The Stovebolt Site Forums The Shop Area Engine Shop "Tweaked Fan Blades On 235"

The re-built 235 is about ready to go in the 51'. While making sure pulleys were lined up, (short shaft water pump), I realized that the fan had already been "tweaked", when I placed it on the water pump, against the pulley, I noticed how little clearance there was, also how almost flat, the blades seemed to be. I don't think there is enough of a twist in the blades to draw much, if any air. Would there be enough room before the radiator to space the fan a little, and un-tweak it some? Also, I ordered the stainless bolt kit from Carters, the kit contains bolts for attaching the intake/exhaust manifolds, there are the six bolts needed for attaching the manifolds, plus two threaded studs, which I know will screw in where the alignment pins are now in the head, has anyone used these? should I? is there room for the washer under the nut here? I will be using Fenton manifolds. Thanks!

I put in as much as and inch of more pitch to pull more air across my airconditioned 216. I did not change the clearance between the fan and radiatior.Lots more coller at idle.

Using a water pump adapter and a stock 216 waterpump rather than the short pump gives you more fan clearance on both the radiator and the front pulley, plus it puts the fan in a better position for cooling. You will probably have to move the radiator forward if you use the short pump.

To add to Baldy's information, you'll notice that your stock fan blade (with the "short-shaft" pump) is located low on the radiator. Using the adaptor plate and the correct early waterpump will give you adequate fan to radiator clearance with the radiator mounted correctly, center your fan vertically on the radiator, allow you to run a 15" 6 blade, and give you the correct pump pulley speed. In addition, by using the adaptor plate and the early pump you can replace a wornout pump from your local parts supplier....not sit and wait for 3-5 days for UPS service from a mail-order vendor on a pump that doesn't work!

Like many others, I tried the "short" pump, fought with the clearance and pulley issues and finally took some good advice and used the adaptor plate. Using a 6 blade flex-a-lite FLX-1615P fan from Summit has completely eliminated my overheating concerns. BTW...I'm also running air conditioning.

I've got a bunch of pix's in my webshots of the "adaptor plate/early pump install. Doing it correctly will keep your re-built 235 cool!!! Hope this helps!

Dave

I've seen the results of bending, or otherwise modifying fan blades, up close and personal. Unless you've got very good health and/or life insurance, it's not a good idea. One pit crew member at the local dirt track caught a fan blade mid-chest when it flew off the hub on a snap acceleration. It had been cut down about 2" on the diameter for crossmember clearance. It stopped about a half inch from his heart, but it left a really nasty scar.

Holes in the hood, sliced radiator hoses, and other mechanical problems from thrown fan blades get pretty exciting, too! The fan turns quite a bit faster than a circle saw blade at times. Doing anything to possibly upset its balance doesn't sound like a good idea to me, but I'm old and cautious. "Your mileage may vary!"
Jerry

Doesn't the adapter plate require drilling or machining of the block some how? Did you do that without getting cuttings inside the engine? If this isn't true pleaswe let me know.

Thanks,

My first old car, a 1954 Chevy 150 Handyman wagon, came with a hole in the hood where a fan blade had flown through.
chris ioakimedes
Fairfax California
1948 1 Ton
www.fattiretrading.com

Bill...you do have to drill and tap two holes outside of the water jacket. However, you use the adaptor plate as a template and if you can use a hand drill it isn't a bit dicey. You use a larger drill bit to make an initial indentation and then finish up with a 5/16. Tape on the drill bit sets your depth...you never go into the water jacket. I installed (2) 3/8" studs and used nuts on the outside. My a/c belt tensioning bracket pivots from this point.

I've got some pictures of the process in my "tips and Tricks" webshot album. Of course it is easier with the front sheet metal removed but the block drills like butter, taps easily and the end result of a cool running engine is worth the effort.

I also have a pic of the entire instruction sheets in the album. Click on "full size" in the upper right corner for complete instructions.

If you follow the instruction sheets to the letter you won't have any problems with the install and you can forget about fan clearance to the radiator and harmonic balancer issues and just enjoy driving your cool truck.

Dave

BTW...the instruction sheets are on page 12 of my "Shoebox album". SBT!

here is what an original 216 fan blade looks like after it breaks off and gets crunched on by the belt, pulley, and front cross member.
[img]http://inlinethumb10.webshots.com/17673/2879017530080251109S200x200Q85.jpg[/img]
I was about 3,000 miles from home at the time, and luckily it did no damage to anything else, it was just laying on the cross member like it was placed there.

This was the temporary solution and worked fine until I found a replacement a few hours down the road.
[img]http://inlinethumb60.webshots.com/20091/2456447380080251109S200x200Q85.jpg[/img]

The fan had a preexisting crack that I did not spot early on, then it finally finished cracking off.
Do check your old fans carefully for cracks between the rivet holes.

Grigg

Dave,

Thanks. For some reason I thought the holes went through to the water jacket. I read somewhere that this modification was easier to do before the engine was rebuilt. They just must have been talking about needing full access to the front of the engine to drill the two holes. Thanks for the pictures.

Grigg: Glad you didn't get hurt or damage the truck when that fan came apart. I threw a fanblade in a 67 Dodge I once had. It went thru the hood!

Thanks everyone! Fla54Chevy3100, thanks for the link,nice Truck! Grigg, those pics are more than a million words! Needless to say, all of you answered my question, I have ordered my early pump adapter plate. Thanks Again.

Agree with ya 100% Jerry, I've got two blades sitting in with the scrap, one's been welded (full of stress risers). The other is just loaded with cracks emanating from the rivet holes like Grigg described.
Is anyone producing aftermarket replacement blades?
Denny Graham
Sandwich, IL

It would be wise to inspect your fan regularly for cracks as it is constantly being flexed with RPM changes even in stock form.

I don't know of any being made new, but I have seen a few NOS one on E-pay.