the combustion chamber and the oring gets thin.

[DUSTY05]

Mine was stock cyls, stock bore, Noss head and 19cc domes.. Kevin at HJR said it was from "compression".... Idk

[Brap_Life]

Piston pocked on exhaust side at all?

[J-Madd]

Is it a dome with an oring groove, or just the ledge to hold the oring on? If it was a groove, did you put a lot of grease on the oring? The grease won't compress and will blow oring grooves when the head is torqued down.

[DUSTY05]

Mine has a ledge... i had 19cc domes and ran 93 pump gas in it,would detonation cause this?? My plugs and pistons are in great shape...

[J-Madd]

Deto can cause that, but it's gonna show on the piston and plugs first usually.

[DUSTY05]

Deto can cause that, but it's gonna show on the piston and plugs first usually.

 

Exactly What i Thought Also.. fuk if i Know What Happen

[Jaystre]

it is a dome with a o-ring groove ...didnt put that much grease i would think . piston and cylinder are fine but the o-ring on the other dome was starting to  break up at the same spot above the exhaust port...ill try to get pics .

 

bore is 64.5

Edited October 8, 2013 by Jaystre

[trickedcarbine]

Just pro design shelf domes.

[camatv]

if the "break" is obviously a material failure ( just snapped off)  then can be a lot of things...

 

if its sand blasted off or blown off  melted off etc  its DETO>

 

i have seen SOME heads blow out where the o-ring seals from to much internal pressure or bad dome design, and/ or weak ass head studs.    the banshee stock head pattern has a very weak inherent problem in that area.  the dome just does not have the same sealing pressure that the rest of the head has. 

[Jaystre]

its not melted off ...the domes seem fine except that broken part . these were domes cut for a 4 mill 

[J-Madd]

Still no pics? Was it torqued properly? Oring might have blown and let water on a hot dome??? But that usually causes deto and other damage so I guess we're back at square one. Had this motor been run for a while or was it a new build? Maybe the deck wasn't square?