test fan clutch?

[Clem Z.]

Re: test fan clutch?

do you have a fan shroud? if you do the fan blade should be 1/2 inside the shroud and the 1/2 outside the shroud, in other words the edge of the shroud should split the fan blade tip to get proper air flow.

[Clem Z.]

Re: test fan clutch?

do you have a fan shroud? if you do the fan blade should be 1/2 inside the shroud and the 1/2 outside the shroud, in other words the edge of the shroud should split the fan blade tip to get proper air flow.

[don whitehead]

Re: test fan clutch?

Brand new dewitts top tank aluminum hi flow rad.

[don whitehead]

Re: test fan clutch?

Brand new dewitts top tank aluminum hi flow rad.

[John H.]

Re: test fan clutch?

Don -

Do you have the shroud installed? It will NOT cool at idle without it. My stock '57 270 runs at I.R. gun-verified thermostat temperature (180) all the time, in town or on the highway (re-cored original copper-brass radiator).

[John H.]

Re: test fan clutch?

Don -

Do you have the shroud installed? It will NOT cool at idle without it. My stock '57 270 runs at I.R. gun-verified thermostat temperature (180) all the time, in town or on the highway (re-cored original copper-brass radiator).

[Don Stewart]

Re: test fan clutch?

If it's an after market clutch, it may be set up for the wrong rotation. I did the same thing and after replacing the hub with one from MaryJo, everything setteled down.

[Don Stewart]

Re: test fan clutch?

If it's an after market clutch, it may be set up for the wrong rotation. I did the same thing and after replacing the hub with one from MaryJo, everything setteled down.

[Thomas D.]

clutch test

Here's the best way to find out if your clutch is the problem. Remove it! Take it off and run the fan direct without one. If you still experience the same temps then it ain't the fan and my bet it isn't. Many people have experienced running a little hotter after a rebuilt motor. Some have had to even start over! When you bore out a block you thin the cylinder walls that insulate the combustion chamber to the water jackets. Most problems are with your CU size because they had thin walls to start with. The biggest trouble is with the .060 and .080 over. Knowing what I know today, if my engine needed to go more than .030 over, I'd look for a new block. Another common mistake is engine builders trying to out do the general. If the book says .005 clearance then go .005. Tighter motors have more friction and create more heat. Clearence is good! It lets oil get in and reduce friction, and thus heat. Now I'm not saying rebuild the motor, just let it break in a while. Run 60/40 (water/anti) if you don't need the freeze protection of 20 below and see what happens after a couple thousand miles. You may have to go to an electic driven fan if the problem remains.

[Thomas D.]

clutch test

Here's the best way to find out if your clutch is the problem. Remove it! Take it off and run the fan direct without one. If you still experience the same temps then it ain't the fan and my bet it isn't. Many people have experienced running a little hotter after a rebuilt motor. Some have had to even start over! When you bore out a block you thin the cylinder walls that insulate the combustion chamber to the water jackets. Most problems are with your CU size because they had thin walls to start with. The biggest trouble is with the .060 and .080 over. Knowing what I know today, if my engine needed to go more than .030 over, I'd look for a new block. Another common mistake is engine builders trying to out do the general. If the book says .005 clearance then go .005. Tighter motors have more friction and create more heat. Clearence is good! It lets oil get in and reduce friction, and thus heat. Now I'm not saying rebuild the motor, just let it break in a while. Run 60/40 (water/anti) if you don't need the freeze protection of 20 below and see what happens after a couple thousand miles. You may have to go to an electic driven fan if the problem remains.

[Duke W.]

Re: test fan clutch?

Hmmm. Sounds like you've covered all the bases. If I had a 270 I would probably get a tach drive single point distributor, blueprint it (shim up the end play to two to eight thou, and install a new breaker plate that is snug and rotates without any wobble) then set up the centrifugal and vacuum advance to the '65 FI specs and use the 28-32 oz. points. All you have to do is find a vacuum port to communicate full manifold vacuum to the vacuum can, and I'm sure this can be done as an easy on easy off swap if you want to install the dual point for judging.

If you give me your distibutor specs I might be able to make some more suggestions. You want total initial plus centrifugal to be in the range of 36-38 degress, so your initial is determined by how much centrifugal is contributed. Give me the specs if you have them (I don't) and then test on the car with some tape marks or an accurate dial back timing light to determine how much centrifugal you have and the current total.

A good way to test total advance is to make a mark on the balancer at 30 degrees. You can do this by measuring the circumference and then making a mark 1/6 the distance clockwise (when viewed from the front) from the TDC notch.

Rev the engine up until it quits advancing and then read where your 30 degree mark is on the index tab. The total is the index tab reading plus 30.

I think the 270s only have a specified CR of 9.5:1, so you could probably even over advance it a bit. When I was working in a gas station in the mid-sixties I had a regular customer with a 270 who always had me fill it up with regular. I warned him about detonation, but he said it never pinged.

Duke

[Duke W.]

Re: test fan clutch?

Hmmm. Sounds like you've covered all the bases. If I had a 270 I would probably get a tach drive single point distributor, blueprint it (shim up the end play to two to eight thou, and install a new breaker plate that is snug and rotates without any wobble) then set up the centrifugal and vacuum advance to the '65 FI specs and use the 28-32 oz. points. All you have to do is find a vacuum port to communicate full manifold vacuum to the vacuum can, and I'm sure this can be done as an easy on easy off swap if you want to install the dual point for judging.

If you give me your distibutor specs I might be able to make some more suggestions. You want total initial plus centrifugal to be in the range of 36-38 degress, so your initial is determined by how much centrifugal is contributed. Give me the specs if you have them (I don't) and then test on the car with some tape marks or an accurate dial back timing light to determine how much centrifugal you have and the current total.

A good way to test total advance is to make a mark on the balancer at 30 degrees. You can do this by measuring the circumference and then making a mark 1/6 the distance clockwise (when viewed from the front) from the TDC notch.

Rev the engine up until it quits advancing and then read where your 30 degree mark is on the index tab. The total is the index tab reading plus 30.

I think the 270s only have a specified CR of 9.5:1, so you could probably even over advance it a bit. When I was working in a gas station in the mid-sixties I had a regular customer with a 270 who always had me fill it up with regular. I warned him about detonation, but he said it never pinged.

Duke

[Duke W.]

Correction

That 30 degree mark would be 1/12 the distance of the circumference, not 1/6. Sorry for the error.

Duke

[Duke W.]

Correction

That 30 degree mark would be 1/12 the distance of the circumference, not 1/6. Sorry for the error.

Duke

[don whitehead]

Re: test fan clutch?

Yes, the shroud is installed, original and proper,,,Don