Mother

I must be routing my belt wrong if I use the same amount of pulleys and you are using a 103.5" belt.

Mother

Woops guess we are thinking up same lines hear and I need to put the caccpachino machine back in mine. Anyone draw a picture of there belt routing for me I seem to be inept Maybe this is the reason I am not charging my bat when I start my car?

redridge

I think you may be good Mother, but maybe you're not catching enough meat on your alternator... need to look further... BTW 1 is the very top left... left of #2

Mother

I Agree and thanks for taking the time to post pic, It seems mine is the same, but my SC alignment is different in realative terms "note modded pic". Still hard to beleive 10" of belt defference. It also looks like you are running a 3" or so inch SC pulley size. So much for hoping on the charging problem. There be enough biting on the alt for sure at idle to get a charge what should I read at battery with multimeter as far as voltage have any idea.

Mfletch

Mother, thanks. I need both visors. When I get mine, I'll try to snag an extra for you. I found another local salvage yard that has about a dozen 996s and Boxters (www.mazdaporscheparts.com).

1999Porsche911

Mother. There is no way your alternator will spin up to speeds necessary with only such a small surface of the pulley contacting the belt. Moving pulley #3 to the left will help. Or, if room, install a much larger #3 pulley? The alternator will pivot left to right. Maybe you can modify the pivot so you can move it to the extreme right which will increase the belt contact with the pulley.\

Jim

Tippy

+1

The only thing I see possible is rotate the blower downward. Probably squeeze 90+ degrees of wrap doing this.

redridge

okay mother, I think I see a difference, there is a guide bracket between 1 and 9, that travel seems long and maybe vibrating modulating the throttle agressively.

roberga

just wondering if anyone has a long history of a force fed 996 and say 30,000 miles? Since it would have been less costly for Porsche to bolt a turbo on your engine rather than keep make a different block. I have been told that the 996 motor over time will not like to add pressure. I do not have a clue just looking to gain some knowledge.

1999Porsche911

I have much more than 30,000 miles on my blown 996 (3.4) and run a far greater boost than any 996 I know of running an 11.3:1 compression ratio. No problems here. No oil burning or leaks.

Tippy

How much boost you running?

roberga

thanks. Any ideas as to why Porsche stays with the old blocks?

Mother

Am removing mine now, are you reffering to the guide built into the bracket that goes around the SC pulley?

redridge

yes, its a welded (on the SC bracket) strip of metal piece between 1 & 9. It also serves as a shield for the coolant hose on the left side of the belt.

Mother

Blower is off and first thing I noticed is that I could not turn the Alternator because it was hitting my SC "marked pulley with paint so I can see that it is turns now", also the alignment seems off from the alt pulley to pulley #9 power steering pump and to the alt. I'll remove the bracket tomorrow for new belt and reshim as nesessary. I try a laser light and if that does not work eye ball it I guess for alignment.

Summary: The grooved pulleys alt, air pump etc have an outer ridge higher then the ribs themselves and if alignment moved the belt could have tried to jump pulley and if it was the SC pulley it jumped it's edge is sharp enought to cause belt failure.

Regarding the alternator, it freewheels very easy and does not require much to turn it and if you can tell by picture I have maybe 30 percent deflection which seems ample to me, but just in case a larger pulley is needed like 1999 suggested seems the logical fix considering the SC is clocked as much as possible to get a better pulley wrap Tippy.

Redridge: I may fasten the belt retainer as bolt on the SC that can be removed easily later, but do not like the idea of not seeing what is going on underneath it during testing or TS.

Now if I can find a way to keep a back up belt ready to use in there without removing the SC incase of a belt mishap I know I would sleep better.