Tim knapp's 460 swap into Walt's '69 F250

[MostMint]

these things never go as expected, but looks like the outcome was good and now all you need is a couple gig of RAM to really get that thing going.

[Fred32v]

I always knew that was a cool truck, now it's really cool.

[wxo]

This new arrangement seems to work real well. Don't stand too close to the front of Ol' Blue when she's running. It'll suck you right up against the grill and you won't be able to move.
But, now that I've gotten to this point, I'm thinking that I'd really like to find a viscous clutch and fan that would fit into the measly four inches of space between the water pump hub and the radiator. The original fan and clutch will fit, but there's only about a 1/2 inch of space left over. Too close for comfort. Ideally the fan should be between 1 and 1 1/2 inches from the radiator.
Maybe I should leave well enough alone, but I'm open to thoughts and ideas.

[Fred32v]

I think your onto something. Somebody must manufacture a fan clutch the thickness of your spacer
with the same bolt pattern for the water pump and the fan. Someone in our group might even have one.
What is the length of your spacer? Or, maybe you should just leave well enough alone.
Love the "CAUTION-FAN" sticker detailing.

[ttamrettus]

electric fans. not to mention it'll free up some HP.

[wxo]

I already gave electric fans a lot of consideration and decided against it/them. There are four reasons not to use electric fans:
1) Price of the fans
2) Cost of upgrading the alternator and wiring to handle the fans
3) Complexity of installing the shrouds. I was advised not to use the fasteners that go through the radiator core itself.
4) If an electric fan quits, you got no way to draw air to cool the engine.

[MostMint]

The correct offset clutch fan might be the best way but I have to defend the electric fans a little:

4) If an electric fan quits, you got no way to draw air to cool the engine.

If there is a problem, you have some options:
- Have two fans and wire them separate so you will at least have 50% capacity
- If you are moving you can usually get enough air to make it home (at least in Ohio) even if fans don't work
- You can also use the heater core as auxilary cooler. Makes for a hot ride home but it will help get you home.

I don't know about the alternator situation, that is the only possible issue I see with it. But seeing as how you fashioned a way to get that 460 in there along with an unusual transmission, a little alternator, wiring and fan bracket fabrication would be a walk in the park. I used 1/8" by 1/2" flat metal to fabricate brackets to attach the elec fans to the radiator supports and core support in my TA.

With all that said, I am not really sure you would notice that much power improvement w/ elec fans on the 460.

[ttamrettus]

I don't think you would need a shroud as the electric fans I've seen have one molded to them. Basement Paul may even have a set laying around. You can wire one fan automatic and one for a manual switch. I can't say about the alternator.

If the clutch on the viscous fan goes bad you're in the same boat.

[wxo]

All good points you make, but I'm done with this mini project. The big flex fan cools just fine, it won't quit on me, and didn't cost all that much except for my time. There's not much sense in fixin' what ain't really broken. I need to move on to other issues if I'm goin' to drive this thing up to Truck Carlisle.

[MostMint]

OK. So what are the other issues?

[wxo]

Ol' Blue has come up with a new interesting cold starting problem. I haven't yet gotten a handle on it, so I thought I'd throw it out to you nice fellas for your input. Just to remind you, she has a spreadbore Holley with a thermostatatic choke.
First I activate the choke by pressing the footfeed about half way down and releasing it. When I turn the key the engine fires then immediately stalls. The interesting part is that using the throttle to keep it running has no effect at all. It's like the gas pedal is disconnected from the carburetor. Each time I attempt to start it, the same thing happens over and over again. The first time it happened, I pulled the air cleaner and found the choke half open. I set it to full open and the engine fired right away and ran normally. I had no trouble over the next several days. Then it happened again yesterday. I pulled the air cleaner again, checked that the squirters were working (they were), cleaned the choke linkage with carb cleaner, put everything back together. It started and ran normally again. Then it happened again later in the day. I'm a bit mystified by the fact that operating the throttle when this happens has no effect on the running of the engine. It just starts and quits no matter how much I pump the throttle.

[Basement Paul]

I've had the base of an aftermarket air filter hit the linkage on my carb before, and had to modify the base to accomodate the linkage. Does it start normally with the air filter off?

Also, maybe the carb is draining down while it's sitting so there's not enough gas to keep it running until after the motor is turned over and pumping.

-BP

[wxo]

I may have found the answer. I want to wait for more time to pass before I call it fixed. I will buy breakfast at Carlisle for first one who guesses the reason for the problem.

[wxo]

We talked over each other, BP. To answer your questions, first it makes no difference whether the air cleaner is on or off. Secondly, it would not start after as many at 10 attempts. It just fires then quits each time.

[Basement Paul]

I'm guessing it's not a carburetor problem at all, but something related to the ignition. How about a bad ignition tumbler (or broken wire related to the tumbler)?

-BP