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Overheating at idle
- Thread starter Kenflo
- Start date
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ir3333
Well-Known Member
Oh my! You must be totally messed up.
A lot of info, but my money is on the rad.
A lot of info, but my money is on the rad.
MDNTEXPRS
Member
CVF serpentine kits as mentioned have 6.4" Crank & 5.3" Water pump pulleys. Their V belt pulleys are 1:1.
Part #'s as follows:
360-SERPENTINE-ALT (Alternator only)
360-SERPENTINE-PS (Power Steering)
360-SERPENTINE-AC (AC & PS)
These are polished. Prefix with B- for what they call their stealth black finish.
I've preached that a lot on here before and it falls on deaf ears. You look at every new car made and the under side of the engine bay is closed off so that air has to be forced through the grille and radiator.
Well......not all of them are less efficient. Most of the el cheapo chinkesium radiators are, but a true 3 row high efficiency radiator will stomp the guts out of most any two row for cooling.
There is a LOT that contributes to rad efficiency. Copper tube rads are limited to tubes about 1/2" long because of copper's poor strength. Alum tubes are often 1 or 1.25" long. The extra length allows for much more fin area. Even though alum is not as good as radiating heat as copper, the great increase in fin area & fin design result in a more efficient radiator. The fins are what dissipate the heat...
Dale Davies
Well-Known Member
I would look for an A/C WP pulley.
Kenflo
Well-Known Member
Going to try a new radiator cap today as that's the cheapest easiest thing to do. If that doesn't work I do plan on trying to find a 7 blade fan. I'm not sure about the pulley swap just yet as they are super hard to find and the 1:1 ratio available from cvf is too small of a difference to justify. Also going to try directing more air through the front of the Rad by playing around with some panels under the car to prevent hot air short cycling back into the Rad.
Dale Davies
Well-Known Member
I was told in the early 1970's that a 340 A/C WP impeller had one less "blade" on it.
I believe Caterpillar rads had alternate tube rows at a slight angle so that the air exiting from between two tubes in the first row, was directed at the sides of tubes in the next row.
2 row, 3 row, and 4 row radiators are somewhat counter productive. All the coolant is passing through all the tubes at the same time. The front row gets the coolest air. Each consecutively gets warmer air, reducing its effectiveness.
A cross counterflow radiator is more effective. You can not buy them, you have to build it. Your coolant will flow horizontally like most new vehicles. You look for an aluminium radiator with a width that will fit your core support. Take a measuring tape to a wrecking yard to find a couple of vehicles with adequately large cores. Then check for new radiators that are less expensive from the same manufacturer, you will need two.
With the plastic tanks removed, you need to build or have a welding shop weld hot and cold tanks with hose connections. These will both be on the left or right side, so the tanks will be tapered so the one hose will pass the other tank. For the other ends, you need a small radius 180° aluminium bend to weld between the two tanks where the coolant will make the 180° turn out of the rear core and into the front core. Then you need another piece for the outside and two end caps to seal it up. On the hose connection end 3- 1" tabs can be welded between the welds between the tanks and cores. Small "channels" can be bent and welded to the left and right ends to seal the air between the two cores. A bit of foam pushed between the tabs to seal the hose connection end tanks.
Hot coolant goes into the top hose connection on the rear core and the coolant returns to the WP from the lower hose connection on the front core. The hottest coolant is cooled by the warmer air. Then the coolant returns to the other end through the front core to be cooled by ambient air. This should keep coolant flow velocity in the tubes high enough to be turbulent, increasing efficiency.
Paul Lamar described this in his royaryeng.net blog or chat. Yes I know, rotary engines and aircraft. Paul has diagrams for this in the discussion. Consider this, rotary engines are notoriously difficult to cool, aircraft run at 75% power for hours, and weight is a concern. Paul passed about 4 years ago. Sad loss as he was very intelligent and inventive. Should still be able to find the site.
I just tried to find the original site, but since Paul passed, it has been changed. I sent an email to see if the original site can be accessed or if I can get a pdf of the cross counterflow radiator process. Paul Sr used two Dodge diesel radiator cores to build a radiator for a time to climb aircraft. This light kit plane had a 650HP two rotor engine that ran on methanol. It is now at the Smithsonian.
They had problems with the injectors getting plugged with corrosion in the aluminium fuel lines after sitting for a week or two. I wrote Paul and explained that Indycar teams drained the methanol every night and put a gallon or two of gasoline in the tank and started it until it ran crappy, indicating the fuel system was purged of methanol. The next time they needed to run the engine they drained the gasoline and put methanol in.
They started doing that with the time to climb engine, and had no more problems.
Hopefully I get a positive response from Paul Jr or another admin.
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Newbomb Turk
Well-Known Member
I can pull out the receipt and give you the part numbers for V pulleys that will get you to 6% over. If you are less than 1:1 now and you can get to 6% over that’s a huge increase.
But, I will say you will have to do some shim work to get the pulled lined up. IIRC I’m using. BBM WP pulley and a small block crank pulley. Or the other way round. But it’s not hard to get them lined up.
Kenflo
Well-Known Member
Thanks! I would greatly appreciate those part numbers when you get a chance.
65TerrorCuda
Well-Known Member
I'm suspect of the efi. I know my afr gauge thinks it's rich when the plugs show lean.
Running hot after Sniper EFI install
Hope you get this fixed!
Running hot after Sniper EFI install
Hope you get this fixed!
Kenflo
Well-Known Member
So tried the new radiator cap (MOTORAD 16 Psi), took it for a nice cruise with very normal operating temps 180-200 depending how fast I was going, brought it home sat in the driveway idling in park for approximately 15 mins and slowly temp increased up to 235 so I shut it off. I could hear coolant going into the recovery bottle. Don't have the IR gun yet but see pics for some temp readings I took of the incoming air going into the rad. Air coming in the bottom through the open space under the bumper is SIGNIFICANTLY higher by 33 degrees. So I'm going to try to cover that spot up with something and recheck.
I guess there is a need to be able to sit stationary for 15 minutes at near 90F? If you can't find the right pulleys at the moment, a pusher aux fan with a toggle control or a thermoswitch would help. Ignore the seller bs cfm ratings (a lot of junk on ebay) and look for the fans for the size that will fit that pull the most amps. It doesn't need to cover the whole core to be effective but bigger is better. Nylon zip rod mounting through your core will clear the engine driven fan and won't damage the core. Use the included foam tabs against the fins. No need to try and make the zips as tight as possible. They are one-time use zips.
I used a pt cruiser fan for primary cooling on a d100 with a 318 by trimming the plastic and riveting on aluminum tabs to pickup the original shroud attachment points, but not as many amps as the early taurus 3800 fan. Just showing ideas for mounting.
I used a pt cruiser fan for primary cooling on a d100 with a 318 by trimming the plastic and riveting on aluminum tabs to pickup the original shroud attachment points, but not as many amps as the early taurus 3800 fan. Just showing ideas for mounting.
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The reason you don't overheat while in motion is because your water pump is spinning at a higher speed and building pressure plus even 20mph air is enough to be just as good as any fans you could be using. So you have a potential air flow AND sounds like water pump pressure issue. someone pointed out water pump pulley ratio. Look into that.
I solved my problem simply by utilizing a much bigger radiator. 4 row copper/brass didn't work, Big dual 1" aluminum rad helped but still didn't fix problem. Dual 1 1/4" tubes completely solved my problem.
I solved my problem simply by utilizing a much bigger radiator. 4 row copper/brass didn't work, Big dual 1" aluminum rad helped but still didn't fix problem. Dual 1 1/4" tubes completely solved my problem.
Kenflo
Well-Known Member
So I spent hours looking at cooling specs from 68-73 and it turns out that ABSOLUTELY my water pump pulley ratio does not add up to my modified 340 application. My pulleys are OEM from a 1973 318 engine and have a ratio of 0.95:1. According to 1971 340 spec there was this same ratio with NO AC however 1972-73years 340 spec have a 1.2:1 STD and 1.3:1 AC spec. So I agree 100% change pulleys however these pulleys are unicorns and super hard to find. I called a machine shop yesterday and turns out I can have a water pump pulley made 5" diameter which would give me 1.31:1 ratio. Cost is around $500 for this custom pulley. I'm pretty sure that 5" diameter will be ok after measuring it looks like the water pump will clear the inside diameter of the pulley. Would the milodon 8 blade high flow water pump need to be swapped to a 6 blade with this ratio?
Newbomb Turk
Well-Known Member
Hey if you are getting one set made can you ask him if it’s cheaper if he makes 3 sets. I want one set and if I can’t find an owner for the other set I will buy them both.
Thanks.
Kenflo
Well-Known Member
I can check into this for sure. I am only getting the water pump pulley made as I plan on using my current 318 2 groove crank pulley. That is unless I can find something on eBay this evening that will work.
Newbomb Turk
Well-Known Member
Reading through your post I see you are getting 5 inch WP pulleys made. Are we sure that’s big enough to fit over an aluminum water pump. In my research (going off memory here) that a 5.5 inch is the smallest diameter that fits the later pumps.
If we can fit a 5 inch on there I’m all for it. If you verified a 5 will fit I’m in. Even if it’s 5.5 I’m in.
Just let me know what he says.
THANK YOU!
Edit: I just read your post again and I see you verified it would fit and since you are looking at 1973 numbers that’s certainly an aluminum pump.
Sorry if I’m not making sense. It’s been a crap show with my parents since Sunday and I don’t see that getting better anytime soon.
My dad has dementia and he fell twice Monday. He’s been in the ER since 2000 hours Monday.
So getting stuff organized and trying to get the VA benefits he earned is taking a big toll on everyone. Plus trying to line up an outside facility to rehab him so he can come home.
So if I’m not making sense I apologize.
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Kenflo
Well-Known Member
UPDATE!!
So I swapped my pulleys. I initially had the 318 pulleys on this set up with a water pump pulley/fan ratio of 0.95:1 under driven. I managed to find some pulleys here on FABO which are according to the factory service manual 1973 340 with NO AC 1.20:1 overdriven. Crank pulley measures 7.25 for water pump drive as well 7.25 for power steering drive. Water pump pulley measures 6". Took it out for a good cruise and temp maxed out at 200 after idling for about 15 mins in the driveway at home after the cruise. During the cruise temperature maintained close to my thermostat temp which is 180. This is A 40+ degrees difference at idle! I am super happy with the results and I would like to thank all the members here on FABO That have helped me out on this one! I attached some pics to show the pulley difference.
Thanks FABO!!
So I swapped my pulleys. I initially had the 318 pulleys on this set up with a water pump pulley/fan ratio of 0.95:1 under driven. I managed to find some pulleys here on FABO which are according to the factory service manual 1973 340 with NO AC 1.20:1 overdriven. Crank pulley measures 7.25 for water pump drive as well 7.25 for power steering drive. Water pump pulley measures 6". Took it out for a good cruise and temp maxed out at 200 after idling for about 15 mins in the driveway at home after the cruise. During the cruise temperature maintained close to my thermostat temp which is 180. This is A 40+ degrees difference at idle! I am super happy with the results and I would like to thank all the members here on FABO That have helped me out on this one! I attached some pics to show the pulley difference.
Thanks FABO!!
Newbomb Turk
Well-Known Member
Chrysler wasn’t stupid when the over drove the water pump.
Just keep the secret to yourself.
I would still fill that lower splash area with the correct panel, and replace the fan with a 7 blade.
mopowers
Well-Known Member
Do you happen to have the part number of that water pump pulley?
The slant 6 with AC pulley is also small and will work. I have a few of those myself.
Kenflo
Well-Known Member
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