TiZiK Posted March 4, 2023 Share Posted March 4, 2023 (edited) Need some feedback from the hive. Looking to buy a cylinder head that’s outfitted with oversized valves and bronze seats with some porting. One cylinder has some cracks around the sparkplug hole. Is this easily repairable? One crack is pretty much right to the seat. Will the seat have to be removed to weld it? What would be involved with a repair like this? I really want this head for my turbo slabby but am hesitant due to the cracks. Edited March 4, 2023 by TiZiK Typo Quote Link to comment
george 1100 Posted March 4, 2023 Share Posted March 4, 2023 Personally I wouldn't run that head like that. Those cracks are decent which could lead to the seats falling out. The cost to fix properly would outweigh the cost of the head. Shortcut repair would be to weld up as is but the risk remains Quote Link to comment
Gixer1460 Posted March 4, 2023 Share Posted March 4, 2023 Seen plenty of cracked heads GSX and GSXR used on the street and in racing and not one ever had a seat move or cause a problem other than looking ugly! 3 Quote Link to comment
Duckndive Posted March 4, 2023 Share Posted March 4, 2023 never worried about them Quote Link to comment
Swiss Toni Posted March 4, 2023 Share Posted March 4, 2023 Triumph 8 stud heads were noted for it. Hence the move to 9 stud. As said above, quite an expensive fix, but eventually would crack again. Just live with it. 1 Quote Link to comment
TiZiK Posted March 4, 2023 Author Share Posted March 4, 2023 11 hours ago, Gixer1460 said: Seen plenty of cracked heads GSX and GSXR used on the street and in racing and not one ever had a seat move or cause a problem other than looking ugly! Good to know. So no risk of the seat moving? I guess having my welder do a small pass to close them up wouldn’t hurt? it’s a good chunk of change the guy is asking but it really is needed with my build. 85mm block and stock valves would be the limiting factor I’d think. appreciate the input Quote Link to comment
Gixer1460 Posted March 5, 2023 Share Posted March 5, 2023 And what happens if the welding causes them to move? Does his price include re-cutting all the seats as if they move, that's what will be required! Why give the engine big lungs and ask it to breathe through straws? Quote Link to comment
TonyGee Posted March 5, 2023 Share Posted March 5, 2023 my thoughts are if it was a totally standard motor then maybe I'd be happy with it but it would always be on my mind !!!!!! on a tuned motor with a turbo I'd be looking for another head. yeah im probably paranoid Quote Link to comment
no class Posted March 5, 2023 Share Posted March 5, 2023 (edited) ….or just find a good stock head … send it out for all the machine work and porting …. new seats, bigger valves etc etc …. and perhaps that will give you peace of mind ?….until that very same head develops cracks as well . All those cracks are surface cracks that are in a very narrow portion of the casting … thermal expansion and contraction is what causes the cracks . I had a draw through turbo gsxr with a complete worked head ….water/merh injection ….and all the fancy junk to go fast….. at some point a piston shat itself and upon dissassembly …. guess what …. the head had 2 chambers with small cracks ….. the motor was rebuilt and when on running like a shitty drawthrough does…. made good power and those little cracks did not change a thing . Edited March 5, 2023 by no class 2 Quote Link to comment
dupersunc Posted March 5, 2023 Share Posted March 5, 2023 I reckon 75% of the heads I've seen have those cracks. Never seen a failure from one. 1 Quote Link to comment
Fazz711 Posted March 6, 2023 Share Posted March 6, 2023 Heard and seen a lot of cracks but never heard of one going catastrophic. Quote Link to comment
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