73-78? Eldorado fan and fan shroud centering question

Started by TJ Hopland, July 18, 2016, 10:20:08 AM

Previous topic - Next topic

TJ Hopland

Was out starting to catch up on about 5 years of neglect on my 73 and noticed something about my fan and shroud I have never noticed before.   All directions are as viewed from sitting in the car facing forward.    My fan is not centered in the shroud.  There is maybe 1/4" clearance between the fan blade and shroud from about 4 o'clock to about 7.    Up around 10 to 1 there is maybe 1 1/2".     I know this car was in a accident very early in its life but I don't think its bent up that bad.  My body gaps are not perfect but I don't think are off over an inch anywhere.

Anyone with a 73-78 Eldo take a look at theirs and see if its centered?   I'm going with 73+ because I know there were quite a few changes to the front end and such for the impact bumpers that started in 73. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

"Cadillac Kid" Greg Surfas 15364

TJ,
ANY fan has to be geometrically centered in its shroud or scroll to work correctly.  The blade in my 73 (CDV) was perfectly centered.  If this were mine the first thing I would check is all three motor mounts.  If they are all good and the frame itself is not twisted, they might have replaced the frontend sheetmental without the proper shims or mounts.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Scot Minesinger

Second what Greg wrote, most of the air on a propeller fan of this type is moved at the fan tips and misaligned prop fan to shroud will cause imbalance (due uneven fan loading), strain on fan shaft (water pump bearings), and etc.  This should be corrected.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

TJ Hopland

Mounts are not very old so I don't think that is the issue unless they are just made wrong.  I don't remember any alignment issues either time I had to pull the motor, bolts just dropped in.   My current air and fuel system puts the top of the air cleaner about 1/4" from one of the hood trim studs and there are no signs of contact (yet) so I don't think its moving around.   I kinda looked around and didn't see anything that looked bent or where you could easily shim things and still get everything to bolt up. 

What is the normal or ideal gap?   If I was centered I would guess that would put me 3/4 range all around.  Is that correct?  Or have I got a slightly undersized fan?

It does not really seem to be hurting anything but makes me wonder if it was better if I could get a few more degrees out if the AC and make the gauge come up a little slower on those hot stuck in traffic days.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

"Cadillac Kid" Greg Surfas 15364

TJ,
Your fan should be  18 inch in diameter and have  7 blades. The fan and its shroud (any) are designed as a matching pair, with the focus of the blade curvature centered in the shroud.  Realistically, you are in a climatealogical region that has  nowhere near the maximum conditions the system was originally designed to operate in, but if it is out of whack as far as fan alignment, your guess is as good as anyone else's as to what performance you are actually getting.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

TJ Hopland

How much space should there be between the edge of the blades and edge of the shroud?   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

RobW

check the body mounts on the radiator support. also note the gap on the rear edge of fenders to the front edge of the doors. it should be even.
Rob Wirsing

"Cadillac Kid" Greg Surfas 15364

TJ
If you have the standard, HD, 7 blade 18 inch fan and your shroud is the standard 20 inch (nom) diameter, that leaves you with about 1 inch clearance.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

TJ Hopland

Mine has a clutch fan which I don't think was an option for 73, it may have come off my 75.   I ended up with that because I brought a whole pile of fans to the radiator shop and he picked the clutch one as the most aggressive one I had to offer.   I will have to go look but I'm pretty sure its got 7 blades.    There was a fixed fan that I was using before because I thought it looked more aggressive but he said it had to do with the the overall curve or maybe the curve or twist at the ends.    I remember when I first got it installed and started it blew some leaves out of the cowl area that the other one didn't bother so it did seem to be flowing more air. 

I should see if I can get actual measurements rather than just eyeballing it.   If an inch is normal it may not be that far off.   

My car seems to do fine overall but the last few days with ambient temps in the 90's stuck on blacktop with the AC on the gauge starts climbing.   It never boils or anything, just makes me nervous.  Thinking the fix may be tape over the gauge and just rely on the stock light to tell me if I am really in trouble.   Thinking that may be one reason Cadillac went to a light in the first place.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

TJ Hopland

Just went out and looked.   Its hard to measure those buggers since the blades don't quite ever seem to be 180* across from each other.   I could believe that the hole in the shroud is 20".   The fan I currently have on there appears to be like 17 1/2" maybe but hard to tell especially in the car.   I have a couple other clutch fans pulled from my junk pile for a friends car project and one of those appears to measure about 19 1/2" the other in that 17 1/2 range.    Both have quite different blade designs but are still 7 blade.   The big one came from a 70's Chev 1/2 ton truck with AC.   The smaller one I thought was off a Olds powered Cad but it doesn't clear the power steering pump on an Olds's I had at my disposal so must have come off something else.

Guess I should get ambitious and pull the fan out to get a better measurement and maybe see if that bigger one could fit.   The big one is newer to my collection so I didn't have it when I asked the radiator guy for his opinion.     
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

RobW

forget it...just keep ignoring the obvious. it doesn't matter what size fan, or the pitch of the blades or any of that. the nose of the car is misaligned or any fan would be centered. that's how we used to put them back together after an accident. center the fan in the shroud and then the radiator support is right. then align fenders, hood, etc.
Rob Wirsing

TJ Hopland

I forgot to actually measure the gap around the fan when I was just out there. 

I will have to see if I can get a look at my other 73 to see what things are supposed to look like.  There are some things that look maybe bent but they are symmetrical on each end they way they are bent so that makes me think that was just how they were made.  The hit was apparently on the drivers side.  Fender was not original and what ever hit it ran the full length of the car, there was even a scratch on the side of the tail light.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

RobW

ok so maybe move the radiator support slightly. hopefully it doesn't open a can of worms.....
Rob Wirsing

TJ Hopland

I will have to dig out my manuals and see if any show what bolts to what up there.   I can see there is a welded piece between the frame rails then I can see 2 spots that must be what you called the body mounts.  I assume the lower cradle sits on those?  And the lower shroud bolts to the cradle?   

I think I had that all apart when I first got the car but it was 20 some years ago so I could have put something together wrong.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason