I have a newly machined block, new rotary kit, new water pump, new thermostat, new aluminum radiator with twin 12" spal fans and a shroud, but, I can't keep this thing cool. I'm running a 160 thermostat and once I take off driving, it jumps to 230 quickly. I run back home before it gets hotter!
I did lose a lobe off a cam I had in the motor and put a new one in. It took 3 sessions to get enough time at 2k to break in the cam because the temp kept jumping up to the 230 area...
I had the radiator flow checked last week and it's fine.
Any ideas as to what could be causing the overheating?
Try a 180 or 190 thermostat, your 160 is staying wide open you have no control of your fluid. The motor will run little hot until the rings set seated in.
as this car wasnt a 400 to start with (judging from the hood), you most likely dint have 3 items that were on 400 `s and AC cars...and when you put a 455 in it those would be required 1) X filler panels 2) lower baffle 3) rubber or 'masticated' fillers on ea side of bottom of radiator
If you have those...keep looking, but if you dont have those , I bet installing those will bring you down 20-30 F....
as this car wasnt a 400 to start with (judging from the hood), you most likely dint have 3 items that were on 400 `s and AC cars...and when you put a 455 in it those would be required 1) X filler panels 2) lower baffle 3) rubber or 'masticated' fillers on ea side of bottom of radiator
If you have those...keep looking, but if you dont have those , I bet installing those will bring you down 20-30 F....
I have already run my car with a practically brand new 455 in Oklahoma summer heat WITHOUT my original x panels, lower baffles or rubber fillers (to be installed after I get it painted) without any cooling problems whatsoever.
It's my opinion that if you have solved your cooling problem, the added benefit from those factory fixes is not all that great and should not make the difference between boiling over and not.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
Until we get more info on the car we're flying blind, a fresh motor running 230 degrees isn't horrible, remember pontiac idiot lights came on at 243ish. Definitely ditch the 160 degree stat though for at least a 180.
Take the thermostat out and test it. I've had plenty of bad ones right out of the box. What kind of a bore is on that 455 and are you running high pro parts? I believe the 74 and newer blocks (correct me if I'm wrong) were not as heavy duty as earlier years. So if your running a sixty over bore with high pro pistons, cam, high compression, whatever, on a 75 block, there may be problems in cooling no matter what rad, pump your running. Also throw in timing too.
as this car wasnt a 400 to start with (judging from the hood), you most likely dint have 3 items that were on 400 `s and AC cars...and when you put a 455 in it those would be required 1) X filler panels 2) lower baffle 3) rubber or 'masticated' fillers on ea side of bottom of radiator
If you have those...keep looking, but if you dont have those , I bet installing those will bring you down 20-30 F....
I have already run my car with a practically brand new 455 in Oklahoma summer heat WITHOUT my original x panels, lower baffles or rubber fillers (to be installed after I get it painted) without any cooling problems whatsoever.
It's my opinion that if you have solved your cooling problem, the added benefit from those factory fixes is not all that great and should not make the difference between boiling over and not.
maybe.....when I got my car it had been a 350 car and no AC...PO had installed a 400...evidently it ran hot as he added a pusher help fan ,which didnt help...I drove the car back from DFW area to Houston...235F most of the way ,240 uphills...I got rid of the helper fan, added one missing rubber filler and the X fillers, reduced 15F right there...for some reason my car had a rubber filler and the lower baffle (must have been installed along the different ownerships at some point)....after several other small Items over the past 11 yrs I got the car to run 200-205...last year I added a 3 core Champion alum radiator...now runs 190-195 F
Yes, but I'm talking about cruising with no overheat problems at the speed limits for most of the central streets in Norman: 30 - 40 mph in the late afternoon during the summer here. Temps in the high 90's with 40 - 50 % humidity.
At the speeds I was experiencing - the factory baffles and stuff would not be helping.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
Yes, but I'm talking about cruising with no overheat problems at the speed limits for most of the central streets in Norman: 30 - 40 mph in the late afternoon during the summer here. Temps in the high 90's with 40 - 50 % humidity.
At the speeds I was experiencing - the factory baffles and stuff would not be helping.
yes its different...I`m talking about speeds of 70-85 on freeways, with temps in 95-100..and 80-90% humidity...with the 'old' radiator it would stay at 200, you exit slow down to a red light, temps go up to 115, as soon as you start moving again on a street 40+- mph,down to 205....
baffles and fillers push the air that other wise go around the radiator ,thru it...at 'most' driving speeds....not at standing still or under 35 mph...
True, it was a 326 car with AC. The filler panels and baffles are in it too. But even still, I'm running the aluminum radiator with 2 12" pull fans. It ought to be drawing enough air I'd think.
yeah, like I can put a 455 in the car but put a thermostat in upside down?
has happened before.....not you maybe... I`ve even seen pros do stuff you can believe...cant get a car to start, checking everything....and...its out of gas!
I've tried 3... 2 - 180's and this 160. The block was a .030 bore and I'm using a rotary kit from Butler (new everything - pistons, connecting rods, crank, etc).
* New Crank 4" Stroke * 3.25" Main (428-455 blocks) or 3" main (389-400 blocks) * 3" Main has 2.200 rod journals o 6.635-6.700-6.800 4340 forged H-Beam Bushed rods *3.25" Main has 2.250 rod journals o 6.625 4340 forged H-Beam Bushed rods * Ross Pistons *Pin Fitted * Total Seal Classic Race Rings * FM/CL Main & Rod Bearings * Balanced Internally
I'm using a MEL-SPC-8 cam and an Edlebrock Peformer intake.
I'm using a set of 6X heads off a '79 400
My water pump came from Butler as well and is the 11-Bolt 1969 1/2-77 Pontiac Hi-Volume Aluminum Water Pump-FlowKooler.
How's the divider plate clearance between the impeller blades and the plate? This is one point that can be optimized.
Yes it is possible, very possible, to have great technical skills and miss a minor point. Not to say you did, but finding those minor points when by the books everything looks right is how I make my living.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching
New divider plate, good. What is the clearance between the impeller blades and the plate? Should be as tight as possible without interference. Generally speaking that means flattening up to 1/4" or more to get that tight fit to enhance circulation.
With cooling issues as severe as yours, though, it's probably more than one issue.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching
Does anyone have photos of the rubber masticated fillers and lower baffles? I don't quite know what to look for.
I run hot as well. Ran hot, run hot. Had copper original style rad & clutch fan, 68 style pump & TC cover. Now on aluminum, 2 x electric fans, 69 style water pump & TC cover. All water flow thru engine area is clean. Water flow through radiator is aggressive with the 69 style pump. I definitely have the upper "x" baffles between the nose and radiator, just don't know if I am missing elsewhere.
Low temp thermostat. I don't understand the science behind getting lower temps with a higher temp thermostat...
185 at night. 220+ at red lights or 3000 rpm. 230+ with A/C and speed or traffic.
1968 Firebird 400 Convertible Original: Engine, Intake manifold, Heads, Body, Stereo, 3.08. THM400. Engine rebuilt by Ken Keefer early 2012. New: Holley 4bbl 670 HP, hidden iPod setup, RobbMC mini starter, A/C, front disc brakes
OK, I'm going to have to say it again - because I see a pattern developing here.
EVERYONE I have ever personally known with a classic car overheating problem seems to have experimented with electric fans and found relief finally by going back to a good 'ol HD clutch fan and shroud that the factory designed for their car for A/C or HD cooling applications. This has crossed different makes AND models of cars, too.
I have seen this enough times that I would never consider electric fans as a potential solution. I just do not see how 12 Volt electric fans can come close to pulling the CFM of air like a belt driven metal fan.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
OK, I'm going to have to say it again - because I see a pattern developing here.
EVERYONE I have ever personally known with a classic car overheating problem seems to have experimented with electric fans and found relief finally by going back to a good 'ol HD clutch fan and shroud that the factory designed for their car for A/C or HD cooling applications. This has crossed different makes AND models of cars, too.
I have seen this enough times that I would never consider electric fans as a potential solution. I just do not see how 12 Volt electric fans can come close to pulling the CFM of air like a belt driven metal fan.
Agreed, as far as the previous question about thermostat temp rating, if you have a 160 degree stat, it will initially open and then more than likely never close(hot climates)therefore the coolant is not spending enough quality time with the radiator to transfer the heat from the engine to the atmosphere...get it? got it? good
Agreed, as far as the previous question about thermostat temp rating, if you have a 160 degree stat, it will initially open and then more than likely never close(hot climates)therefore the coolant is not spending enough quality time with the radiator to transfer the heat from the engine to the atmosphere...get it? got it? good
just as why you never take the T-stat out as some think will help, water runs thru radiator too fast
I have pics of the clips I used.... lets see if that helps?
the first two pics are of the rubber filler as now sold,with the Chrysler headliner clips I found in "Help" section....the other two are a real 'masticated' filler, (see the difference?) and the original GM clips used...(hard to find)....hopefully you can at least see what how they fit....on either side of the bottom of the radiator, where there`s a rounded triangular shaped 'hole'...there are 2 (3?? , I think 2) holes ea side for the clips to fit in....
You are missing the lower baffle that attaches to the valance and fender extensions...the air is going in and instead of being forced through the shiny new aluminum radiator, it is chosing to go right under it...path of least resistance.
looks like no masticated fillers also...looks like they should close up the opening in your last picture...to stop the air from going besides the bottom of radiator also...
Jeff and Bjorn! Thank you! I will get those parts ordered up!
I have a car that was originally non-AC but is AC now. Do I go for the AC masticated or non-AC masticated?
the "AC fillers are the same as non AC , w exception of a cut out for evaporator line...but as yours is most likely not "factory" air, I`d go with the non ac fillers
