rcx132
Philip
- Messages
- 2,816
- Location
- London, UK
This engine from my Suzuki SJ413 never ran right, I couldn't find the fault, in the end I fitted a new (used) engine and this one sat around for three years until I've found the time to look into it today.
Two of the cylinders were not igniting correctly. Gunson colour tune showed that at idle they were only igniting on every other cycle. Other two cylinders were fine. Above idle, with the gas pressed, all four cylinders ran perfect. This caused bad idle and was an MOT fail due to unburnt hydrocarbons.
The car got new spark plugs, new HT leads, valve clearances checked, compression checked, idle jet adjusted, carb cleaned, new ignition coil, still the problem persisted. Eventually it got a brand new factory jetted Weber, and still the problem persisted. At that point I gave up.
Today I whipped off the cylinder head. The cylinder bores look great. But two of the valves are a totally different colour as shown in the photo. Does the colour give any clue to what the fault is ? Please ignore the oily combustion chambers, they were completely dry when I took the head off but then oil drippled into them when I put the head on its side.
If I recall correctly the two cylinders with the orange valves are the ones that were running correctly, but I could be wrong, it's been so long.
Two of the cylinders were not igniting correctly. Gunson colour tune showed that at idle they were only igniting on every other cycle. Other two cylinders were fine. Above idle, with the gas pressed, all four cylinders ran perfect. This caused bad idle and was an MOT fail due to unburnt hydrocarbons.
The car got new spark plugs, new HT leads, valve clearances checked, compression checked, idle jet adjusted, carb cleaned, new ignition coil, still the problem persisted. Eventually it got a brand new factory jetted Weber, and still the problem persisted. At that point I gave up.
Today I whipped off the cylinder head. The cylinder bores look great. But two of the valves are a totally different colour as shown in the photo. Does the colour give any clue to what the fault is ? Please ignore the oily combustion chambers, they were completely dry when I took the head off but then oil drippled into them when I put the head on its side.
If I recall correctly the two cylinders with the orange valves are the ones that were running correctly, but I could be wrong, it's been so long.