Hi All Fitting a Gilmer drive to my SBC, and for some reason water pump flange is too far forward (see photos). My question is, can I strip the pump and press the flange further down the shaft?, is there a step machined in the shaft?, or is it held solid? I need to push it about 1/2" more, very close to the pump housing. See photo's. Details for those who like the details... It's a 305 (70's) but came with a short pump set-up. Not keen to mess around with a LWP, balancer etc as the parts can be hard to find, plus not so cheap in New Zealand. Worst of all I'd need to move the alternator forward. And it took me a ton of work to get it correct (with the V belt fitted), as it was originally made out of alignment and started cracking due to flex. I could just add spacers all around, but it will become weak and prone to flex once again. Other option was of course to add a spacer to the crank pulley out, but again the alternator would need to move. So in theory the simple fix is to move the water pump flange, if I can. Open to ideas as this is all new territory for me. Thanks.
Something is mismatched there. Wrong pump? Wrong pulleys? Try a new water pump and see where it sits. You can always return it.
If you take the cover off the back of the pump and are able to put the pump flange down in the press so the shaft is going through an orfice, you should be able to press just on the pump shaft and move the flange. Make sure the pump body doesn't hit anything as to change the distance from the impeller to the cavity on the inside. Question. How thick is the mounting flange on the pump pulley? If it's real thick, you could machine the inside for more depth. Be aware that anytime you mess with an old pump, there's a good chance the seal will start leaking. If for some reason, the flange is seized, it will gall on the shaft and ruin it.
Yes, The shaft can be pressed further on, but how thick is the mounting flange on the water pump Gilmer back side? Maybe do 2 things, push water pump flange back and take a little off inside mounting surface of water pump Gilmer?
Most setups i've seen have single v belt pulley behind the crank pulley. As far as the altnator goes you need to move it . most are on the right side. https://www.google.com/search?q=sbc...WBbc0KHd_XBjIQ_AUoAXoECAwQAw&biw=1242&bih=568
The answer to your question is yes. I've done it before and call it Dumb Luck without any further problems. The real problem was that when it did start to leak I was in Nebraska and my shop was in Washington. The cost to get it done in another shop was just plain Stupid and it cost me a second day. Being able to buy over the counter parts is PRICELESS! In looking at what you have going on there, personally I'd go machine myself a 1/2" spacer and put it behind the lower pully and space my Alt forward leaving my pump an over the counter part. It don't look like you have a fan space issue that requires the need for that 1/2".
Almost every sbc water pump Iv'e bought in the last few years had serious misalignment issues . I routinely pull the cover off and press the flange to align em.
Yes, breakdown, I had not considered that. I was thinking of doing the mod to a new pump and keeping thew old one spare, but not in the car - no storage. Thanks.
Fantastic response guys, thank you. I'll but a new pump and mod that so I'm less likely to suffer leaks, I'll keep the old one stock along with the pulleys in case I ever need to go stock. Thanks Again, the project continues.
Have pressed the flange back many times. I actually do this to gain more radiator clearance when puting a SBC in my Fords. Run a 302 Ford top pulley on the Chevy WP, then press the flange bacl to align it to the Ford pulley. Cheers! -Shiny
The only real issue is as Pist-N-Broke said, if you have water pump trouble on the road away from home base it may cost a chunk to have someone else do the work if you can't find a place you can do it yourself. You may already have the gasket in a batch of left over gaskets from an overhaul kit as they usually have that gasket in them.
If you are concerned about an on road breakdown with the modified pump, modify both the new pump and the current used one. A water pump isn't that big and I would think you could find a place to keep the used one in the car and have it with you. It would surely get you home if you had a breakdown. But overall water pumps are usually pretty reliable if you maintain the cooling system. SBC pumps come in both 5/8" and 3/4" shaft diameters. With that Gilmer belt setup perhaps the 3/4" shaft pump might add some life span?
Ninnies. Ya could press that flange back on the side of the road with a socket and a good hammer. Ya guys never fix anything out in the bush where there is no other option?
How about going with one of the deep set crank pulley as per top one in the picture and moving your alternator forward
I did one a big block Ford a couple weeks ago. An aluminum aftermarket pump needed another 3/16" to line up properly. Make sure the shaft on the bottom is supported with something solid or when you start pressing the whole bearing, shaft, impeller will s push out.
Straying somewhat here, but what is the point of a gilmer drive for the water pump and alternator? Besides the issue of maybe having a water pump failure on the road, you could also throw and shred a belt, so in addition to carrying a spare pump you should also carry a spare belt. The stock v-belt arrangement has worked for decades on millions of vehicles. I'd be inclined to stick with that instead of worrying about a failure on the road, and the continuous butt-cheek compression that typically accompanies that worry.
Got the Gilmer set up because.............well because I wanted it and it looks COOL! Carry a spare belt and have had to use it once(at a rest stop in Ga.) I even put a white mark on it so when the engine is idling I can see the white mark go by as the belt goes around..........looks like what the "Big Boyz" have that run a blower set-up. Yep......my nick name is poser! 6sally6
Op , you can press shaft like others have said. Make sure there is clearance between shaft and propeller plate.Is that water pump pulley 1/4 or 1/2 inch thick ? If 1/2 inch you can cut 1/4 on inside where it mounts with Lathe , And you can cut The distance (Gap measurement ) between pump & chain cove where it mates to water pump & block with mill, or Lathe , One off parts , but it can all add up to more then the 1/2 needed to align .
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