Have a 65 L76 no A/C or Powder steering my pulleys do not line up the water pump pulley is 1/2 back towards water pupm damper pulley has GM #358533 no number on the water pump pulley belts do not lone up the way they are now is the fan belt is on the inside pully groove and it is rubbing the lower raditor hose called several dealers I can not get a answer.Also in the picture book it shows a second belt that looks like it driving nothing.
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Re: Pulleys
This issue (non-alignment of belts/pulleys) almost always stems from the following problems:
(1) Pulleys installed are NOT the correct/originals (see your copy of the AIM for specific GM PN's used in each position.
(2) Water pump problems. When an aged original pump is rebuilt, the mounting ears are typically resurfaced to remove rust/pit to get a good gasket seal. There's only so much metal you can remove before you start to 'shorten' the pump... Plus, the drive hub is press-fit onto the water pump's shaft and there's a 'correct' geometry to obey there.
(3) Bolt-on items 'remote' from the engine (PS pump, AIR pump, alternator, and/or AC compressor) need to have the correct mounting hardware, installation geometry and pulleys on them too.... -
Here's the W.P. pulley you should have
By your description of your 1965 L76 w/o air conditioning, you should have the 3770245 water pump pulley shown in the pic. This is a large diameter 7_1/8" and may NOT be stamped with the part # (at least the one's I've seen -- this pulley is off a '64 L76).
You have the correct lower (crank) pulley. The outer (forward) groove is for the alternator, w.pump and crank. The inner groove is for the idler (another pulley on the left side of the block which your book may show).
Now, as Jack H. mentions, the geometry is of the essence (well maybe he didn't say exactly that ). The face of the flange that the pulley contacts should be 5_9/16" from the mount surface of the legs of the water pump (or the flat table in the pic.) I measured this one and it was more like 5_11/16". This pulley will come EXTREMELY close to rubbing against the pump body (in fact you might see the groove where this one did). Also, this pulley will come within a few thousandths of rubbing against the crank pulley. This is normal.
Notice the "reinforcement" in the upper left corner. This is still available from GM and will move the pulley 0.050" forward for each one you add between the pump flange and the pulley). You can "stack" them to achieve perfect alignment IF the pump flange was not forward enough.
If you can take a photo of your current situation, we may be able to determine other factors that may be affecting your alignment.
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Re: Here's the W.P. pulley you should have
Hi Wayne:
I've always wondered what the purpose of the "reinforcement" was. I once saw one on the outside of the water pump pulley, and could not figure out what benefit it would provide there.
Putting it on the inside, between the water pump flange and the pulley, would suggest it is simply a spacer.
I looked in my 67 AIM and in UPC 6, A3 there is reference to a 3720616 "reinforcement" that appears to go between the water pump flange and the pulley. Is 3270616 the part that you referred to that is still available from GM?
BTW, I also looked at the C60 section of the 67 AIM, and the "production reinforcement" is explicitly called out for the 427 engine but is not mentioned for the 327.Comment
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Reinforcement & Fan hub location
Joe -- Yes, Gr. 1.062 # 3270616; may still be available. Found first reference to this "reinforcement" in Chev Service News June-July 1964. Shows 3720616 used on FRONT of pulley on certain in-line 230 cu.in 6 cylinder engines; on the back of others (Chevelle 6 cyl), and another reinforcement # 33788629 used on back or BOTH front and back of Chev Truck with 348 and 409 cu.in engines. So intended use was really was clearly a reinforcement, and not a spacer.
Speaking of spacing, I found a table showing correct fan pulley hub locations in Chev Service News March 1965. For all Corvette small blocks '55-65 is 5_11/16" (which I measured on the pump/pulley in the pic) and NOT 5_9/16", which is for Chevy II, Chevelle and '62-65 Chevrolet SB's.
I know I've seen a tech bulletin somewhere on this reinforcement due to pulley failures on some Corvettes with a lot of belts driven off the water pump (and crank). Will post if I can find.Comment
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Re: Reinforcement & Fan hub location
Wayne -
The fan hub location chart in the 1967 Chassis Overhaual Manual shows Corvette small-blocks as 5-9/16" (along with all other car lines' 283's and 327's. Same dimension is shown for Corvette 350's in the 1969 Chassis Overhaul Manual.
Wish they'd make up their mind.Comment
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Re: Reinforcement & Fan hub location
Hi Wayne:
Thanks for the information. I ordered a 5-pack of the "reinforcements" today from gmpartsdirect.com, just to have them on hand for my little side project of substituting a set of deep-groove pulleys on my 67 300 HP with A/C.
This exercise has turned out to be much more complicated that it first appeared, due to all the variables with pulley centerlines and water pump centerlines.
Based on John Hinckley's post and others, it sounds like there is still some uncertainty about the applications for the different water pump spacings. With some luck, I *might* be able to determine what water pump spacing is correct for the two pulley sets I am comparing. Since the location of the face of the balancer was the same for all applications (I think), it should be possible to work backward from there and determine where the water pump flange should be.
One thing I have wondered about is how the various water pump rebuilders decide which location to use for the flange. For example, I sent my 1967 '608 casting pump to Arthur Gould to rebuild, and no one asked me what engine I was using it on. When it came back I simply bolted it on and the pulleys lined up fine. Later I read all these threads about the two different spacings that were used, and wondered how Murphy didn't get me on that one.Comment
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Re: Reinforcement & Fan hub location
John,
If that is the Chasis Overhaul Manual that starts with 1966, is there a water pump hub chart for that year? Does it show any other hub locations for certain optioned small block Corvettes?
Thanks,
ChrisComment
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Re: Reinforcement & Fan hub location
Wayne,
In the case of my '63, having bolted up both my original base engine pulleys and substituted a reproduction set of the solid lifter engine pulleys, the hub spacing is NOT the same for all Corvettes, at least for '63 and most likely through '65. The original set lined up at the shorter hub dimension, the high performance set required the hub to be moved forward that 1/8" to line up.
As the 250 & 300 horse engine was shared with other platforms this does make sense. People often default to the high end options whenever you hear "Corvette engine".
Mr. Adams' book quotes that tech bulletin in the L-79 section of the 1966 Chapter. Confirms its recommended as a reinforcement to prevent pulley failures. Even shows the GM drawing.
"Some 1966 350hp. 327 cu. in. Corvettes equipped with two or three groove water pump pulleys may experince pulley failures due to insufficient support of the pulley in the hub area. Effective with the start of 1967 production, a pulley reinforcement will be installed on this engine as standard equipment. For service, whenever the above condition is encountered, or work is being performed involving the fan or pulley, add pulley reinforcement njmber 3720616 between the water pump and the fan."
Attribution listed Chevrolet Technical Service Bulletin DR-66-10, December 16, 1965.
So originally is was a reinforcement but its use seems to have been hijacked along the way. In the 1970 parts book, it's entry has a note. "Pumps having a fan and pulley hub pressed to .348 dim. (presumably hub to front end of shaft) must use this reinforcement when replacing pump with pressed dim. of .288.
In the quantity field it only lists one but to get that 1/8" you'll need three since its stamped from .0478" sheet.
Joe, good thing you got the five pack.
Chris.Comment
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The deeper we dig ..
...the more it seems, like John H. says, (they couldn't make up their minds).
You are correct; the '63 Corvette Shop Manual calls for L76 & L84 pulley flange further forward; also warns that this dimention is critical +/- 0.005" (b.s., in my opinion). BUT, they never said what the dimension was -- only referred to the use of 2 different Kent-Moore depth gauges, depending on hi or low horse. The 1964 Chevrolet shop manual makes a reference back to the dimension shown in the 1962 and 1963 shop manuals.
The 1966 Chassis Overhaul Manual finally shows a chart, which calls for ALL 327 Corvettes to be 5_9/16" (396 & 427 are 5_3/4"). This flatly contradicts the March '65 Chev Service News (see pic below) @ 5_11/16". I don't have any later manuals to compare.
But really, 1/8" difference is not that much, at least visually speaking.
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