A friend just had a new S&S 110 kit fitted to his 2015 103 Breakout
the local shop fitted the kit, sold here as the stage 6 kit - with heads,635 cams and HPI 55 tb
they did the heat cycles, put a few break-in road miles on it and then did a preliminary dyno tune.
The bike was returned to the owner to get some miles into the engine and then return it for a full dyno tune.
No problems with the engine during this time and was about ready to go back to the shop with about 700 miles on it when an oil leak at the rear head/header pipe fitting became apparent.
The bike was returned to the shop where the head was pulled off and a leaking valve stem seal was found.
I am curious, first of all, to find out whether any one else has experienced a similar problem with a new S&S head.
Also, I am aware that valve stem seals can be a problem with older heads
and that a new build may have problems early on if the seal did not seat properly or was faulty.
I am interested in theories as to why this might have occurred after putting a reasonable number of miles on the engine.
Thanks
Exhaust valve? Bob
not sure Bob
they are more common due to heat aren't they ?
its a matter of being able to retain the seal on the guide , some times they are lifted off the guidegoing high into the top of the valve then float up and down with the valve, who ever replaced it the seal would know as to why it leaked ,there is no reason for it to leak if the head was reco right ,other wise it could be several issues , loose guide , loose fit with valve , cracked seal , lifted seal ,fitting clearance to valve lift at open cam lift,cracked guide to head fittment, this is a few reasons, lot more , but as i said , not worth putting it back togeter with out knowing as to why it leaked , cheers
Have the rocker housings and lids been clearanced? If not, then maybe the retainers are hitting the housing and causing a vibration causing the seals to shake loose.
Quote from: les on April 23, 2019, 07:34:38 AM
Have the rocker housings and lids been clearanced? If not, then maybe the retainers are hitting the housing and causing a vibration causing the seals to shake loose.
Wouldn't that be cause to grab some heavy duty ear muffs?
The shop that installed the 110" kit did they rebuild the heads with new guides, etc.? Could be leaking oil past the guide through the guide bore. Valve spring retainer hitting seal at full lift . Or just a bad seal. :nix:
FWIW, vibration won't loosen a seal, unless the wrong seal was installed during the rebuild.
John
The heads are new heads
part of the S&S 110 kit
it would be a proven combination in respect of clearances and tolerances ??
Quote from: jsachs1 on April 23, 2019, 01:59:28 PM
The shop that installed the 110" kit did they rebuild the heads with new guides, etc.? Could be leaking oil past the guide through the guide bore. Valve spring retainer hitting seal at full lift . Or just a bad seal. :nix:
FWIW, vibration won't loosen a seal, unless the wrong seal was installed during the rebuild.
John
The first build I ever did (95") had a problem with the retainers clipping the rocker housing. I was learning at the time. I replaced about 3 sets of valve seals until I learned about rocker housing clearance. Once I did that, the seals never came off again. This does not confirm the problem, but the reason I'm asking if rocker housing clearance has been examined.
Have you asked S&S about it?
Quote from: Evo160K on April 23, 2019, 08:52:06 PM
Have you asked S&S about it?
The shop has sent the heads back to the S&S dealer for examination
Quote from: jsachs1 on April 23, 2019, 01:59:28 PM
The shop that installed the 110" kit did they rebuild the heads with new guides, etc.? Could be leaking oil past the guide through the guide bore. Valve spring retainer hitting seal at full lift . Or just a bad seal. :nix:
FWIW, vibration won't loosen a seal, unless the wrong seal was installed during the rebuild.
John
Saw that twice here (between guide and guide bore )last year at another shop I tune for.
Generally S&S uses a little tighter guide to bore fitment on their production head castings than the MoCo does. I've done a ton of S&S head castings, and never seen oil pass between the guide and guide bore(unless the guide boss was cracked). As far as seals go, they use the best available viton seals on their production heads. If the S&S heads are the same as on their crate motors, NO vibration on this earth will make them come off. The average owner will probably pull their hair out trying to remove them, and probably stand a good chance of ruining the new replacement seals installing them. :emoGroan:
John
Quote from: jsachs1 on April 24, 2019, 02:33:25 PM
Generally S&S uses a little tighter guide to bore fitment on their production head castings than the MoCo does. I've done a ton of S&S head castings, and never seen oil pass between the guide and guide bore(unless the guide boss was cracked). As far as seals go, they use the best available viton seals on their production heads. If the S&S heads are the same as on their crate motors, NO vibration on this earth will make them come off. The average owner will probably pull their hair out trying to remove them, and probably stand a good chance of ruining the new replacement seals installing them. :emoGroan:
John
Got it. Thanks.
Quote from: jsachs1 on April 24, 2019, 02:33:25 PM
Generally S&S uses a little tighter guide to bore fitment on their production head castings than the MoCo does. I've done a ton of S&S head castings, and never seen oil pass between the guide and guide bore(unless the guide boss was cracked). As far as seals go, they use the best available viton seals on their production heads. If the S&S heads are the same as on their crate motors, NO vibration on this earth will make them come off. The average owner will probably pull their hair out trying to remove them, and probably stand a good chance of ruining the new replacement seals installing them. :emoGroan:
John
The heads are the S&S 89cc heads
The 110 kit is the same as below with the 110 cylinders, pistons substituted for the 107s