Hi,
It’s been a while since the last time I was on this forum… I rebuilt my 1973 (well, at least the body is from 1973) alfa GTV 2000 engine (and all the rest indeed) and now she’s on the road! This started as a small leak from the gearbox I wanted to fix, and when I removed it I noticed the engine was not ceased, but turning it was requiring a lot of effort. So gearbox rebuilt turn into an engine rebuilt.
It turned out the second main bearing span at some point, and the genius who “fixed“ that just filed the bottom of the cap, and pressed the crankshaft against the engine block. So I had oil pressure, but huge forces on the crank… that was why it wasn’t turning free. But some miracle happened as the crank journals and alignment were in very good condition (Still don’t understand how)!
I found another block added some high compression lightweight pistons (Alfaholics - 10.7 to 1 as per my calculation), lightweight rods, fast road cams, and voilà: Totally new engine!
So as compression increased, burn chamber is changing (pistons have flat heads), I thought it might be a good idea to purchase a link Knockblock to make sure ignition timing is not causing knock. I attached the sensor on the drain plug in the back of the engine, behind exhaust manifold (I was’t able to attach it to the intake manifold studs), and got a clear signal. However, at full throttle the engine is so noisy it’s difficult to identify knock (I got some audio file to be able to recognize it, but my untrained ears were just not sure…)
I also got myself a knock light from link too. It’s self calibrating, and should flash red when/if knock occurs. And it does! I’m not sure if these are false signals or real knock, but it seems that in its new configuration, the engine need muuuuuch less advance! Stock max advance it arround 38 at 4000 and I’m now at 22 and still get warnings at about 5500 rpms. So not sure if this are false signals (I’m in contact with Link) or if these are real.
I suspect it’s false signals as I it happens always at the same RPM, and even if I lower the advance by 10+ degrees.
I’ll keep you posted
Ludo
It’s been a while since the last time I was on this forum… I rebuilt my 1973 (well, at least the body is from 1973) alfa GTV 2000 engine (and all the rest indeed) and now she’s on the road! This started as a small leak from the gearbox I wanted to fix, and when I removed it I noticed the engine was not ceased, but turning it was requiring a lot of effort. So gearbox rebuilt turn into an engine rebuilt.
It turned out the second main bearing span at some point, and the genius who “fixed“ that just filed the bottom of the cap, and pressed the crankshaft against the engine block. So I had oil pressure, but huge forces on the crank… that was why it wasn’t turning free. But some miracle happened as the crank journals and alignment were in very good condition (Still don’t understand how)!
I found another block added some high compression lightweight pistons (Alfaholics - 10.7 to 1 as per my calculation), lightweight rods, fast road cams, and voilà: Totally new engine!
So as compression increased, burn chamber is changing (pistons have flat heads), I thought it might be a good idea to purchase a link Knockblock to make sure ignition timing is not causing knock. I attached the sensor on the drain plug in the back of the engine, behind exhaust manifold (I was’t able to attach it to the intake manifold studs), and got a clear signal. However, at full throttle the engine is so noisy it’s difficult to identify knock (I got some audio file to be able to recognize it, but my untrained ears were just not sure…)
I also got myself a knock light from link too. It’s self calibrating, and should flash red when/if knock occurs. And it does! I’m not sure if these are false signals or real knock, but it seems that in its new configuration, the engine need muuuuuch less advance! Stock max advance it arround 38 at 4000 and I’m now at 22 and still get warnings at about 5500 rpms. So not sure if this are false signals (I’m in contact with Link) or if these are real.
I suspect it’s false signals as I it happens always at the same RPM, and even if I lower the advance by 10+ degrees.
I’ll keep you posted
Ludo
