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240 LS swap cooling system thread

2turbotoys

2turbotoys

Salaminizer
Joined
Nov 13, 2007
Location
Reading pa
Since we have a LS swap suspension thread, I thought it would be helpful (at least to me haha) to have a cooling system one. I've seen some minor info but not many specifics, overall sizes, overflow bottles, fans, what are ya running? What did it take to get the radiator in there? I don't mean simple brackets, was there a sawzall or cutting wheel involved? What didn't work?
Anyone using an electric waterpump? What GPM are you running, are there turbos involved?
 
Guess this idea went over like a loud, very wet fart in an elevator. So here's what I've found so far.
Radiator:
Corvette C4 (84 to 89) radiators fit as far as height, use 3 row core
Custom built unit
940T radiator, is this really good for 450+ hp? When does it become a problem?
Electric water pump:
Nothing at all
Turbo involved? :
Who knows? Have to track down build threads that may not exist,..backtrack thru hours of other threads and get nowhere
 
2turbotoys said:
Guess this idea went over like a loud, very wet fart in an elevator. So here's what I've found so far.
Radiator:
Corvette C4 (84 to 89) radiators fit as far as height, use 3 row core
Custom built unit
940T radiator, is this really good for 450+ hp? When does it become a problem?
Electric water pump:
Nothing at all
Turbo involved? :
Who knows? Have to track down build threads that may not exist,..backtrack thru hours of other threads and get nowhere
Click to expand...

I can confirm that the 84-89 C4 rad fits almost perfectly. Even the stock Spectra Premium replacement rad is 1.25" thick (single core), which is the same as the stock 240 small rad. It fits perfectly between the frame rails, with just about an inch of wiggle room. Height-wise, it sits a bit lower, but is still level with the top of the core support. I recently installed one in my 240 for the i6 whiteblock swap, and it's a great fit.
 
I haven't gotten to this point on my swap yet, so nothing to offer. Just glad to see the discussion and learn from it.
 
using a Champion dual core rad from a C4 Vette (bought at Jegs)
Flex-a-lite dual pusher fans mount perfectly to rad
waterpump is a moded (truck) waterpump from a 5.3
 
I've been running the c4 eBay rad for almost 2 years now with a hacked up 940 efan. No issues, drive the car and abuse it just about every day
 
Stock 92+ 940NA here as well. Used a thin Spal fan hacked into the stock radiator shroud, to achieve clearance from the intake elbow and truck-depth accessories. Cools sufficiently for autocross-run-length events. Also, I can confirm the weird behavior in freezing temperatures without a heater line bypass (either hacked together from T fittings, or fancy like a LOJ conversions piece).
 
Too bad I scrapped a perfectly good 940 radiator last month haha. I am getting rid of that huge accessory bracket and just running the alternator on a relocation bracket.
I really like the look of Seans radiator location....might go that route.
Hackster: "Northern 209620. It will have their dual fans and shrouds on it as well. Z40081" to save some searching for people, but that thread...dam, worth every second looking through it.
 
I got a ~$100 radiator from summit for mine, it's a big ol nasty unit from Northern. Only qualm is it has a pinhole in it in the core.. I didn't check that before I did the modz to make it drop in...
 
you don't have to. I'm just ignoring it, it's not bad enough to cause problems, just annoying.
 
Im using the 940 e fan also. I think the highest temp I see 204? with my lm7. They usually run around 209-210 in the trucks.
 
I have a bunch of 940 fans, the radiator surface area is more important I guess, on a hot 85+ degree day my stock 242 engine is hitting 210+ with 940 fan with a 740T shroud, and thats with a gutted thermostat. Just an FYI for those that read this later, searching for C4 Corvette radiators on sites like Summit or Jegs triples or more the price of a universal radiator. Dimensional searches seem to make it a lot cheaper.
 
2turbotoys said:
I have a bunch of 940 fans, the radiator surface area is more important I guess, on a hot 85+ degree day my stock 242 engine is hitting 210+ with 940 fan with a 740T shroud, and thats with a gutted thermostat. Just an FYI for those that read this later, searching for C4 Corvette radiators on sites like Summit or Jegs triples or more the price of a universal radiator. Dimensional searches seem to make it a lot cheaper.
Click to expand...

I think your problem is the gutted thermostat. You need to slow that coolant down to cool it.
 
yeah, run a thermostat. I dropped mine to a 180 from the stock like 205 or whatever, with the a/c on (when it works) towing things get a little warm, but that's about it.
 
I thought that, no dwell time in radiator. The reason thats in there is I couldnt figure out why it was overheating, and so I fired both barrels of the parts shotgun. New waterpump, thermostat, radiator, temp sensor, nothing worked...till I put an Autometer temp gauge in and the entire problem was a bad gauge cluster. It never was overheating. That's the very condensed version... sorry thats off topic.
 
ah. I get my data from the ecu, I don't even know if the dash is hooked up. wait, no, it's not. I probably should hook that up sometime.
 
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