I know there are more Amsoil Saber threads all over the internet than you can poke a stick at, but ill add my own to the mix too 
Firstly, id like to let you all know of my experiences with Amsoil Saber (full synthetic, pre-mix, 100:1).
[For those of you that dont want to read the whole story, just skip to the bottom where I have my recommendation]
I bought my 1978 'rude 115hp V4 almost a year ago. I was told by the previous owner that it had a rebuilt only a couple of years back (the engine had seen minimal use since then) and sure enough each cylinder was giving me ~125psi compression.
I used normal TCW-3 semi-synth oil for the first few months then switched to Amsoil at 100:1. Yes, it was a bold move but not one made without reading many articles about it first.
For over 6 months the engine ran without a problem and it was cleaner, more responsive, faster, less smelly and less smokey. GREAT! Loved it!! But... then I began to wakeboard behind the boat on almost every outing and one day when I had my wife being towed on the wakeboard (she is only ~50kgs, so not heavy and she was already planing) one of the cylinders blew a head gasket (I doubt this had anything to do with the oil) and unfortunately I was in a position where I had to keep driving the engine with a blown gasket. After I replaced the gasket I went out for another day of boarding and this time with myself and few other (big) boys. When towing quite a considerable weight we stopped for a break and while the engine was in idle the *same* cylinder spat a ring!! I was devastated!
Upon inspection I found the cylinder had a deep scratch down the side and the top piston rings had broken. The damage looked to be due to lack of lubrication. The machinist I took the engine to agreed.
Now, I am not saying running Amsoil Saber at 100:1 shouldnt be done. What I am saying is that I was running it at 100:1 while putting the engine under *considerable* load (we had a full boat AND towing). Also, he same piston that had a blown head gasket was the one that spat the piston ring. I dont believe that was a coincidence. I am pretty sure that while running the engine with the blown gasket the lubrication to that gasket was compromised (even though the cylinder wasnt firing). Once the cylinder began firing again (after replacing the gasket) the cylinder decided to call it quits.
So, moral of the story. [My recommendation]
You are walking a thin line when running 100:1 Amsoil while punishing the engine. If you want to use Amsoil on your engine that you use for fishing and nothing too strenuous, then I highly recommend it. Otherwise, if you plan on punishing your poor old engine, then I suggest you richen up your mixture.
I did a top end rebuild on the engine. Bore out the 4 cylinders and using 0.03 oversize piston/rings. In the process I found that the previous owner had oversized 1 of the cylinders and left the other 3 standard (wobbly crankshaft!!??). I have been running 75:1 for a couple of months now. Still punishing the engine and its holding up well. Its a little smokier and smellier now, but its running much better and more responsive than before. But that is due to the rebuild.
===========
Bonus question:
Anyone use Amsoil Saber? if so, do you have any recommendations? I would like to know if 75:1 is good for my engine. or should I yield and drop back to 50:1 with Amsoil Saber? In any case, I am sticking to the oil and its bloody great stuff!
Firstly, id like to let you all know of my experiences with Amsoil Saber (full synthetic, pre-mix, 100:1).
[For those of you that dont want to read the whole story, just skip to the bottom where I have my recommendation]
I bought my 1978 'rude 115hp V4 almost a year ago. I was told by the previous owner that it had a rebuilt only a couple of years back (the engine had seen minimal use since then) and sure enough each cylinder was giving me ~125psi compression.
I used normal TCW-3 semi-synth oil for the first few months then switched to Amsoil at 100:1. Yes, it was a bold move but not one made without reading many articles about it first.
For over 6 months the engine ran without a problem and it was cleaner, more responsive, faster, less smelly and less smokey. GREAT! Loved it!! But... then I began to wakeboard behind the boat on almost every outing and one day when I had my wife being towed on the wakeboard (she is only ~50kgs, so not heavy and she was already planing) one of the cylinders blew a head gasket (I doubt this had anything to do with the oil) and unfortunately I was in a position where I had to keep driving the engine with a blown gasket. After I replaced the gasket I went out for another day of boarding and this time with myself and few other (big) boys. When towing quite a considerable weight we stopped for a break and while the engine was in idle the *same* cylinder spat a ring!! I was devastated!
Upon inspection I found the cylinder had a deep scratch down the side and the top piston rings had broken. The damage looked to be due to lack of lubrication. The machinist I took the engine to agreed.
Now, I am not saying running Amsoil Saber at 100:1 shouldnt be done. What I am saying is that I was running it at 100:1 while putting the engine under *considerable* load (we had a full boat AND towing). Also, he same piston that had a blown head gasket was the one that spat the piston ring. I dont believe that was a coincidence. I am pretty sure that while running the engine with the blown gasket the lubrication to that gasket was compromised (even though the cylinder wasnt firing). Once the cylinder began firing again (after replacing the gasket) the cylinder decided to call it quits.
So, moral of the story. [My recommendation]
You are walking a thin line when running 100:1 Amsoil while punishing the engine. If you want to use Amsoil on your engine that you use for fishing and nothing too strenuous, then I highly recommend it. Otherwise, if you plan on punishing your poor old engine, then I suggest you richen up your mixture.
I did a top end rebuild on the engine. Bore out the 4 cylinders and using 0.03 oversize piston/rings. In the process I found that the previous owner had oversized 1 of the cylinders and left the other 3 standard (wobbly crankshaft!!??). I have been running 75:1 for a couple of months now. Still punishing the engine and its holding up well. Its a little smokier and smellier now, but its running much better and more responsive than before. But that is due to the rebuild.
===========
Bonus question:
Anyone use Amsoil Saber? if so, do you have any recommendations? I would like to know if 75:1 is good for my engine. or should I yield and drop back to 50:1 with Amsoil Saber? In any case, I am sticking to the oil and its bloody great stuff!
