Jump to content

rossiz

Just Did The Honda Blower Motor Swap

Recommended Posts

after reading a few posts on this (most recently the great write-up by hardway) i decided to go for it. my fan has been making some pretty horrible noises - whining, screeching etc. and the output was weak. picked up a honda fan assembly for $30 on fleabay, gave it a quick clean and got myself geared up for the job. 

 

i won't go into all the details, as this has been posted before, but i will whole-heartedly validate the improvement. the new fan is quiet and blows like crazy. couldn't believe how much more efficient it is at moving air. the design is basically the same, but the honda fan has a lot more vanes, which are smaller and it's a slightly larger diameter - about 1/4". this meant i had to open up the hole 1/8" all around, but that was pretty easy: just scribed the circle around the new fan, put the housing gently in the vice and went at it with an angle grinder, then cleaned it up w/a file. done in 15 min.

 

the new fan fit perfectly - had it's own nice rubber gasket and the holes lined right up. i made some additional rubber isolator washers for the mounting bolts and used the large washers from the z. the honda fan comes with a little vent tube, which i believe cools the motor by pulling in a little air through the windings. i used a paddle bit to drill an 11/16" hole in the z housing and the hose plugged right in. the plug on my honda motor happened to be the same 2 wire T plug as the z, but i made a little jumper/extension to give me a little more room for the wires. the honda motor can run either way, so i tested the polarity, then clicked it all together.

 

the biggest pita of the whole thing was getting the assembly out from under the dash, then putting it back in. holy crackers - what a miserable job. it would have been easier with the glove box or dash out, but i'm stubborn and was determined to win. and i did. while i was in there, i replaced the foam gaskets between the plenum and the fan and put a hose clamp on the vent hose that runs horizontally in front of the fan - this hose was continually falling off, not anymore.

 

anyway, it was a successful adventure and now i hope to be able to keep my windshield from fogging up every time it rains!

  • Like 4

Share this post


Link to post
Share on other sites

I'm considering doing this and have been reading some of the threads.  Which Honda fan motor did you use?

 

Greg

Share this post


Link to post
Share on other sites

Thanks for the info.  I read about civic and accord blowers and now Preludes.   I'm actually looking a doing the heater valve and the blower motor is right there, so I might as well make a party out of it right?  But literally diving in head first into that cramped, dark, void of the floor is making me a little hesitant.  It seems that I'm not as agile as I used to be. 

Share this post


Link to post
Share on other sites

I did this swap a few years ago and have this advice:

 

1) Disassemble the motor and clean the inside.  Mine was full of dirt, grease and metal particles.

 

2) Make sure that your ducts have tight connections.  I used black duct tape to seal the connections.

 

Even after doing this, I really didn't get much of an increase in airflow. Perhaps my motor was worn, so I'd appreciate comments from others who've made this swap.

 

Peter

Share this post


Link to post
Share on other sites

I did this swap for my '70 Z last year, using the blower motor and impeller from a Civic.  While bench-testing the unit with the newly-installed Honda parts, I discovered that the output performance (CFM) of the Honda impeller is extremely sensitive to direction of rotation.  Perhaps you have your motor wired so that it's running the impeller in the low-output direction?

 

FWIW, I tried the same test with the old Nissan motor and impeller and found that the OE set-up provided about the same CFM output (modest) in either direction!  This suggests to me that the Z's impeller is poorly designed and performs more like a paddle wheel than a centrifugal fan.

  • Like 1

Share this post


Link to post
Share on other sites

I don't have a need (yet) to do anything with my blower as it thankfully still works just fine. I know that could change in a moments notice however, so I've kept an eye on the concept of the Honda blower motor conversion.

 

But since you mentioned impeller design... One thing I've always wondered about is people say the Honda blower moves more air, but WHY does it move more air? Is it simply consuming more energy and spinning faster for a given selector switch position, or is it a more efficient impeller design that moves more air at the same speed? Is it a more efficient motor design that spins faster for the same amount of current?

 

I don't understand why people even care if it moves more air, Were all you guys who have done this conversion running their OEM blowers on the highest speed all the time and STILL wishing they had more airflow? Because if you're wishing you had more air and you're NOT running on the highest speed, then just move the lever to a higher speed. Or was it simply that the motors are failing and this is the cheapest and easiest replacement for NLA parts?

 

I assume nobody has measured current draw have they?

Share this post


Link to post
Share on other sites

Noise and air flow are somewhat proportional on squirrel cage fans. Plus there is the wear and tear of 40 years of use on the stock fans. Those both could contribute to the difference in airflow.

 

Frankly with driving a car without AC in Georgia or Texas, the more airflow you can get, the better off you are.

 

I think some conversions on the 240Z have mentioned current flow, though I don't recall seeing any quantitative measurements.

  • Like 1

Share this post


Link to post
Share on other sites

for me there were a couple of issues that made me decide to do the conversion:

1. on the highest setting the fan made a lot of air noise but very little air flow - severe fogging of the glass is a problem as its my dd and it does rain in seattle from time to time.

2. the motor was clearly in trouble, as it would screech and howl intermittently, loud enough to drown out the radio.

i haven't actually driven the car yet with the new fan (still getting the head replacement finished) but i'm hoping it makes a difference.

when i compared the two impeller designs i noticed 3 things:

1. the honda fan is larger in diameter, so the blades are traveling faster at the same motor rpm. since the blower housing remains the same size, the blades are closer to the side walls of the housing. maybe this has an effect on the amount of air that is engaged, reducing turbulence/inefficiency at the outside of the blade area?

2. the blades are smaller, and there are more of them, maybe a more efficient design?

3. the oem motor mount is set on spacers that put the impeller 1/2" farther away from the back of the blower housing. the honda fan doesn't use those, so the impeller pushes right up close to the back wall of the blower housing. perhaps this engages more air and/or reduces leakage around the impeller?

i have no training in airflow design, so this is all just my conjecture... all i can say is the honda blower is much quieter and moves more air.

  • Thanks 1

Share this post


Link to post
Share on other sites

Thanks for the concrete input guys. This change is on my wish list for upgrades and I appreciate the input.

 

I currently don't use my blower much at all. I suspect however, that if I had A/C (which I currently don't) I'd use it a lot more.

Share this post


Link to post
Share on other sites

Any update on your blower swap's performance & its impact on the window fogging issue?

 

I am considering this swap as well to make my AC more efficient.

Share this post


Link to post
Share on other sites

well, i have a whopping 110 miles on the car now that the head is back on, and the defroster definitely works better. the airflow up over my head is enough to actually clear the rear hatch glass. don't get too excited - this ain't no cure for my electric defroster elements not working, because it takes about 10 minutes of driving after the engine is good and warm for it to clear the hatch glass, and thats of fog, not frost... BUT, the oem motor would never even dent the fog on the hatch no matter how long i drove. so it's a good thing.

 

the motor is a bit quieter too, which is a plus - although mine was pretty worn out, so ymmv...

Share this post


Link to post
Share on other sites

Probably won't make anyone feel better, but after I fixed all of the leaks in to my cabin and got the inside well-dried (a nice hot summer), my back window fogging problems are dramatically reduced.  It just takes a small seep to allow enough moisture in to fog things up.  I had leaks up front and in the back.

 

For while though, I had an auto parts store heater/blower/defogger mounted on a board, pointed at the window. and wired in to the defrost grid power.  The circuit handled the load easily.  Noisy and took some work to keep it from sliding around but it did the job.

 

The other "fog" problem though was outside condensation on the cold hatch glass.  Who's got the rear wiper modification they want to share?

Share this post


Link to post
Share on other sites

How about anti-fog by Rainex? Anyone try it?

It definitely works. I drive Motor Coaches for a living and they are a SOB for keeping the windshield clear. Especially when you load up 50 soaking wet kids from a Ski trip and humidity shoots to the moon inside the Bus. Most of of the drivers always carry a bottle of Rain-Ex Anti-Fog in their kit bag. Makes a huge difference.

 

In a jiffy, a few drops of dish washing detergent, wiped onto windshield, also works very well. Old Scuba divers trick.

 

A good glass cleaner helps as well. " Invisible Glass " is a very good glass cleaner, as is GM or AC Delco glass cleaner. Windex is crap. Leaves a lot of streaks.

Share this post


Link to post
Share on other sites

I did this swap a few months back and my OE kicked the bucket.   Civic EF fan, although for some reason the cage fit in without trimming (Although it was TIGHT).   Good improvement in airflow, better yet, it works again!

Share this post


Link to post
Share on other sites

I finally did this swap with an ebay honda fan, and glad I did it. Not TONs of difference for a 280, but certainly more air volume especially for defrost and center vent.  I had a lot of issues to deal with under the dash so Instead of lying on my back and eating whatever I dropped, I removed the dash. It made that part of the job very easy to do.  While I was there I replaced the leaking heater core, heater hoses, side air ducts, bulbs, re-sealed and painted the blower box.  Now the air even smells better  :) .

Share this post


Link to post
Share on other sites

Been researching the blower motor swap and didn't see much recent info.  I have my dash out for repair and the blower motor out as well and thought I'd go ahead and swap.  I'm guessing this is still the best swap but wanted to confirm.  Thanks for your input.

Share this post


Link to post
Share on other sites

I don't recall any other substitute for the blower, but mine still works like a champ.  Also be sure to replace the foam seals on the heater box mode door and where the air duct connects to the center dash vents.  That will increase air flow dramatically.

  • Like 1

Share this post


Link to post
Share on other sites
7 hours ago, 72ZDave said:

Been researching the blower motor swap and didn't see much recent info.  I have my dash out for repair and the blower motor out as well and thought I'd go ahead and swap.  I'm guessing this is still the best swap but wanted to confirm.  Thanks for your input.

The real benefit to the Honda blower motor swap is not the motor, it's light plastic squirrel cage. It is a fraction of the weight of the stock steel fan, the motors are similar but the Honda unit blows harder because it doesn't have to spin up the weight of the stock fan.

I tried to find a way to install the plastic squirrel cage on the stock motor but couldn't find an easy safe way of doing it.

  • Like 1

Share this post


Link to post
Share on other sites

I've got a 240 blower (of unknown year) and a 77 280 blower here, and both of them have a plastic squirrel cage. I'm guessing the early 240's used a metal cage?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.