Joda76 Posted February 11 Report Share Posted February 11 (edited) Hello good people. I bought my self a cheep defective Ossa. It is in a rather good shape, only inner head gasket is blown. After cranking it pops like a champagne when opening a radiator cap. Coolant that I have drained smells on gassoline. As I can see 4 side bolts will be the problem to torque with my Nm torque wrench because of a frame interference . Should I use some special tool , or release engine in front and pivot it a bit to make some clearance? One more thing. I read that inner oring is better to be silicone than NBR one, any oppinion on that? Many thanks ! Edited Sunday at 08:41 AM by Joda76 Quote Link to comment Share on other sites More sharing options...
kurtas Posted February 11 Report Share Posted February 11 Silicone has a higher heat tolerance than NBR, so if you can that would be better. Both will tolerate the Glycol. 1 Quote Link to comment Share on other sites More sharing options...
pauls320 Posted Monday at 01:26 AM Report Share Posted Monday at 01:26 AM Be a good idea to inspect the o-ring grooves in the back side of the head for cracks. The exhaust mount bolts to the head stay and if the suspension is bottomed out it tags the header pipe and levers against the cylinder head , have seen it fracture the head in the mentioned location ..hopefully yours is okay 1 Quote Link to comment Share on other sites More sharing options...
Joda76 Posted 1 hour ago Author Report Share Posted 1 hour ago On 2/16/2026 at 2:26 AM, pauls320 said: Be a good idea to inspect the o-ring grooves in the back side of the head for cracks. The exhaust mount bolts to the head stay and if the suspension is bottomed out it tags the header pipe and levers against the cylinder head , have seen it fracture the head in the mentioned location ..hopefully yours is okay Great point! Thank you for advice. I will inspect. I was just checking if the head is flat, while waiting on o ring shipment. Managed to take a head off pretty easy but thinking about changing 25mm T25 M5 bolts with a hex kind, so I can torque them without engine out. Or if I take engine out to drill 2 holes into a frame and weld some small pipes inside of those holes to strengthen frame in drilled points, so I can use those holes to reach 2 most critical head bolts to reach. Also planed to make a comment about a muffler. I mean, even though I really respect Ossa's designe team work in many ways, making muffler into a prying tool for an engine head is such a bad idea. I am seriously considering doing some mod to dissconect muffler fron an engine. Quote Link to comment Share on other sites More sharing options...
Joda76 Posted 1 hour ago Author Report Share Posted 1 hour ago On 2/16/2026 at 2:26 AM, pauls320 said: Be a good idea to inspect the o-ring grooves in the back side of the head for cracks. The exhaust mount bolts to the head stay and if the suspension is bottomed out it tags the header pipe and levers against the cylinder head , have seen it fracture the head in the mentioned location ..hopefully yours is okay The moment I read your comment my friend I had that feelung, fleshing image in my head that I could not see anything wrong on old o rings. So after ansvering first I imediatly took my magnifying lens. And voila...😢 Quote Link to comment Share on other sites More sharing options...
Joda76 Posted 1 hour ago Author Report Share Posted 1 hour ago Any one have a head to sell?🤕 Quote Link to comment Share on other sites More sharing options...
Joda76 Posted 52 minutes ago Author Report Share Posted 52 minutes ago 16 minutes ago, Joda76 said: The moment I read your comment my friend I had that feelung, fleshing image in my head that I could not see anything wrong on old o rings. So after ansvering first I imediatly took my magnifying lens. And voila...😢 If any one curious this crack is on a seccond bolt from a muffler mount not the closest ones. I firs checked that area and was, uff it is fine, but then😭 ...pauls320, thank u so much, I would of slapped this head back in and after would be like🤔 . Fun fact, whet I asked AI about a bolt situation it ansvered, NO, M5 bolts can not be used for an engine head😁 Also in Ossa official manual it says that bolts are T20 M5 so I first welded T20 bit to make a special tool to unbolt them 🤨 Quote Link to comment Share on other sites More sharing options...
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