cooling a tbi (1 Viewer)

[76 PTO]

Hey guys,

I have a question you v8 guys out there. I have a 92 350 tbi with marks adapter stock radiator and a ford taurus fan. with marks adapter the engine is super tight to the taurus fan. My radiator is suspect as I just had them fix the holes and boil it. The engine runs hot 225 plus when going down the road in fourth
gear. In stop and go traffic it will flirt with 200. When I play in the dunes it will over heat. Will a new stock radiator from like radiator barn solve my prblems??? I saw a AL. radiator on e-bay that was the same size as a stock radiator and the same price. I was going to pull the trigger on that one but I thought I might ask you guys first. I would think the taurus fan would do the trick. It has to be this old radiator.

 

[Tankota]

Check your timing. Running hotter at speed than in stop and go traffic indicates some other problem.

I've got a carbed 350. Stock rad worked just ok provided I had a front mounted pusher fan along with my engine fan in a shroud. Stocker finally got bad so I swapped in an aluminum with a custom mud flap shroud I need to put a pusher fan back on it though. Last year in 100degree weather on the trail I was running 225 and that was with my heater on full blast! good times good times

 

[Poser]

What is the condition of your radiator cap?


Just because your engine is running hot, it is not always indicative of a bad radiator.

There are many factors that can lead to an over heating condition, including, but not limited to:


Ratio of antifreeze to water- Not only does anti-freeze prevent the coolant from freezing in the winter time, but it also raises the boiling point of the engine coolant, compared to just water.


A faulty or non-existent thermostat can cause all sorts of cooling issues.



Simply installing a new aluminum radiator could work, but it would be a good idea to find out exactly why your engine is running hot before just throwing money at parts to try and figure it out.

 

[inkpot]

Howdy! Is your stock radiator a 3 core or 4 core? I had my original 4core rebuilt with a hi-density core. The originals are about 7 fins per inch, and the HD is about 14 fifns per inch. This nearly doubles the radiator's surface area to disapate heat. I also recommend a FlowKooler water pump. They are about 1/2 the price of the shinney hot rod upgrade pumps, and it defintely helps. I run a 19" mechanical fan without a shroud, and my rig never gets over 180 degrees even running in the desert heat. John

 

[dgangle]

Running cooler in stop and go than going down the highway is indicative that your radiator is undersized. BTDT. You will get all sorts of opinions/experiences on this. The Radiatorbarn 4 core didn't work for me...220+


Search, search, search, search search. Then search some more. And read every word of it. Read and see what has worked for various folks and make your own descion. There are people in Death Valley that claim a standard rad cools their Cheovta fine. One the other end of the spectrum there are people at the North Pole that say a larger and/or aluminum rad was necessary for them. I have read and posted more on this topic than probably any other topic. It is an unwinnable debate.

Here'a arecent similar thread:https://forum.ih8mud.com/40-55-series-tech/230400-anyone-buy-classic-radiators-ebay.html

 

[Downey]

I actually earn my living with darn near this subject.
(a) normally a chevota would need 45 gpm flow, which a stock radiator could not achieve. Those getting away with a stock radiator are either very lucky or live where it's darn cold????
(b) while aluminum radiators cool better than copper radiators, normally generic "non-Toyota specific" aluminum radiators may not be a remedy at all---again, you need gpm's.
(c) choice and location of fan blade is the biggie. Our experience is that an electric fan will never be able to do what a large diameter engine driven fan is capable of. I always recommend a big 17" or 18" Suburban air conditioning fan blade.
(d) DO NOT put any portion of the fan blade up inside a fan shroud. Shroud should end at the forward edge of the fan blade. This info is documented in SAE studies.

 

[sfrolich]

(d) DO NOT put any portion of the fan blade up inside a fan shroud. Shroud should end at the forward edge of the fan blade. This info is documented in SAE studies.

That's very interesting... do you have any information on the internet about this? This would solve my "fan hitting the shroud" problem.

Thanks, Scott

 

[kb3gun]

One thing that I know causes overheating at speed is a collapsing(soft) radiator hose. At idle it's fine. When you pick up RPM, the vacuum closes the hose. I'm sure you already checked that though.

 

[Tankota]

I actually earn my living with darn near this subject.
(a) normally a chevota would need 45 gpm flow, which a stock radiator could not achieve. Those getting away with a stock radiator are either very lucky or live where it's darn cold????
(b) while aluminum radiators cool better than copper radiators, normally generic "non-Toyota specific" aluminum radiators may not be a remedy at all---again, you need gpm's.
(c) choice and location of fan blade is the biggie. Our experience is that an electric fan will never be able to do what a large diameter engine driven fan is capable of. I always recommend a big 17" or 18" Suburban air conditioning fan blade.
(d) DO NOT put any portion of the fan blade up inside a fan shroud. Shroud should end at the forward edge of the fan blade. This info is documented in SAE studies.

That is very interesting info. Thanks for posting it up.

 

[76 PTO]

Its a 3 core radiator , cap is new and the timing is dead on for tbi. The taurus fan pulls alot of air. You can feel the air just blowing out the vents in the hood at a good rate. I cant run a mechanical fan ddue to the clearance to my rediator.

 

[73fj]

(d) DO NOT put any portion of the fan blade up inside a fan shroud. Shroud should end at the forward edge of the fan blade. This info is documented in SAE studies.

Then why are most factory shrouds 1/2 in 1/2 out? Not being a dickhead, just curious how much difference it would make on temperatures with the fan blades outside. I would think you would produce more vacuum effect with some of the blade in. Not a scientist here, but I will be making a shroud for my truck and only want to fabricate it once.

 

[HeadCase]

I had a heck of a time with this - but began with a 400 small block a new rad like Downey describes and a black magic high flow fan. Ran waaaayyy hot. So, pulled and sold the engine to a hot-rodder, and had swapped in the TBI. Seemed ok on the trails for a while, but would run hot on the highway. Deduced that the electric fan was actually limiting flow of air at speed. Went wheeling and broke some blades off the fan; so threw that out in the yard and switched to a GM performance fan setup (I'm running that serp system as well). Had IPOR make a shroud. All seems well so far...can post pix of the shroud, etc., if you like.

 

[Cat Scan]

76 PTO,

You are getting a lot of good advice here. I'll bet most who have done the SBC conversion have dealt with this issue and have become somewhat of an expert in such matters.

Just for the heck of it, and along the lines of what Tankota suggested, pull the cap off your HEI and make sure the advance is not stuck. Sorry guys, that was the solution to my long running over heating issue.

As for Downey's item "d", obviously Detroit and Japan ignore the SAE studies.

Good Luck!

 

[my64fj40]

I run a 400 SBC in the South Texas heat and I've never had a problem with overheating.

But then again I started out with this:

 

[76 PTO]

its a tbi so no timing issues due to the computer controlling it. I wish I could run a mech fan but the engine with the serpintine system is just too close.

 

[jimr]

I started out with a 4 core and a toris fan on my tbi and ran hot. changed to an aluminum 4 core, works great for the last year. Any one want to buy a 4 core with 2 hours time on it? $100.00 In Colorado close to Denver.

 

[dgangle]

Not me but post it up the for sale section. Someone will buy it. I too sold mine there after finding it inadequate for the task. $100 life lesson.

 

[Downey]

I am not the expert on why an auto manufacturer opts to put their fan up inside a fan shroud, or not. In the law suit I was involved in we used the Society of Automotive Engineers studies as evidence. Their studies showed that the engine ran cooler when there was a fan shroud, but that the engine ran coolest when the fan was not inside the fan shroud. The plaintiffs attorney had a 735i BMW with the meanest exposed fan blade I've ever seen. His chainsaw massacre looking fan blade helped us win that case.

 

[73fj]

Possibly a safety issue with an exposed fan blade? How much cooler did it run? 20, 30 deg? Or 2-3 deg?

 

[inkpot]

Possibly a safety issue with an exposed fan blade? How much cooler did it run? 20, 30 deg? Or 2-3 deg?

Howdy! I would imagine that considering how many newer cars have automatic transmissions that have to have the fluid level checked while the engine is running, the safety of "idiot" fingers is certainly a part of it.

Depending upon size, shape, pitch, rpm, and phase of the moon, fans produce a 5-10% radial dispersement. Otherwise, some of the air goes out to the sides, not just straight back. When this dispersement is not contained by a shroud, it MAY allow for a slight increase in air flow/colling ability. Automakers probably feel the slight increase is not a fair trade for the liability if "idiot" fingers!! John