First I'll apologize for this excessively wordy post, but I want to make sure people understand my issue and my question.
All of this is on a factory A/C 68 Dodge Dart, originally 318 car, now has a 360 that I did not install nor do I know much about it, automatic (727).
So I've run into what appears to be a unique issue (probably not, but didn't find it through page 12 of the search function for fan clutch)
Most people seem to have an issue with needing a shorter fan clutch than a Hayden 2747 and use the 2947. I have the opposite problem, the fan clutch doesn't space the fan far enough forward to clear the A/C compressor pulley or the larger crank pulley, see picture for reference with direct drive fan installed and clearance to A/C pulley.
As you can see with the curved 7 blade fan with a spacer there is not quite a 1/4 inch of clearance to A/C pulley, this also places forward leading edges of fan blades right at 15/16" to radiator (see pic below), spitting distance to perfect right, all good right?
Overhead view for reference.
Nope, because I'm picky and really want to run a clutch fan.
I was going to run the Cold Case shroud and fan that comes as part of their kit, but somebody failed tape measure class and the specs on their web page lists total thickness of 6.5" which is a whopping 3/4" shy of actual measurement, shockingly that won't fit in the available 7" of space between the nose of the water pump and core support! Measure closely then add a random amount before ordering because we didn't! Rant over. I've already returned the kit and gotten my new radiator, Summit took care of me on that end. Side note, the quality of the radiator appears really nice, construction looks good, welds are decent, 1/2" thicker than stated measurements, but I digress, time will tell but so far I am pleased with the radiator itself.
Now we get to the issue at hand, the problem I'm running into is that with the 2747 clutch installed with the curved 7 blade fan the fan itself is moved back approximately a 1/4" causing it to hit the fan pulley, using the flatter style 7 blade fan helps, but still less than a 1/16" or so of clearance, not nearly enough when you account for pulley wobble, water pump movement, etc.
Ok, no problem you say, just put a spacer between the clutch and pulley, problem solved you dummy, why are you even here asking us?
This brings us to the second issue, because of the clutch/fin design of the 2747 clutch the front of the clutch is within approximately .320" (approximate because I didn't actually measure, just used two piece of cardboard that measured right at .160" each and slid in between radiator and fan making contact with both. So as you can see, reducing gap by even an 1/8" (.125) reduces my clearance to less than 1/4" between radiator and clutch, and only gives me approximately an 1/8" to the A/C and crank pulley anyways. Too close for comfort in my opinion given engine movement, etc.
Here is a pic of a standard duty (I believe stock) and the 2747 Hayden which is a heavy duty clutch
There is approximately a 1/2" of difference in overall height, so i could run a 1/2", maybe slightly more, spacer I believe, haven't taken it back apart yet to verify. Then since the front of the factory standard duty is flat, not finned, should alleviate my clearance problems on both sides, again, problem solved.
Except I'd really prefer to run a heavy duty clutch that will drive the fan at 80-90% of pulley speed as opposed to the standard duty that will drive the fan at 60-70% of pulley speed. I'm already dealing with an issue of the car heating up at idle, so slowing the fan down probably isn't the answer. I've already got a reproduction shroud to put on the car to help with the concern, we'll see where that goes. Car runs 170-180 in 85 degree GA heat/humidity going down the road with the A/C on or off with a 160 thermostat in it, so I'm certain it's an airflow at low speed issue. Not really the answer I'm chasing here, but I will probably change back to a 180 thermostat once this issue is sorted out, I just like having the extra 10 degrees or so cushion until then (so no need to tell me it's not really helping, thank you though).
So, for all of you that actually made it through this incredibly long post for seemingly a simple concern, here is my question.
Has anybody else run into this specific concern before, and if so did you find a solution that allowed you to run an HD fan clutch, different manufacturer, milled mounting flanges on fan clutch to move fan forward ( I thought about this, but decided after measuring that approximately 3/8" thread engagement was not something I was comfortable with), modified fan clutch in some other way, modified fan blades to increase rear clearance (also thought about this, but didn't want to reduce effective surface area of fan and doing this leaves the fan moved back 1/4" from radiator, just out of the sweet spot I'd like to maintain), etc. If so, please let me know what your solution was, part numbers, specifics on what you did, suck it up buttercup and just run the direct drive mechanical fan (what I'm doing right now obviously, but not preferred) be a man and delete the A/C (no, again, GA, black car, wussy), cut the flanges off your brand new radiator and move it forward the half inch you have available, re-weld and run a spacer, solved (maybe what I do eventually, time constraints and a general I don't wanna prohibit at the moment), etc. Any and all answers relevant to my specific questions appreciated.
Thanks for reading, and as a reward haha, a front crank pulley I've never seen, it seems like it has some kine of elastomer in the pulley assembly.
I'd love to know if it's factory, as far as I know it is, but I've never seen it before, that may or may not mean much, but I've been around Mopars for a minute, possibly I've seen it before but just wasn't paying enough attention. Also the size of the pulley ring on the A/C compressor seems exceptionally large compared to what I'm used to seeing. Again, factory? Original for 68 A-bodies? Came off whatever the 360 came out of?
Thanks for looking
All of this is on a factory A/C 68 Dodge Dart, originally 318 car, now has a 360 that I did not install nor do I know much about it, automatic (727).
So I've run into what appears to be a unique issue (probably not, but didn't find it through page 12 of the search function for fan clutch)
Most people seem to have an issue with needing a shorter fan clutch than a Hayden 2747 and use the 2947. I have the opposite problem, the fan clutch doesn't space the fan far enough forward to clear the A/C compressor pulley or the larger crank pulley, see picture for reference with direct drive fan installed and clearance to A/C pulley.
As you can see with the curved 7 blade fan with a spacer there is not quite a 1/4 inch of clearance to A/C pulley, this also places forward leading edges of fan blades right at 15/16" to radiator (see pic below), spitting distance to perfect right, all good right?
Overhead view for reference.
Nope, because I'm picky and really want to run a clutch fan.
I was going to run the Cold Case shroud and fan that comes as part of their kit, but somebody failed tape measure class and the specs on their web page lists total thickness of 6.5" which is a whopping 3/4" shy of actual measurement, shockingly that won't fit in the available 7" of space between the nose of the water pump and core support! Measure closely then add a random amount before ordering because we didn't! Rant over. I've already returned the kit and gotten my new radiator, Summit took care of me on that end. Side note, the quality of the radiator appears really nice, construction looks good, welds are decent, 1/2" thicker than stated measurements, but I digress, time will tell but so far I am pleased with the radiator itself.
Now we get to the issue at hand, the problem I'm running into is that with the 2747 clutch installed with the curved 7 blade fan the fan itself is moved back approximately a 1/4" causing it to hit the fan pulley, using the flatter style 7 blade fan helps, but still less than a 1/16" or so of clearance, not nearly enough when you account for pulley wobble, water pump movement, etc.
Ok, no problem you say, just put a spacer between the clutch and pulley, problem solved you dummy, why are you even here asking us?
This brings us to the second issue, because of the clutch/fin design of the 2747 clutch the front of the clutch is within approximately .320" (approximate because I didn't actually measure, just used two piece of cardboard that measured right at .160" each and slid in between radiator and fan making contact with both. So as you can see, reducing gap by even an 1/8" (.125) reduces my clearance to less than 1/4" between radiator and clutch, and only gives me approximately an 1/8" to the A/C and crank pulley anyways. Too close for comfort in my opinion given engine movement, etc.
Here is a pic of a standard duty (I believe stock) and the 2747 Hayden which is a heavy duty clutch
There is approximately a 1/2" of difference in overall height, so i could run a 1/2", maybe slightly more, spacer I believe, haven't taken it back apart yet to verify. Then since the front of the factory standard duty is flat, not finned, should alleviate my clearance problems on both sides, again, problem solved.
Except I'd really prefer to run a heavy duty clutch that will drive the fan at 80-90% of pulley speed as opposed to the standard duty that will drive the fan at 60-70% of pulley speed. I'm already dealing with an issue of the car heating up at idle, so slowing the fan down probably isn't the answer. I've already got a reproduction shroud to put on the car to help with the concern, we'll see where that goes. Car runs 170-180 in 85 degree GA heat/humidity going down the road with the A/C on or off with a 160 thermostat in it, so I'm certain it's an airflow at low speed issue. Not really the answer I'm chasing here, but I will probably change back to a 180 thermostat once this issue is sorted out, I just like having the extra 10 degrees or so cushion until then (so no need to tell me it's not really helping, thank you though).
So, for all of you that actually made it through this incredibly long post for seemingly a simple concern, here is my question.
Has anybody else run into this specific concern before, and if so did you find a solution that allowed you to run an HD fan clutch, different manufacturer, milled mounting flanges on fan clutch to move fan forward ( I thought about this, but decided after measuring that approximately 3/8" thread engagement was not something I was comfortable with), modified fan clutch in some other way, modified fan blades to increase rear clearance (also thought about this, but didn't want to reduce effective surface area of fan and doing this leaves the fan moved back 1/4" from radiator, just out of the sweet spot I'd like to maintain), etc. If so, please let me know what your solution was, part numbers, specifics on what you did, suck it up buttercup and just run the direct drive mechanical fan (what I'm doing right now obviously, but not preferred) be a man and delete the A/C (no, again, GA, black car, wussy), cut the flanges off your brand new radiator and move it forward the half inch you have available, re-weld and run a spacer, solved (maybe what I do eventually, time constraints and a general I don't wanna prohibit at the moment), etc. Any and all answers relevant to my specific questions appreciated.
Thanks for reading, and as a reward haha, a front crank pulley I've never seen, it seems like it has some kine of elastomer in the pulley assembly.
I'd love to know if it's factory, as far as I know it is, but I've never seen it before, that may or may not mean much, but I've been around Mopars for a minute, possibly I've seen it before but just wasn't paying enough attention. Also the size of the pulley ring on the A/C compressor seems exceptionally large compared to what I'm used to seeing. Again, factory? Original for 68 A-bodies? Came off whatever the 360 came out of?
Thanks for looking
