With the metals we have it really isn't required anymore. When truck engines or Mercedes and Porsche used sodium they were typically 3/8 or bigger stems to give enough wall thickness for strength. Even Alfa used 9mm. Ferrari wanted to stay with 8mm (5/16) and ended up with too thin a wall to have any strength. Using the low bidder didn't help either.
IN 2011, I couldn't enjoy the car anymore knowing it was a timebomb, so I decided to replace them with quality S/S units along with new seats and guides. I also did a bunch of "while we're in there" upgrades at the same time. I did all the work myself, and the parts were around 6K including machine work. The aluminum campulleys alone were over $1200.00,
I just did mine last year. Engine out. 50K miles. Ordered SS GEN II valves directly from Manley. Cost $683.50 delivered. Guides were in spec so we left them alone. Head Gasket set from Superperformance $638.50 including head gaskets and stem seals, etc. I replaced all the tappet buckets because I found two were cracked, ~$450. Machine shop work took around 10 hours (prices vary by location and skill of machinist). Mine were done by a buddy who builds TopFuel dragster motors for a living. A real pro. Meticulous attention to detail. I've been taking care of his computers for years so he "comped" the job. He usually charges $100/hour. So parts and labor to just change out the exhaust valves is under $3000 if you remove and disassemble the engine yourself, then reassemble and install it yourself. That's what takes all the time (and costs all the money if you have a shop do it). Of course, there's always mission creep. "While I'm in there and the engine's out I might as well..." In my case it's been a year-long quest to replace EVERY hose. But it's been a labor of love. More here, with photos: http://www.ferrarichat.com/forum/308-328/458208-observations-gt4-engine-pull.html
Far too many variables to put a number on it. This engine required a specially built puller and about a week just to get the heads off. The head required significant repair that included all new guides and three intake valves (in addition to the eight exhaust valves) and the cylinders received a 0.010" overbore for new pistons. Of course all bearings and seals were replaced as well and distributors were gone through. In the end, it was as new and certainly ran like it. It was expensive but considering the alternatives and how much the early 308s have appreciated lately, certainly worth it. Sodium-filled exhaust valves are an obsolete technology that dates to WW2. They were used on aircraft engines that were never expected to be in service decades later. Modern stainless steel valve technology has produced a product that is far superior in every way. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Hilarious, something breaks, blame the shop. Don't see any evidence it's the shop's fault as yet. I broke a sodium filled valve one just by picking it up off the bench. I broke another by simply turning the motor over by hand and it went "Ping" inside the engine. Luckily it wasn't running and I heard it. Others I've pulled out I've whacked with a hammer and the stem has bent! It's a lottery. With regards to the valve technology, there is absolutely nothing wrong with sodium filled valves at all. Plenty of post war Mercedes-Benzes still running around for example, and they don't break. The problem with the Ferrari valves is the manner in which they are constructed. The valve head is spun onto the stem. Notice they always break at the same place? With the Mercedes-Benz valves, they are once piece. With 4 and 5 valve per cylinder engines, the valves are small enough so that heat dissipation is less of an issue, so they are usually solid. For the Americans, LS6 and LS7 engines for example use sodium filled exhaust valves. Image Unavailable, Please Login Image Unavailable, Please Login
Old, but not out dated. The LS6 and LS7 Corvette engines used sodium filled valves. As was pointed out, it's not the technology that is the problem, it's the implementation.
For those who care Here's a good article re valve technology; it's four years old but worth reading for those interested: MOTOR Magazine Article | MOTOR Information Systems
For the cars that were built in the leaded gasoline era, I would recommend using a lead substitute to help keep temperatures lower. I put it in mine every fill up. You can get it at Canadian tire for all you Canadian drivers. Even a 25 year Ferrari veteran at the local dealership in Alberta agrees with that additive.
My BIL is running out of the lead additive he uses in his 63 Corvette and his distributor in the US can no longer sell it because the EPA shut them down. Is there a supplier who still can sell this stuff in the US. Sorry for the highjack but doese anyone have a source for a led additive in the US??
Move closer to the boarder. Or drive your car to Canada and buy out the supply from the closest Canadian tire. It's a great excuse for an awesome drive. One trip will last a season of driving.
Very good article to cover the basics, also the seats are another critical area. Ti valves need a cu-prate material for the seat due to Ti's low thermal conductivity, so usually it's a BeCu seat. However cu-prate materials are not exclusive to Ti valves, advances in material science have led to copper-nickle blends that can be used with stainless, inconel etc.. valves. So by using better materials for thermal conductivity we now have hollow valves as well to reduce weight. BTW Ti valves would be a waste of money in a street or daily driver engine, life cycle is too short. With our development engines I've changed the valves to 5mm stems, that alone has dropped the weight by almost half on the 4V engines. I'm also working with a mfg of copper cuprates for custom seats and guides, they also service IRL and Nascar.
Never said a pick up truck load. Just a bottle for each tank of gass per year. 10-15 bottles should do it.
exactly! lead was helpful on cast iron seats and iron heads. Ferrari heads are aluminum with steel seats, no lead needed at all. Lead additive in petrol prevented wear (recession) of the exhaust valve seat under the combined effects of heat (due to combustion) and valve closure (hammering on the seat). Lead acted by inhibiting impact welding of the valve on to the valve seat. Such welding, even on a microscopic scale, eventually leads to a significant loss of soft metal from the valve seat in cast iron heads, and allows the valve to sink further and further into the head.
I'm pretty sure with our enviro-terrorists in this country you wouldn't be able to get a pint in the country. He used a dozen cans this year and with the shut down of US production most likely will need either a few years worth until he needs to replace valves , seats and guides. His fun show/parade and cruise car , 63 340HP convert.
No 308 was built in this era, so the point is moot. Run that additive in your 308 and see how much your catalytic converters like it (hint: not at all).
From a purely legal perspective, I'd flatbed the car to the nearest Ferrari authorized service center to check the alignment of the belts. PERHAPS - if in fact the shop is at fault for mis-aligning them and causing the implosion - they neglected to go back and cover their tracks by re-aligning them properly. In that case, you'll have an official Ferrari diagnostic report placing the blame on a belt service and/or valve adjustment done wrong. Given the breadth of the expense you're about to have to undertake, spending a few hundred for a proper inspection could be worth it.
The only thing to do is pick someone to rebuild the engine, then do it. There is no such thing as an official Ferrari diagnostic report. Why waste money finding out the obvious? Timing belts had nothing to do with it.
Unless I've missed something, the USA was about the only unleaded market when the 308 was released, and the only market where the cars featured thermal reactors and later a catalyst. Leaded fuel for automotive purposes (Not aviation) was available in Europe and most other markets until it was banned at the pump in 2000.
I think its a great idea. Then someone can hire me to be the retained expert to disprove the official diagnostic report like the other times. By the time it is done the experts and lawyers will have all the money and there will be none left to fix the car.
