Converting L6 250, to a clutched fan.
 

Has anyone taken the 4 blade direct drive fan blade off their 250 / 292 and replaced it with a fan cutch type assembly? I'm thinking it should cut down on noise at highway speeds and maybe, just maybe help fuel mileage... If you did the converson, what did you use? All new parts, or something creative from the boneyard?

Re: Converting L6 250, to a clutched fan.
 

SUBSCRIBED!! I was just about to make this same exact post after watching the 350 dyno video where a direct fan can rob up to 30hp

Re: Converting L6 250, to a clutched fan.
 

I believe a 1979 Nova with a/c has a clutch fan. OEM parts....

Re: Converting L6 250, to a clutched fan.
 

I put a clutch and fan on my 64 with a 292 and thought it cut noise. I used a new Hayden 2705 clutch and Derale 17119 fan to match my original fan diameter. The also make the fans in smaller diameters if you have to fit it in a shroud.

Re: Converting L6 250, to a clutched fan.
 

That's some good info right there. I'll look into that.

Re: Converting L6 250, to a clutched fan.
 

My truck just has the little safety fan shroud at the top, so blade size shouldn't be a issue.

Re: Converting L6 250, to a clutched fan.
 

Given the 6 cyl, the 18" fan, 17118, should be fine for the 6cyl vs the 19" 17119. Less rotating mass.

I have yet to have any cooling issue with the fixed 4 blade here in SoCal summer....although a cutch fan would reduce fan noise....turning up stereo can do that to :-)

Not sure of an overall length of the fan clutch so a spacer may be required to keep the fan same distance as the fixed 4 blade is from radiator. The 6 cyl just has a top safety shield vs a "shroud".

Re: Converting L6 250, to a clutched fan.
 

Possibly having to run a spacer to keep the fan close to the radiator is a good point....

Re: Converting L6 250, to a clutched fan.
 

As 72SB is saying, if it ain't broke, don't fit it. Inline water pumps are not that particularly robust, so hanging the weight of a clutch and the stress of a multi blade fan does not sound like a good idea to me.
Inline Chevy six engines generally run fairly cool. I never heard of anyone describing the fixed 4-blade fan as noisy. 4-blade fans just don't move enough air at idle to make much noise. Once your truck is moving, you don't need a fan and the 4-blades don't offer much restriction to air flowing through the radiator especially without a shroud.

This sounds like one of those internet things like, if you don't convert to a internally regulated alternator, the sky will surely fall and your truck will never run again. Somethings done to these old trucks isn't always a necessary as others would have you believe. I installed headlight relays. I though the change in headlight voltage was marginal. I had just replaced the headlight switch and I hate farting with that damn button on the side of the switch and wanted to make sure I never have to do that again on this vehicle. Installing headlight relays is easier than that damn button on old switches.

If you are looking for more air flow because you are adding AC, then I think adding a electric pusher fan is a better idea. At least that was my thinking. I had to remove and modify the center support and hood latch in order to install the condenser, so I added the pusher fans at the same time. One fan runs with the CCOT system to help with the cycling and the other is on a 208* thermostat, but has never run.

Re: Converting L6 250, to a clutched fan.
 

This thread inspired me to take a closer look at my 4-blade fixed fan on my 72 I6. I have a 5-blade asymmetrical 18" fan and clutch I had on my 327. Its also a 18" fan.

The stock 4 blade, 18", has a 3" spacer. If I put the fan clutch and 5 blade on I would need a 1 1/2" spacer to put the fan in the same spot as the 4 blade which is about 2 1/2" (center) from the 4 blade to radiator.....but the fan clutch sticks out 1 1/2" in front of the fan making it about 1", actually less, away from radiator. seems fairly close to radiator so likely coil opens sooner, IDK. I could use a 1" spacer giving more room from front of fan clutch to radiator which sets the fam 1/2" further away than it is now. Not likely a issue as no shroud is involved so the 1/2 in/out of shroud thing does not apply.

Anyway just looking at what spare parts I have and other than buying a spacer and bolts I can put it on but like mentioned above..."If it ain't broke"

I will use the 5 blade with fan clutch if I ever drop a V8 in though

Anyway, sharing some mockup 411 I just did

Re: Converting L6 250, to a clutched fan.
 

I bought a clutch from LMC listed for inline 6 cylinder. Although they don’t list the corresponding fan on LMC. So I went around the net and ended up on eBay to source the correct 7 blade to fit the clutch. Truck is way quieter and blows substantially more air at idle. Worth the investment in my mind. Next thing is to get a shroud to work

Re: Converting L6 250, to a clutched fan.
 

Well, IDK if I need a Fan Clutch on my 292. Never had one.
In Yuma in 1977, I got talked into a bigger diameter multi blade Flex Fan -- for the desert.
I know everybody rags on them now, but I've never had a problem with it in How Many years? Have to use higher math to calculate. Lifetime warranty, even if the chain I bought it from is long gone.
Ain't broke: ain't fixin' it.

Re: Converting L6 250, to a clutched fan.
 

I put a clutch style fan on my 250 six when it was in the truck. A lot less noise with a clutch fan.

Re: Converting L6 250, to a clutched fan.
 

I have the 292 in my truck, it came with a 250 with a full shroud when I bought it in CA. I added the 292 and vintage air, haven't drove it much but plan on changing the 4 blade to a multi flex mainly just because I have it on hand.

Re: Converting L6 250, to a clutched fan.
 

I don't know which study the OP is referring to, but most of the fan studies conclude that an electric fan is less of a HP drain. Yes you would need a bigger alternator, but I would do a bigger internal regulated alternator (like a 78A 12SI AC-DELCO #321-247) and a single 1-speed electric fan from like a Cavalier or Cutlass Cierra. I have no use for aftermarket electric fans, but the OEM ones are very reliable and work well-and parts are availble anywhere. A nice single speed OEM electric fan would give you faster warmups in Winter and less HP draw while cruising down the highway. And less weight on the water pump.

Re: Converting L6 250, to a clutched fan.
 

Good move.
Does the fan shroud help with A/C?
Just to satisfy my curiosity, what did you use for the Passenger Side motor mount?

Re: Converting L6 250, to a clutched fan.
 

I built a 292 to replace a wore out 250. I could never get an engine mount to last without ripping apart. I did use the correct passenger side 292 mount.

Re: Converting L6 250, to a clutched fan.
 

I had an '82 Regal with a V-6 that ate the passenger's side mounts. Weird, that's not even the "mega" torque side. How's that chunk o' grille I sent working out? Have you "welded" it in yet?

Re: Converting L6 250, to a clutched fan.
 

I wish the Aftermarket produced a correct Passenger Side Motor Mount for the Chevy L25, 292 L6.
Tom Lowe sells ''292 motor mounts'', but the RH side one [Pass.Side] bolts to the Mechanical Fuel Pump mount so you are forced to use an electric fuel pump.
Also, the more-forward stance of the 292 PS mount helps to offset the torque of the Long Tall L-Six.
As far as the pad with the rubber sandwich -- I never had one come apart, but I used the later Safety style with curled metal edges that won't let go.

Re: Converting L6 250, to a clutched fan.
 

Hello Brian,
Hope you're doing well, haven't conversed with you lately. I have only put 15 miles on this truck, but it's about ready to go this summer, so can't really say on the fan shroud helping. I don't know if it came on the truck or was installed later, but looks like it's been on there a long time. I'm doing some last minute things to it, one of which was getting the gas gauge and tack working, have gotten that done, but want to change the lower radiator hose to one with a spring in it just in case and plan on installing the fan blade at that time because like I said I have it. I used an original 292 mount so that should be fine. I don't plan on working the old girl to hard anyway. Take care, Donn

Re: Converting L6 250, to a clutched fan.
 

What a neat and clean engine!
While my Orange Stepside is ''technically down'' -- it still starts and runs, so in the emergency that the Jimmy's battery died after 4 years, I ran it 3 miles round trip to O'Reilly's for battery service. It's Down until I get the propshaft off and into the driveshaft specialist's shop. It caught a big ding when I got broadsided in 4/22. The shaft was pushed hard into the side of the hole in the Trailing Arm Crossmember. The dent went unnoticed after fresh Trailing Arms and a rebuilt 12-Bolt differential were assembled to the chassis. When I got excessive vibrations above 59 MPH, we put it on a rack and found out. I have not dropped the propshaft yet. Waiting to line up mechanically-inclined friends to operate.
The truck also steers two points to the left -- so the Frame may be out of alignment. An alignment shop said they couldn't deal with my problem.
So much for my sad story. It can still be fixed.

I see an elongated booster in front of your master brake cylinder. Is that Hydroboost?
And is the P/S Pump bracket a 292-only one, or could you modify a 250 unit?

I don't see a need for Power/Steering on my Stepside. It's usually underloaded and I don't have problems handling it, but I'm pondering building another 292 for my '67 K/10 Suburban. That was a beast to pull around. An attempt at adding P/S failed due to an earlier style of steering geometry. But a Dana 44 front differential w/ P/S and P/Disc Brakes from a '71 MY or later would fix that.
Sorry we are sailing far afield of the OP's querry RE Fan Clutches, but the '67 Sub had a 454, also with an unclutched Flex Fan.
:chevy:

Re: Converting L6 250, to a clutched fan.
 

I remember the ordeal with your stepwise, but thought you had that all taken care of, maybe a different frame would be your best bet. After I switched it over to disk brakes I need a new proportioning valve and also need a different booster because of the 4 barrel carb. I bought the whole package including master cylinder. It's not a hydroboost that I'm aware of.
The PS is original 69-72 I believe, as you know like hen's teeth to find, worst than the frame mount. In searching for this one I bought parts of one, I have an original bracket that the ears are broke off from, the bracket it self is fine. A person should have a block that it could mount it to to check alignment while welding ears back on. Was going to do this till I found the one on my truck. Not in any hurry to sell it but if you're interested we could talk.

Re: Converting L6 250, to a clutched fan.
 

Old51Sedan -- GMail sent.

A Frame Swap is deeper than I want to get into at this time.

Re: Converting L6 250, to a clutched fan.
 

QUESTION ! Can you remove the fan, pully without removing the radiator ? 307

Re: Converting L6 250, to a clutched fan.
 

Yes