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620KC on 720 bare frame build


EDM620

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12 hours ago, EDM620 said:

I'm really seriously rethinking the 720 dash/HVAC as a result. The fan is definitely bigger & moves more air, plus has 4 speeds. 

 

So I have jumped on refurbishing the 620 system, and will find a way to get more fan speed, possibly make some ductwork to move air to the end vents.

 

Use the blower and resistor from the 720? 

 

FWIW, I know some people who have replaced the stock squirrel cage fan with a PC fan, since they are compact, move a lot of air, and are usually 12V. This on a rheostat could provide a wide variety of fan speeds? 

 

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24 minutes ago, Stoffregen Motorsports said:

 I wouldn't think that fan would move enough for HVAC.

 

AC, probably not. Heat, maybe?

 

You raise an interesting point though. Stock fan seems to be maybe 200cfm (when it was new, not now), and a strong PC fan looks to be around 100-150cfm. 

 

I actually looked at using something like this (no water involved), but they draw about 18 amps at full blast...

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I have been using the vintage air stuff lately on my resto-mod builds, and while the quality isn't as good as OEM, they are compact. This is partly due to the modern high efficiency cores available now. But yeah, if the vintage air system fits, use that instead.

 

Any fan would work for heat, but for defrost, you need to move a bit more air.

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Over the weekend I jumped onto the task of refurbing the heater assembly and investigated a replacement core. As I ultimately wanted to increase the airflow, I made the assumption based purely on # of fan speeds, that the 720 blower motor spins faster, coupled with a bigger hamster cage fan. As this whole project seems to be going, nothing is ever a simple swap, and this includes the motors and fans. The larger fan was just a few mm too big for the housing and the motor mounting was different. At least the shaft was the same diameter and length so I could just use the original fan, however the little coiled wire heater block had to be changed, and the "newer" motor features a tube that direct vents back into the housing (???).

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I cleaned the housing thoroughly, modified the motor mount to fit properly, created a vent connection where the old single coil heater block was, and mounted up the larger 3 coil heater block. The stuck flow control valve was freed up and flaps for air control were cleaned with new foam applied.

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Everything works like new and won't smell like old dirt or dead mouse.

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The heater core itself was a different issue, as the original is NLA as many others have found, I did some research on Spectra Premium website for alternatives Products (spectrapremium.com). As I found researching for my radiator replacement, there are hundreds of different heater cores - making the task of finding a suitable replacement a hit & miss search that was ultimately a miss, either the inlet/outlet were not in the right place or the dimensions were off. After that I decided to have another look at my core and it was in pretty decent shape, mostly just fins were clogged with mouse nest. A thorough cleaning and new foam wrap and I'm calling it good. When/if it does leak, I'll dive deeper into the world of replacement core swap. 

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Last thing on this is I decided to make a screen to keep leaves & other debris out of the blower assembly. I'll finish that today.
 

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2 hours ago, EDM620 said:

 the "newer" motor features a tube that direct vents back into the housing (???).

 

i believe that is to keep the motor from overheating when running at full blast. It uses the air rushing past to suck air out of the motor housing. Really common on newer stuff, never used on older stuff (slower spinning motor doesn't overheat?). 

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13 hours ago, EDM620 said:

Over the weekend I jumped onto the task of refurbing the heater assembly and investigated a replacement core. As I ultimately wanted to increase the airflow, I made the assumption based purely on # of fan speeds, that the 720 blower motor spins faster, coupled with a bigger hamster cage fan. As this whole project seems to be going, nothing is ever a simple swap, and this includes the motors and fans. The larger fan was just a few mm too big for the housing and the motor mounting was different. At least the shaft was the same diameter and length so I could just use the original fan, however the little coiled wire heater block had to be changed, and the "newer" motor features a tube that direct vents back into the housing (???).

IMG-8142-small.jpg


I cleaned the housing thoroughly, modified the motor mount to fit properly, created a vent connection where the old single coil heater block was, and mounted up the larger 3 coil heater block. The stuck flow control valve was freed up and flaps for air control were cleaned with new foam applied.

IMG-8145-small.jpg

IMG-8144-small.jpg
 

Everything works like new and won't smell like old dirt or dead mouse.

IMG-8060-small.jpg

IMG-8152-small.jpg

IMG-8154-small.jpg


The heater core itself was a different issue, as the original is NLA as many others have found, I did some research on Spectra Premium website for alternatives Products (spectrapremium.com). As I found researching for my radiator replacement, there are hundreds of different heater cores - making the task of finding a suitable replacement a hit & miss search that was ultimately a miss, either the inlet/outlet were not in the right place or the dimensions were off. After that I decided to have another look at my core and it was in pretty decent shape, mostly just fins were clogged with mouse nest. A thorough cleaning and new foam wrap and I'm calling it good. When/if it does leak, I'll dive deeper into the world of replacement core swap. 

IMG-8097-small.jpg
IMG-8147-small.jpg


Last thing on this is I decided to make a screen to keep leaves & other debris out of the blower assembly. I'll finish that today.
 

All of my builds here get the HVAC thoroughly cleaned to get rid of the mouse and cigarette smells. New foam on all the doors and joints too.

 

image.thumb.png.362aeb542f60b54ce7b29d711ba8c537.pngI buy the foam in bulk rolls.

 

Nice work.

 

 

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I'm going to have another look at the screen, as a friend pointed out this will reduce the airflow which is opposite of what I'm after. The screen I used looks to give a fair reduction to the intake flow.

If possible, I'll try to dome it up into the cowl area to further prevent leaves etc. from covering it.

 

Stoffregen, the Sprite you're planning to build reminds me of a conversion done on a buddy's Midget, we swapped in an A14 and a hand-built (crude work but way back in time) fuel injection using a Bosch system out of a Rabbit. Car was lighter and much more nimble with the British boat anchor gone. We retained the British clutch master which didn't function quite right when mated to the Datsun clutch slave, and were going to solve that but life intervened...          Have a few friends who played with Series 1 LR's too.

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2 hours ago, Stoffregen Motorsports said:

I have varied tastes when it comes to old cars and trucks.

That sounds amazingly similar! I swapping a 360 into my 304 "75 CJ5 that I pulled outta full size Cherokee. That Jeep was one hell of a beast off roads, kitted out perfectly. Had full 1/2T rating instead of regular 1/4T.

1975-jeep-cj-5-renegade-levis-edition.gif.10fff53af53302202660e25bd7f0ebfb.gif

Honestly out of the mix I've ha, I miss that one the most.

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Most common place to find a Land Rover - on the rope of my CJ 🤪 They never got out without a face fulla mud

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Nice. The 360 in my Cherokee runs perfect. I just re-sealed it and gave it a new paint job, but when I pulled the heads off, the bores looked perfect and the oil pressure was awesome, so I just left the bottom end alone. It's my first AMC V8, but they appear to be built tough with good materials.

 

I've owned about that many 510s.

 

Right now I have 9 trucks, half of them duallies.

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On 12/16/2021 at 2:01 PM, Stoffregen Motorsports said:

appear to be built tough with good materials

The AMC blocks were not given the due they deserved, the bottom end was really stout and read often that the mains were strong enough that were equivalent to bow-tie 4 bolt mains.

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10 hours ago, Stoffregen Motorsports said:

make a stronger design and execute it better.

The only real difference between the 360 and the 304 blocks is a taller deck height for the increased stroke.

Are you going to feature that build on Ratsun as well?

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On 12/18/2021 at 11:06 AM, Stoffregen Motorsports said:

It's pretty common for lower volume manufacturers to make a stronger design...  I suspect it is because they don't have enough experience to know which corners to cut.

 

This.  😁

 

One of their biggest issues was just not knowing where to spend money. Over-engineer the engine to last forever, but short cut other things that reduce consumer confidence in the product. GM seems to do this with cheap interior plastics that always feel crap, even on a $70k Cadillac...

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I owned a 1969 Wagoneer with the Buick 350 in for a while.  I loved that thing, but unfortunately had to sell it to pay for a semester of college.  A worthwhile investment for me, but still, this is one of the vehicles I regret selling the most.  Interior was in awesome condition.  Black vinyl with just a few split seams that I hand stitched back together.  You could steer that thing with a pinky the steering was so easy to move.  I'm a fan of FSJ, even if I'm building an International now.

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