RADIATOR FAN FZJ80 - long

[Waggoner5]

The vents have no catch cans. They are offered but will hamper air flow big time. This is why I put them far out to the sides. Also, on an 80 or any standard rotation engine the DS will be the hot side, so 1 big hole in the hood on the DS will suffice. Get the sawzall.

Seriously though, a couple of really good powered bilge vents should help a bunch. Both mounted DS and ign powered. I really like the idea of raising the hood off the hinges with spacers as a test. The air flow coming out of my little vents is like a hair dryer on high, I can only imagine how a 1" gap all the way across the cowl will help. Now if it does, someone ought to make a hood like was shown a few posts back but with a larger vent farther back, and yes make some type of water pan.

Thanks D.

 

[IdahoDoug]

The 80's engine bay is actually pretty roomy and with only the straight 6 in there and no full belly pan under the engine bay, plus a low output/nonstressed engine I don't understand what all the "80s run too hot" fuss is all about. Does somebody have numbers to compare say an 80's underhood temps to a Suburban's underhood temps taken at the same time and same place to support all the perceived issues?

Usually, we don't get this "my 80's overheating, whups the radiator's clogged and I've never changed the coolant or noticed my fan clutch is toast, nevermind" stuff until spring when temps climb. Glad to see we're ahead of the curve this year - heh.

For the underhood temps, ventilation can work as long as some attention to airflow when the vehicle's in motion is paid. Unless it's just for low wheeling speeds, in which case opened up is good. I mention this because I once watched a bit of windtunnel work on a vehicle where a scoop intended to take air in was actually exhausting or stalling due to its location. Moved a bit and it then sucked air in. So more to it than plopping openings here and there, which is news to nobody I suspect.

DougM

 

[IdahoDoug]

Which reminds me, didn't some of the 60's come with a supplementary thermostatic electric fan that moved air around the engine bay??

DougM

 

[Waggoner5]

Agreed. At higher speeds I can see a lifted hood trying to suck air in like a cowl induction setup.

My 80 never got close to overheating supercharged, so I can't imagine what I would change either. I'm just stirring the pot.

 

[SUMOTOY]

Holy 80 batman!

Off to the races!
Go here first, this guy has good toys and a working mind....
http://jeepsunlimited.com/forums/showthread.php?threadid=413088&perpage=20&highlight=cooling&pagenumber=1

Bilge pump? Dan just use a small electric radiator fan (saab turbos have 8in diameter ones that would work great - in fact, any junk yard with turbo cars is a great place to look) if you really feel the need to 'move' it. If you don't want to hole the hood, put two fans at the vents in the wheel well, and turn them on at low speed events. At high speed heat will find the way out without restriction (like you'd find with bilge ducting)

Holes in the hood. Find hot spots, put holes. Audi's 1/4 million dollar 1984 pikes peak winner used chicken wire and a 2in hole saw.

With any underhood temps you are dealing with convected heat (radiator fan blowoff) and radiant heat (SC, turbo, exhaust manifold, etc). Addressing the convected heat at high speed (trapped) requires more testing to get it right as noted above (read: boundary layers, aerodynamics of front end variations, cowl inducting). Addressing radiant heat is a no brainer, it goes above the SC and the exhaust manifold.

I generally find good luck with the following guidelines. Stay away from the windshield at least 6-8in, because of cowl induction. Use vents that aren't straight, slight angles in the vents with the flow of air are better. Also you want to direct air to the outside of the truck, it just makes the interior smell better. I find 3-4in drops (vents) or scoops (ram air) above/below hood line are optimal guidlines, less works, just needs more testing. I have also found that below the center ridge line has less high pressure boundary (read outside the center engine hump lines on the hood). I have also found that the biggest challenge to hood vents, is making sure you don't put ugly smelling vents in line with the HVAC intake.

Hood cutting for vents does not require repaint, btdt. I use masking or box tape over clean paint with a rotozip cutting wheel or fine saber saw blade.


SJ

 

[SUMOTOY]

Outer vent placement

So, with all the above factored in, I'm thinking this for up top...

SJ

 

[IdahoDoug]

Passive vents, or are you going to power them?

DougM

 

[Scamper]

I think placing them far off center is going to be a must with a S/C. The blower is snug against the top of the hood and a duct with drip tray of any kind is going to be a problem. But I like the idea...just not wild about cutting into my hood at the moment .

 

[SUMOTOY]

Passive vents, or are you going to power them?

DougM

IME, powering a hood vent isn't necessary, and it would be a first (lots of hood vents on production cars/trucks- never seen one with a fan). Radiant and convection will find their way out without the push. If one is considering pushing air to somewhere other than hood exit, I would consider one of the electric aux fans at the wheel well for low vehicle speed heat removal.

Scamper, lucky for me, my hood is already a bit tweeked from the previous owner, so cutting it up doesn't bother me at all. That said, I've done a couple dozen hoods over the years, and never had to add paint. A bunch of silicone around the hole keeps the water from going under the cut paint.

BTW, another source for awesome hood vents are Big Rig trucks. Many of the new aero 18 wheeler cab engine bays have vents on them.

SJ

 

[Dusty]

scott
earlier you spoke of the merits of oil cooling. are you going to use this also?

The hood vents sound neat. I have seen a post on this forum of how much a snorkle was able to decrease intake temps as read by an OBD reader. I hope similar objective data will be obtained with the hood vents. If they made an objective diff I may consider cutting holes in my hood.

The 80 series cooling system may be just fine but a few things leave me suspect. 1st there are plenty of "overheating" posts. 2nd the oe temp guage is almost useless till its too late so its hard to tell how hot these trucks are getting as a whole. 3rd the 1fzfe has head gasket issues and who's to say this isn't related to points 1 and 2.

 

[SUMOTOY]

scott
earlier you spoke of the merits of oil cooling. are you going to use this also?

Yes, definitely

The hood vents sound neat. I have seen a post on this forum of how much a snorkle was able to decrease intake temps as read by an OBD reader. I hope similar objective data will be obtained with the hood vents. If they made an objective diff I may consider cutting holes in my hood.

I think this is worth chasing much more so than rad fans. I had massive drops in underhood heat in a variety of cars I've done this to. Just about all new cars/trucks use low pressure venting (in wheel wells especially). High underhood trapped heat caused by turbos and SC have always had hood vents (Evo 8, all dodge 2.2 turbos, Z34 chebby, audi sport quattro, landrovers).

The 80 series cooling system may be just fine but a few things leave me suspect. 1st there are plenty of "overheating" posts. 2nd the oe temp guage is almost useless till its too late so its hard to tell how hot these trucks are getting as a whole. 3rd the 1fzfe has head gasket issues and who's to say this isn't related to points 1 and 2.

I'm fanatical about making sure a guage sits where it does all the time. I put a sharpie dot on the guage face, after referencing a guage. Simple and cheap.

I believe in keeping engines at 210 degrees, oil and water, wth extreme prejudice. This allows moisture to get relieved from the oil, and usually is the 'normal' operating termperatures for most production motors. Get the engine to that temp, then keep it there, no matter what the conditions, fans, coolers, etc.

Running too cool can cause more problems than running 'normal'. I have done extensive testing on 'definiing' 210 on the audis by using head temps, not necessarily water temps. This also helps baseline the water temp sender location to the highest heat on the motor. Head temps can vary significantly from block, radiator, or guage temps.

In a supercharged or turbo truck, a better way to address piston ring temps is with oil cooling, especially since the 80 already uses piston oil squirters.

SJ

 

[bjowett]

Oil cooling is great stuff... especially, as mentioned above by Scott, when the pistons have oil squirters to keep their temps down. Cool (relative) pistons are strong pistons.

Here is one install.

https://forum.ih8mud.com/showthread.php?t=54132

https://forum.ih8mud.com/showthread.php?t=62375

Any updates, Dusty?

I'll be measuring temperature on my built engine prior to installing the cooler.

 

[Dusty]

brian
still have the oil cooler on. its not leaking even though i never put rubber spacers on it to isolate vibration. im still monitoring oil and water temps but of course they are both low right now. i got the water temp to hit 205 degrees last month running up monarch pass on hwy 50 here in co. i was in 2nd gear at 3800 rpms wityh cruiser loaded-it couldn't have been more than 20 degrees outside. i have found that when it is real cold outside and i am on highway my water temp will sit at 180 on my electric guage. under these conditions my oil temps are in 130s and my oil cooler is only warm to touch. the mocal thermostat is working. i cant wait to see how your motor build turns out


scott
you probably know that the oe FZJ80 h20 temp guage is not proportional-it only shows "nl" (in mddle) and "hot" when things are getting bad. the trick you do with the dot on the guage wont work in your truck. you probably have plans on an aftermarket job. please cut your hood up soon

 

[SUMOTOY]

scott
you probably know that the oe FZJ80 h20 temp guage is not proportional-it only shows "nl" (in mddle) and "hot" when things are getting bad. the trick you do with the dot on the guage wont work in your truck. you probably have plans on an aftermarket job. please cut your hood up soon

Dusty,
I'm aware that the stock guage isn't proportional, but it does trend quite quickly (I found that out today in fact when I done sprung another rad leak drag racing some now bummed Lx470 dude...). It's not proportional to actual temp, but I can/did pick 3 points on the guage that seem to reference an actual temp well.

I've mounted dozens of oil coolers over the years Dusty. You want to rubber isolate it, and quickly. I have found (esp on the earls) you will get leaking at the bottom of the core with excessive (rigid mount) vibration. VW/Audi has some cool (radiator) mounts available at the dealer that have 2 isolated 6mm studs coming out of them (audi PN 443121273E), that fit perfectly into the holes of the earls cooler tabs. I chuckled when I read your posts about the rubber oil hose being 'expensive'. I only use the braided stuff because of high startup pressures in cold weather, now that's pricy stuff.

Amazing how an oil cooler mounted in a good airflow can stabilize water temps, almost to the point where water cooling is a non issue. I do find in cold weather that blocking the cooler/radiator is the only way to get up to temp. Remember too, that most oil cooler sandwich plates have different thermostats available, I normally go for the closest to 210F you can get, the industry oil thermo standard is 87C (190F), don't use the 80C one. Did you use -10AN lines?

Scott Justusson

 

[firetruck41]

It's not that it's not proportional that makes the gauge unreliable, it's that it is "dampened". It will not neccessarily register any change even though the temp has varied. Third or fourth time someone has tried to tell you about the temp gauge, do a search then maybe you'll believe.
You keep talking about how water cooling isn't important and you don't need a fan in your supercharged 80, so why are you going to cut holes in your hood, seems like you are bent on exercises in futility.

 

[Dusty]

Ben dont discourage him-the nice fellow is about to hack his hood and you are going to ruin it for everyone

scott I didn't use rubber isolators on the earls cooler because I surrounded the entire cooler in an alum box so there is no conflicting tension on the tabs. vibration may be an issue.... but I might as well take the thing off because I honestly didn't see any diff in water temps with this cooler-and a good cooler it is (yes 10an/5/8 line) That said I havn't run the mojave pass in the summer since the install and I dont have forced induction (yet)

this past summer I also did weeks of testing with cardboard over the cooler and again I didn't see any significant diff in oil or water temp. im sure the cooler makes a diff in race cars and may make a diff w heavy loads or forced induction. it probably makes more of a diff as the engine/oil/water temp gets hotter because there is more room for heat exchange but still, my expensive experiment (n=1) didn't indicate the cooler makes a diff at temps bw 200-210

 

[SUMOTOY]

It's not that it's not proportional that makes the gauge unreliable, it's that it is "dampened". It will not neccessarily register any change even though the temp has varied. Third or fourth time someone has tried to tell you about the temp gauge, do a search then maybe you'll believe.
You keep talking about how water cooling isn't important and you don't need a fan in your supercharged 80, so why are you going to cut holes in your hood, seems like you are bent on exercises in futility.

I completely understood every post written. I have also done a search read the threads on the subject FT. I also have a very keen eye, or a really sensitive one, that can differentiate between a needle width of difference. Look, I've had 5 core leaks since May. I've never overheated, and in fact, was alarmed each time when the guage moved to the center position.

Experience, paranoid, or lucky?

Regarding the fan, I have never said I don't need one. I said that in cold temps I didn't *use* one, and without catastrophic failure. I won't tow a trailer that way, I won't even run it in the spring that way. I'm holding off doing a lot of money spending on radiators and fans until I'm confident I'm doing the right things for the right reasons. That's my way.

Regarding holes in the hood... There are those that have and those that havent, just about in every marque. Those that have; not only believe, but can usually share real world measures. I'm looking to get trapped heat from under the hood caused by me adding a heat pump to my motor. YMMV

I'm also quite aware that you may think I'm nuts. That doesn't bother me, especially when speaking to forced induction issues in vehicles, but please don't let it bother you. Hang in there FT, you might find some good information comes from all this. I already have most of the items we are talking about in my shop: variety of oil coolers, oil thermos, vents, fans, and the experience in fitting and testing them.

If you have any experience or data you'd be willing to share, I'd be happy to hear about it.

Thanks

Scott Justusson

 

[firetruck41]

I only wish I could find out how you can tell the engine coolant temp has risen when the needle has not moved, very keen senses indeed!

The only personal data I have to share, is that the only cooling system problem I have encountered has been a stuck thermostat, other than that I haven't had any issues yet.

 

[SUMOTOY]

I only wish I could find out how you can tell the engine coolant temp has risen when the needle has not moved, very keen senses indeed!

YMMV. Mine does. FT, 5 for 5 coolant losses (including 1 yesterday), haven't blow a head gasket, and I knew well before my temps hit 250f. Confidence enough on baseline to run without a fan or shroud in cold weather. IME, my guage needle pegs one needle width below half. Which indicates to me that at half, I have a potential problem. I don't need to read about coolant issues, I've had more than most in just 5 months.

The only personal data I have to share, is that the only cooling system problem I have encountered has been a stuck thermostat, other than that I haven't had any issues yet.

Yet is a key word. Add a supercharger, turbo or other heat pump.

I appreciate your experience on a stuck thermostat. I've replaced mine and already had other issues, which I'm trying to resolve with sound theoretical and practical solutions.

SJ

 

[SUMOTOY]

scott I didn't use rubber isolators on the earls cooler because I surrounded the entire cooler in an alum box so there is no conflicting tension on the tabs. vibration may be an issue.... but I might as well take the thing off because I honestly didn't see any diff in water temps with this cooler-and a good cooler it is (yes 10an/5/8 line) That said I havn't run the mojave pass in the summer since the install and I dont have forced induction (yet)

The tensioin isn't what causes them to fail, it's vibration, this is a known issue Dusty. My suggestion is two fold on the oil cooler. First, take it away from the fan, mount it in natural airflow, so it's only cooling when moving, faster speed = more cooling. Second, find a thermostat that opens at 100C, that's the optimal oil temperature. The problem with most sandwich coolers, is that they are meant for race cars, so thermostats are set at 175 or 190 so they are fully open at 210. It appears you don't need your cooler to operate that much. So open it at 210, so it's fully open at 220.

this past summer I also did weeks of testing with cardboard over the cooler and again I didn't see any significant diff in oil or water temp. im sure the cooler makes a diff in race cars and may make a diff w heavy loads or forced induction. it probably makes more of a diff as the engine/oil/water temp gets hotter because there is more room for heat exchange but still, my expensive experiment (n=1) didn't indicate the cooler makes a diff at temps bw 200-210

You really don't want it to either. Dusty, every single factory turbocharged audi from 1982>today has a thermostatically controlled oil cooler from the factory. Every single one of these applications (1mm+ production cars - no exceptinos) also has 2 noticeable features with them: 1) a 100c thermostat and 2) no fan attached to it. I've experimented with 80 and 87C thermostats in them, and actually gotten oil blowby because the engine never got hot. Hence, my claim that cooler running engines isn't necessarily a better thing, without a definition. I target all my machines (race, street, offroad, etc) to hit 100C, then stay there, at all costs. Including attaching 48 and 60 row oil coolers...

I support these opinions and my experience with these SAE references:
880258 - which speaks to breakdown of oils running too rich a mixture
860103 - which speaks to temp stability and heat buildup on force inducted engines
970922 - "Development of Modern Engine Lubrication Systems" - which addresses ideal temps, pressures, saturation and aeration of oils.

The risks of too cold are well documented, oil blowby, premature bearing wear because no oil vaporization, cold/enriched ECU timing and fuel, emissions issues, oil saturation, oil areation and engine thermo inefficiency.

Change the need with a heat pump, or hot climes, or hot towing, the oil cooler will be your most effective weapon in the heat arsenal. I wouldn't ditch it quite yet, maybe change it's location to be away from the fan, or put in an electrically operated fan.

Scott Justusson