602 Overheating

Requesting suggestions on how to cool down my asphalt racetruck . It has been running consistently hot: 220 to 230 to 240 degrees. Race before last, the temp went to … well I don’ know, it buried the needle. But for only a lap and a half (turned out the fan fuse popped).

During cautions, I bump it up to Drive (T-350 run in 2nd gear) and it will cool down to about 200. But once we go Green, doesn’t take long to heat back up – excessively.

And no, I don’t think it’s a faulty gauge because I’ve seen it “look like a steam locomotive as the water comes out of the overflow vent routed to the right side of the lexan windshield.

It’s a 602 crate motor racing on a 3/8 mile in Houston TX

The nose has many openings in it. The “air box” between the nose piece and the radiator forces 95%+ of the air through the triple pass radiator (distilled water, 27# cap, 1 bottle of water wetter). When I fill the radiator with water, I usually pull the cap off, run it up to around 2,500 RPM, top off the radiator, and put the cap back on.

I run a 16” electric puller fan, mounted on a shroud on the back of the radiator. 100% of the air passing through the radiator is pulled through the fan.

No restrictor in the “thermostat hosing” of the water neck on the intake manifold. 15% gear reduction pulleys.

The upper hose is the Gates hose with the spring vulcanized in the rubber. Lower hose Gates green strip with internal spring (it’s in good shape)

The 4412 had 75 jets, but when I looked at the plugs, looked like the truck was running a bit rich. I changed the jets to 75 (local carburetor agreed and supported the change, plus many others in this class are running anywhere from 72s to 75s)

Need to check the timing, but I’m speculating it’s set for 35 or 36.

Thinking about putting a water neck on it with a pet(not a nice word)(not a nice word)(not a nice word)(not a nice word) so I can make sure an purge all of the air out of the system. And maybe replacing the lower dual pulley and both v-belts thinking maybe the belts are slipping (I run an alternator, so I can’t really put marks on the v-belts and see if one belt or the other is slipping).

Think that covers it.

Any suggestions? Help please

And thanks

A tripple pass takes over 60 times the amount of pressure to flow the equal amount of water as a single pass. You want to keep it cool: Single pass radiator, GM style 4 blade fan and soak the radiator about once a month in a kiddie pool to clean it.

http://stewartcomponents.com/

Look through the Tech tips and FAQ's.

i agree w/ egoracing. no need for a triple pass. takes way to much pressure. we run a double pass, well because it was the only thing they had on the shelf when we went to replace our old rad that had a nice big hole right through the middle of it. put 1:1 pullys on it and get rid of the electric fan. if the fuse already failed once it will fail again. a good metal/nylon fan will never give up just because a 10cent fuse goes bad.

since you are down in texas im guessing you are on a dusty track alot of the time. take the rad out and put it face down in a kiddy pool for an hour and man you wont believe what comes out of it. especially a triple pass. that thing must be thick.

He said it is an asphalt race truck...Doubt there is a lot of dust! LOL I agree, get rid of the triple pass radiator, we run a double pass with a 32 lb cap, no restrictor, the radiator will do that, and change to 1:1 pulleys. The 602 doesn't turn enough rpm to need a 15% reduction set up, IMO...We run a 15% set up, but turn the engine 8400 rpm...

maybe dusty wasnt the right word...might not be dirt(however, i bet there is more than you think) but there could be lots of junk that gets sucked up there. rubber and such that will still make the radiator look clean on the outside but still have junk in the fins.

I agree. 1:1 pulleys, lose the triple pass radiator and the electric fan. Get the new fan about 1 inch away from the radiator and put a nice shroud on it.

Get rid of the electric fan. That's 90% of your problem.

1st of all, I sincerely appreciate all of the replies.
I'm leaning towards the following:
1) Replacing my lower pulley (the one mounted on the balancer). It looks to be worn out, so the belts may be slipping.

2) After talking to Stewart this AM, replacing the water pump that came on the truck when I bought it. It is a “CAT LJ WP 350 HP”, whatever that is. Google didn’t help me in identifying it either.
I’m replacing it with a Stewart Stage-2 I had in the attic (off my old Mod before I went with the RaceMate Alternator/Water pump combo). According to Stewart, I will want to leave the 15% reduction in place. We’re chipped at 6,200; therefore, with 15% reduction turning around 5,200 at the pump. The Stewart guy s said that is right about where you want to be with the Stewart Stage-2 pump.

3) Replacing the radiator with either a Single- or Double-pass. Stewart said that I could probably get by with the Single, but the Double wouldn’t hurt. He agreed to remove the Triple.

4) Staying with the electric fan. 100% of the guys I run with run them. So in my 2 reason to stay with the fan: (1) I know the majority are not having overheating problems like me (2) Are lap times are so close, that I don’t want to give up any HP if I can prevent (and yes, that is taking into the consideration the HP I could/will lose if the truck gets hot.)

5) And yes, I already cleaned the rubber out of the radiator (dropped it on the wooden shelf a couple of times). Fortunately, I’m an old dirt racer, so this part of the equation wasn’t my 1st rodeo ()

Please keep those comments and suggestions coming. If not only me, no telling who else this thread may help.

on pavement electric fan is the way to go.

you need a good one though.

I ran the ones of gm front wheel drive mid 90s cars they have a built in shroud and pull a ton of air, in fact the nascar teams use parts from these type of fans they just pay a whole lot more for them.

if your messing with a aftermarket fan, none of them worked for me on pavement even the 320 dollar black magic electric fan set up... the oem gm did the trick.

Keep the electric fan, run it through a relay and a 30-50 amp or so circuit breaker, NO FUSE. This elimantes blown fuses and burnt switch contacts. Make sure fan is sealed to the rad very well. As stock car mentioned oem fans pull a ton of air. We ran a street stock on dirt (yes dirt) with a ford taurus (3.8L v6)rad and the electric cooling fan which have 2 speeds, never got over 195. With good duct work in the front we hardly needed the fan at speed.

If you can fit the taurus fan its really a good air mover and two speed as mentioned. I didnt know about it back when I was running the oem gm stuff in the 90s, both have a nice shroud so you can use alum angles accross the radiator and just attatch the electric right to the back.

Use less energy-users like phone chargers, sound, and electric fan.

I disagree about the 6,200 chip and 5,200RPM water pump speed. The math may be correct, but is the engine turning 6,200 all the way around the track? I'll bet not.
After you make these changes and it still runs hot, put 1 to 1 pulleys on it.

Help.

Getting at wit’s end on how to cool down my 602 crate motor in my HMP racetruck .

Had to pull off the track last race when the water temp hit 240

Change I’ve incorporated:
; Replace triple pass with dual pass.
; Replaced pump with Stewart Stage-II I had been running on my Mod
; Replaced v-belt pulley system with serpentine: ~5% reduction system. I went to the serpentine in the hopes of reducing if not eliminate possibility of belt slippage, plus I had to make room for the upper radiator hose to clear the alternator.
; Changed timing from 38 to 32 degrees (big swing, but getting desperate)

As before:
; distilled water with 1 bottle of water wetter / 1 of purple ice (only purple ice for sale at the track)
; 16” electric puller fan mounted to a very nice Jeg’s shroud (putting in a plug for Jeg’s because I was impressed with their shroud)
; openings cut in nose piece to direct air directly on the radiator
; .040 aluminum box between nose piece and radiator to direct 95%+ of the air to and through the radiator

Any more suggestions?

Anything I should maybe be looking at in the engine itself.

And thanks again all

16 inch aftermarket fan of ANY make wont pull enough air

get a gm oem fwd car fan from the 90s
or the two speed taurus fan also from the 90s

Put the timing at 34 degrees. At times to little timing can cause cooling troubles.

Well, in case anyone is interested or can learn from my experience...

Removed the shroud, sealed off the radiator cap and plumbed in an expansion tank.

Results: never got over 200!!!

Unfortunately, was caught up in a wreck (someone blew a motor and dumped fluid all over the track) and the 3 race old radiator is trash, and the bumper and ....

The bright side is next time out I shouldn't have any overheating issues. :)