My understanding is that for optimum cooling, 50% of the fan should be inside the shroud. Mine is not (the leading edges are even with the shroud and I have a clutch fan). In searching for a spacer, every spacer that I see states for use with a flex fan. Can anyone provide me with guidance? Thanks! Bernie
The fan clutches kinda sorta come with their own built-in spacer. Even though I have a 455 in my car, the OEM fan clutch for my year/engine placed the fan in the perfect position. So you could have an issue with the wrong fan clutch or fan pulley.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
The fan clutches kinda sorta come with their own built-in spacer. Even though I have a 455 in my car, the OEM fan clutch for my year/engine placed the fan in the perfect position. So you could have an issue with the wrong fan clutch or fan pulley.
Hmm...The pulley is correct (recently ordered and installed). My guess would be it's not the correct fan. So, in order to get the fan placed in the optimum position in the shroud, other than not being correct and assuming it fits, what would be the harm in using a spacer that would normally be used for flex fans?
Being an engineer, I would be a tad worried about the forces on the bolts, which would be extra long to deal with a spacer. On a normal fan, there are no torque differences between the fan and the pulley (through the spacers) thus no differential sheer forces on the bolts. However, a fan clutch has the fan rotating at different speeds than the fan pully, thus places sheer loads on the bolts and now those bolts are longer. The different rotational speed of the fan/clutch will try and twist the assembly in relationship to the spacer and twist the spacer in relationship to the fan pulley...
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
Is your radiator the original one? I know I run an after market alum radiator and the car came with a 4 core. Once i removed the bad 4 core, the 3 core alum was not as thick and I had to use a half inch spacer to place the fan blades back half way in the shroud.
I had the same problem, but since my fan clutch was weak I replaced it with one from a Cadillac that was 1/2" longer than stock. Worked perfectly and is a lot cleaner look than a spacer. I had always been told that using a spacer on a fan clutch would move the weight off the clutch further forward and lead to early water pump failure. Don't know if that's urban legend or not. What salmon38 posted is another concern. Here's the website that I used to figure out the fan clutch I bought- Hayden
I had the same problem, but since my fan clutch was weak I replaced it with one from a Cadillac that was 1/2" longer than stock. Worked perfectly and is a lot cleaner look than a spacer. I had always been told that using a spacer on a fan clutch would move the weight off the clutch further forward and lead to early water pump failure. Don't know if that's urban legend or not. What salmon38 posted is another concern. Here's the website that I used to figure out the fan clutch I bought- Hayden
Desert68, please provide more info so I can try and get the same fan clutch. I would also like to do away with my spacer for that cleaner look. What year cady was that clutch fan from and what did you use to figure out that is the clutch fan you needed. Thanks man!
Wow, glad I asked the question. Lot's of things that I wouldn't have thought of and that I need to consider. Salmon, thanks for the input on the torque concerns....that certainly makes sense. USMC Ordy, not sure about the originality of the radiator, but I would suspect it's not original. Desert, thanks for the link to Hayden. To me it looks like what they call the "fan height" is the issue (distance/length between where the clutch mounts to the water pump/pulley assembly and where the fan mounts to the clutch). Mine is about 1.5 inches and I would need that distance/length to be about 2.5 inches to get the proper fan blade depth in the shroud.
Ok, I ran the numbers on the hayden site http://www.haydenauto.com/Online%20Catalogs-eCatalog/Content.aspx and used the "Parts Specification Search" tab (under the "part number" tab) and this allows you to select the different attributes of a given clutch fan. I pulled up the thermal clutch fan that is suppose to be for a 69 Firebird with A/C which is part number 2705 and copied all the part specs for that clutch fan and then went into the above mentioned search tab and started adding the different attributes and values for the 2705 clutch fan as I want them all to match with the exception of the fan mount height and overall height. Once those were all added I went to add the the fan mount height (I never touched the overall height as that would be determained by the fan mount height) and was only left with two options for the values. And that would be the standard 1.53 or 2.03 height. I selected the 2.03 height which brought back only one part number. Part number is 2707. This is used on a whole host of vehicles to include CADILLAC BROUGHAM (90-87) CADILLAC DEVILLE (86-82), CADILLAC ELDORADO (84-81), CADILLAC FLEETWOOD (86-82), CADILLAC SEVILLE (83-81). It is also used on PONTIAC BONNEVILLE (87-70), PONTIAC CATALINA (81-70) , PONTIAC FIREBIRD (81-77), PONTIAC GRAND AM (80-73), PONTIAC GRAND LEMANS (83-75), PONTIAC GRAND PRIX (84-76), PONTIAC GRAND SAFARI (77), Pontiac GTO (73-72), PONTIAC LAURENTIAN (81-76), PONTIAC LEMANS (81-68), PONTIAC PARISIENNE (85-76), PONTIAC PHOENIX (79-77), PONTIAC SAFARI (69), PONTIAC TEMPEST (70-68), PONTIAC VENTURA (77). There are a lot more that this fan works on. So for what you need it looks like this is going to be the longest or tallest one you can get that will actually mount up for our purpose. I will wait to see if this part number 2707 is the same thing Desert68 used.
First went to the Hayden catalog and found the replacement pn - 2705 (std duty) / 2747 (heavy duty). Then I measured what I had in the car because I have no idea what was put in by the previous owner. It was the "correct" length, and I needed between 1/4 and 1/2" more fan height to get the fan 50/50. I matched up all the other dims and ordered the 2731 heavy duty from Summit. 77 to 82 8 cylinder Caddy is what Hayden lists as the original application. I think most big box auto parts stores carry Hayden, but Summit is easier and it just shows up at my front door in a couple of days.
Thanks Desert68, I guess if you were wanting a heavy duty one, then that would be the one to go with. I am looking at the standard duty, which the 2707 and it is right at 1/2 inch taller from the standard 2705. Even if I wanted a heavy duty one, the 2731 is about 3/4" more in height over the standard and that would most likely put me about a 1/4 or little more too far inside the shroud, but that looks like more what Bernie needs to get his close.
Ok, I ran the numbers on the hayden site http://www.haydenauto.com/Online%20Catalogs-eCatalog/Content.aspx and used the "Parts Specification Search" tab (under the "part number" tab) and this allows you to select the different attributes of a given clutch fan. I pulled up the thermal clutch fan that is suppose to be for a 69 Firebird with A/C which is part number 2705 and copied all the part specs for that clutch fan and then went into the above mentioned search tab and started adding the different attributes and values for the 2705 clutch fan as I want them all to match with the exception of the fan mount height and overall height. Once those were all added I went to add the the fan mount height (I never touched the overall height as that would be determained by the fan mount height) and was only left with two options for the values. And that would be the standard 1.53 or 2.03 height. I selected the 2.03 height which brought back only one part number. Part number is 2707. This is used on a whole host of vehicles to include CADILLAC BROUGHAM (90-87) CADILLAC DEVILLE (86-82), CADILLAC ELDORADO (84-81), CADILLAC FLEETWOOD (86-82), CADILLAC SEVILLE (83-81). It is also used on PONTIAC BONNEVILLE (87-70), PONTIAC CATALINA (81-70) , PONTIAC FIREBIRD (81-77), PONTIAC GRAND AM (80-73), PONTIAC GRAND LEMANS (83-75), PONTIAC GRAND PRIX (84-76), PONTIAC GRAND SAFARI (77), Pontiac GTO (73-72), PONTIAC LAURENTIAN (81-76), PONTIAC LEMANS (81-68), PONTIAC PARISIENNE (85-76), PONTIAC PHOENIX (79-77), PONTIAC SAFARI (69), PONTIAC TEMPEST (70-68), PONTIAC VENTURA (77). There are a lot more that this fan works on. So for what you need it looks like this is going to be the longest or tallest one you can get that will actually mount up for our purpose. I will wait to see if this part number 2707 is the same thing Desert68 used.
Thanks for digging into to this. Now I am wondering if moving the fan 1/2 inch inside the shroud with the 2707 fan clutch would make enough of a cooling temp difference to justify the expense.....
Thanks for digging into to this. Now I am wondering if moving the fan 1/2 inch inside the shroud with the 2707 fan clutch would make enough of a cooling temp difference to justify the expense.....
Why dont you go with the 2747 (heavy duty) that Desert68 went to? That is about 3/4 inch longer then the one you have now and you did say you needed about an inch more. That would get you real close and would tend to pull more air through, even if your fan blades where sitting 1/4 inch in the shroud, vuce not even sitting in the shroud!
Thanks for digging into to this. Now I am wondering if moving the fan 1/2 inch inside the shroud with the 2707 fan clutch would make enough of a cooling temp difference to justify the expense.....
Why dont you go with the 2747 (heavy duty) that Desert68 went to? That is about 3/4 inch longer then the one you have now and you did say you needed about an inch more. That would get you real close and would tend to pull more air through, even if your fan blades where sitting 1/4 inch in the shroud, vuce not even sitting in the shroud!
Good point. In reading his post again and looking at the product dimensions, it looks like he ordered the 2731 which has a fan height of 2.5 inches vs. the 1.5 I have now. Thanks again for the guidance.
Just to chime back in again, I can't point to the fan being 50/50 in the shroud as the magic bullet in cooling temps. I made the change when I rebuilt the engine. So I started with a clean and de-flashed block, did the water pump plate mod, have all the radiator side fillers, x panels and lower filler panel, clean 3 row radiator. What I will say is that after reading a ton about overheating problems and the fixes, I did all I could to not skip any steps. This will be my second summer with this set up on my 68 vert with a 461 and a/c. So far I have not seen it get above 185, even here in Phoenix.
Just to chime back in again, I can't point to the fan being 50/50 in the shroud as the magic bullet in cooling temps. I made the change when I rebuilt the engine. So I started with a clean and de-flashed block, did the water pump plate mod, have all the radiator side fillers, x panels and lower filler panel, clean 3 row radiator. What I will say is that after reading a ton about overheating problems and the fixes, I did all I could to not skip any steps. This will be my second summer with this set up on my 68 vert with a 461 and a/c. So far I have not seen it get above 185, even here in Phoenix.
Thanks for the guidance Desert. I'll probably bite the bullet and buy the longer clutch fan which will push fan into the shroud and closer to the radiator. I also plan on doing the the water pump plate mod. It will be interesting to see if I notice a temperature difference.
I had to replace the water pump in my 69 last year, the fan before I did the work was way out of the shroud. So I did the mod on the back plate to pump distance. I used a 2 in. spacer to move the fan into the shroud, now the car runs way cool just sitting in traffic. Will have to check to see if anything is going on with that big a a spacer on the pump.
I had to replace the water pump in my 69 last year, the fan before I did the work was way out of the shroud. So I did the mod on the back plate to pump distance. I used a 2 in. spacer to move the fan into the shroud, now the car runs way cool just sitting in traffic. Will have to check to see if anything is going on with that big a a spacer on the pump.
Coilster, do you have a clutch or flex fan? I assume clutch since you referenced checking things out.
