VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 fan blade for 1926 pickup

I apologize if this topic is worn out, I did not find any threads so here goes. Is it acceptable to have a four-blade fan on my '26 pickup or should I stick with a two-blade? Will a four-blade move more air than a two? If the two-blade works just as well then I'll keep what I've got.

tks,
Jerry

Hi Jerry,

If you have the Truck Chassis (Series X), 124" wheelbase, then the Parts Manual says its a 4 blade fan. If you have the Commercial Chassis (Series V), 103" wheelbase, then it's a 2 blade fan. I think you determined earlier that you had the 124" truck chassis.

http://chevy.oldcarmanualproject.com/1916_28parts/cp4cm07.htm

Happy Motoring,

Dan

The 4 blade fan was only used on the heavier trucks due to their low speeds and heavy loads. After about 10mph the fan is not needed. A fan typically costs you about 8% of your horsepower (learnt this in my motor racing days). A mate of mine has fitted a modern radiator fitted behind a 1/4" honeycomb screen and he doesn't use a fan at all.
It go for the 2 blade myself.
Chris

I am just amazed by the amount of common sense and knowledge here. I need to get one of these manuals. Where do I find the best one?

tks for the good info,
Jerry

Hi Jerry,

You can obtain a lot of the manuals from The Filling Staion:

http://www.fillingstation.com

There is also an online site with a lot of scanned information:

http://chevy.oldcarmanualproject.com/

It is run by Keith Hardy with all its information free of charge. Since Keith does run this site as a free service, a small donation to help keep it up and running is greatly appreciated.

Happy Motoring,

Dan

Chris,

I'm not positive, but I probably get pretty close to 10 mph if I have the windows up and the windshield rolled in, and if there is a slight downgrade, and if there is a wind to my back (on blacktop or pavement). So, maybe it doesn't matter if I have a two or four-blade fan. On the other hand, if you spent much time in a parade or traveling from red light to red light it might be important to move as much air through the radiator as possible.

Maybe I'll check into a four-blade after all.

tks,
Jerry

One other thing to be careful of Jerry is the 2 blade fans are prone to cracks and flying to bits unexpectedly, give it a good clean and check for hair line cracks around the bolt holes, RAYCYCLED

Four blade fans are twice as prone to throw a blade.

I would dispute that, the 2 blade fan is made of 2 thin pieces of sheet metal sandwiched together to make the blade and each piece was not strong enough for the job at hand and you get rust between the 2 layers which weaken the blade,the 4 blade fans are a single one piece of metal for each blade, much stronger. Also if you need a fan GM cars up to the 50's have the the same size and stud pattern, RAYCYLED

About the only later model 4 blade fan you can use(the experts may get in on this one)on a Chev 4 cyl,is up to 1936.After that the hub bore was smaller,and the mounting bolt PCD was also smaller.I'm currently running a 2 blade fan on my '28 1 ton truck in our cold weather,and if I'm carrying a load up any hills,switch to a '36 Check 4 blade truck fan.
The original 4 cylinder truck fans were not 2 separate pieces spot welded together to make 1 blade,and crossed,but just 2 pretty thin blades,crossed at 90 degrees,with a square "re-inforcing" plate spot welded to the fan blades.Now those suckers are prone to fatigue cracking!

Ray,
Your experience may be different that what I have observed. The majority of fan blades coming apart have been four bladed. In fact I have never seen one of the two bladed fans that came apart but have heard of it.

That was then, this is now.

Sorry folks, I have to come back and address this topic again. Now that I don't have a '26 but in reality have a '28, LO 1 ton, do I need a 4 blade or do I leave the two blade fan on that she has? I don't have to be a hardline "everything original" if a different part is better for the old gal, safer and logical.

tks,
Jerry

Heavyhands I bought a 4 blade fan for my '26 sedan because I was having an overheating problem. I took it to a machine shop and had them open the mounting hole and it works just fine. It's a very simple job if you have the right tools. (drill press & special dial indicator)The guy did it for free... Then I replaced the radiator with a new honeycomb, head gasket and valve job, original AC 'B'series spark plugs, new wiring harness, cleaned out the vacuum & fuel tanks and put the RX-O carb on. Now it runs great.

All,

I'll let you know after this weekend how it goes, IF it fits, I will have a four-blade fan on my 1 ton LO. It came in the mail yesterday. Got my fingers and toes crossed.

Jerry in Tallahassee

The hood and radiator are on the garage floor and the fan pulley is pulled. True enough, there is one bolt sheared off. Tomorrow (Monday) I am going to take it to a shop and have it drilled and removed. I have a drill press but I don't want to take the chance of buggering it up. It will take me longer to drive to the machine shop than it will for them to drill it out I am sure.

Funny how these things happen for a reason but while draining the radiator and taking the bolts out from under the radiator, I discovered one bolt was missing a nut. Think about this, I might not have noticed the missing nut if y'all had not talked me into removing the fan pulley to drill out the broken bolt. I think you folks are psychic or something. You are all scaring me! Ha, ha.

I'll keep you posted. Hey, are y'all (see I'm southern cause I say y'all), getting tired of me posting yet? BTW, I am actually from Pennsylvania (not Transylvania) and I just say y'all to confuse everyone...y'all.

I do have a real question though. As I pulled the pulley off the hub shaft, it seemed to pull out about one inch (that much play). I can easily slide it back in and out, is this normal or do I have another problem back there?

staying warm in Tallahassee,
Jerry

I suggest you take the pump body to the machine shop as well. If the pulley is loose on the water pump shaft it is a BIG problem. The machinist can determine the tolerance and either decide to bush the pulley or install it with loctite so it will not be loose.

Part of our pre-op checks in the army was to check the complete vehicle for loose or missing nuts and bolts. I know that most folks didn't/don't do it, but I was a stickler for doing it myself and having the soldiers who worked for me do it. Of course I still didn't know whether they did it or not, because it's hard to keep track of what 20-30 people are doing.

But it is a good idea to occasionally give the whole vehicle a good going over. No telling what you might find; or not find.

As for the shaft play; how far is your fan from the radiator? If you can move it an inch, it can move itself an inch. And going back and forth, it can definitely get worse. Best pull the whole thing and get it checked out and repaired. Doesn't the hub have to come out anyway for the bolt removal?

Richard and Chipper: You're killing me! Ha, ha. Ok, let me make sure I am describing this correctly so I don't mislead anyone. The pulley came off the water pump shaft. The shaft itself moves in or out of the water pump housing (not the whole water pump) about an inch (I don't think it did before I tapped the pulley off), and I am now concerned that I may have done something inside of the water pump to have so much play. The pulley didn't just slip off into my hand, it took considerable effort to "tap" it off. In fact I had a friend helping me and he did the tapping. We of course took the allen screw out of the pulley before we began tapping.

I know someone here knows about these things and any one of you will probably tell me how unwise I was in tapping the pulley off. Am I going to have to pull the water pump and replace the shaft...or something else?

You are correct Richard, if it travels 1 inch by itself, it will be very, very close to the radiator. Arrrrrrrrgh!

tks, learning by doing,
Jerry

You will need to take the pump off the block. The pulley must be pushed back on the shaft with only a few thousands run out (forward and aft movement). Take the pump body, shaft with impeller and pulley to the machine shop. Have it pushed back together once the broken bolt is removed. He may want to use loctite to secure the pulley instead of the allen screw (modern adaptation).

Actually I don't know anything about your vehicle, having never seen nor worked on one in person. But it seems that you have a problem with the shaft movement. It also seems that, since you have all the other stuff off already, now would be a good time to make sure you don't have a problem where you'll have to dismantle it again in the near future.

Tapping the pulley off was probably not a good idea. A steering wheel puller probably would have done a better and easier job of it. But, again, I don't really know.

As for asking the machinist to "drill out the bolt"; it may be better to ask him to "remove it". I know; subtle difference, but some folk will do as you ask rather than what is best. If he does what you ask, it may cost you more than it has to. I've found that many broken off bolts can be removed without going the drill and tap route. So I'm just saying, give him the option to do it his way and you may pick up a pointer you can use in the future (if he lets you watch without charging too much more...) ;-)

Ok, the continuing saga...as the stomach turns! No trip to the machine shop today. I'll go home this afternoon and remove the water pump and we'll all go to the machine shop tomorrow and ask Mr. Machinist "to remove the broken bolt." Good call Richard! You are also correct about the puller for removing the pulley in the first place, I even told my friend, "I wonder if we should use a puller?". It seems like my life as of late revolves around wheel pullers!!!!!!!!!!!!

Now I am having great concerns that I may have damaged the shaft and/or the water pump. I hope I don't have a new water pump in my near future. NOT A WORD OF THIS TO MY WIFE! Ha!

Tks,
Jerry the wheel puller

Rebuild kits are available for your pump and now may be the time to consider ordering one. They are available from the Filling Station.

Once you get the pump body off, inspect it for damage to the impeller, make sure that the baffle plate is intact and secure and that the packing nut is not bottomed out. You may need to add some packing while you have the pump out.

Also have the machinist check the bushings for wear. He will be able to wiggle the shaft in the body and tell if there is to much wear to put back together or if a rebuild kit or new bushings are needed. It is best to have the pump in first class condition before putting it back on. Repairing them is not too hard but requires a press and reamer to do the job correctly. Any first class machine shop should be able to do that in a sort amount of time. Just make sure that the front bushing is oilite and not just a standard bronze bushing.

Hi,
From previous experience,I have found it safer to pull the pump off completely,support it in a press and press the shaft out through the pulley.The use of a steering wheel puller or similar on waterpump pulley usually results in breaking a part out from the flange where the belt runs.
End float is from a loose pulley,worn bush at the rear where the impellor runs or missing wear washers.

The machine shop was able to remove the broken bolt and it now has a nice new thread. I also asked them to check the water pump and make sure it looked, felt and moved okay, then they pressed the pulley back on the shaft. We checked the packing and it was topped off. There is absolutely no play in the shaft or pulley and it turns marvelously. I am ready to reinstall everything and in the next day or two take her for a spin.

I've come up with a new reference to this old truck (actually a friend did). As the beginning topic indicates, I thought this was originally a 1926. Later and through the efforts of some of you folks it was determined it is really a 1928. So, my friend calls it and I will too, the 1926 + 2. How appropriate. Hummmm, I wonder if I can get that on a license tag????

I'll be back,
Jerry