TAC Tech => Mechanical => Topic started by: Brandon_78TransAm on June 25, 2024, 10:32:37 PM
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I've got a '78 with a pontiac 400 and I'm having a hard time with my pulleys. Had the engine rebuilt so I've been working on getting the accessories back on and I noticed that my crank and water pump pulleys are aligned but the alternator and power steering seem off. The alternator really seems to be almost 1/2" off and the P.S. pulley maybe half that. I tried shimming the b ack up with washers to mock it up but I noticed that with almost 1/4" of washers spacing it out, the P.S. is lined up but the alternator is still 1/4" too far back and needs to go forward more. My list of pulleys are
P.S.= 10009669 WD
Crank= 481038 Yb with the reinforcement plate and the 480509 XS A/C Pulley
Water Pump Pulley= 481040 xt
Alternator Bracket= 499749
Alternator is stamped 1102433 63A Which is a little weird because that comes back as an externally regulated Alternator and this is an internally regulated one.
If anyone has any advice I would greatly appreciated because I am stumped.
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I'm not a Pontiac engine guy so this will be general info only, and probably obvious. Do you have an assembly manual? Or the 76-81 Parts? Or even service manual? A few diagrams in there showing the order of assembly for brackets etc.
Sounds like something off, a bracket added in wrong order, or a spacer or washer where it shouldn't be. If you have to add any washers to line things up you already know something isn't right. I'm not sure if Pontiac used different length water pumps or swapped pulley types to suit. Did you have all of it together before? Apart from the brackets coming off, new parts that are affected are water pump only?
Many rebuilt alternators simply use an existing case, doesn't mean that's what it currently suits, just began life as decades earlier.
I have #10009669 as a 301 power steering pulley. It may or may not be the 'same' as used on 400 with updated number, but will add that in case it matters.
I have #481038 as standard Pontiac 400 family (and 301) pulley with AC. Should be ok. Same also for #480509 pulley.
I don't have a listing for #481040 water pump pulley, will look elsewhere.
Alternator bracket looks to be correct.
Is this your general pulley and belt arrangement?
(https://live.staticflickr.com/65535/53816729601_964fa49a88_b.jpg) (https://flic.kr/p/2pZANLi)20240626_170308 (https://flic.kr/p/2pZANLi) by Ben (https://www.flickr.com/photos/196419001@N03/), on Flickr
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Just went through this
There is a quarter inch spacer that goes on one of the studs of power steering pump - one stud was a little longer on old pump but my replacement came with no studs.i can take a pic of old pump to show which one if you need it
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Just looking through several diagrams now in the Assembly manual, but too many to know which you might need.
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Wallington, That is my pulley set up. Also I used this https://imgur.com/DbvlxBl (https://imgur.com/DbvlxBl) from the 78 SM as my guide for assembly of the alternator/P.S.. When I get home later I can reassemble everything(I took everything apart last night to get the part numbers because I was hoping it was something like mismatched pulleys) and take some more photos.
apfstg, before I posted this I saw that come up in my search so I will give that a try as well.
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Is the 78 Service the only manual you have?
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I've got the 78, 79, and 80 fisher body Service manuals. The 78, 79, and 80 Service manuals and the 79 and 80 supplementary service manuals. I've also got a book on rebuilding Pontiac V8s and the W72 performance package book by John Witzke.
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Once you post up some photos I’ll take a look at mine (I’m at work right now) and can maybe post some for comparison.
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All good, I have a parts manual and assembly manual with possibly extra diagrams, will have a look.
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Pontiacs are absolutely NOTORIOUS for their variations in pulleys, bracketry, and spacers over the years. Blame this mostly for the change in timing covers in 1969. Often, parts get mismatched or left out.
The only solution is to get a service manual for your model year and actually reference correct part numbers, cross-reference them with what's on your car, and fill in the blanks so to speak by hunting down the correct parts. Also often missing are the correct spacers. The power steering pulley for my 1979 400 W72 was angled downward when I first got it and I discovered it was missing the 1/4" spacer that goes between the PS bracket and reservoir. Thankfully, all of the other brackets and pulleys were correct so I got lucky.
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Brandon, check your PM. I'll shoot you a copy of a few manuals. Might be easier to flick through.
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Thank you Wallington! That parts manual really helped! Sorry I wasn't able to get any photos like I planned. I was out in the garage Wednesday working on getting all the pulleys back on that I took off for the part numbers and my community courtesy officer drove by and stopped me to tell me working on my car is not allowed. Which is news to me because I have been out here almost daily for 3 years now. So that kind of stumbled me a bit. But I'm just going to have to work on it with the garage shut so I can get it tagged and insured and find a new place. That being said I used the parts manual and mocked everything up with washers in stacks that matched the correct thickness on the diagrams and used a laser level, everything is aligned now. Just waiting on the actual spacers to come in and I can throw them on and be done with this. Thank you everyone for the help, I really appreciate it!!