At 10:52 am 7/20/97 -0400, you wrote:
>Jim,
>
>Your 351 is probably putting out over 350Hp. How do you keep things cool?
>I am constantly on the virge of overheating (blowing the radiater cap;
>16psi) and cannot keep the temp down under 220. I had a 4 tube 17fpi
>radiator built and that helped but I don't hink there is encough air
>circulation under the hood. My next, more drastic step is to put a scoop
>and NACA exit vents in the hood. I don't want to but I cannot think of
>what else to do. (electric 12" pusher, water wetter, big radiator, timing
>set on retarted side of power by a couple of degrees, 195 degree stat).
>
>Any suggestions?
>
>Regards,
>
>Jim
>B9470139
>
I agree that your problem is too little air circulation under your hood.
In a regular Tiger there is no space around the motor to allow the
exit of hot air from the radiator.
You can prove the problem with lack of air exit on Your Tiger
by raising the rear of your hood. Before I enlarged the area under the
hood I raised mine. I fabricated 2" extensions on the two rear rubber
hood bumpers bolts and extended the hood latch 2" with another bracket.
This way the hood would latch ok while being open by 2" on the rear.
This helped some in the summer with the stock Tiger. However; I got
a lot of helpful hints that "YOUR HOOD IS UP!!!" from people driving
next to me.
Check this open hood idea out with a spacer and a bungy cord to
see if it helps cool things.
I solved that problem by making the
under hood area bigger with the inner fenders moved out, new frames
and the firewall moved 6" back. I also made the radiator 4" wider
( allowed due to the new wider frames).
I also have a reversed scoop. The scoop previously was a
JC Whitney ABS Camaro scoop. It looked good, but after 5 years it
cracked and now I have a hand made reversed scoop about the same
size. The reversed scoop allows hot air to exit only when under 35
miles per hour. Above that speed the high pressure at the base of the
windshield causes air to enter at the rear.
For a while I had an air dam in frount and that helped tremendously.
The air dam causes a low pressure area to develop under the Tiger
and therefore more air can flow through the radiator. It was good for
15 degrees of drop. The air dam was made from plastic 1/4"
thick by 1 foot wide and a length that extended completely around,
mounted to the sheetmetal lip behind the bumper. I partly cut two
3" by 12" areas spaced 3 or 4" apart ( cut sides and top) and then
bent the cut areas in toward the radiator (actually at the oil cooler
area) I then had a pair of nicely curved "ducts" to the oil cooler and
the radiator at the bottom. I re-enforced the plastic all the way around
with a "bent to fit" horzontial aluminum strip mounted about 3" up from
the bottom. On the outside I mounted some MG-B side trim .
The trim was lined up and secured to the fasteners holding the
aluminum strip behind the plastic.
The air dam also killed the lift problem I had at 135 MPH or more.
The Tiger gets real skittish without the air dam. After installing the
air dam, the Tiger felt very stable. Note that it was difficult to get
a jack under the front cross member as there was only 2" of air dam
ground clearance. The plastic was the same stuff that is installed
on the bottom of air boats here in Florida. It was tough, and flexable
enough to bend around the front of the Tiger. I used 10-32 SS bolts
every 3" to secure the plastic. I had to buy a special spray can
of plastic prep before I could get flat black paint to stick to the plastic.
After about 5 years the plastic started cracking around the
bolt holes and I presently don't have it installed.
Add some sort of air dam and your Tiger will run much cooler
as long as you are moving above 20 MPH.
By the way, I had NACA ducts (sort of) in the hood of my
V6 Alpine. I don't thank they were big enough to do any good.
Also rain ran down through the ducts onto the motor and caused a
lot of rust on the heads.
Jim Barrett Tiger II 351C and others
|