importance of fan alignment in cowling?

Jon March

Member
1) the blades rub at bottom of cowl when accelerating quick in 1st gear
2) experienced people have pointed out to me that the temp gauge (motor newly rebuilt, full coolant, well- flushed radiators) is swinging farther into the red (1/2 way) on water and on hiway than it should travel
(needle is near the "NO" of NORMAL at idle and "MA" inmoderate use - but halfway into the red when running on water and on hiway

So how important is it to get the fan properly centered? - maybe the air isnt pulling like it needs to?

1) the radiator/shroud assembly was done fastidiously accurate per manual
2) assembly is at the lowest adjustment settings provided, and mating perfectly to underside of hood and gasketed perfectly snug against license-plate "wall"
3) new GI motor and tranny mounts
....so everything should be right on...but the best i can get is 1/4 inch of clearance at the bottom between fan tops and cowl , and obver and inch at the top
...And another person said that the fan probably should be centered with the tips of the blades in the narrowest part of the cowl opening, but my fan is a good inch or more in further, and eben the rear edges of the fan do not protrude at all outside the cowl opening.

I have to run my heater and blower to get the temp gauge to not swing up so high into the red- then it comes out of the red.

Thoughts?
 

mschlem

Amphicar Expert & Former IAOC President
Others may have more knowledge than me on the subject, but I find it hard to believe the fan alignment could make that much difference.
In my experience, good seals around the engine cover are important...which you have. The only other thing you might try is putting some Water Wetter in the radiator. That always kept me running a bit cooler.
On a side note (not your problem I’m sure)....but my gauge has always run dead center of normal. Earlier this year, I had the radiator out to better seal up the horizontal bumper area. In the process, I cleaned out the fins of the oil cooler - it was almost clogged after 20 years when I last had it out. After reassembly I run much cooler....closer to the NO of NORMAL, even under load. It takes a long time for the thermostat to even open! Had no idea that the oil cooler did that much, but it sure does.
You also mentioned running your heater. When I put my car together, my heater hose valve (up in the trunk) leaked. Rather than replacing it I bypassed it. My thought was if the water ran up through the bilge and back all the time it might add a bit more cooling, plus, it would keep an infrequently used heater core always flushed and fresh. With no “flow through” air like a standard car, no warm air is forced into the passenger compartment....so I saw (and see) no downside.

Marc.
 

LSolheim

Member
Alignment in the shroud and condition of your motor & transmission mounts will correct the shroud slapping. Orientation of your fan will make a big difference in airflow/cooling efficiency. Search this forum for 'fan'.

Summary: Take a look at your engine cooling fan mounting on the water pump. Proper mounting of the fan is with the rivet heads toward the engine block (the radiused side of the fan is the forward edge in rotation).
Although the air flow is in the same direction either way, you are losing about 15% efficiency if the fan is mounted backwards – perhaps just the same 20 – 30° you are running a bit too warm? Fortunately, the fan can be swapped with just loosening the radiator mounts and some very flexible wrists!
(thanks to the "voice of experience" for this tip)
 

Jon March

Member
thanks Larry- I will check!

Regarding rubbing, Scott Gordon Imports recommended to simply shim the motor up higher by putting some sort of spacers on top of the motor mounts and getting longer 10 mm bolts... like a good solution to get the fan centered top to bottom. But I’m still curious as to how far into the cowling the fan should be located- The best location for the maximum force should be at the narrowest part of the opening, si?
 

Jon March

Member
Well...
1) the fan is indeed backwards. duh. So thats an easy flip, and maybe will be the trick!! ThanksLarry - even all the amphigeeks at Celina missed that!
2) the water pump i bought has a noisy bearing, so i gotta drain system and pull it off.
Question: Once the fan is off, can the water pump then be removed - without taking out the radiator? Please?!
3) Also: how far onto the cowling should the fan be for best air flow? -- shouldnt you be able to see "some" of the blade (like, 1/2". spinning just outside the cowing opening...My blade is totally inside the cowling- ie: the rearmost edge of the blade is a good 3/4" inside the edge of the cowling....(see pic)
>> This has to be reducing the strength of the "pull" of air.
>> BUT: see second pic: The assembly is all the way down in the adjustment holes on the triangular supports, and the radiator shroud assembly is hard-against the rear wall in the upper gasket part...but a the bottom/oil cooler area...its about 1.25" from the lower part of the rear wall , and i needed to add rubber flap material to take up the gap there.
And the fan rubs the cowling at the bottom, even tho the cowling is all the way down in its adjustment travel...and the motor has new, correct height motor mounts, and the oil drain is dead center aligned in the 1" bilge drain

IMG_0104.JPG



IMG_0100.JPG
 

jfriese

Active Member
Jon,

I compared the placement of the engine mount cross member to one of my cars and it looks the same. The only thing I can think of regarding the fan being farther into the housing is the water pump is the wrong one or a really lousy rebuild. Since your pump is bad anyway, check again when you get a new pump. This time get a new, rebuilt one and be sure it's for a Spitfire. What you have may be from a TR6 or something else that bolts up to the housing but is the wrong length. Your lower picture looks about the same as my cars. I don't see a major gap between the end of the rubber and the rear wall.

John Friese
67 White
67 Red
 

Jon March

Member
Thanks for scoping it out, JF. backwards fan. smacks forehead.
So for the pump: NAPA? Victoria British?

And this just in: i looked back at my pre-disassembly pics of the fan & cowl, and indeed the fan is now not lining up with the cowl the way it was. The water pump pulley seems to be exactly in line with all the other puleys, so im thinking somethings off with the way i assembled or installed the radiatior & cowl assembly....I gotta look at some other cars!
 
Last edited:

mschlem

Amphicar Expert & Former IAOC President
50AF9D49-CECE-42D1-AAD7-0BE02DA899AE.jpeg My car looks about like yours, too, along the rear.

This is the alignment of the fan to the shroud on the front.
 
Top