My dad and i are building a '78 FJ40 Landcruiser that has a GM 350 V8 conversion. The engine has a serious overheating problem. A shroud over th fan should solve the problem, and i was wondering if there was an OEM shroud that i could buy or get from a junkyard, or if it would be better to fab one out of sheet metal?
FJ40 350 V8 radiator problems (1 Viewer)
- Thread starter jds78
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I've been running a stock FJ40 radiator with no shroud, and a 19" flex fan as close as is prudent to it. I'm not having any overheating issues.
When people talk over overheating problems, it makes me wonder one of two things - do they live in an area where the ambient temperature routinely runs in excess of 100 degrees? Or do they have some problem with their small block Chevy that's causing the overheating, instead of the problem being the lack of enough radiator?
When people talk over overheating problems, it makes me wonder one of two things - do they live in an area where the ambient temperature routinely runs in excess of 100 degrees? Or do they have some problem with their small block Chevy that's causing the overheating, instead of the problem being the lack of enough radiator?
My 40 used to run up into the 210-212 range at times, ( sbc cool climate). So learning from mud I added a 1" piece of aluminum to my shroud bringing it out to center of fan blade. Also I changed my 195* trermostat to a 160* and that seemed to make the biggest difference. It runs in the 180*-185* range now. Well see when the weather gets hot.
I think it is hard to center the fan on the radiator with an sbc. With my radiator mounted on the front cross member, and the height of the engine limited by the tranny hump I could not pull enough air.
A $20 junk yard fan from a ford, a couple of relays later and I have complete controle over my engine temp.
Good luck
A $20 junk yard fan from a ford, a couple of relays later and I have complete controle over my engine temp.
Good luck
And I also added a electric pusher fan on front of the radiator w/ toggle switch just in case. I dont seem to need it yet, well see.
Torus fan would be my suggestion if sticking with the stock 40 radiator. If you are reusing an older radiator, make sure it is very clean inside to maximize heat transfer. If it is not, and it cannot be saved, just buy a larger non-stock radiator and stick with the mechanical fan. An old radiator will have poor heat transfer unless it has been very well maintained.
i took the stock fan shroud out of my 76 and turned it upside down and cut a notch out of it for the lower radiator hose and it fit perfect for my V-8 swap. you might try it ? and if you don't have one try these guys Welcome to CruiserParts.net and if you need a radiator try these guys Radiators, automotive radiators, condenser, oem radiators, truck radiators
good luck!
good luck!
I would prefer to live where Brian does (in the snow) but I don't... So I had to get a larger radiator and ran an electric fan. I hope to swap it with a mechanical fan with a shroud. I believe the best long term solution is to use as large of a radiator as you can fit, use a large mechanical fan and use a shroud. Some prefer brass to aluminum or vice-versa, but generally more is better.
your welcome! take care!
well i can say i had a problem with mine and i know it was not getting the air flow it needed. the coolant was flowing right but ai also have a billet grille and lack of air flow. what i did was a bunch of stuff but i finally found the perfect combo. i built a shroud and used a flex a lite 7 blade fan which i and they say pulls more air than their best riged fan. i also put a flex a lite trim line 14 inch pusher fan in front for extra precaution. it has not needed it yet though. the temp runs about 160 all day now but it only got up to 60 degrees. i dont think i will have any problems in the summer but at least the pusher will help. it goes on about 195 goes off at 170. the fan in the picture is a 5 blade i did replace with a 7 blade fan
I have started with the MKVIII(on 19x26 radiator) and swapped it out becuuse it was a beast of an electrical load and failed to manage and my underhood temps. This made the floorboards and tranny tunnel hot as well. I really wanted something that was less of a failure point.
I started with a 19" 7 blade flex and ran it without a shroud and it definately helped with the underhood temps but in traffic the temps would climb. The fan was at least 3" from the radiator though. I did not try it with the shroud, but I am confident it would have enough flow to work with a shroud.
I got a 19" 7 blade clutch from a friend and swapped out teh flex. It would not keep the engine cool without a shroud either, but the underhood temps etc. were much improved. I finished the shroud and now it won't warm up enough to open the thermostat. I have several small holes in the thermostat to try and help with flow. It seems the flex fan provides enough flow to cool but the clutch fan gives a larger margin of safety. Once it gets hot here again I will liklely swap the thermostat out with a normal one and see how it goes.
I started with a 19" 7 blade flex and ran it without a shroud and it definately helped with the underhood temps but in traffic the temps would climb. The fan was at least 3" from the radiator though. I did not try it with the shroud, but I am confident it would have enough flow to work with a shroud.
I got a 19" 7 blade clutch from a friend and swapped out teh flex. It would not keep the engine cool without a shroud either, but the underhood temps etc. were much improved. I finished the shroud and now it won't warm up enough to open the thermostat. I have several small holes in the thermostat to try and help with flow. It seems the flex fan provides enough flow to cool but the clutch fan gives a larger margin of safety. Once it gets hot here again I will liklely swap the thermostat out with a normal one and see how it goes.
Flexi-i-lite makes some nice 7 or 6 blade readiator fans designed for a fan clutch. It looks very similar to the fan pictured above, use one of those with a HD GM Fan clutch. Have the fan shroud where the radiator fan sits in the shroud about 1/2 of the depth of the fan, and with about 1inch clearance between the shround and the tip of the fan. YOu'll need a nice 3 core or better a 4 core radiator too. That should get you going. I would run a 180 degree thermostat on the old school SBC setups.
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I have issues with mine, have had some bad advice in the past, including mainly, using a high flow thermostat sold to me by a local radiator specialist with a single opening temp.We live in a colder climate in NZ, varying from average 25°C in summer to average 2° winter, so plenty of frosts and warm weather.As a farm hack, it works perfectly, but on a recent trip away it wouldnt cool on a 3000ft climb.At 40km/h.I'm running brand new standard radiator, and electric fan running constantly.My current plan is to fit thermo fan to front, connect temp switch, and fit a second single core very large radiator directly behind factory one, running to toyota radiator first, then to Holden V6 (later model of 3.8 buick v6) radiator before returning to block.I cannot see how this will not cool it.Failing this, I will be looking for a reverse cooling kit (where the cooled coolant goes to the heads then down to the block) such as LS engines run, as this is a far better system but means the thermostat must be located on the bottom radiator hose.
What v8 engine are you running and what is the electric fan off?
Downey
SILVER Star
jds78, FWIW the coolest running Chevota I've ever owned (of many) used a large 18" diameter 7 bladed, rigid, air conditioning fan blade on a fan clutch, similar to Brets photo above. These fans have very thick blades on a very thick angle, they create the hurricane that is necessary to create enough prop wash to blow the heat out of the engine compartment. I did not use, or need a fan shroud, but I did lower the radiator to: (a) position the fan centered on the center of the radiator surface, and (b) lowered so that path of 18" fan did not cut through the lower radiator hose.
Now, here's what a radiator manufacturer schooled me on: (a) copper radiators work better in lower temps, i.e. they keep 200 degrees down to 180 degrees better than an aluminum radiator. (b) An aluminum radiator works better in higher temps, i.e. they keep 240 degrees down to 200 degrees better than a copper radiator.
Now, here's what a radiator manufacturer schooled me on: (a) copper radiators work better in lower temps, i.e. they keep 200 degrees down to 180 degrees better than an aluminum radiator. (b) An aluminum radiator works better in higher temps, i.e. they keep 240 degrees down to 200 degrees better than a copper radiator.
I'm in the process of making my own fan shroud. One big problem with my rig '72' fj40 with an sbc stroker is moving the air under the hood. I've finally decided that the efforts I've made in the past do not allow for enough air movement over the top of the engine (this is documented on Ih8mud many times). I kept frying my ICM in the distributor. So... Long story short, I'm going to make a shroud and try to do it right this time. FWIIW, this is my plan. Making a Custom Fan Shroud - Route 66 Hot Rod High Thot I'd pass it on and will report the success or failure.
Wow, beautiful work!
I will probably end up doing that myself some day. Thanks for this info.
B.
edit: I'm running a Taurus fan and its usually good enough, but has no reserve capacity and isn't quite adequate for really hot days or driving over mountains. Would love to have the additional air flow and reliability of a big mechanical fan.
