| Author |
Message |
Mark (Markg)
Member
Username: Markg
Post Number: 313
Registered: 2-2001
| | Posted on Friday, November 29, 2002 - 8:43 am: | |
My '69 911S had 2 chaines, 11 guides and I believe 4 tensioners; my 308 revs like a tractor compaired to the P car, and like a Ford or Chevy P car chains good for 100k miles +....over the years I have heard all the reasons / excuses for belts, bur none of them add up to a $15k engine repair for belt failures.
Some car maunfacturers have the ability to design their engines so the don't self destruct if a chain or belt brakes, but these are all in-line engines, may not be so easy a designing on a V type engine... |
Steve (Steve)
Junior Member
Username: Steve
Post Number: 216
Registered: 2-2001
| | Posted on Friday, November 29, 2002 - 8:27 am: | |
I just got a Jag X-Type and they continue to use chains. Although it a ford in cats clothing Jag has always used chains. Even in my V-12 and 4.2L sixes they still had long chains and I never had one go even after 100k miles. Belts are quite but with the whine of the gears and the carb. noise who could hear a chain.I don't think I could hear my 308. |
Paul Newman (Newman)
Member
Username: Newman
Post Number: 724
Registered: 12-2001
| | Posted on Thursday, November 28, 2002 - 10:35 pm: | |
Ford is going back to chains on most of their engines. The 4.6/5.4 SOHC and DOHC 32v v8s have them. The chains are quite long and last the life of the vehicle, self adjusting, no troubles. The engines also rev out. I took a new maurader out for a test drive and they shift at 6500rpm wot. Not bad for a domestic grandpa car. |
Ron R (Ronr)
New member
Username: Ronr
Post Number: 17
Registered: 10-2002
| | Posted on Thursday, November 28, 2002 - 10:22 pm: | |
I imagine part of it has to do with inertia. Two metal chains of that length have a lot of rotating mass. Not good when you want to spin up an engine in a hurry. Not a big deal for Chevy engines and such, having such a short distance from the crank to the single cam. Most of the sportbikes use a chain, but their engines are more compact than F-cars. |
Paul Newman (Newman)
Member
Username: Newman
Post Number: 723
Registered: 12-2001
| | Posted on Thursday, November 28, 2002 - 9:46 pm: | |
Noise reduction, cost and vibration reduction to valvetrain are 3 reasons I can think of for going with a belt. If they went with the round tooth design like a late model OHC engine, belt changes would be low on the list of things to do. |
Daniel B Reese MD (Dbr328gtb)
Junior Member
Username: Dbr328gtb
Post Number: 127
Registered: 5-2001
| | Posted on Thursday, November 28, 2002 - 9:37 pm: | |
I know belts are a built-in source of continuing revenue for Ferrari, but is there a performance or technical reason that belts are used instead of chains? |