Mishimoto vs copper 4 row radiator.

[Wolfshark]

Hey guys, time to swap the radiator in my 87 k5 (350 tbi, 700r4).

I've read as many k5 radiator threads as I can find, lots of good info + pros & cons for both aluminum(welded) & copper/brass radiators.

I've narrowed it down to these 2 radiators:

-Mishimoto aluminum ck-78x:
https://m.summitracing.com/parts/mio-mmrad-ck-78x

Summit OEM 4 row copper/brass:
https://m.summitracing.com/parts/sum-382018

Any thoughts or feedback as to which I should get, or does anyone have personal experience with these models? Better options in this price range?
-Will be running mechanical fan not electric.

I live in the south(Georgia) so I need all the cooling help I can get.

Many thanks in advance!

 

[Wolfshark]

Anyone?

Anyone running that Mishimoto radiator?

I'm guessing that copper/brass is likely the same mfg as other new 4 rows on the market.

 

[6872xtc]

I can't help you with any experience on either radiator.
I know that if you go with a 4 row, you will have to change the radiator mounting pads and trim the shroud. I did it on my '90.
Maybe the aluminum one will match better? ???
I can tell you that the '98 or so vortec fan will move a lot of air and help too. It will bolt on to your stock fan clutch, it has 9 blades.

 

[Justin V]

Do not use a fan from a 98 unless your truck is a factory serp belt setup or you have swapped to the serp belt. If I remember correctly, 90 was the year they went to the single serpentine belt, in 87 you should have multiple belts still. The fan spins the opposite direction on the serpentine motors, which would cause airflow reversal if installed on the wrong year (read: wrong belt style) engine.

 

[6872xtc]

Whoops, sorry. I forgot what year. ...
Justin is correct!

 

[Big Ray]

I believe the reverse rotoation pumps have a 5/8"s snout whereas the standard has a 3/4"...of course I may be wrong. BTW, my '90 DIESEL has v-belts on it.

Also, IMO the aluminum rad will work better. Aluminum has a huge heat transfer coefficient. I'd use one on my 6.2l rig if I could afford one.

 

[Wolfshark]

Right on, thanks guys!

I think I'll give the Mishimoto ck-78x a shot. I'll report back with feedback after the install for anyone else considering this radiator in the future.

As for the fan, @Justin V, correct, it has multiple belts(4 if I remember correctly).
It has the stock type 5 blade fan.
I'll likely go with a flex-a-lite wide 6 blade (with 2" spacer) + new fan clutch & call it a day.

 

[sweetk30]

a lot of aluminum rads these days SOCALLED drop in replacement don't fit the stock rubber isolators and or upper clamps. its a all on your own design to hold it in place.

even the griffin I got specificly for my truck wont hold in place with out full custom hold down points.

3-4 row copper/brass better read up . lots say a good working 3 core with shroud and fan system works better than 4 row .

 

[yellowK20]

Aluminum has a huge heat transfer coefficient.

Actually thats not true, copper is a MUCH better conductor then aluminum . The advantages to an aluminum rad is weight, cost , and strength . All things being equal (tube and fin size ect) a copper brass rad is much more effecient .

 

[nutt7]

a lot of aluminum rads these days SOCALLED drop in replacement don't fit the stock rubber isolators and or upper clamps. its a all on your own design to hold it in place.

even the griffin I got specificly for my truck wont hold in place with out full custom hold down points.

3-4 row copper/brass better read up . lots say a good working 3 core with shroud and fan system works better than 4 row .

I had the same issue with my champion mc716. Minor mods required for the "drop in" radiator. I used isolators a from a 90s Chevy...also, it says it has a 1.5" inlet. Your stock one might be 1.25" like my suburban so be prepared to buy a hose. The factory hose goes from 1.5" at the t-stat to 1.25" at the rad. Hit me up and I can dig up the part number of a hose that will work. Lower hose fit fine on mine.

 

[Big Ray]

Actually thats not true, copper is a MUCH better conductor then aluminum . The advantages to an aluminum rad is weight, cost , and strength . All things being equal (tube and fin size ect) a copper brass rad is much more effecient .

I did not know that....

 

[Wolfshark]

Just an update-
Got the Mishimoto yesterday, and while the stated dimensions read almost identical to stock, was actually a pain getting the upper radiator clips/brackets to fit it. Took a few hours of modding both upper brackets and lower feet to fit it.
Lining up the fan shroud wasnt pretty either but got it all sorted out.
That radiator is pretty thick and you'll need longer fan shroud bolts (1/4"-20-1.5" or 1.75" vs the stock 1") .

Finally got everything in place and started hooking up all the plumbing and the damn threading for the lower trans cooler port was off.
If It was me doing it, I'd figure it was my fault, that i cross-threaded it or something.
But it was my stepdad, who's a master hvac tech and has been building airplanes for 30 years.
He said the threading was bad from the factory, so had to undo everything, pull it all back out, return it today to Summit.

I ended up getting that summit 4 row copper/brass radiator, rather than another Mishimoto. That bad threading bummed me out.
Plus, kind of a niggle... But we really didn't love the flimsy radiator cap and how it fit. Plus at 19psi... Just seems a little high.

The Summit 4 row copper/brass rad, while having almost the same listed dimensions as the Mishimoto, just fits much easer, with only minor trimming needed on the brackets/rubber.
It has to do with the fill spout side tank side, and the location of the fill spout.
On the Mishimoto, the spout is centered on top, closer to the center.
The summit copper radiator- the spout is more towards the outside and the bracket clears it easily.
It just the little things.

The Mishimoto seemed like a nice radiator, and I hope this doesn't come off as a knock on it. Getting a dud is normal with any part, and I don't hold it against them. They also have the best radiator warranty out there.

But for me and my blazer... The summit copper/brass 4 row just seems to be a better fit.
Think it was $75-85 more?
To me, worth it. Just feels like a really high quality radiator. And pretty much plug & play.

Ps- for anyone getting the Mishimoto- the upper radiator hose you'll need is Dayco 70724 (or listed as Dayco E70724 at some places like autozone).
1.5" on both ends

Cheers and thanks to the guys who chimed in

 

[6872xtc]

Do we get to see any pictures?

I am assuming that you get to walk in to Summit?
That must be rather handy!

 

[Wolfshark]

Yeah I live about 10 miles from Summit, it's pretty convenient.

I didn't really take pics but here's a couple.

Here's the neck on the copper radiator- it's a cool design- you can use 1.5" hose or 1.25". I had the 1.5" hose still on from the Mishimoto so I used.


Here's a shot showing the fill spout, you can see they moved it all the way to the left which really made the difference in mounting ease.
The Mishimoto was more towards the middle, right where the bracket is.


And here's a pic of what I used under the radiator as support feet- they're anti vibration pads for air conditioners.
(And my goofy dog that photobombs everything).
I cut groves in them to fit over the metal place holder ridges for the old feet.
In hindsight, I should've cut about 1/4"-3/8" off of these. As is, they made the radiator sit a little higher than it should and caused me to have to make some fan shroud adjustments.


And a shot of my blazer. 1987 Silverado on 3/4 ton axels.
4" lift + 315/75r16 (35") Cooper S/T MAXX tires.

 

[Big Ray]

clean rig!