QUestion about ALternator pulley size and belt size

[5ABI VT]

Im not sure if Im correct but the oem pulley seems to be a 2.75. Im considering an aftermarket alternator but they only have 2.5 and 2.9 inch pulleys. I would want the tensioner to have enough tension either way.

Can anyone tell me the oem belt length? If there are options for slightly bigger or smaller I can search it up and feel comfortable with either. I would guess the oem tensioner would still work on a 2.5 but I don't want it to not have full tension in case there is too much belt length etc.

[Dynomite]

You can get longer or shorter serpentine belts. You are looking for 1/2 inch or more between the belt over the belt tensioner and the belt between the water pump pulley and alternator pulley.

[geezer]

OEM length is 80.5 in.

[WVZR-1]

Speak to "whoever" you're considering using as a source and investigate the use of the OE pulley and fan to keep the belt at OE length.

1978026 should be the correct "as built" fan and 10498550 should be a correct "as built" pulley. A competent reseller should be able to connect you with a tech person to address the issues. The OE belt is actually spec'd at 2037mm which is 80.1969.

You need to watch where you measure a pulley for diameter, what's considered a replacement for the 10498550 is mentioned to be 62mm which is 2.44 - you have your alternator measure it.

Use this to compare and to use as reference points for your measurements. It would be interesting for you to post your measurements vs. those referenced in the link. I've never measured an OE first hand, yours is original so it could be valuable information. Check the pitch dimension mentioned also.

http://store.alternatorparts.com/241...130-cs144.aspx

[-=Jeff=-]

Some info when I looked at this in the spring

http://www.zr1.net/forum/showthread.php?t=22894

[5ABI VT]

I'll measure mine up and post. I originally measured from the outer edge on the face of te pulley. So 2.75 is definitely larger than the surface the belt rides on so 2.44 may actually be the right length. If that's the case 2.5 seems to be the choice to go with. The alternator is a billet unit and I'm told that it can handle quite a bit more rpm than a cs144 without even warming up.

[WVZR-1]

You want to confirm before a purchase all of the dimensions and you might want to "circle" all of the mounting points on the rear housing(slip ring end) and send snapshots to the vendor to confirm the fitment before the purchase. Confirm also the mounting configuration for the forward housing(drive end frame) also, maybe they can confirm using your OE number.

You might mention in this thread the brand and part number before purchase also, maybe someone has experience with the product and can confirm fit or potential issues.

[5ABI VT]

Originally Posted by WVZR-1

You want to confirm before a purchase all of the dimensions and you might want to "circle" all of the mounting points on the rear housing(slip ring end) and send snapshots to the vendor to confirm the fitment before the purchase. Confirm also the mounting configuration for the forward housing(drive end frame) also, maybe they can confirm using your OE number.

You might mention in this thread the brand and part number before purchase also, maybe someone has experience with the product and can confirm fit or potential issues.

Definitely no secret I've been posting on FB and cf I think I just forgot I never mentioned it on here. It's a mechman alternator and I've been in touch over the last several days and have sent numerous photos of the alt and other details. I do agree though I will try my best and confirm the mounting point dimensions and I'll ask them to reference the oe part number.

Does anyone know of the difference between the zr-1 and lt1/4 alternators? They didn't say they were the same at first they said they don't have anything for the z until I sent photos .. So I do have a slight feeling they may think it will work.

I'm going with a black anodized unit 170 amp.

[WVZR-1]

Originally Posted by 5ABI VT

Does anyone know of the difference between the zr-1 and lt1/4 alternators? They didn't say they were the same at first they said they don't have anything for the z until I sent photos .. So I do have a slight feeling they may think it will work.

I'm going with a black anodized unit 170 amp.

Comparing LT1/4 applications to the LT5, the forward housing is different, the fan is likely different and the pulley is different for OE applications. It depends which LT1/4 is compared, 124AMP or 140AMP.

According to their application charts there's certainly "hints" that they don't offer a fit. Their application charts don't cover what you mention buying. Can they build one? Only they can answer that. Of course their application chart is only for their 240AMP unit so any 170AMP that they did for you would be a "custom" build.

Your '94 would use these OE components, the forward housing 10470800, rear housing 1989706, the pulley 10498550 and the fan 1978026.

I didn't mean to "hint" there was a secret but there's not a specific model #/part number that they can supply you that would help someone mention it did or didn't work.

Has anyone used or considered a Mechman alternator build?

http://www.mechman.com/

[5ABI VT]

There was a post a while ago on corvette forum Ill try and search it. I cant remember how long ago but I didn't have my zr-1 but I saw the post in the z section on cf and inquired about it for my 93 non z car because of the improvements at higher rpm. From what I can remember its a billet unit but they offered a LT5 specific fitment. ALso from googling all night Ive come across several vendors that pretty much all market the mechman alternators and rebrand them.