Pulleys or Balancer

[Old Chevy Mech]

Looking for some wisdom here....

My "new" 70 chevy C/20 4 X 4 came with manual steering (worn out). I've bolted on the new PS box & pump with no problems, all fit nicely. The truck originally had a 350, but the previous owner swaped it out and put in a Small block 400. Thats the situation.

Here is where it gets dicy. (I'm not being lazy just seeing if I can save a little time in resolving the pully misalignment problem.) Nothing lines up to the crank pulleys, so I am wondering if that harmonic balancer isnt pushing the crank pully's out too far? (It looks that way) The Alt pulley is on a stock bracket and it is back far enough to line up with the water pump but not the crank pulley.

So, can I change the Harmonic balancer on a SB400 to one that allows the pully's to sit back closer to the block and hopefully line up with the alt pulley?
Has anyone ever had this problem with the crank pulley not sitting back far enough?

Thanks

Frank

[chris71]

IMO, swapping out the balancer isnt the solution, GM didnt make many balancers of different thickness'. be careful with the 400's. 400's are externally balanced wereas 350's and all other small blocks are internally balanced. meaning that if you were to swap your 400 balancer for a 350 or other small block balancer, your whole rotating assembly will be out of balance. it sounds like you have a 2 grooove pully and need to get a 3 groove crank pully the extra grrove should help. another thing is your water pump. the original motor came with a short water pump, if the 400 has a long water pump that will through things all off whack. maybe the balancer isnt pressed on all the way either. tighten your main crank bolt until the engine turns. it should then be pressed on all the way. post some pics if you can. good luck man.

[71tahoe]

I would recommend pulling the balancer and inspecting to see if there is anything keeping it from seating and then use an install tool. You can't get it properly seated any other way. You can beat it on but that is bad for the balancer and will likely cause the pulley to no longer run true. You can also strip out the threads trying to press it on with the bolt. (I've done both many years ago).

You can measure the distance from the front seal to the timing chain drive gear and mark the balancer to make sure it seats. If it is still off then someone else may have a suggestion but I've never had that problem so I can't advise.

[cdowns]

are you sure you have the right pulleys?? pulleys are different for long and short waterpumps

[Old Chevy Mech]

I'll take some pics tonight, the balancer (to me) looks weird. Its hollow on the back side so if you look at it from the side it looks like its @1-1/4" wide but from the back its hollow. Tha balancer on my 350 is an 8" and its solid. I didnt put the 400 in, and I know its rebuilt so I'm not even sure if its the correct balancer.

I did know that I needed a short neck water pump, but whats really driving the misalignment is the crank pulley. When I post pics It'll make more sense. I have an old stock waterpump pulley, so I believe its the correct one.

How do most of you check alignment? I "eyeball" it myself, does anyone have a more presice method?

Thanks!

Frank

[chris71]

Originally Posted by Old Chevy Mech

How do most of you check alignment? I "eyeball" it myself, does anyone have a more presice method?

eyeball it, but also put a belt on it and give it some tension, even by hand, if the belt looks like it is at an angle or is crowding on on side of the pulley versus the other side, make some adjustsments or new pulleys or something. sometimes i end up shimming the alt or ps pump with 3/8 bolt washers to get as best alignment as possible (when i have the right pulleys). there is a tool out there that is a laser that mounts to one pully , you spin the pulley and the red laser shines on another pulley and from this you can tell if they are in alignment. i dont think many people use this though.

[Old Chevy Mech]

Originally Posted by chris71

eyeball it, but also put a belt on it and give it some tension, even by hand, if the belt looks like it is at an angle or is crowding on on side of the pulley versus the other side, make some adjustsments or new pulleys or something. sometimes i end up shimming the alt or ps pump with 3/8 bolt washers to get as best alignment as possible (when i have the right pulleys). there is a tool out there that is a laser that mounts to one pully , you spin the pulley and the red laser shines on another pulley and from this you can tell if they are in alignment. i dont think many people use this though.

I do that too, although I do wonder why we have to at times.

I was wondering if placing a straight edge across the front face of the heads and then measuring from there would be good. I've not had to do this since most of my stuff came stock & complete so I 've had all the right parts to work from.

The 400 balancer is hollowed out in the back somewhat. I have a 400 balancer on my 383 stroker, and all the pulleys align up correctly. You might have the wrong pulleys or take the balancer off as stated earlier. If you have to do that, go and rent a balancer puller/installer. Don't ask me why.....I learned the hard way. .

So it sounds like I have the right balancer. If it is then thats one less hump to jump. I'll pull it tonight with my balancer puller but if it was NOT seated all the way in wouldnt it leak oil?

Frank

[cdowns]

I did know that I needed a short neck water pump, but whats really driving the misalignment is the crank pulley. When I post pics It'll make more sense. I have an old stock waterpump pulley, so I believe its the correct one.

Frank[/QUOTE]

you'll have an alignment problem when using a longpump crank pulley on a shortpump installation

[Old Chevy Mech]

It looks to me like if I shim out the alternator bracket 1/4" that'll align it with the water pump. Then the only 2 remaining issues are the crank pulley and the PS pump pulley. I looked at what my 70 Blazer has and its crank pulley is only about 3/8" off the harmonic balancer. The pics may be off slightly and not show the alternator within the 1/4' i mention, thats because I was off angle a bit.

Any thoughts?

Frank

[70GMCer]

The 400 balancer is hollowed out in the back somewhat. I have a 400 balancer on my 383 stroker, and all the pulleys align up correctly. You might have the wrong pulleys or take the balancer off as stated earlier. If you have to do that, go and rent a balancer puller/installer. Don't ask me why.....I learned the hard way.

[Sport/Truck]

Definitely long water pump style crank pulley. Not sure about the water pump pulley though. I would try the crank first, then water pump.
I hope you don’t end up like me…..with the crank pulley not sticking out far enough.
But from what I’ve seen this weekend it seems to be common for these to be off in the like mine (short direction).
I think this is why they make spacers?
s/t