550 engine cooling improved!

Because then I would have two relays per fan, doubling the chances of a failure. As I've placed the harness in the foot well, routing the signal from the fuse board to the new relay was easily done with a short wire. If I had installed everything in the engine bay then of course I would have used the power from the stock relays to drive the new ones.

Stefano

 

Good timing for me with this thread as I am experiencing similar issues with my 550.
I wanted to do some testing first, so I bought the exact tool in @Mirek 's post #50 (it's only $45 on Amazon). With the car running on my 4-post lift, I was getting numbers around 750 ft/min. Then putting 12V directly to each fan with some test leads, I was getting upwards of 1,000-1,050 ft/min.
My car already has the stronger aftermarket fuse board, but I think pulling the power for the fans off of there is a no-brainer regardless.

Check out the harness side of the left fan connector!
My assumption is that this is from excessive resistance in that fan motor, so I will likely go ahead and replace both fans with the 30102113 as well.

I see that in the other thread, cribbJ used 70A relays, whereas @AVIMAX and others have used 40A. Would be nice to get one with a a plug&play connector with 12AWG wires ready to go.
Image Unavailable, Please Login

 

Here is the 70a relay

Cole Hersee RA-700112-RN-BX 70A Relay (Form_A 12V Res_Bracket) https://a.co/d/0xyQ8bq

Relay Bracket, if you so choose. These attach to form a block so both (new) fan relays can be secured together

Cole Hersee 99025-BX 70A Relay Socket https://a.co/d/1wc8OBL

I found best prices on the connector parts at http://www.cycleterminal.com/

Get a priper set of open barrel crimpers and ends and wire

 

Just finished the upgrade and the new fans seem to be working well! I won't really know until next May when it gets hot again, but so far so good as I was seeing the needle creep past 190 at idle even in cooler weather before.

Couple of notes that may be helpful to anyone who plans to do this in the future:
-The wiring supply company I used recommended circuit breakers vs fuses as the plastic fuse holders tend to melt. The breakers are triggered when the circuit gets too hot and auto-reset once it cools down.
-Factory connectors are Metripack 280s (not 630s as mentioned in jcribb post in the other thread).
-New fans motors are a bit deeper than the originals. The stock ones came out the bottom very easily. The new ones didn't clear the frame with the shroud in place, so I removed the right side airbox (makes running the wiring down to the fans easier anyway), and put them in from the top.
-I grounded the wire to the fans on the chassis bracket that holds the secondary air pump. There are 3 studs there which are perfect and made sense with where/how I routed the wire.

Not a difficult job, just a bit tedious like all things with these cars.

Fans:
Image Unavailable, Please Login

Everything needed to build the harness:
Image Unavailable, Please Login

In process:
Image Unavailable, Please Login

Here's how/where I mounted the breakers:
Image Unavailable, Please Login

Mounted the relays on a factory bracket below the headlights:
Image Unavailable, Please Login

 

Beautiful work and great info from your other thread!!

One question about the circuit breaker, as I'm not at all familiar with these, How do you know if its working and cycling off, or even worse masking an electrical problem until it theoretically welds itself shut? As opposed to the sacrificial and simple fuse?

Would it be appropriate to still leave a fuse inplace downstream from the circuit breaker as an added precaution or is that bordering on overkill and overcomplication?

Im gathering everything together to do this as well

 

Honestly I took the advice of the company I bought the wiring stuff from (Texas Industrial Electric). I personally valued being able to one-stop shop rather than piecing together the solution from multiple sources. I sent him the diagram and explained what I was trying to accomplish, and the first thing he said was that he would recommend the breakers vs fuses due to the plastic holders having propensity to melt without blowing the fuse. We didn't get into details beyond the basic functionality of the breakers (as explained above), but the way I see it, they will (obviously) trip if there is a problem in the circuit. This will manifest itself in the fans not coming on....which should be pretty easy to identify by looking at the gauge. If there is a problem, something is going to give somewhere. I would rather it be a designed failure point like a circuit breaker which keeps the other components intact vs melting a fuse holder, or wiring, or connector (like my picture), etc. I guess there is technically no way to tell whether the breakers are working properly internally, but I am OK with operating under the assumption that they are until something gives me an indication otherwise.

 

So what are the capacities or part numbers of the breaker?

 

It's a 40amp breaker. PN on the invoice is listed as "BUS CB124B40"
This is my best guess....looking at the datasheet it has all of the info you could want: https://www.mouser.com/ProductDetail/Bussmann-Eaton/124B40-00P?qs=r5DSvlrkXmJuMOxnW5Cuvg%3D%3D

If you google "40 amp automotive circuit breaker" it shows a bunch of similar items, such as this https://www.amazon.com/Amp-Auto-Reset-Circuit-Breaker/dp/B07H6QDSG8

If you're getting ready to do this and want the easy button, send me a message and I can put you in touch with the guy I worked with. It was around $160 all-in for the wiring components.

 

I understand and appreciate all the effort put by many into this mod back in a time when there was no other choice but to put up with the original fuseboard and its serious design flaws, but is this all still needed (*) with an upgraded/rebuilt fuseboard which should allow the fans to be fed with just as much current as originally intended?

(*) assuming the stock wiring and connectors are still 100% fine.

 

Ill be able to report back on this first-hand. I feel I have safe cooling properties, but still see more temperature movement at idle and slow speeds than others and want to try and dial that into more steady temps

I have the Guido updated fuseboard.

I have done a G05 coolant flush
R&R electric waterpump
R&R coolant sensor in radiator

Stil to do...

Rewire fans per this thread
Rebuild Monovalve for cabin heat circulation. Aside for comfort, seems like another total picture of keeping the car and cooling system running properly

Further down the road..
Replace sensors under manifold
Replace fans

 

I do have an upgraded fuse board, and still had this issue. As noted in my post #77, I did a test with an anemometer with the car running on my 4-post lift. With factory wiring and original fans, I saw numbers in the 650-750 ft/min range. When I put 12V directly to the fans with my test battery, I got numbers around 1,000 ft/min. After the wiring upgrade and new fans, I got numbers around the 1,000-1,200 range (the tool is very sensitive and it depends where you place it, etc.) but there is a quantifiable improvement with this setup, regardless of upgraded fuse board.

 

Great thread, and as others have said I like the idea of updating the car during its life as newer/better components become available. I just completed my routing coolant flush, and I think I will tackle this job as it looks to have a decent ROI. Upgrading to newer fans and taking some load off the circuit board seems like a great idea.

Thanks for the detailed explanations and wiring diagrams. Adding this to the list of things to do (apart from adding way too many miles to her).

 

I have added this wonderful mod to my car as well now. I’ll admit I was a bit intimidated at first read, but great instructions and methodical planning made this another very satisfying project.

I went with 70a relays and 10GA wiring on all but one signal wire from the fuse board. I used 40a fuses on each line. Being somewhat anal on wiring, I strive to make it practical, serviceable, but as out of sight as possible. I ran from the + behind the battery, with enough slack around the fuses to service them if needed, but also tuck them away out of sight and away from concentrated heat. I sheathed everything in heat shrink for chafe protection, neatness and to blend in.

Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login

I used a metal T-bracket to mount each relay block to the frame below and behind the right headlight and ran each new harness over the washer reservoir and behind the radiator, where the original wiring meets up. The metropak 280 were perfect as well. An over abundance of zip ties has everything held in place. For a ground, I used some of the wire holder posts on the crossmember.

Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login

Obviously a lift makes all the difference in ease of doing, but otherwise a good set of open barrel crimpers, heat gun and proper electrical components are all this took. All in all, this was a very reasonable project for the potential upside it offers.

 

Another shot of it all in place, its very stealthy and unseen.

Image Unavailable, Please Login Image Unavailable, Please Login

And to put it to the test i opened the garage the other night to this.

Image Unavailable, Please Login


Fortunately it’s only blowing flurries and the ground is still dry and unsalted. The main cooling fan kicks on and dropped temps back down idling. I was unable to get the left side fan to kick on, I think It was just too cold to get the oil warm enough or the A/C working with any real effort. That will have to wait for product testing until a warmer time or a much longer idle. Still I did about a 30 mile run today, and while only 30 degrees outside the car performed wonderful. At least if there are any issues, I’m only a cut zip tie and a few plugs away from being back to stock if needed.

I also found the anemometer inconclusive, it’s just so sensitive to placement I was unable to get a definitive improvement in airflow on the STOCK fans.

 

Great Stuff @Aerosurfer! Nice, clean install.

 

Sounds weird saying those photos are sexy but they are!

 

we all have our kinks! Actually I really need to update my own thread with all my updates the past few months, really put all the pretty photos in one place.. ah but I digress.

Again HUGE Kudos to AVIMAX Cribbj F456M and the others who really trailblazer the ideas for this?

As far as this mod goes…. I’m hesitant to want to offer this as a kit, but really this wasn’t a complicated project. Anyone unable or unwilling to fabricate wiring themselves but can follow directions on hooking up things could certainly use it

 

Bump to this thread before I put in a formal classified add.

I’m wanting to offer these harness for sale as a ready made plug and play kit. I was approached by another member on here to construct one for him and figured if I do one, I may as well make a bunch and see what the interest is going forward.

These are constructed with Tinned Copper strand lines (not copper clad aluminum) using AWG 10ga wire on the load carrying lines and 14 ga on the signals
Full sheathing for heat and wire protection.
40a fuses
70a relays with 9.6mm spades on the power lugs
Custom fit, Ready to install bracket, differs for the 550 and 456 with relay mounting hardware
Install sheet

Currently I’m finishing up and nearly ready to ship 2 full harnesses for the 456.

On my 550 prototype harness , which is now installed we found the harness length needed to be much shorter than the 456. The 550 fan plugs and location is closer to the right side of the car than the 456. I’m still working with getting adjusted measurements for shorter lengths, before I can deliver a 550 harness. These should be available to produce within the week.

Would love to provide another superior part to for these cars to everyone.

I’m looking to sell these for $300 shipped domestically.

If demand is strong, It'll be about 10 days to order components and build the next batch of these.

By the way, many thanks to those who have done the electrical theory work, I like to think I'm just building on that foundation with this. Look forward to your feedback.

 

With the heat in the engine compartment, the fans run alot, also from the AC running. These are 20+ years and to replace them is just a great thing to do. But a "rebuild cooling fan upgrade" with different wiring and relay locations should actually be well documented with a letter into the owner's manual. For a workshop who need to trouble shoot the car in the future, it can be frustrating if the car is not like when it left the factory. Makes everythig more complex. Just an explanation and a wiring "map" will be extremely useful in such a situation or if you are stranded in 110 degrees at Miami Beach and the fans are not running any more and the original fuses are not blown... Just sayin'

 

I couldn’t agree more. While anyone doing any mod to their car should have the know-how and know-where to locate and troubleshoot whatever it is they undertook, subsequent owners or owners who had someone else do their work may not be as savvy to any particular addendum to their car.

I already came up with an install sheet I included with my first package, which had a parts list. I’ll adapt to it to a glovebox or emergency kit sheet as well. Down the road, even a sticker or magnet to place under hood as a reminder.

Ultimately, I would love to brand these and have them become more well known. Ala… some of the MSW parts or other independent vendors. Have people know about the “Aerosurfer Harness” upgrade. I Imagine other models of the period could potentially use a version of it as well.

 

I would be interested in one of these wiring kits for my 550.

 

“Aerosurfer Harness” does sound pretty cool.

My car has a nearly identical set-up w/spal fans and I could not be happier with how rock solid the temp stays in traffic, in the LA heat.

 

Aerosurfer- I'm interested in your kit, what grade of 10ga wire are you using? TW, THW, USE, USE-2,THHN

 

I am working on a conclusive answer to that, waiting to hear back from the vendor.

10ga is 100% copper strand OFC 109 strand
14ga is Anchor marine cable that's tinned copper strand.

Please keep any questions coming. Offering a modification that touches both electrical and cooling systems, I want to assure a top notch product.

 

I ask because 10ga TW or UF cable is only rated to 30 amps, up to 140dF, 10 ga THWN-2, THHN, XHHW-2, USE-2 wire is rated to 40 amps, up to 194dF, but only for short periods. How hot is it in that engine bay? In general 10 ga wire should have a 30 amp breaker. If you are going to be pulling 40 amps, you should be using 8 ga wire. After all this discussion, I don't remember what these fans are drawing.