Small pulleys And cooling problems

Posted by: RAY1969CARS

Small pulleys And cooling problems - 03/08/18 01:34 AM

what are the best ideal pulley sizes to have on a small block for cooling I believe I do not have a matching set or may be incorrect
I just put new heads on the motor and put new freeze plugs on the block and cleaned out the gunk out of water jacket I do have a brand new three core aluminum radiator with 210 inch fans I did put thermostat But took out the guts
Timing at 34. 650 double pumper


Any ideas ?

Non-power steering car
Posted by: ahy

Re: Small pulleys And cooling problems - 03/08/18 03:59 AM

I like the fan and water pump to be at least slightly overdriven. The crank pulley should be larger diameter than the fan pulley.

Another thing to look at is the fans. Dual 10" fans I believe. Often this does not flow enough air at a stop to keep cool. When running down the road the fans and their shroud act as air restriction and not enough air.

Can you put the stock fan/shroud on at least as a test?
Posted by: RapidRobert

Re: Small pulleys And cooling problems - 03/08/18 10:37 AM

are you haveing cooling issues at the moment? iirc the AC ratio is ~1.33 overdriven. what pulley diamenters do you have now. what temp is it running (around town & highway)? confirmed with a good mech gauge? You absolutely need a 180-185 high flow functioning stat (unless 1/4 mile drag raceing only). EDIT it highly likely is what Ahy said, the elec fans cuz theres been alot of problems with em not moving enough air.
Posted by: therocks

Re: Small pulleys And cooling problems - 03/08/18 01:17 PM

We run March under drives on BBs and SBs.They were all running stock rads and Flex fans.None ever ran over 190.All were buit and my 440 is radical.It now runs a Champion rad with everything else as stated.Never gets over 180 even when its in the 90s.Rocky
Posted by: PurpleBeeper

Re: Small pulleys And cooling problems - 03/08/18 01:21 PM

I've personally tested the following:

1. Two 10" electric puller fans
2. One large electric puller fan
3. One large electric puller + two 10" pusher fans
4. Stock fan/shroud

For all the electric fans, I used low-profile, high cfm fans with no additional shrouds.

What I found was that in traffic, I would run cool with the two pushers + one big puller BUT I would overheat on the highway. If I used any less electric fan combo, I would overheat in traffic.

I switched to the stock fan/shroud & used a "Jaguar" (big block thing that is a short fan clutch to clear big radiators) & a cheap 3-core aluminum Champion radiator (hard to make fit) & my engine runs at 180F in traffic OR on the highway & I was able to put a thermostat back in it.

Also, you might try using more distilled water & less antifreeze and throw in a bottle of Water Wetter (iron heads) or Purple Ice/Lucas Super Coolant (your choice) for aluminum heads. None of these products does anything useful unless you run more water, less antifreeze......like 2 parts water + 1 part 100% antifreeze or even water-only + additive.

Water cools better than antifreeze, BUT it freezes. Many antifreeze bottles have "freeze protection charts" on them or look at engineeringtoolbox.com & calculate your own blend (antifreeze = ethylene glycol in most cases). Run the least antifreeze you can safely and not freeze up in the winter, then use one of the additives to keep your corrosion protection. HOPE THIS HELPS
Posted by: Rob C

Re: Small pulleys And cooling problems - 03/08/18 11:21 PM

Originally Posted By therocks
We run March under drives on BBs and SBs.They were all running stock rads and Flex fans.None ever ran over 190.All were buit and my 440 is radical.It now runs a Champion rad with everything else as stated.Never gets over 180 even when its in the 90s.Rocky

Ditto on small blocks of good street power. OE radiator, fan shroud and a MP viscous 5 blade fan. Cool as can be, zero issues. IMO, the factory set up is as good as it gets except for serious racing. If your not on the track most of the time, leave the factory cooling in there.
The best upgrades to the OE system is the MP viscous fan package and a new radiator. Stock or not, it will more than likely be better than the old unit in there now.