| Author | Message | ||
| Timothy J. Dressel (Tjd)
New member Username: Tjd Post Number: 50 Registered: 4-2001 |
Steve, Chuck, David, Thanks for the images. --tim d | ||
| David Feinberg (Fastradio2)
New member Username: Fastradio2 Post Number: 32 Registered: 4-2002 |
More reliablitiy/durability with a BB...I like that idea. Seems that the round tooth style pulleys/belts that are used on say a 328 would do the trick? And the motor is "still" out of the car...What could be easier? Thanks for the tip... | ||
| '75 308 GT4 (Peter)
Intermediate Member Username: Peter Post Number: 1843 Registered: 12-2000 |
The part #'s are the same for both 308 and 365BB (belts, tensioner pulleys, cam pulleys, drive pulleys, drive gears[up until 308 engine# 03044] and bearings). So Ed, if your cam pulleys will fit early (with three dowel holes) cams, your system will work on 365 Boxers. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1364 Registered: 2-2001 |
That appears to be the old square tooth belt system. if it were mine I would change it over to the more modern round tooth belt. | ||
| David Feinberg (Fastradio2)
New member Username: Fastradio2 Post Number: 27 Registered: 4-2002 |
Here's the timing belt setup on a 365BB...  | ||
| William Badurski (Billb)
New member Username: Billb Post Number: 46 Registered: 6-2001 |
F50 diagram appears to be chain drive with adjustable sprockets (using movable dowels) same as Daytona. | ||
| Chuck Rine (Chuck348ts)
Junior Member Username: Chuck348ts Post Number: 92 Registered: 5-2001 |
More stuff from the "Research Department": F40 belt diagram, which looks a lot like the 308/328:  F50 belt diagram (gearing looks unique):  I'll try to get some other models per Ben's suggestion over the weekend. | ||
| Michael Fennell (Mfennell70)
New member Username: Mfennell70 Post Number: 50 Registered: 7-2001 |
I have to check, but I think Lotus is now recommending tension checks every 10k. They are free at a dealer. Changes are 30k. I have a service manual at home. I'll see if I can get a pic up. | ||
| Ben Lobenstein 90 TR (Benjet)
Member Username: Benjet Post Number: 588 Registered: 1-2001 |
Thanks Chuck Rine in the research Dept.! *wink*  Can we come up with any others? F50, F40, 288, 512bb, 400/412, 246 Dino, others? That would cover nearly all Ferraris for the last 25+ years. Just curious! -Ben P.S. Can anyone post the Lotus v8 belt system to compare? I have a friend locally with a '97 v8, IIRC his recommended belt change was 12.5k miles, which is about when he did it, altho it can be done in 8 hours with engine in car. What's up with that? | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1286 Registered: 2-2001 |
That I know of, other than the Lotus. | ||
| Edward G. Salla (350hpmondial)
Junior Member Username: 350hpmondial Post Number: 128 Registered: 2-2002 |
I wish Ferrari would drop their belt system and do the "Right" thing,,,,pneumatic actuation. Think about it, if your system fails,,, all your valves stay shut. | ||
| Chuck Rine (Chuck348ts)
Junior Member Username: Chuck348ts Post Number: 91 Registered: 5-2001 |
Edward, the 550 manual says every 50,000 km but not longer than 3 years. Sounds like another perpetual dealer service gimmick.  | ||
| Michael Fennell (Mfennell70)
New member Username: Mfennell70 Post Number: 49 Registered: 7-2001 |
"Seems kind of strange that Ferrari is the only car in the world that uses a two belt system." The Lotus V8 uses two belts. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1285 Registered: 2-2001 |
Chuck, iF you have a 550 owners manual, what mileage and or time do they show for belt replacement? | ||
| Chuck Rine (Chuck348ts)
Junior Member Username: Chuck348ts Post Number: 90 Registered: 5-2001 |
Per Ben's request, here are the 456 and 550 cam belt images. The layouts are very similar as I believe they are variants of the same base engine. The 456GT cam belt layout (from 1st ed. 1993 owner's manual):  And the 550 cam belt layout (from 1st ed. 1996 owner's manual):  I will post the F40 and 288GTO this afternoon if I have time. Also, the TR belt layout might be interesting for comparison to the other 12's. | ||
| Dave Penhale (Dapper)
New member Username: Dapper Post Number: 9 Registered: 4-2002 |
and the Porsche 928 has a single (very long) belt system. Changed one of them that was a gas! | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1282 Registered: 2-2001 |
Seems kind of strange that Ferrari is the only car in the world that uses a two belt system. Even Subaru uses a single belt on their four cam flat 6 which looks identical to the TR setup. Originally Subaru used two belts to operate their SOHC engines but had early failures due to the belt design {square tooth} and construction {neoprene}. Yes, a wider belt is necessary but I had much rather have a wider belt than all the extra pulleys and gears and bearings. All other Mfgs use the crankshaft snout to turn the cam belt and most are now using automatic hydraulic tensioners to control tension and appears to be the ultimate setup. Belts on most modern cars will now go well over 100,000 miles with no problems. Toyota appears to have the best systems as they use belts with a more narrow pitch meaning more teeth per inch thus distributing the load further. The problem with belt design is not with the belt actually breaking, but stripping the teeth off the belt. The construction material and tooth profile of the belt is one of the most critical longevity areas in the drive system design. | ||
| Edward G. Salla (350hpmondial)
Junior Member Username: 350hpmondial Post Number: 125 Registered: 2-2002 |
A one belt system puts more then two times the tension in (on) the belt. Thus, you need a wider belt....... and Wider pullies. Wider pullies have a larger polar moment. Thus, they put more tension on the belt during acceleration and deceleration. Thus, you need more belt tension or, again, need a wider belt. After a few iterations of the above logic, you will end up with a working cam belt system. (I guess the Ferrari engineers returned to two belts for the above reasons.) ????????? comments? | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1279 Registered: 2-2001 |
Looks like a HUGE step backwards to go back to the two belt system. They get to sell more stuff with 2 belts. I keep forgetting, PROFIT is involved. | ||
| Paul Newman (Newman)
Junior Member Username: Newman Post Number: 165 Registered: 12-2001 |
Just curious why they returned to the twin cam drives? Are there problems with the 348 setup that made them go back? Im assuming the f40 is the same as 288, 308.....How about the f50? | ||
| Ben Lobenstein 90 TR (Benjet)
Member Username: Benjet Post Number: 586 Registered: 1-2001 |
This is quite intesting! So we've almost covered 25 years of Ferrari Timing belt variations (ok, not all but a majority of), anyone care to add the 456/550 images? and even more of the older models if diagrams can be found...sorry I have nothing to add but the request to post more! -Ben | ||
| Edward G. Salla (350hpmondial)
Junior Member Username: 350hpmondial Post Number: 124 Registered: 2-2002 |
Thanks guy's,,,, this is the best string ever! | ||
| Chuck Rine (Chuck348ts)
Junior Member Username: Chuck348ts Post Number: 89 Registered: 5-2001 |
Here is the 355 cam belt diagram:  And here is the 360 cam belt:  Both diagrams taken directly from the owner's manuals availabe on the Ferrari Owners web site. | ||
| Dave L (Davel)
Junior Member Username: Davel Post Number: 119 Registered: 7-2001 |
This is great...Thanks for posting this. Very very cool Steve | ||
| Steve Magnusson (91tr)
Member Username: 91tr Post Number: 702 Registered: 1-2001 |
Like Bret said in the 348 cambelt thread -- can someone post shots of the cam belt/cam belt drive layouts for 355s and 360s for comparison? It's interesting to note the variations: 308/328 2 short (stiffer) belts and only 2 cams stop turning when a belt breaks on the plus side, but the extra cam drive gears/shafts/bearings/seals are a significant minus.  testarossa 2 longer cam belts (a bit of a minus) which eliminates the extra cam drive gears/shafts/bearings/seals (a plus), but also requires a longer snout on the crankshaft (another small minus). Only 1/2 of the motor gets wacked if a belt breaks (a plus).  348 1 very long belt (minus) and everything goes if the belt breaks (minus), but, on the plus side, no long crankshaft snout and no extra cam drive gears/shafts/bearings/seals.  I'm just curious to see what other changes evolved on the 355 and 360 or if they brought back some elements of earlier designs. |