Okay, I have 3800 SC and it has been up and running for a few years. No real issues.
I recently went with a smaller pulley (3.5) on the SC and I worry that I am going to have a belt-pulley failure soon.
Why? When I did my belt routing I went with a low mounted ALT, and in the routing I included it with the SC. So, from the crank, my belt routes to the ALT (low-mounted) and then up to the tensioner then to the mighty SC.
Most recently, after I upgraded to the 3.5 (SC pulley) I noticed the ALT is squeaking. I believe the added tension is going to burst the bearing in the little guy (the ALT).
So, as a very wise person told me -- Why didn't you follow the original design from GM and route the SC independently? Well, it was just easier to use the ALT, route the belt to it, and then to the SC. I had not idea the stress the crank draws and placing the ALT between it and the SC is just too much to demand from anyone.
I don't have AC.
Well, What I need to do is get it right. But, I am not sure what I have, as far as l pulley (sizes) and tensioners. I hot-rodded this together.
I've looked at the online routing of the 3800 belts and, except for the crank, WP, SC, I have moved quite a bit around. I believe I can get the ALT moved back inline with the WP, and mount it solid. But, from what I can tell I need to add another pulley (idler) for the SC to work around everything else.
My original designed eliminated a pulley and so I thought I had out smarted the GM engineers, but I guess the ALT needs to be with the ACC side for longevity.
I low mounted my ALT where your AC compressor is located. If I relocate to where you have yours it seems it would be easier route?
I did look at some images, but I was even more confused. I moved my tensioners around and find the correct mounting holes is hard especially with the engine in the car.
I'm not against moving the ALT but I never wanted it top mounted. Just for because it aesthetically doesn't look good.
Darth, any chance you have a set of ALT brackets? Or, drawing to make such?
[This message has been edited by RotrexFiero (edited 12-05-2017).]
I low mounted my ALT where your AC compressor is located. If I relocate to where you have yours it seems it would be easier route?
Having the alternator located in place of the A/C compressor and not having anything where the alternator is located in my picture presents a distinct problem for the tensioner. You would need a tensioner that could work in the space allotted above the water pump pulley but also clear the supercharger. In your case, I think it would be easier to relocate your alternator to where mine is and just run an A/C delete idle pulley in place of the A/C compressor you don't have. Note that the tensioner & bracket it is part of in my picture is the stock 3800 alternator mounting bracket but the bracket the tensioner arm attaches to has been modified to allow "re-clocking" of the tensioner.
quote
I did look at some images, but I was even more confused. I moved my tensioners around and find the correct mounting holes is hard especially with the engine in the car.
I'm not against moving the ALT but I never wanted it top mounted. Just for because it aesthetically doesn't look good.
You don't have to top-mount the alternator. You can do what I did and just use the factory alternator/tensioner bracket as a coil pack mount or something to bolt your dog bone mounting bracket to (if you have a manual transmission - which my picture does not show).
quote
Darth, any chance you have a set of ALT brackets? Or, drawing to make such?
Sorry, I don't.
[This message has been edited by Darth Fiero (edited 12-08-2017).]
My first task is going to be removing both belts and get my SC belt mounted independently.
I am still concerned, even with looking at your routing and the original GM routing. This design was meant for a standard 3.8 SC pulley, and not a smaller pulley. With the smaller SC pulley doesn't that put more stress on that outer idler directly above the AC compressor?
I cant imagine the bearing in a ALT not being as strong or those little idler pulleys being more stout.
Even so, I am still committed to getting that SC routed independently. Those idlers are easier to replace than a ALT (and cheaper too!).
My first task is going to be removing both belts and get my SC belt mounted independently.
I am still concerned, even with looking at your routing and the original GM routing. This design was meant for a standard 3.8 SC pulley, and not a smaller pulley. With the smaller SC pulley doesn't that put more stress on that outer idler directly above the AC compressor?
I cant imagine the bearing in a ALT not being as strong or those little idler pulleys being more stout.
Even so, I am still committed to getting that SC routed independently. Those idlers are easier to replace than a ALT (and cheaper too!).
Forgive me if I misunderstood what you are saying above - but the SC belt system is completely independent of the other belt system (for the w/p, p/s pump, alt, and A/C) on the Series 2 and 3 engines. (Series 1 SC 3800 engines are different in this respect.) On Series 2 and 3 SC engines, the supercharger belt only serves to drive the supercharger; and aside from the crank pulley, it does NOT share any other pulleys or brackets with the other belt drive system on these engines. So I'm not sure what you mean by routing the SC belt "independently". It is already independent.
Running a smaller diameter SC pulley does not put more strain on any of the SC belt idler or tensioner pulleys. However, depending on how small of SC pulley you switch to, you may need to run a shorter SC belt to avoid the SC tensioner from reaching its tension limit - or "stop" it rests on when no belt is installed. In other words, if you switch to a smaller diameter SC pulley, it could make your current SC belt too long which may not allow the SC belt tensioner to put enough tension on the belt to keep it "tight" - and you may need to switch to a shorter SC belt to correct this issue.
I can mount my ALT, a single ear to the engine block, there is a recessed bolt hole and it appears to align almost perfectly with the inside belt track on the crank.
It looks to be close in routing from there up passed the WP, but I think it will do.
Alas, one issue is the ALT is very close to the exhaust. Should I be worried? Heat rises, and I believe the ALT inside the engine compartment would see more heat.
I have to get some grooved pulleys. Probably have to wait till after the holiday.
I hope you might share a single belt routing if you pull it off, I am hoping to do the same, with the alternator where the stock A/C compressor was on L67's. I have not attempted to even see how it might mount or if I will need a custom bracket.
I'm returning my SC belt route to the stock configuration along with all the stock components. I had to order a tension, which comes as one assembly including the idler. It mounts with three bolts.
I don't think you can route anything inline with the SC. Here's why -- The amount of torque under sudden acceleration pulls hard on those belts. The SC becomes very resistant, especially as it starts to compress air. As it becomes harder to physically turn, the belt absorbs the tension, along with any other pulley inline with it. The tensioner not only keeps the belt taunt but also absorbs some of this torque. Putting a ALT inline with that only puts tension on it that it was not made for. That's my understanding of it.
I can mount my ALT, a single ear to the engine block, there is a recessed bolt hole and it appears to align almost perfectly with the inside belt track on the crank.
It looks to be close in routing from there up passed the WP, but I think it will do.
Alas, one issue is the ALT is very close to the exhaust. Should I be worried? Heat rises, and I believe the ALT inside the engine compartment would see more heat.
I have to get some grooved pulleys. Probably have to wait till after the holiday.
Where the alternator is located in the picture I posted earlier, it is very close to the exhaust. But I'm also using the stock exhaust manifold heat shields and I've never had an issue with the alternator overheating in that location.
Thanks Darth for your input. It will be close. I am running stock manifolds with exhaust wrap. I wouldn't worry in the winter, here is must dipped to 10 degrees. But, in the heat of the summer it is another story.
Thanks Darth for your input. It will be close. I am running stock manifolds with exhaust wrap. I wouldn't worry in the winter, here is must dipped to 10 degrees. But, in the heat of the summer it is another story.
If you've got header wrap on the pipe nearest the alternator, you should be ok.
If you have a trunk fan in your Fiero, you can modify the pipe to aim at the back of the 3800 alternator and that should help keep it cool as well (assuming your trunk fan still works).
Darth, I was studying your pic and I had this feeling something was odd about it. Your tensioner is connected to your WP. That explains why your pulley sits higher, closer to the SC pulley. Mine is a bit lower which is why I may have a clearance issue as I route from the ALT (down below) upward. I'm not sure how it even got there.
I love a challenge. I'm determined to get this resolved. Going down to zero all this week, and so that cold garage floor is all the more appealing. My friend cant understand the reason anyone would put themselves through such personal torture, but he is a man without passion and so he does not understand soul. It's the hard work, the messy entanglement of cognition and emotion with another, that gives a car its soul. (Or anything else for that matter.) Without that, the would is lifeless and boring.
Darth, I was studying your pic and I had this feeling something was odd about it. Your tensioner is connected to your WP.
Yes, it is the factory alternator/tensioner bracket that comes stock on the 3800. I just modified it (more precisely: reclocked the tensioner arm by drilling a new hole for the spring to seat in, grinding down the factory stop and adding a new one in a different position) so the tensioner arm could swing closer to the supercharger snout.
Darth, get me started. I have to clock that tensioner up about 90 degrees. How do you get it a part? As far as I can tell there is no bolt or screw on the darn thing.
My other solution was to go with a bigger pulley, but I think I would still have clearance issues.
Darth, get me started. I have to clock that tensioner up about 90 degrees. How do you get it a part? As far as I can tell there is no bolt or screw on the darn thing.
My other solution was to go with a bigger pulley, but I think I would still have clearance issues.
Remove the cover from the center of the tensioner. After you get this off, you will see a black washer holding the tensioner on. The end of the shaft has been rolled over to retain the washer, so you will need to cut the washer off. I use a dremel and small cut off wheel. Be careful that you do not cut too deep as this will damage the tensioner's bushing. After I get the tensioner off, I grind the rolled area of the shaft down where the washer was until flush - then drill and tap a hole so I can bolt on a new retaining washer. As I said earlier, you will need to drill a new seating hole in the bracket for the spring, grind off the old stop and add a new one to properly reclock the tensioner. I have some pics of this mod somewhere but can't seem to find them right now.
I had a few minutes this evening and I tried to pry the outside cover off. It's pretty secure. I am not sure how much prying to do without damaging it. Should I drill out the center?
Okay, with a little more time and muscle I popped the cover off. I was preceding cautiously, worried about damaging the tensioner.
I pretty much see what to do. I'll have to do some measuring to clock it in the right place, but I see you drilled a hole through to re-attached the outer cover that holds the whole assemble together.
Thats the way I did it on my 3800SC swap, by disassembling and reclocking the position but after fierorog came out with his bracket I switched over to his setup. His bracket uses a Ford Taurus tensioner which is being used at it should and IMO provides more tension on the belt than a reworked 3800SC unit
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
