Moparts

big block cooling issues

Posted By: tex013

big block cooling issues - 02/07/14 07:12 AM

having problems with a 440 wedge just gets hotter etc .Have replaced blocked radiator with cross flow type , no change . Waterpump , iron curved impellor fittel paddle type , no change .Thermostat or not , no change .
I recall there was a guy here who plugged or reduced the size of the bypass port in the waterpump housing . Am I correct ? It does have a aluminium housing
Motoris a bit of an unknown , maybe 11:1 , eddy heads . Does only have 17deg BTDC , probly a bit low but should not be that far off , may need 20

Thoughts ,
Tex
Posted By: Jeremiah

Re: big block cooling issues - 02/07/14 07:23 AM

a) Have you checked the water pump housing for casting flaws blocking flow?

b) Is that initial or total timing advance?

c) What fan are you using?

d) Type of carburetor and jetting?

All of my engines past and present that utilized big aluminum radiators had to work to get and stay up to temp unless it was the middle of summer.
Posted By: tex013

Re: big block cooling issues - 02/07/14 07:44 AM

Jeremiah,
the housing is my next move .
timing is initial
big electric fan
1050 dominator running a bit rich
there is about 35degree F drop across the radiator but at tstat is 230-240
thanks

Tex
Posted By: Jeremiah

Re: big block cooling issues - 02/07/14 07:52 AM

I assume you are using a infrared temp gun to troubleshoot? Have you verified it is correct. Dumb question but I had to ask.

Have you checked the thermostat?

What turns the fan on and off?
Posted By: Gabby63

Re: big block cooling issues - 02/07/14 07:57 AM

You say the engine is an unknown , could the block have filler , hardblock , if so could be too full . I had one of those once . Gary
Posted By: GTX MATT

Re: big block cooling issues - 02/07/14 09:07 AM

That initial timing is likely sufficient, but you could try more it wont hurt. It sounds like a more radical build so it may even like it. If you've got vacuum advance you can just hook it to manifold vacuum to test it easier.
Posted By: an8sec70cuda

Re: big block cooling issues - 02/07/14 02:44 PM

Tap the bypass hole in the housing underneath the thermostat w/ an NPT tap and install a plug...then drill a 1/8" hole through the plug.
It's been so long since I did it I can't remember if it was 1/4 or 3/8 NPT.

This helped dropped the temp 5-10 degrees if I recall correctly.
Posted By: MR_P_BODY

Re: big block cooling issues - 02/07/14 06:39 PM

How long of time are you talking here... from a cold
engine up to 240... if its a short time I would think
its not flowing water
Posted By: Crizila

Re: big block cooling issues - 02/07/14 09:40 PM

Quote:

having problems with a 440 wedge just gets hotter etc .Have replaced blocked radiator with cross flow type , no change . Waterpump , iron curved impellor fittel paddle type , no change .Thermostat or not , no change .
I recall there was a guy here who plugged or reduced the size of the bypass port in the waterpump housing . Am I correct ? It does have a aluminium housing
Motoris a bit of an unknown , maybe 11:1 , eddy heads . Does only have 17deg BTDC , probly a bit low but should not be that far off , may need 20

Thoughts ,
Tex

If good at cruise, but over heats at idle / not moving enough air over the rad. Other way, not enough rad or coolant flow problem. Most filled blocks don't have a coolant problem. They got higher oil temps - unless the block is 100% filled.
Posted By: Thumperdart

Re: big block cooling issues - 02/07/14 09:46 PM

Quote:

having problems with a 440 wedge just gets hotter etc .Have replaced blocked radiator with cross flow type , no change . Waterpump , iron curved impellor fittel paddle type , no change .Thermostat or not , no change .
I recall there was a guy here who plugged or reduced the size of the bypass port in the waterpump housing . Am I correct ? It does have a aluminium housing
Motoris a bit of an unknown , maybe 11:1 , eddy heads . Does only have 17deg BTDC , probly a bit low but should not be that far off , may need 20
Thoughts ,
Tex




Which fan are you runnin............
Posted By: rickraw

Re: big block cooling issues - 02/08/14 03:10 AM

Are u useing a shroud & a puller fan? If not, the biggest rad u can fit still won't cool.
Posted By: tex013

Re: big block cooling issues - 02/09/14 10:49 PM

guys,
it just gets HOT . you drive around the block at work it will go 230/240
the $64 question is I hope there is no filler .
thanks for coming on with the housing plug - didn't think I dreamed that.
Monday morning now - back into it

Tex
Posted By: RapidRobert

Re: big block cooling issues - 02/09/14 10:54 PM

Quote:

a) Have you checked the water pump housing for casting flaws blocking flow?


X2. EDIT I'm assuming the gauge is accurate but if it IS that hot I'm sure there is no doubt about it. For it to be getting that hot that fast I'd look at. Adv weight frozen or partly stuck (not likely). restriction in alum housing (very likely in early 'source ones). combustion leak into cooling system from cracked block or head or head gasket issue (does happen). No experience with hard blok
Posted By: TJP

Re: big block cooling issues - 02/10/14 02:11 AM

Pull the cap and see if it's moving coolant, years ago had a big block that constantly overheated, Pulled the water pump and the impeller was laying in the housing, HMM wonder why it was getting hot.

Start with the basics and collect data, analyze and report back. if it's getting that hot after a drive around the block the problem should be readily apparent, IE: stuck thermostat, plugged radiator, collapsing intake hose, plugged radiator hose (think shop rag, incorrect fan, incorrect pulley ratios, extremely lean etc.
Collect the data, keep it simple and report back
Posted By: fourgearsavoy

Re: big block cooling issues - 02/10/14 02:30 AM

Are your pulleys correct? I had some cooling problems of my own for a while until I put the factory pulleys on and a proper clutch fan.
I wasn't moving the water fast enough through the cooling system with a "drag race" type cooling system.My car was going up to 230 with no signs of cooling down until I put a stock system on it and all was well
Gus

Attached picture 8033560-frontveiwsavoy.jpg
Posted By: 340SHORTY

Re: big block cooling issues - 02/10/14 03:23 AM

What brand of water pump housing do you have? I hear the 440source housing have small passages and are very restrictive..
Posted By: Supercuda

Re: big block cooling issues - 02/10/14 03:43 AM

Quote:

guys,
it just gets HOT . you drive around the block at work it will go 230/240
the $64 question is I hope there is no filler .
thanks for coming on with the housing plug - didn't think I dreamed that.
Monday morning now - back into it

Tex



If you are driving around the block and it gets hot, either you have some large blocks there or something is not even close to right.

Does it puke coolant?

Is the hose really that hot? careful you do not burn yourself.

How do you know your gauge is right?
Posted By: bonefish

Re: big block cooling issues - 02/10/14 04:02 AM

make sure your belt is tight enough.sometimes the old original pullies can get worn and even spread out just enough where you need to run your pully tighter than recomended.
Posted By: Dodgem

Re: big block cooling issues - 02/10/14 04:16 PM

Pull the thermostat and fill block from there may be a vapour lock?


Fan blades on right way around? don't laugh I've seen it!

Check the timing mark is right on the balancer (use a piston stop) and the timing to 36 total no vacuum advance hooked up at this point.
Posted By: tex013

Re: big block cooling issues - 02/10/14 10:54 PM

Hi,
cooling fan is 16" electric blowing the correct way , pull type. no thermostat . fitted factory iron housing , had aluminium with way smaller intake ports . restricted bypass in housing . raised rear of bonnet to release air better , no gain though after driving and with motor idling 225temp opened bonnet and temp dropped to 205 . tried 2 waterpumps , 1 had curved fins - 1 had pressed metal paddles . pulleys appear stock steel , 6 3/4" crank similar size on pump . I do have a slightly smaller pump pulley , maybe 1/4" . when you pull the cap on rad you can see water flowing
I can open up the hole under the hemi style scoop if need be .
I can try a 7 blade fixed fan though I have no shroud to suit .
I will check timing though it does have TCI rattler
thanks again ,

Tex
Posted By: Jerry

Re: big block cooling issues - 02/10/14 11:00 PM

I would start looking at your ignition and cam timing. what do the plugs look like? are you running way lean? a 16" fan maybe a little too small for a big block. might be better off with two 10" or two 12" fans
Posted By: RapidRobert

Re: big block cooling issues - 02/10/14 11:29 PM

Quote:

cooling fan is 16" electric. raised rear of bonnet to release air better , no gain though after driving and with motor idling 225temp opened bonnet and temp dropped to 205.

My you need more airflow. A good properly spaced clutch fan/shroud will pull a tornado of air thru the rad. A smaller pump pulley will likely help tho how much I ain't sure.
Posted By: tex013

Re: big block cooling issues - 02/10/14 11:34 PM

Jerry,
balancer is pretty close 17BTDC bit low but not too far off probly needs 20 . Plugs are black , I know it is running rich , has a 1050 dom which is an old crap one no ability to fit a power valve
Fan
it does pull noticeable temp out top tank to bottom , 195/140 with fan on
I was told motor was built by Ed Miller
Tex
Posted By: RapidRobert

Re: big block cooling issues - 02/10/14 11:37 PM

Quote:

Fan
it does pull noticeable temp out top tank to bottom , 195/140 with fan on

Correct, that is a pretty good drop
Posted By: TJP

Re: big block cooling issues - 02/11/14 12:53 AM

you are saying you have good flow, and a good temp drop across the radiator but are still running warm

How are you measuring your temperature
IE: what type of gauge, mechanical ,electrical etc.
and
where are the sending units located. I do not trust gauges until I have verified their accuracy. I DO NOT TRUST GAUGES UNTIL I HAVE VERIFIED THEIR ACCURACY.

I use a digital thermocouple meter with probes that can be placed in multiple locations to do so

Once the probes are in place I will compare the gauge readings to the meter.


First test At IDLE. Write both the gauge and meter readings down from a cold start.
How long does it take to warm up and at what temps does the fan turn on.
Does the temp start dropping shortly after the fan turns on????

Second test: repeat the above tests while driving the vehicle short distances.

If the temp increases abnormally while driving it,
you either have to small or a blocked radiator, restriction in the system somewhere, (Do you have a spring inside the lower hose to keep it from collapsing IE: sucking shut as the rpms increase.)
lack of airflow to the radiator,
air going around rather than through the radiator or
worst case an overfilled block.
Do be aware that the thermostat also serves as a restrictor to keep the coolant in the radiator longer to exchange the heat and removing it can cause heating issues. One can substitute a large washer or gut the thermostat.


FYI I have seen more than one aftermarket gauge be off by as much as 60 degrees at 200. It seems as though the warmer the temp is the farther out of whack a bad gauge /sending unit will go.
keep us posted
Posted By: HemiSportFury

Re: big block cooling issues - 02/11/14 01:59 AM

Quote:

Quote:

Fan
it does pull noticeable temp out top tank to bottom , 195/140 with fan on

Correct, that is a pretty good drop



That's a good drop IF there is good water flow through the radiator. Low water flow will also show a good drop but not provide much cooling.
Posted By: fastmark

Re: big block cooling issues - 02/11/14 01:59 AM

Since the motor is unknown, I'll throw out what happened to me, twice. I bought a NOS 440 short block from Mopar in the eighties. Built a set of 906 heads and used it in a tow truck. It always got hot, 220 to 240 all the time. Vapor locked all the time.Gave up and put a 400 back in and it was fine. A buddy bought a block from the wrecking yard at the same time and we built a HP street motor using 906 heads. We could not keep it cool at all either, just like yours. We changed the block in his with a 70 440 and cured the problem. All the other parts were the same. I did some research and found out that motor home blocks cast in 76-78 had extra cooling holes down by the bottom of the cly and you MUST use the correct matching motor home heads or it will not circulate and over heat. I looked and both blocks had the cooling holes. The proper heads are just 452 heads but they have an extra hole that is drilled around the steam holes.I finally found some motor home heads and now that motor runs cool. They are the heads that run the small tapered head spark plugs lick a chevy. check the date of your block.
Posted By: 67coronetman

Re: big block cooling issues - 02/11/14 02:43 AM

Use a clutch fan setup & a shroud and a good stat...
Posted By: tex013

Re: big block cooling issues - 02/12/14 06:31 AM

ok ,
well now I am getting somewhere .
As a last try I fitted a 18" fixed 7 blade fan with no shroud . It ran 170-185 , go figure.Not the ideal combination but can be worked on , not keen on running this combo at the strip . I did try a 20" clutch fan , no shroud ran closer to 200 .May end up like my Satellite , 5 blade clutch fan with some sort of shroud with a 12" pusher fan with manual control .May also open up the bonnet under the hemi scoop to allow more heat out like my six pack bonnet .Oh I also refitted the aluminium housing and pump, no difference .
Now to run it more than 15-20 minutes on the street
thanks again ,

Tex
Posted By: RapidRobert

Re: big block cooling issues - 02/12/14 06:53 AM

Quote:

well now I am getting somewhere .
As a last try I fitted a 18" fixed 7 blade fan with no shroud . It ran 170-185

Progress . Was that stoplight to stoplight or out on the highway?
Posted By: tex013

Re: big block cooling issues - 02/12/14 11:43 AM

Just the local streets ,and industrial area
Just suprised a big electric fan that covered over half the new radiayor core wouldn't cool like an unshrouded fan 4" off the core . Especially with the original core being partially blocked.
Tex
Posted By: TooMany62s

Re: big block cooling issues - 02/12/14 01:17 PM

It seems the pursuit of a cooling system that works better than what the factory had continues, with no success. Even un-shrouded a factory fan is pulling some air over the entire surface of the radiator. An electric fan, with no shroud, or one that covers only 50% of the radiator is only pulling air over 50% of the radiator surface.
© 2024 Moparts Forums