MiltonV Posted March 7, 2023 Report Share Posted March 7, 2023 Hi all, i need to confirm some measures on a supposed head for a J13 im rebuilding like chamber volume and the size of the hole in the head gasket. Quote Link to comment
datzenmike Posted March 7, 2023 Report Share Posted March 7, 2023 Measure the cylinder bore. Gaskets larger that the 73mm bore are ok. J13 cylinders and head gaskets are 73mm diameter. Only the 520 and L521 used the J13 engine. The MG engines may use the same head gasket. Unlikely you will come across any larger J series engines. J heads are likely all the same and the differences in displacement/compression ratios is taken up by a larger piston dish. The J15 and J16 head gaskets are 78mm and would also work on a J13, though a J13 head gasket would not work on the J15 and J16. J15/16 were sold in Mexico and south. May also be in some fork lift trucks. 1 Quote Link to comment
Stoffregen Motorsports Posted March 7, 2023 Report Share Posted March 7, 2023 An MGA with a 1500cc motor had a 73mm bore. MGB bore was 80mm+/-. 1 Quote Link to comment
MiltonV Posted March 8, 2023 Author Report Share Posted March 8, 2023 8 hours ago, datzenmike said: Measure the cylinder bore. Gaskets larger that the 73mm bore are ok. J13 cylinders and head gaskets are 73mm diameter. Only the 520 and L521 used the J13 engine. The MG engines may use the same head gasket. Unlikely you will come across any larger J series engines. J heads are likely all the same and the differences in displacement/compression ratios is taken up by a larger piston dish. The J15 and J16 head gaskets are 78mm and would also work on a J13, though a J13 head gasket would not work on the J15 and J16. J15/16 were sold in Mexico and south. May also be in some fork lift trucks. Hi Mike, cylinder bore is 73 so that's my doubt because the gasket measures like 77 so can't be sure if the J13 gasket really comes with that measure or if previous owner just installed a J15 gasket since J13 gasket are not available locally anymore. Quote Link to comment
datzenmike Posted March 8, 2023 Report Share Posted March 8, 2023 If from a J15/16 the gasket would never be below 78mm. It's very possible that the gasket is not round. L20B HGs aren't Quote Link to comment
Stoffregen Motorsports Posted March 8, 2023 Report Share Posted March 8, 2023 Right, the combustion ring in the head gasket is not round. Quote Link to comment
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