Pulley sizes

[Tim Brewer]

I've been fighting an overheating problem for quite some time now. It's been in and out of Keith Craft's shop in plano, Tx. about three times now and all I can say is it's only a little better. I have a March pulley system on my car and never have had the stock pulleys to compare sizes. My question is, what are the stock 460 crank and pump pulley sizes? I'm thinking maybe I'm turning the pump too slow?
Thanks,
Tim

[392cobra]

Tim,
I don't have to answer to stock pulley sizes,but....

What diameter is your water pump pulley ,6" or 5.25" ?

6" pulley is 4% underdriven
5.25" pulley is 10% overdriven

March will sell you a water pulley by it's self.I did that.

If you have the 6", 14% increase in pump speed could help.

http://www.marchperf.com/pg37.html

[Tongue Pirate]

You could possibly pull the water through the system too fast but if that's your problem you may want to check elsewhere first. What size & type of radiator do you have? How hot is your guage reading? Is your thermostat working correctly? Are you running a thermostat? Some guys run a restrictor plate instead of a thermostat just to keep the water from going too fast.

[392cobra]

Q4. What about my pulley set-up (what ratio do I need)?
A4. For STREET applications, the water pump speed must at least match the crankshaft RPM, to a maximum of 10% faster than the crankshaft speed.

http://www.stewartcomponents.com/Stewart_faq.htm

[Tim Brewer]

Hey guys, thanks for replying.
Here's what I have: March serpentine pulleys. It's kinda hard to measure exact, but it looks like the crank is close to 6 1/2" measured on the lip and the pump is aprox. 5 3/4 " on the lip. It's part # 30240.
My radiator is custom made 4 core by Griffin, it's 20.5" wide and 18" tall and 3" thick. I have a drilled 160 thermostat that is working. My water pump is an Edelbrock, part # 8866. I ditched the Cool Flex hoses and replaced them with universal rubber hoses because someone told me they will make big blocks run hot. I mainly only run the car in the evenings the keep the temps down. I would say on average the temps are in the 210-220 range. But on a warm day (like today) it will go over 220 and boil over and out my catch tank,(which is one of those chrome long round ones). My cap is an 18# one.
Thanks for your help guys,
Tim

[Tongue Pirate]

The first thing I would ask is if you have run a higher temp thermostat? I'd try a 190. I know it sounds crazy but if your thermostat is not closing & it's drilled it may not be letting your radiator do it's job.

[Tim Brewer]

Hyde,
I had the same thought as you on the 190. I tried it last weekend and it just to the 200's+ quicker. Bummer.
Tim

[Tongue Pirate]

Where is your temp sending unit located? At what point is the temp leveling off, or is it?

Location can obviously hav a big effect on the reading you are getting. Closer to the head would likely give a higher reading.

[rblong]

Tim,

I am right where you are right now. Since my new KC motor I also noticed higher temps. Last summer with my tame 428 I would have 190-200 all the time. I am running 190 thermostat, Griffin 22 x 19 (part # 1-55182-X) 2 row 3 inch radiator, Spal 2350 CFM fan with 190 switch. Now with the new 580 hp motor I am seeing 210 or so and that was a week ago when we were in the mid 80's. I am sure today would have been scorcher!

I have a call into Griffin. I know that I can buy a shroud that will help, but I have also seen some spal fans in the 3000 cfm range. I also want to find out what HP my radiator is rated for. I was going to pull the stat and try, but I want to see if I am going to end up doing more of everything anyway.

I gotta run out of town for a few days but if I get ahold of Griffin tomorrow I will try and post before I leave.

Bruce

[Tongue Pirate]

If you can borrow one of these to check tempuratures around your engine you may or may not get different results from the guage on your dash. it's worth a try. Summit lists them as a Pyrometer, others a Non Contact Thermometer.

[392cobra]

Hyde,
I got one of those last spring.I have/had the same cooling problems after changing from a Ford crate 392 to a KC 418w.
I found that my VDO tempt guage reads 10* high.That is with the engine running.If I turn off the engine and then switch the key to ON without starting the engine,it reads correct.I changed senders,same thing.

Still runs too warm,just not as bad as I was thinking.

[rblong]

I just got off the phone with Ron at Griffin. He knows a lot about Cobras! We went through all the usual belt tight, full of water stuff etc., just so he knows I at least know what to look for. He indicates the 19 x 22 is a small radiator for the HP, but if all is set up correctly he thinks it will work. The biggest thing he recommends first is to duct in the radiator to the nose so no air can go around it. He says this is the biggest culpret he sees. Mine has the ducting on the lower, but not at the top. As we all know air will take the path of lease resistance, so at speed (when your making more HP) a lot of the air goes around the radiator and the CFM of the cooling fan is not enough for the increased HP. I mentioned that at idle with the hood up the fan would cycle, but I had noticed it seemed to have a harder time catching up idling at a light (of course with hood down). He indicated again without the shroud that my fan is probably pulling some air over the radiator out of the engine compartment and recirculating air.

He said this may not be all I have to do, but he said to make sure it is ducted in before I spend any money.

I guess I will try that next.

Bruce

[Tim Brewer]

Hyde, My temp sending unit is next to my distributor. I'm not sure the temps will level out or not. At around 220, I usually start getting scared and return home and shut it off.
Bruce, Lonestar says your Griffin radiator is good for 600 hp, I ended up getting a larger (thicker) one and it's not doing any better. I also have my radiator fully shrouded, a fan shroud and a 3000 cfm fan. I also have an oil cooler thinking it might help keep the temps down as well, (it doesn't).
Thanks,
Tim

[Tongue Pirate]

Check with your engine builder on temps because he is the one to warranty the work if something goes wrong but 220 may be OK. It's seems a little on the high side to me but if it is not going above that he may tell you not to worry. You may also consider a couple of the front fans for the radiator to aid in airflow. Like stated before check everything you can before spending money

[rblong]

Tim,

Man - you sound like you have it covered. I have the 3 inch thick radiator and oil cooler also, but no inlet shrouding or fan shrouding. I do have the radiator shroud on the inlet of the bottom only.

Does your overheat all the time? You have all the shrouding and it sounds like it is overheating more than mine. Until the mid 80's I never got above 200 with the new motor and it still did not get above 210. I would call Ron S at Griffin - 18007223723. He is hard to get to and only there Monday thru Wednesday. He says to call him between 8 and 8:15 EST to get him quickly!

I know one thing - I have a Griffin in my boys 69 Camaro and it is a whole lot bigger and has dual fans and is rated at 600 HP.

We will keep working through it - but we will get it worked out!

Bruce

[rblong]

Tim, now that you mention it I think I remember some pics of your radiator shroud, but they are not there anymore. Did you fab it yourself? I just went and looked at mine and it will definately be a hand fit job. Guess I will mock up with a piece of poster board and then get a sheet of thin aluminum to fab?

Bruce

[Tom Wells]

Hello Tim,

Finally got around to measuring my pulley sizes. They are stock F250 460 steel pulleys, but obtained from dealers, so I don't know if they are a legitimate factory pair or not.

They are: crank -> 6-3/4" OD and water pump -> 5-3/4 OD.

The ODs are outside of flenge to outside of flange, and these are serpentine belt pulleys, NOT v-belts.

Also, since the pulleys are hard to see & reach, the diameters may not be accurate but to a 16th or so...

This does indicate the pump is overdriven (faster than crankshaft speed). The pump itself is a Ford Racing aluminum pump, same as comes on the crate motors of a few years ago.

I use a Griffin aluminum radiator and the car always runs in the 90-100C range. It can and has idled for 30 minutes without moving, and cools off to below 100C immediately after it starts moving. Never an overheating problem even when the thermometer stays above 90F.

Hope this helps,

Tom

[xlr8or]

If you are using the serpentine system is it still turning the water pump in the same direction as stock? Your pump is the standard rotation.

Some serpentine system spin the water pump the opposite direction. This will definitely cause overheating issues.

[Tongue Pirate]

Good point!

[392cobra]

Tim,
Right now you are 13 % overdriven.Tom's stock pulleys are 17 % overdriven.
Your serpentine system is for a standard rotation pump.

As I said before,I have been fighting the same battle after getting my KC.Been dealing with it for a year now.
I'll tell you the steps I went thru and ended up lowering it 20*. Maybe something in it will help you.

This is all in city traffic,stop & go.Tempts in low-mid 80's

1. 200-205* 180* thermostat
2. Installed new Moto-Rad 180* thermostat , no difference
3. Replaced WP pulley. From 12% underdriven to 5 % overdriven. Lowered 5* to 195-200*
4. Gutted old thermostat. 1 1/8" opening.LOWERED tempt 15*. Now 180-185*
5. Removed gutted thermostat and install 1" restricter plate. Raised 5* to 185-190*.

6. Put bleed hole in gutted thermo and reinstalled.
Now 180-190* with tempt in mid-80's.