Overheating Issue 1:1 pulleys

[Cranky]

I'm having an over heating issue with an all steel 358. PRC double pass radiator, GM four blade fan with fiberglass shroud and also added a piece of aluminum across top just to help fan pull. I am currently running a set of 1:1 pulleys and I have always run under drive pulleys in the past. Could this be the issue? Anyone have any ideas with heating issues or pulley set up? Thanks in advance.

[CCHIEF]

Fuel quality, timing, air flow restriction (dirty rad or valence tight to track). Do a leakdown test with waterneck removed. I doubt it's from pump spinning too fast

[TALON75]

Depends on rpm, really don't want the pump over 7500rpm , that why most LMs have the under drive pulleys.

[Dirtmod13]

We had same issue first 4 races this year, removed the year old PRC radiator, installed a cheap afco and boom, 40 degrees cooler with no other changes. We even have a racing thermostat in it to help get up to temp faster and zero problems.

[dorman19]

are you running a honeycomb in front if so get rid of it
if the shroud isn't placed perfectly it will stall air try removing it

[DEKconsulting]

How old is the radiator? If is more than a season get a new one

[DK1]

I was going to run the same set up you described but I was told by my chassis guy to remove the aluminum i had placed across the radiator bracket (which I put there to help seal the radiator and keep my hand out of the fan). He said the aluminum piece traps the air trying to escape the shroud leading to increased temps.

[7uptruckracer]

Ok how does a smaller crank pulley slow down the water pump?

[lovinlatemodels]

7uptruckracer and Cranky a smaller crank pulley and larger pump pulley develops about a 30% reduction in water pump speed hence slowing down the water flow and fan speed. This is very popular on motors running alky, we never had any heating problems with this. Now on gas I recommend the 1:1 pulleys to get the fan speed for drawing air with the fan no more then 2 1/2 inches away from the radiator also go to Jones racing products and get a water restrictor and place in the bottom radiator hose this should solve the problems, if not then you need to look at radiator, fuel volume, or even just a faulty gauge.

[Matt49]

Not to get off topic but some friendly advice: When pressure washing your car, blast water through the radiator back-to-front (don't get so close you bend fins). This helps expel a lot of dirt and you'll see this in the form of mud in your shaker screen. Every 5 or so races, take the radiator out and repeatedly drop it on the shock floor (front facing the ground) from about an inch off the floor until no more dirt comes out. If you haven't done this, you would be VERY surprised how much dirt gets clogged in the radiator. In the hotter summer months, consider doing this more often. July and August we usually do it every other week.

[7uptruckracer]

Just curious working on a high RPM car and think we found we need an under drive crank pulley and bigger pump pulley we had another car with a 4" crank pulley and 6" pump pulley and it runs almost too cool the other car we have had heating issues so thanks guys reading this set off some red flags


7uptruckracer and Cranky a smaller crank pulley and larger pump pulley develops about a 30% reduction in water pump speed hence slowing down the water flow and fan speed. This is very popular on motors running alky, we never had any heating problems with this. Now on gas I recommend the 1:1 pulleys to get the fan speed for drawing air with the fan no more then 2 1/2 inches away from the radiator also go to Jones racing products and get a water restrictor and place in the bottom radiator hose this should solve the problems, if not then you need to look at radiator, fuel volume, or even just a faulty gauge.

[powerslide]

Vbelts or serp? The serp setup from jones is the cats ass for keeping the belts tight and no slipping. As others have stated take the radiator out wash it back to front with a garden hose, drop it a couple times on its face from a couple inches up to get rocks out.

[ric78]

keeping the radiator clean. One thing I do every couple of weeks is take the radiator out. Fill up one of those little kiddie pools and soak the radiator for a day. Take the hose and spray the fins from inside out(opposite of air flow). You will be surprised at the amount of dirt and fine pebbles in the bottom of your kiddie pool.

[FlatTire]

I would first recommend calculating out my current water pump speed. Stewart recommends no more than 7000rpm and would like to see 6500-6750rpm.

Here's the equation:
D1 * N1 = d2 * n2

D1 = crank pulley diameter
N1 = crank pulley rpm(max engine rpm)
d2 = water pump pulley diameter
n2 = water pump pulley rpm

n2=(D1xN1)/d2

I just got done battling all this. And Jones has a pulley kit that will likely work. They make nice stuff.

[Bdcase19]

No restrictor with the use of a double pass. We switched to a 18 inch 5 blade with 30% pulleys and it helped a lot you could tell the fan would move more air even at idle.