Fan Clutch Install

[skokie]

I am going to install the fan clutch and steel fan that I got for christmas in the 68. Right now I have a felx fan on there with a spacer. I have the bolts that attach the fan to the fan clutch. Will the fan with the fan clutch need the spacer?

Thanks

[BobbyK]

My old clutch and 7 blade fan setup did NOT have a spacer.They all bolted directly together.

[skokie]

How far is your fan clutch from your radiator?

Thanks

[BobbyK]

I have electric fans now but if I recall they were a good 5"-8"s away.With my shroud on the blades were about half showing.
I don't have a pic of my actual fan setup just one showing the shroud installed.

In this pic you can see the width of the shroud and just a little of the rad.

[skokie]

Thanks for the info. It looked like it might be around 4-8 inches but without tearing it all out I couldnt be sure. Plus its raining here now. Should the fan be in the shroud completely or does it matter if its out of the shroud by a inch or two?

Thanks

[BobbyK]

the blades should be about 1/2 in and half out of the shroud.

[BobbyK]

I think too far in will cause cavitation and too far out will not draw enough air through the shroud.

I'm at work right now otherwise I'd go measure things for you.It's raining here too.

[skokie]

Thanks BobbyK I appreciate the info. Once it quits raining I will get out there and get it swapped. Cant let a Christmas present collect dust

[4x4Poet]

Fans should be all the way in a shroud with the back edge of the blades at the shroud edge. The blades can stick out less than an inch, but you lose more draw effect with every increase rearward beyond the shroud edge. I'd guess that the length of the clutch fan's shaft w/flange will prolly near match your flex fan's spacer.

[Tx Firefighter]

That's what happens when you get lazy and don't bolt your intake on.

You hit the brakes real hard in a panic stop and the intake pops right off the engine. It's hell on the fan when it hits it.

I was always taught that the fan should ride 1/2 in 1/2 out of the shroud.

If you have the right fan clutch, fan, and water pump, it should take care of itself. Don't sweat it if it's a little too far forward or back. Your truck won't overheat just because of a little variance.

[GMC AMI]

Must have sent the dist. in orbit?

[Robert1970C20rstbukt]

Looks like the alternator went flying out of the hood too.

[junkyardjohn]

I WAS ALWAYS TAUGHT 1/2 IN & 1/2 OUT WAS PERFECT.
BY THE WAY.. WHAT KIND OF FAN SCHROUD IS THAT IN THE PIC. JOHN

[mrein3]

I just finished changing out my tired old 350 engine. It had a 4-blade fan with no clutch and a 3 or so inch long spacer.
In my shop I had a 7-blade fan and clutch from a 1971 Monte.
Before the swap the old 4-blade and spacer had half the fan in and half the fan out. The "new" clutch and fan WITHOUT the spacer has about half the fan in and half the fan out of the same shroud.

Of course I used MUCH shorter bolts to bolt the clutch on to the water pump. The old ones went through the spacer. You might want to run to the hardware store before you jump into the project.

I don't have a good before shot from this angle. This is after...

[Stocker]

Originally Posted by 4x4Poet

Fans should be all the way in a shroud with the back edge of the blades at the shroud edge.

Just checked mine, and it's exactly like this. Bone stock as far as I know. No overheating problems ever... :p

[BobbyK]

HAHA,that's funny.I thought the velcro would hold...I was wrong.
That pic was taken when I was installing my TPI.

The shroud I found in a junk yard.It's a GM application just don't know what it came off of.It is a 2 piece design the splits half way down on each side.

I had moved my eng forward when I installed my 700R4 so the orig clutch fan ended up too far forward in my orig. shroud.

It worked great while I had it in there!

[Javy]

Hello,
Why are you replacing your flex fan with a clutch fan ?
The reason I ask is because when building my big block 69
I bought an expensive flex fan.
It was louder than the Erson gear drive I run.
I replaced it with a GM clutch fan and couldn't
be happier !
With flex fan my temp averaged 182 degrees.
With clutch fan it runs about 4-5 degrees warmer
but well worth it (in SOCAL using Redline's Water Wetter)
Just my 2 cents
Thanks

[Longhorn Man]

Are we talking the original flex fans that GM recalled back in the 70's...
or are we talking the gay looking blue and alluminum auto zone special (same one as summit/jegs) that explode and cut through your hood.


Clutches are way better than any flx fan can ever be.

1/2 in 1/2 out is what I was tought in school and from word of mouth. In reality, this is the very first time I have ever heard anyone say different.

[Javy]

Hello,
I'm talking about Flex-O-Lite brand(I think,it's been over a year)
In my old school days, I was preached to eliminate
stock clutch fan but as you say and I've learned
go with GM clutch.They are expensive but well worth the
cost over economy types.
Just like another typical myth here in SOCAL (chicano style)
to take out thermostat. BUT THAT IS A WHOLE NEW SUBJECT
TO LEAVE ALONE,NOT IN THIS THREAD.(sorry to mention it,but
it is the same old school mentality,just like removing air filter
and turning cover upside down.OOPS,there I go again! sorry)

[junkyardjohn]

Originally Posted by Javy

Hello,
I'm talking about Flex-O-Lite brand(I think,it's been over a year)
In my old school days, I was preached to eliminate
stock clutch fan but as you say and I've learned
go with GM clutch.They are expensive but well worth the
cost over economy types.
Just like another typical myth here in SOCAL (chicano style)
to take out thermostat. BUT THAT IS A WHOLE NEW SUBJECT
TO LEAVE ALONE,NOT IN THIS THREAD.(sorry to mention it,but
it is the same old school mentality,just like removing air filter
and turning cover upside down.OOPS,there I go again! sorry)

SOMEONE SURE HAS BEEN GIVING YOU SOME BUNK ADVICE. READ ANY BOOK OR MAGAZINE PRINTED AFTER 1950, & THE ODDS ARE YOU'LL GET THE STRAIGHT ADVICE YOU SEEK. JOHN

[Longhorn Man]

Flex-o-lite...the gay looking blue and alluminum auto zone special...what ever.
Those things are junk.I wouldn't put one on my dash let alone on my engine.
Who ever came up with that was probably sniffin the same glue as the idiot who made the triangle foam air filters that catch fire.

[skokie]

Heres the fan installed on the fan clutch ready to go. Will install tonight and post pics when done.

[4x4Poet]

Purdy pics. I luv new parts! I have a very expensive 7-blade GM fan awaiting install in my K10 with a new fan clutch to replace the 4-blade fixed fan & spacer the PO installed behind a 2-row rad. Since I'm rebuilding the engine, replacing the heater core, upgrading to a 4-row rad, and running a Robert Shaw high-flow thermostat with FlowKooler water pump, I'm also going to use Evans Coolant. No more rust, steam, high pressure that's hard on hoses, etc. 375º boiling point @ zero pressure.

As for the fan/shroud position, ask an experienced radiator shop owner/foreman.

[skokie]

Well its done. That quieted it down a bit and it seems to cool better now. There is more air coming over the intake manifold than before.

Thanks for the help
Here are the pics.
2nd pic is the fan I removed. Was this thing stock?

[mrein3]

Originally Posted by Longhorn Man

Flex-o-lite...the gay looking blue and alluminum auto zone special...what ever.
Those things are junk.I wouldn't put one on my dash let alone on my engine.
Who ever came up with that was probably sniffin the same glue as the idiot who made the triangle foam air filters that catch fire.

Back in the late 80s my buddy and I were looking at the 1971 Chevelle convertable that I ended up buying. When we fired it up it made a REAL funny noise. At that time I had never seen or heard anything like it. It had one of those flex fans on it. It sounded like crap! I didn't know at that time that they came apart while spinning. I just knew it was coming off. That was the first mod I did to that car. No more flex fan.

BTW it was blue and aluminum and VERY gay looking.