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I am having trouble assembling all my pulley bracketry and would appreciate any help. I have the long block setup on a run stand at the moment.
I am pretty sure the bits and pieces I have all went together before, when I swapped this 455 in place of a 307 in the '84 Delta (using the associated 307 brackets where able) - not sure what the problem is now. I can't decide if the alternator bracket was really off like this the whole time, and I just acted like it wasn't a problem (spacing the alternator out with nuts/washers and going racing instead of worrying about it) but I can definitely see its a problem now.
I was using the aluminum alternator upper mount from the 307 (three bolt holes to the front of the head) combined with the later (metric) Power Steering pump/bracket. I spaced the PS bracket's top and bottom holes off the water pump studs (three small washers top, factory spacer bottom), and also the larger PS bolt that goes into the lower driver's side of the block.
To achieve optimum pulley alignment, the belts (counting from closest to block and away, towards the radiator) run: A/C, PS, Alternator...I believe that is not factory stock, as in the PS and alternator belts are switched - however running them that way causes all the belts to line up.
THE PROBLEM: I can get all of the other brackets to bolt up straight and true - but the curving, slotted portion of the alternator bracket (that secures the bottom bolt of the alternator, after putting tension on the belt) is "cocked" forward (towards the radiator) and away from the alternator (not parallel at all with the front face/plane of every other pulley on the motor). This bracket that's "cocked" is attached to the front-most exhaust manifold bolt and to the PS bracket - its not possible to "uncock" the alternator bracket in such a way that it is both parallel to the alternator and also still bolts up thru the exhaust manifold/to the PS bracket.
I have an older "top" alternator bracket that I tried as well (two bolts to the head, with a curving arm that attaches to the top of the intake manifold) - it spaces the alternator much farther back on the block, totally exacerbating this "adjustment slot too far from alternator" problem. I think I recall this being a function of "using a 307 PS bracket, better use a 307 alternator bracket"...if I kept the older alternator bracket I'd be obliged to swap the belt order back to A/C, Alternator, P/S (as the mounting position of the alternator would change that much - mounted farther back, so have to use the middle slot on the water pump/crank pulleys instead).
I have the still-assembled 77 Pace Car (w 403) to look at as a guide (in addition to the '70 and '84 manuals). The Pace Car has the older alternator bracket, the metric PS pump - and no bracketry line-up weirdness. The 455 bracket spacers I've used (all three points on the PS bracket) are consistent with how those brackets are installed on the 403.
Anyways - I will take some pictures and post them very soon. In the meantime, f anyone has any tips on:
why/how the alternator bracket could be bolting up to all the other brackets it has to bolt up to, as well as the block, while also curving forward and away from the alternator
Sorry, but can't help without seeing what you have. I ASSUME you've installed the 1" spacer between the alternator and PS pump brackets to account for the taller deck height.
Yes Im aware that pics are vital. However - you may have helped me without:
I searched this forum and found many posts on this and similar topics (like the gold 350 with the cobwebs) l, and redid my stuff last night to match...still not 100% though. I do have the spacer at the bottom of the block, and on the timing cover.
So the alternator bracket and PS bracket are supposed to be spaced out from one another? I had them connected as stock (I think), touching bracket to bracket and secured with a single bolt and nut...Is there a thread or pic already that shows this particular arrangement (the alternator bracket spaced off of the PS bracket)?
I think spacing the alternator bracket off of the PS pump would in fact **** the alternator's adjustment bracket back far enough to true with the rest...
So the alternator bracket and PS bracket are supposed to be spaced out from one another? I had them connected as stock (I think), touching bracket to bracket and secured with a single bolt and nut...Is there a thread or pic already that shows this particular arrangement (the alternator bracket spaced off of the PS bracket)?
I think spacing the alternator bracket off of the PS pump would in fact **** the alternator's adjustment bracket back far enough to true with the rest...
I'm guessing that you DON'T have the alternator bracket bolted to the first exhaust manifold bolt at the moment, do you?
The BBO deck height is an inch taller than on an SBO. The PS pump bracket bolts to the block and the alternator bracket bolts to the head, which is now 1" further away...
A Google search using 307 455 swap will bring up this webpage, which is a pretty comprehensive list of the bracket mods required. Scroll about halfway down the page.
I had previously looked at that page as well. In the picture the white man finger is pointing to the alternator bracket so as to identify it. He talks about sourcing a 455 alternator bracket instead of the 307 piece, but doesnt mention spacing it off the PS bracket...that I can see. Maybe Im a blind idiot but I _am_ here because I know what I dont know.
Re your other Q: I do have it bolted up everywhere, to the forward exhaust manifold bolt and to the PS bracket.
This is where I'm at as of just the moment - I took the pictures and posted them before experimenting with:
a) spacing the alt bracket 1" off the PS bracket
b) trying the older alt bracket
I'm hopeful that (a) above will be AWESOME. If I missed a pic somewhere of an arrangement like this that has the alt bracket spaced off the PS bracket (instead of flush as shown in my pics here) then I'd like to see it
OK, now I can see the issue. Just get a longer bolt and about a 1" spacer between the two brackets here. Problem solved. You might need to fine tune the length of the spacer or use a stack of washers to get the alignment exactly right.
The older bracket doesn't appear to have a way to bolt it to the PS pump bracket. The earlier cars used a separate link bracket from the front PS pump bracket to the exhaust manifold bolt. This stabilizes the PS pump in the fore-aft direction. The 307 alternator bracket also serves that stabilization purpose as well as holding the alternator.
I corrected the bracket issue with a stack of washers https://flic.kr/p/QEg2im. I did not have calipers handy but I did get a shot of them against a tape - they are a little less than 7/16" (0.4375" height).
Fun fact - I had previously been using this very stack of washers to fulfill the "PS bottom bracket spacer" role (GM P/N 398917 & 0.402" as denoted on the link below). I am now using the stock spacer against the block instead, and using the washers as shown to make up the gap in the bracketry.
I think it extremely likely that the stock "larger PS spacer" would fit and function quite wonderfully in place of the homebrew washers re: adapting later brackets to the big block. When I clean the thing up for final assembly I will order another "larger spacer" for this purpose.
The spacer thickness should match the deck height thickness, which is about an inch. You can go taller on that spacer to get it perfect.
I don't _know_ why, but there was no more room in the gap between the brackets to fit any more washers/thickness. When I couldn't fit any more in (with the spacer at the same overall height as the PS spacer) I felt like the Universe was talking to me and I decided to leave well enough alone.
I am aware of the deck height and overall width differences. I cannot explain why a larger spacer was not required.
I am moving forward re: firing this engine for the first time in fourteen years and will swing back around to bracket and pulley alignment if it proves problematic.
I've swung back around to this. I put two new photos in this album that focus on the front of the alternator, and where it mounts to the adjustment bracket:
I'm pretty sure this is still not hooked up right ("brackets still curving forward towards radiator") although it certainly ran OK as-is. I would appreciate any Help either getting it Right, or punting for something that will work better - like maybe the 307 aluminum alternator mount + the 403 PS pump and bracket? This guy says 307 brackets are small-block only:
Originally Posted by joe_padavano
The 307 accessory brackets will not fit on the 455. Prior to 1980, most Olds brackets were capable of fitting on both big and small blocks, but the 307 brackets are small block only. Note that the brackets, pulleys, and water pump must be a matched set. Olds used different water pump lengths and the pulleys must match.
On the pictures, especially re: the jackscrew - it's spaced out with a nut and two washers at the top, and the dimpled piece it rides in at the bottom is cocked precipitously towards the bow (as is the entire PS adjustment bracket as a whole). Pretty sure none of that is right.
Can someone direct me to a picture of a correctly-setup 307 with this type of adjustment screw?
Is the alternator supposed to be on the _other_side_ of the adjustment bracket? That would take up about the same amount of space as the nut and two gold washers. That would also make the spacing between the adjustment bracket and the PS pump bracket closer to the 1" figure JoeP suggested earlier.
I'm not in love with any of this bracketry EXCEPT the aluminum alternator piece re: I need it to mount up the electronic cruise control.
This is someone else's picture. Note the alternator tab installed forward of the bracket. Is that, in fact, the factory correct way to use the adjustment jackscrew?
For some reason your alternator bracket is too far forward relative to the PS pump bracket. If you look at the picture in the link you posted, the alternator bracket mounts to a bolt about one inch back from the front face of the PS pump bracket.
Note that the alternator goes in FRONT of the bracket, not behind like yours. That's why you need that extra spacer and washers - that is making up for the thickness of the ear on the alternator.
Your PS pump bracket appears to mount the alternator bracket too far forward. Also, on the 455, you will need about a 1" spacer between the alternator bracket and PS pump bracket to make up for the deck height difference.
December 20th, 2016, 01:12 PM
