OK I've searched Fchat and google but can't find the answer to the following: are ALL 308 gear pulleys aluminium or were /are there steel versions as well? Thanks in anticipation,
Do you talk about the upper pulleys on the camshafts? I'm not quite sure, but I think, aluminium never was OEM. Early 308 had plastic pulleys and when I ordered a new set from Ferrari in 1998, I got them made from steel. Best Regards Martin
Early cam pulleys are hard plastic sprocket teeth w/ fences over a steel cam-mating core. Somewhere in the QV or 328 line they went All Steel. No OEM were aluminum in part or whole. Only Aftermarkets like mine are. Can someone prove the actual conversion date/time?
+1 MWR4440... Just been to check the set I recently took off my 83 QV and they are indeed hard plastic over metal core The actual teeth are plastic as is the "gate"or guard that keeps the belt on the pulley (supposedly). The guards on 2 of mine had partially broken off and I though there may be a risk of the broken guard lifting the belt off the cam pulley, sufficient to jump the belt on a notch....replaced mine with new Aluminium ones...just in case. The guards breaking is a very common problem but just unsure how much of a risk this is ? Kind regards, Steve
Why fences break, I have no idea. People doing belt changes wrong putting too much pressure on them, maybe? If the 3 cogs are infact parallel and the belt cut well, the fences are just there to calm the nerves of the observer. The belt will run true for many, many years, long after its acknowledged service life if nothing else changes. Belts in numerous applications run continuously and perfectly fine for 40 years or more w/o fences.
Mark, depends on the design. On some engines there are tensioners with two fences. Then the fences on the driven pulleys are unnecessary. Best Regards Martin
Funny my '83 is a fairly early QV and the QV motor seems to be equally as early in the run. And I have all steel cogs.
Thanks folks...my mechanic wants to replace the current 13 year old aluminum ones with steel - anyone know if they're still available anywhere?
Sure, check in with the normal sources...but, he feels yours are worn out?? Ther is not much wear, on a rubber belt against metal I would think...maybe others can chime in. Going thru Ferrari you will get the superseeded part replacing the OEM nylon/steel I would think. Which, it seems is what you have now.
What's there now are aluminum ones that went in 13 years ago. My mechanic (very elderly, very grumpy, Italian man of few words) just asked me if there were any steel ones available as the aluminum ones are "rubbish" (polite version of his comment). Seems there's some wear, but nothing catastrophic.
I thought mine were steel. They looked like steel, felt like steel but a magnet revealed that they were plastic. This is one of the plastic pulleys I replaced Image Unavailable, Please Login Image Unavailable, Please Login
It's not only wear, why one should get rid of the plastic pulleys. This picture shows the result after I checked mine with a slight push with my thumb while changing the belts. No big force, no tool. Best Regards Martin Image Unavailable, Please Login
ISTR sometime in the 80s there were some pulley failures and Ferrari changed to the all metal version. My 308GT4 ones were all replaced at the time and had some evidence of hairline cracks in the plastic. I don't think I'd want to be running a car with 35 year old plastic pulleys now. It could get very expensive.
Kerrari, Can you post a pic? Would love to see what 13-year old 'rubbish' aluminum cam cogs look like. I am putting brand new one-piece aluminum cogs on my 308.
Sorry, my car has the locally designed belt covers so the pulleys aren't normally visible. Mechanic made the comment when he replaced belts and tensioners recently. Unfortunately I didn't see them myself as the car was reassembled ready for me to pick up. He wasn't concerned enough to keep the car apart. Was a 'next time we should' comment. PS Mark did you come across any steel ones when shopping?
This is what my vetro has. Is this not standard? Not done by me. Image Unavailable, Please Login Image Unavailable, Please Login
I checked the spare parts bin, I have metal cam pulleys for both 2V and QV/328 engines, so the factory did indeed make them for all engine variants. Now as to the rhyme or reason why most all 2V's got fiberglass pulleys, I have no idea. Mike those are metal pulleys for a number of engines, the 308/328 ones can be seen in the middle of the pic, the 'pin' holes do not go all the way around. The plating looks like yellow zinc chromate, OEM was gold Cadmium so not as yellow but so highly caustic to get done now it can be cost prohibitive.
I've seen timing pulleys that are made of aluminum wear out often in industrial applications. I usually buy timing pulley stock and remake them out of steel, they last much longer. And the conditions In my work place the pulleys are working with highly abrasive contaminates affecting the life span of said pulleys. Under normal circumstances steel would last much longer than aluminum. Though they can be coated and last longer. Belts are abrasive by themselves and will wear the aluminum pulleys much faster than steel ones. Just saying.
True for bare aluminum. 6061 would be the worst choice bare, adding a layer of anodizing would help for a bit but would wear down as well. Best choice is 7075 and hard anodizing, that would last as long as the steel in a clean environment. Belt material construction also plays a role, in industrial applications the timing belts are of better quality and better materials then automotive timing belts, go figure. I did a lot of R&D on this when I designed the new cam pulleys and went with aluminum cogs.
