offroadinca
Newbie
Was the fin depth the same, the tube pattern the same, the tube wall thickness, the fin density, the flow rate. Did you change coolant, hoses, t-stat water pump or anything else...Really was it all the same?
CK5
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BBC swap - now gets hot**MOD UPDATE
- Thread starter pismorat
- Start date
Everything was new to start with, with less than 1000 miles on any one part. I have no idea as to the tube pattern, thickness, etc. Everything else was exactly the same. Its had dex cool in it since I built it. I tried a 4 core stock rad, an aftermkt 4 core copper/brass rad called a "Turbo Cool" and they both did about the same. Changed to the Aluminum and dropped the temp significantly.
Oh, and the physical size of all three rads are the same.
offroadinca
Newbie
The core design impacts the cooling far more than material. If the tubes, fin density, fin surface and tube layout are different than you are comparing apples and oranges.
GMC1977
1/2 ton status
Running a engine with no thermostat is a bad thing. Cylinders are suppsoed to get up to proper temperature before the coolant get to them. Which is why the thermostat is there.
If you run one without a thermostat you can cause cylinder damage from the proper temperature not being reached.
not going to be hurtful, but there is always coolant around the cylinders. A thermostat only holds coolant in the engine, slowing/stopping it from the radiator.
2 cents, even if I had a train previously run them over, here they are
If a temperature of 210 is reached, that means any T-stat u put in will be open, even a 180/195. You will still run a 210 reading. On EFI/ newer cars, putting that low a T-stat will cause it to run rich, thinking it needs to warm up. Running too rich can cause overheating and timing issues. But, there is no EFI is there lol.
The short hose from intake to pump really only has flow when the engine is cool. It shouldn't have much flow once the T-stat is open, passing it to go into the radiator return hose. Once its running hot (160/180/195) the T-stat is open and coolant is flowing easily to the larger hose. I do see the idea hot water is bypassing the radiator, but is it enough to cause overheating?
Why is a BBC 4 row radiator from back in the day all-of-a-sudden not good enough for everyday driving? It worked in front of BBs all these years. Either damaged fins, it's clogged, flows too quicking in/out, or a damaged condenser is in the way.
Water pump is unknown, "came with engine".
Fan is 6 blade, worked in the past, not mounted backwards lol
Fan clutch, 1 year old, worked in the past, chances its warn out are low
Brand of hoses are unknown. The best lower radiator hose you can buy should be in place. The upper hose can be crappy, there is no strain on it. But the lower has to deal with hot temps and enormous vacuum. Could be bent or constricting flow when hot. Like the old ones with springs, keeping them open. When the truck is hot, take a look see. A good gates or equivalent should be in place. Keep the old ones for trail spares.
Are we sure the engine was put back together correctly? Like an accident was made or gaskets put on wrong, incorrect gaskets, etc I dunno.
just thinking out loud
pismorat
1/2 ton status
Well...my wife's '69 C10 had a 7-blade fan on it that fit a fan clutch, so I swapped them! I will get a 180* thermostat tomorrow and put it in, then give the system a try. I have not re-plumbed anything, but am still curious which way water flows through the 2 ports on the top of the water pump. I have a coolant filter in-line and want to make sure it is hooked up correctly.
pismorat
1/2 ton status
So with the 180* thermostat and 7-blade fan...still no change. With a cool night last night and just driving it easy, it was constantly around 190-200, and even got like 210 or 215 going up a slight hill. I am thinking now the radiator is shot?
The ports at the top of the water pump are pump inlets.
Mountain_man
1/2 ton status
I'm gonna go ahead and say timing will be a good place to check. It's that or a plugged radiator. Timing will be easy to check just to make sure things aren't somehow off.
pismorat
1/2 ton status
The timing is at about 10 deg. BTDC w/ the vac. adv. unplugged. I tried pulling it back some and it didn't run worth a sh** and was still getting hot. My only thought is radiator.
Does anyone know if the 6.2L Diesel radiator (~41" wide) will fit in a truck with A/C? The condensor lines seem like they might be in the way, but I can't tell if they can move out of the way.
Does anyone know if the 6.2L Diesel radiator (~41" wide) will fit in a truck with A/C? The condensor lines seem like they might be in the way, but I can't tell if they can move out of the way.
I put a big 6.2 rad in my 91 K5 but I don't have a/c (anymore). If it helps all of the added width is on the driver side.
pismorat
1/2 ton status
Yeah, I just don't know if it comes over far enough to hit those hard lines from the condenser...or if they can be moved further to the drivers side. Did you have to cut out the hole in the radiator support to make it wider to allow air to hit the extra width of the radiator?
thats what I'm headed to do also. Did you have to make new lower supports for the radiator to sit in?
Did you use the 6.2 shroud?
What fan?
While my 91 was originally a 350 truck with a 2 row rad, the core support had both the extra lower slot and place on the upper tie bar with threaded holes making the big rad a direct bolt in. I used the matching 6.2 shroud as well. I did not cut the core support open for the rad, I figured since it was a direct bolt in the GM engineers made the hole the appropriate size also. I suspect any truck built in the 6.2 era will have a similarly equipped core support.
For the fan I'm using a HD fan clutch (application = '83 K30 dually w/ 454, 4spd & 4.56 gears) and a 7 blade fan.
Two things I did do to make it fit - 1) I had the upper hose nipple on the rad changed to fit a 454 hose (diesel nipple was way to big). 2) On the lower hose I used a 6.2 hose which fit the rad but was too big for the pump. I bought a 454 lower hose and cut about 3" off of the pump end and used it as a bushing to make the bigger 6.2 hose fit.
After all was done the set up fit like stock and no crazy flex or chopped up hoses to remember (except for the bushing which I can reuse).
For the fan I'm using a HD fan clutch (application = '83 K30 dually w/ 454, 4spd & 4.56 gears) and a 7 blade fan.
Two things I did do to make it fit - 1) I had the upper hose nipple on the rad changed to fit a 454 hose (diesel nipple was way to big). 2) On the lower hose I used a 6.2 hose which fit the rad but was too big for the pump. I bought a 454 lower hose and cut about 3" off of the pump end and used it as a bushing to make the bigger 6.2 hose fit.
After all was done the set up fit like stock and no crazy flex or chopped up hoses to remember (except for the bushing which I can reuse).
Check the lower radiator hose to make sure it is not being sucked closed, and restricting the flow of coolant.
A problem I have had with two different older 454 engines, which were not overheating but running excessively hot, was casting-flash in the cylinder head combustion area. I machined the cylinder head combustion shrouds, in order to bring them up to the standard they should have been from the factory, and the engines worked great from then on, without ever getting over 180-degrees even in the toughest of conditions. I am not saying this is the problem with your engine though.
A problem I have had with two different older 454 engines, which were not overheating but running excessively hot, was casting-flash in the cylinder head combustion area. I machined the cylinder head combustion shrouds, in order to bring them up to the standard they should have been from the factory, and the engines worked great from then on, without ever getting over 180-degrees even in the toughest of conditions. I am not saying this is the problem with your engine though.
