Water pump to fan Studs???

[painterljp]

Have a dumb question. Am changing my fan out finally to a clutch fan. How long do the studs need to be? Cant use the ones I had as I had a 4 bladed fan on am changing it out to a 7 blade fan with a clutch. Current studs aren't long enough. What length do they need to be anyone know. Thanks in advance.

[Steeveedee]

The part that threads into the water pump flange needs 5/16" inch minimum thread, and not much more to keep from rubbing on the water pump body. That should be 5/16" fine tread, IIRC. Then add on the clutch flange thickness, about 1/4" and another 3/8" of thread for the lock washer and nut.

So, 5/16"+1/4"+3/8"= 15/16" total, minimum. 1 inch would work, but depending on how close your fan or clutch is to the radiator, if the the studs are too long you might have trouble mounting the fan with the studs in the pump, and might have to finagle it around.

[painterljp]

Thanks for the info. It's a small block that was what i was thinking of using just bolts with lock washers. Got studs but dont like the threads not grabbing enough for my comfort.

[stsalvage]

I found out if you use the 1973-74 extreme fan clutch from the 454 it will work on 350s with the small 283-350 water pumps I use the 7 blade fan from the Dodge trucks or Cars that had the 340-360 to the 440 engines There a 15 1/2 inch 7 blade fan. this is the set up I use.

Plus the straight out Thermostat from 1964--68 Chevy small blocks If you use the Edelbrock Performer alum intake the best place for the Temp sending unit is on the right side of the intake you can't use the water outlet that points to the driver fender gets in the way. They sell all the parts at all the truck part places for are old trucks

[Steeveedee]

Rather than edit the old post, I'll put it here, so that there's less confusion. I did not add in the length for the water pump pulley thickness. Add another 1/8" for that. So, 1-1/16" would work. I have a big block that uses bolts. I can't put the fan and clutch on if there are studs because the fan clutch is too close to the radiator. It's a severe duty job that really pulls some air. Getting those bolts started is a real delight. I'm glad I don't have to do it too often.

[painterljp]

We have a 402 also in a 72 longhorn think we used bolts for that. Have a 7 bladed fan going to use alredy but the clutch fan we had to get I had to look up part numbers on here because parts store kept trying to sell me a non thermal fan. Which would mean it is engaged all the time and think truck would have a horrible wine to it. Didnt want that so crossed number Hayden 2747 and bought that clutch for it. So now studs aren't long enough will probably use bolts if cant find right studs. Going to look in my junk pile and see if old water pumps have right studs to get a correct length on them. Or just use bolts as you have thanks again for all input.

[un4gvn!]

I used carb studs.

[RustyBucket]

A good hardware store should stock 5/16" SAE/USS studs in a variety of lengths. Way easier to start nuts & washers on studs than bolts through the fan hub, pulley and into the water pump flange.

[kwmech]

Yeah, I was going to say I could never get the 'correct' length now-a-days. Had to buy longer studs at the hardware store and trim them down

[geezer#99]

When I want ‘studs’ in an oddball length I find a long piece of ready rod (aka allthread), cut with my hacksaw and dress the ends with a tiny 3 corner file.

[kwmech]

Standard 'all thread' is usually grade 2. Manufactured studs are either grade 5 or 8

[huntznsam]

Dorman 675-001

http://67-72chevytrucks.com/vboard/s....php?p=8564367

[stsalvage]

that's why they call it the extreme Heavy-duty Clutch fan for 1973--74 454 trucks mostly the 1-ton trucks but you can use it on the 283--454 I use it on the 400 sm block I have and i have a 4 core copper and brass radiator.

[RodnRudy]

What huntznsam said in post 13. I just got some from Auto Zone. Thought I was ordering a 4 piece set but they sent a box of 10 studs. PM me your address and I'll send you 4. You'll have to get the nuts and washers. Phil

[hjewell2]

Originally Posted by geezer#99

When I want ‘studs’ in an oddball length I find a long piece of ready rod (aka allthread), cut with my hacksaw and dress the ends with a tiny 3 corner file.

So you say ready rod also,,, last time I went to the hardware store the young man pointing me in the direction of what I was looking for did not have a clue what READYROD was and I didn't have another descriptive word for ready rod

I told him it was threaded rod in very long length. I ended up finding it myself, no disrespect for the young lad, but I know now that my age is showing. this goes along with many other terms of tooling , tools , hardware that has been reworded for the younger generation . I often wondered how the name changes come about .

[Steeveedee]

I know that stuff as "All-Thread", for obvious reasons. I bet there are a ton of names for it!

[71CHEVYSHORTBED402]

Originally Posted by kwmech

Standard 'all thread' is usually grade 2. Manufactured studs are either grade 5 or 8

Good point. I imagine you can locate 5 or 8.

Originally Posted by huntznsam

Dorman 675-001

http://67-72chevytrucks.com/vboard/s....php?p=8564367

Interesting. I may need to try them:

https://www.summitracing.com/parts/r...hoChd0QAvD_BwE

[franken]

Studs can be had from the local napa parts store, much like most ordinary replacement parts under the hood.

[painterljp]

Ok the threads on the short water pump are NOT fine thread. The ones on my pump are coarse thread lies the problem. Wont use all thread. Needing grade 5 at least. Went to napa already auto zone and oriellys. Finally just got grade 8 bolts 1 inch long with lock washers. They were a pain to get in but got it done last night. Am sure choice words helped me quite a bit. Going to put a new belt on tomorrow. Problem done. We will see about this clutch fan. Got the hayden 2747 now others have said to use a different one. Hope this works out. Thanks for all your help.

[hooverfish]

Originally Posted by painterljp

Ok the threads on the short water pump are NOT fine thread. The ones on my pump are coarse thread lies the problem. Wont use all thread. Needing grade 5 at least. Went to napa already auto zone and oriellys. Finally just got grade 8 bolts 1 inch long with lock washers. They were a pain to get in but got it done last night. Am sure choice words helped me quite a bit. Going to put a new belt on tomorrow. Problem done. We will see about this clutch fan. Got the hayden 2747 now others have said to use a different one. Hope this works out. Thanks for all your help.

Glad you got it installed. I too bought a 2747 and it's gonna be a few days before I can install. Hope you will post how it works for you, I plan to post also. Did you use the pilot bushing they provide with the 2747 ??