From the May issue of Road&Track, article on the new Boss 302 Mustang.... "Ford engineers added... high-lift cams, forged pistons, sodium-filled valves, stronger valve springs". Yes, manufacturing techniques have improved in the past thirty years. But enough to handle the basic weakness of a hollow tube instead of a solid shaft, when pounded by a high-lift cam and strong valve springs for hundred thousand miles?
Don't think this will be much comfort to ColoradoTiger http://www.ferrarichat.com/forum/showthread.php?t=322312
I have wondered the same. Why some of the newer cars have sodium filled valves if they are a problem. The engineering has advanced in the last 30-40 years. Maybe they are adding more material at the stress points or less sodium than before resulting in more material at the same areas. Any experts have information would be helpful. By the way ,the Boss Mustang seems SWEET.
1) 308s were old tech as how they attached the heads to the stems 2) age, age, age. after your warranty is out on the Mustang, ect, i bet the dealer wont care you dropped a valve. 3) Nitrogen embrittlement. Google it. It causes metal fatigue and accents flaws and bad designs, again, time / age and heat related.
Alfas have had sodium valves for 30+ years and they've never been a problem, then or now... Think this whole sodium valves thing is a bit overblown.... And, by the way, there's some distinct advantages to sodium valves with regards to cooling - that's the whole point!
Ferrari mechanic in Redondo Beach with 16 years experience on 308's said he has never seen an engine with a sodium valve failure, he said "no problem"
I think this is like any "system". If well maintained they are not an issue. Yes, by sheer nature of the fact they are hollow they are a bit weaker than a non-filled valve. But if you run high octane gas (ping avoidance) and do the maintenance (regular valve adjustments) you will be just fine. A good friend with a 79 308 has over 100K on his motor and when he hears the carbs sucking he just can't keep his foot out of it. He drives his 308 hard all the time. But, he does religious maintenance on it. He's pulled the motor and had the valve seats, guides and seals replaced twice now. I called and asked him if the valves have been replaced and he said over the years he has replaced 5 valves due to minor damage caused by pitted seats and worn guides but has always used factory direct replacements which according to his paperwork are sodium filled like the originals. He says he can tell when his valves need adjusting by how the motor sounds at full song... gotta believe him because his motor hits the high notes every time he drives it. He added on his second top end rebuild (92K) he had the bottom end torn down too. Before they tore it down they did a leak-down with the heads off and all the holes were at 1% (this echos my findings on my motor as well). They did replace the bearings and seals but kept the pistons and ring pack. This gent has 5 Ferraris but drives his 308 the most. He says the others are faster and have more "panache" but he just loves his 308. His favorite thing is to go to local "yuppie" restaurant and park his little 308 amongst all the $100K cars and watch how the public still flock to his little $25K 308. He lets anyone who wants to sit in the car do so, especially kids. He's a one man Ferrari propaganda machine. Rick
I freaked out after reading all the posts about valve failure and the jury is still out. I replaced the EX valves with SS and repeatedly threw the old valves against the floor and managed to finally break one. Then I put a couple in the vice and hit them with a hammer, it took a fair blow to make it break. Bottom line is I sleep better but I can't totally agree. I haven't heard of failures on Volvols either. My decision was simple, the car is 27 yrs. old! Lost
