Hello again, need a lil' help (okay...alot of help)

I recently returned to my swap after a 67 day patrol -- and me being the smart guy I'm not -- I didn't take any pictures of my tear down, I now have a engine I'm trying to reassemble the front of. I have lots of bagged and labled bolts, various brackets, and the Allante intake / 4.9 alternator issue to figure out.

Currently, the only things hung are the water pump and harmonic balancer.

The car never had AC, so that ones easy, no more need for power steering, one more gone.....

So I'm thinking all I'll need is the alternator, water pump, and harmonic balancer -- am I missing anything?
Anyone have a picture of this setup?
Anyone use the smaller Duke alternator?

anyone....Bueller???....class??...anyone??

Thanx, Mike.

Without AC you will only the Alternator, water pump and a belt tensioner. I used a Buick alternator it is smaller with a higher output/

Joe Sokol

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85 SE Daily driver with a 3.4 DOHC build on the road
88 Formula/GT 4.9 Allante Intake (My Baby)

Since you do not have AC, you can mount any alternator of your choice down where the AC used to be.


I made this lower bracket out of some angle and scrap steel:


Belt tension is adjusted at the alternator slotted bracket similar to the stock fiero setup.



Also, if you position the alternator and idlers properly, you can use a stock 88 2.5 fiero belt (like the one above)

quote Originally posted by fieroguru: Since you do not have AC, you can mount any alternator of your choice down where the AC used to be. Also, if you position the alternator and idlers properly, you can use a stock 88 2.5 fiero belt (like the one above)

nice setup - what size of idlers are you using to be able to use the Fiero belt?

To answer the original question: you will need the 2 idler pullies with the alternator in the stock location - the idler located just below and to the left of the alternator and the one near the water pump (to repalce the missing power steering idler). I have had no luck wil not using the idler under the alternator, I always seem to get belt squeal. I may have a picture of this type of setup - I will have to look when I get home.

quote Originally posted by fieroguru: Since you do not have AC, you can mount any alternator of your choice down where the AC used to be.

Except for having to tension the belt manually with the alternator, that looks ideal... lots of belt wrap on the crank. I need to figure something like that out for the Northstar.

[This message has been edited by Will (edited 08-11-2009).]

quote Originally posted by fieroguru:

Is that enough wrap on the water pump pulley?
This was discussed in the context of using a shorter belt and bypassing a locked up A/C compressor in one of Ed Parks' installations, and I was told that the WP needed a lot more wrap than that.

quote Originally posted by Mickey_Moose: nice setup - what size of idlers are you using to be able to use the Fiero belt?

The key is in the position of the lower idler (regardless of size) to take up the needed slack in the 4cyl belt. Nothing really special about the idlers themselves

quote Originally posted by Will: Except for having to tension the belt manually with the alternator, that looks ideal... lots of belt wrap on the crank. I need to figure something like that out for the Northstar.

I had wanted to use an auto tensioner, but couldn't figure out a clean method to do so while keeping the belt down low and below the intake manifold.

quote Originally posted by Raydar: Is that enough wrap on the water pump pulley? This was discussed in the context of using a shorter belt and bypassing a locked up A/C compressor in one of Ed Parks' installations, and I was told that the WP needed a lot more wrap than that.

I believe so... all the hrs of run time and test drives did not show any issues with cooling or belt slipage. Water pumps do not take much effort to turn (not like the alternator or AC compressor) and with the larger pulley it has mechanical advantage on its side.

quote Originally posted by Raydar: Is that enough wrap on the water pump pulley?

Waterpump on a Gen II 3.1 has less wrap than that stock.

quote Originally posted by Will: Waterpump on a Gen II 3.1 has less wrap than that stock.

Here is the belt wrap on the 3.4 TDC, and yes it is less:

quote Originally posted by fieroguru: The key is in the position of the lower idler (regardless of size) to take up the needed slack in the 4cyl belt. Nothing really special about the idlers themselves

Yes, but the size of the pulley near the water pump would also determine the amount of 'slack' you would have to take up with the other pulley. A 4mm difference in the size of the water pump idler makes a difference with getting a belt on that has only a 0.5" difference in length. I have 2 different sizes of idlers, depending on which belt I can get at the time. Yes, I know that is wrong but it's a weak point in "my" belt system with the auto tensioner, and I have figured out a better method with a different tensioner (the problem is that with the Camaro tensioner, the tensioner part rotates the wrong way for the location that it is mounted in - it moves it the same direction as the belt travel (when there is slack, the tensioner tightens, but it is unable to spring back if the belt tension is too much and as such stretches the belt). If the tensioner rotates the opposite way, this should solve that problem - I have found that the tensioner from a 93 Chev Trailblazer should work ok, I just have to build a new bracket and document it for others.

As for the water pump wrap - I don't think it should be too much of an issue since the 4.9's pump turns very easy when compared to some of the other ones out there

[This message has been edited by Mickey_Moose (edited 08-12-2009).]

quote Originally posted by Mickey_Moose: Yes, but the size of the pulley near the water pump would also determine the amount of 'slack' you would have to take up with the other pulley. A 4mm difference in the size of the water pump idler makes a difference with getting a belt on that has only a 0.5" difference in length. I have 2 different sizes of idlers, depending on which belt I can get at the time.

I hear what you are saying and know that pulley diameter will have an impact on belt length if you change pulley diameters after the setup is fabricated.

But in the design stage, once you select the pulleys you will be using (which should be a common off the shelf item), then it is simply a matter of positioning the pulleys (and the 4.9 upper idler position is mostly fixed) to fit the belt you want/choose to use - it is best to design the system around a belt that you know exists and is available at most parts stores so you do not have to go to the trouble of making another one fit after the fact. Sure you need to plan and account for belt stretch over time as well as for brand new belt to be installed, but those are all part of the design process.

It also helps when the tension idler has 90 to 180 degrees of wrap so you can get the most length adjustement from the available movement in the idler.

(my 4.3 swap also runs the 88 2.5 belt, but it does have an auto tensioner in the approximate location of the upper idler on the 4.9)

quote Originally posted by Fieroking: Without AC you will only the Alternator, water pump and a belt tensioner. I used a Buick alternator it is smaller with a higher output/ Joe Sokol

the 4.9L alternator is 140 amps, i have yet to see a stock buick alternator that high. what model is the buick alternator off of?