Just purchased a new short water pump for my 68 big block from classic industries and a repro water pump pulley part # 3906656. Water pump fits fine but the pulley when installed hits the pump. Is there some kind of spacer made for this application to go between the pump and pulley. Has amnyone else had this problem? Any help would be greatly appreciated I am sure this is something stupid on my part seems pretty simple but the simple ones are normally what gets me.:(

I would say that your water pump was pressed together alittle to far. I helped a guy with this and he had a thin shim behind the pulley to line belt up. But if yours is new i would request a new one from classic's. Maybe you could give us a measurement from base of water pump and front edge of impeller and we could measure another for comparison. I have 2 others at home to help if needed for measurement. If pump is not just right it could mean something else wrong.

Not sure if I took the right measurement but from the front base of the pump to the end of the shaft the pulley rides on is 3 and 1/8 inches. does this sound right? Thanks

How far out do you have to put pulley for it to line up with bottom pulley?

How far out do you have to put pulley for it to line up with bottom pulley?

I am in the process of installing all new pulleys and have not bought the crank pulley yet to see how things line up. When I installed the water pump pulley just to see how it fits it goes to far back and hits the water pump.When I bought the car it had a 69 long water pump and 69 model pulley so I did not know if the 68 had a spacer or something that went between the pulley and the pump the 69 did not. It is kinda hard for me to xplain this so I hope it makes sense.

I would think the problem is more likely to be the wrong pulley then a defective pump. JMHO.

I would think the problem is more likely to be the wrong pulley then a defective pump. JMHO.

The pulley part #3906656 is supposed to be for a 68 model with a short water pump L78 application right? Do I need to have anything else special to make this work? Thanks for all of the advice.

Along with any ideas if anyone had an engine bay picture of a 68 L78 with power steering that has a good shot of the pulleys that may be helpful also.
Thanks in advance.:beers:

There is no special shims or anything like that. Buy water pump and correct brackets and away you go. I measured 2 different pumps and both were 5 3/4 inches from water pump mounting to impeller flange. Not the tip but were the bolt holes are. Water pumps are pressed together into front and back into sealed bearings and i can see if they wern't exactly pressed in correctly. Also i could possibly send you picks of my pulley setup but they are not the right numbered ones and my water pump pulley is slightly smaller diameter for increased flow. I did add P/S to my car too.

I had problems with the repro pulleys overlapping and had to go with e 302 water pump pulley. Not sure why they didn't work but they just seemed to be the wrong diameter.

Does the repro water pump pulley have 1 or 2 layers of metal in the face where the 4 mounting holes are located? The originals have 2. You can tell by looking at the holes. I have a pulley at home that I can measure but it's probably 1/16".

There is a spec for the water pump in the Overhaul Manual that tells the distance from the pump mounting surface to the face where the pulley mounts. You need to set the pump on a flat surface and using two straight edges (rulers) to measure that distance.

Martin

The Overhaul Manual lists the distance from the fan hub to the pump mounting face is 5 3/4".

The thickness of the face of the pulley is 1/8".

The distance from the face of the pulley to the backside is about 2.765", just over 2 3/4".

Hope this helps.

Martin

This is a spacer reinforcement that I bought but it won't fit because the repro pulley I bought has an extra layer of metal. I suppose that eliminates the use of it. Shane that is the exact same pulley I bought. I have had 2 different water pumps and no problems. To me it seemed like the pulley hit the pump untill I actually bolted the clutch and fan on. Have you done this yet?


http://i52.photobucket.com/albums/g35/johnnyscamaro67/wp-616reinforcementplate67-68.jpg



http://i52.photobucket.com/albums/g35/johnnyscamaro67/camaros/100_0715.jpg



http://i52.photobucket.com/albums/g35/johnnyscamaro67/camaros/67camaro-2.jpg




http://i52.photobucket.com/albums/g35/johnnyscamaro67/camaros/100_2878.jpg

This is a spacer reinforcement that I bought but it won't fit because the repro pulley I bought has an extra layer of metal. I suppose that eliminates the use of it. Shane that is the exact same pulley I bought. I have had 2 different water pumps and no problems. To me it seemed like the pulley hit the pump untill I actually bolted the clutch and fan on. Have you done this yet?


http://i52.photobucket.com/albums/g35/johnnyscamaro67/wp-616reinforcementplate67-68.jpg (http://http://i52.photobucket.com/albums/g35/johnnyscamaro67/wp-616reinforcementplate67-68.jpg)



http://i52.photobucket.com/albums/g35/johnnyscamaro67/camaros/100_0715.jpg (http://http://i52.photobucket.com/albums/g35/johnnyscamaro67/camaros/100_0715.jpg)



http://i52.photobucket.com/albums/g35/johnnyscamaro67/camaros/67camaro-2.jpg (http://http://i52.photobucket.com/albums/g35/johnnyscamaro67/camaros/67camaro-2.jpg)




http://i52.photobucket.com/albums/g35/johnnyscamaro67/camaros/100_2878.jpg (http://http://i52.photobucket.com/albums/g35/johnnyscamaro67/camaros/100_2878.jpg) Thanks for the Pics. No I have not installed the fan yet. I talked with the guy I bought the pulley from and he said that this is common problem with remanned pumps and said he usually either installs the spacer or grinds down the pulley a little so it does not hit the pump. I cant seem to find the spacer any where around here and I am a little hesitant to start grinding on the pulley.

Do you have a part# for the spacer or place where you bought it?

I will try bolting on my fan tonight to see what kind of difference it makes.

Thanks,
Shane

The spacer won't fit the repo pulleys. I think I got it from ricks first gen.

Grinding down a pulley seems wrong:noway:. Install the fan and take a pic to let us see whats going on.:beers:

Shane,

The original spacer #3720616 (actually it's a reinforcement used between the pulley and clutch) was only used with pulley #3905995 CF... single groove. They were used on LF7/L30(wo/smog),L26/L22(wo/smog),L48(wo/smog),L35(wo/smog) in 67 only, The pulley 3905995 was used but the reinforcement was not used in 68.
You should use this pulley setup for an original 68 L78 with PS (N40).
3869978 BO for the crank...3 groove, cast iron,DG.
3873847 DH for P/S pump...1 groove, cast iron,DG.
1970831 for alt. ................DG.
3925522 AO smog pump......DG.
You have .................3906656 CV water pump.....2 groove,DG
You indicated you were looking for original info.correct? These pulleys will cost you some major bucks(even in reproduction).
I am presently restoring a 67 L78 (no smog) and know what you are going through.
Hope this helps.

Bob C

3906656 CV water pump.....2 groove,DG is what I have on my car in the pic. It is for a 67 L78 and should work on a 68 although not correct for the year obviously.:beers:

Thanks for all of the response guys. I installed my fan the other night and the pulley still hit the pump but not as bad. I marked where the pulley was hitting and grinded it down slightly painted pulley again and installed everything seems OK now. I know this is probably not the right thing to do but need to move on with this project and didnt want to hastle with shipping pulley or water pump back.

The pulley is a CV I am trying to go back orginal and believe me I know this stuff gets very expensive. Big Iron what kind of fan and clutch did you go with and where did you get it?

Thanks again guys for all of the response.

3906656 CV water pump.....2 groove,DG is what I have on my car in the pic. It is for a 67 L78 and should work on a 68 although not correct for the year obviously.:beers:
3906656 CV was used on 67,68 L78's .

Bob C

Shane,
OK, let's back up!
You should not grind on the water pump, you should correct the problem with the w/p! If you do not want to send the w/p back or can not, there is another way to correct for this problem.The first thing you need to do is put the correct crank pulley 3869978 on the engine. This is the drive pulley and all other pulleys are adjusted to it! With the c/p installed you install the w/p/p 3906656.
Now go to the hardware store and get a 3' straight edge ruler, if you do not have one. Make sure it's edge is straight (check it on a piece of glass) you will use this to align all your pulleys. Go to Maroso.com and order a universal w/p shim kit # 64035 you will use these shims to align the w/p/p.
Lay the flat side of straight edge against the pulleys and align the edge with rear edge of the lower pulley. Look at the rear edge of the upper pulley and add shims to align the upper pulley. When this is done use the same straight edge to align and adjust the alt. and p/s.
Fans and clutches are another topic which sometimes require a compromise depending how you are going to use the car..Will discuss them after you have the pulleys installed.

Any problems let me know.:yes:
Bob C

Important note. If you add shims you may not be able to use original clutch to water pump bolts, be sure to check engagement length !!!!!!
If you have to use longer bolts use grade 5 or higher.