cooling - conversion help

[Kcustom73]

I am currently working on dropping a 89 6.2L into a 75 FJ40 Landcruiser. I know people might say I'll have problem with the drivetrain being to long but stretching the frame/body 27" solves that problem. I'll be keeping the 700R4 behind has well as 3.7 geering and 33" tires.

From all the reading I have done, it seems like the 6.2 was a good choice, lots of after market support and it can be a good high milage motor. I not looking for huge power but I might be looking at adding a turbo just to give it that little extra pep when towing (probably 4000lbs max).

My question is that I'm a little worried about cooling. I have read that cooling these engine right is critical to there longevity. I've seen picture of the radiators the full size truck have and it make the one that I have seem tiny. The original radiator in the FJ40 only has a core size of 19" tall x 17" wide. They are standrad 4 core but I can also get a nice 2 core aluminum rad.

I think that if I keep NA I should be fine but what if I turbo? Any insight would be great here. Thank you

[rustyk]

I can't answer that, but I can help muddy the waters by saying my '87 Ford diesel van originally had a four-pass radiator. That was replaced by a Modine three pass, which was 7% more efficient due to its design. The OEM radiator was replaced because I had it out to have cleaned, and a UPS truck ran over and destroyedit (for which UPS paid for the replacement).

So the number of passes isn't necessarily a useful clue, but total tube cross-section and design and fin area are, as is design (cross-flow, top to bottom flow, etc.).

The radiator on that Ford is about 30"x24"x4" (I can measure it tomorrow); at 6.9L (NA) it's rated at 170 HP. That said, the truck is equipped to pull ~6800 lbs. curb weight, and 9500 loaded, with a GCVW of 18,000 lbs. Your little FJ40 is going to nowhere near have to stress the 6.2L as much as mine. That said, the Ford radiator has about 2.4x the frontal radiator area of your Toyota.

Longevity (and catastrophic failure mode) of any engine is related directly to heat. If it were I, I'd try the stock-size radiator, with the vision of adding an electric auxiliary fan. If the specs of the two-pass AL rad exceed the stock (I'm skeptical), start with that.

A turbo pushes more air into the cylinders, allowing more fuel, and increasing temps at higher powers than the NA engine can muster.

IMHO, the bottom line is you may find yourself experimenting, but the stock rad does seem small - what is the stock engine? I seem to recall the Land Cruisers of that vintage came with a 2.6L I6, but then again, I can't remember what I had for breakfast, either...:D

No doubt other TDP members can add their advice.

[Kcustom73]

Thanks Rusty,

I'll see if I can get more info on the stock and the aluminum options and hopefully see which has the better design. I've been reading a thread on another page and the guy was able to put a bit larger radiator in his Fj40 and he had swapped in a larger (hotter) engine without any issue. Might have to get some info on where he got his.

[convert2diesel]

There are a number of ways to get around the restrictive size limitations on this kind of conversion. GM rates the heat shed rate of the NA 6.2 at about 7,000 BTU/min at full power. About 40% of that is out the exhaust meaning you have to size the rad for about 4,200 BTU/min or 250,000 BTU/hr. assuming you intend on running the truck flat out.

Most automotive cooling systems are based upon a 30% duty cycle and thus the radiators are considerably smaller, on the base option package, and are sized upwards from there. Any rad shop worth it's salt will be able to size a rad accordingly as heat exchangers are rated based upon there shed rate. I made the mistake of oversizing my radiator when I did the Buick and have had a real problem of getting the engine up to temps when I am not towing. Even with 5,000 lbs. of trailer out back, the temps never get over 195F on the flats.

Not a big fan of aluminum rads, especially up here in the rust belt. I feel the copper rad core is more then sufficient and will probably last longer. Check with the guys over at Capital Dominion Radiator on Gladstone (near Bank). They built my rads and have been a great help.

Another thing to consider, would be to move the oil and tranny cooler out of the main rad and give them their own exchangers. This takes considerable heat load off of the main core and you can re-locate the smaller exchangers to anywhere you have air flow. All of the aftermarket cooler companies even have exchangers with their own fans. Good idea for your application. Just make sure they are equipped with thermostatic bypasses (at minus 30, you will have a hard time getting the oil and tranny fluid up to temp.).

Hope this helps. If you need help with this conversion, don't hesitate to ask. Sounds like fun.

Bill

[Kcustom73]

Bill,

Thanks for the info. This was the kind of info I was hoping for. I'm also glad to find someone local that has done some swaps with the 6.2. Hopefully you don't mind me picking your brain over the next little while.

PS know anybody reliable in Ottawa that can rebuild the 6.2?

Kevin

[convert2diesel]

Kevin:

Give me a call at 613 692 3070 and hopefully I can steer you in the right direction.

Bill

[BigGun J]

Kevin,
I am just rapping up a 6.2 swap in my FJ60. I used the FJ62 radiator and use the radiator cooler for the oil. I have a fin cooler for the 700R4 infront of the radiator. I went with a 1 inch larger fan blade then the original 60 and it is 1 inch smaller then the chevy. I modified my fan shroud to accept the larger fan blade. It is a V belt set up with a heavy duty fan clutch. I have only driven it a few times but my ential thought is it is going to be fine. The 6.2 power pulls through the gears and I am very happy. I don't beleive the motor is even running to potential and still has plenty of power. If you sign on to IH8MUD.COM there are some good build threads with success. They are running them in 40, 60 and 80's.

My next project will be a 40 with a 6.2.

Jim

[Kcustom73]

Thanks for the info BigGun,

I'm already on MUD (same user name as here) and I've read most of the conversion on that site. I'm just getting info from multiple sources. This also gave me a chance to meet a local guy (convert2diesel) that has done swaps with the 6.2 and has info on where to get stuff done localy.

Do you have a build up thread on MUD? I would interesting to see.

[BigGun J]

Not on MUD as it has been covered. My goal is to put one togeather and post it on this site.

Jim