Cursed overheating..

[defiance]

Yeah, but when it comes down to it, when I bought this car, I knew the engine had probably been configured ... very weak, let's say.  The dyno confirmed that.  I knew it could use some major changes, but I just didn't want to tear it open...


I'd say this is a good excuse.  Finally enough of a kick in the pants that I'm ready to tear the thing apart in frustration anyway, so I might as well channel that effort into tearing it apart for some major improvements

[Mike DC]

 
Nothing major to add to this discussion, but a few tidbits:


--  This has gotta be a real cooling system problem.  240 degrees isn't a minor issue anymore.  Plugged radiator, really bad airflow at speed, a bubble in the cooling system . . . something bad is really going on here.  Maybe some combination of these factors.

--  Modern gasoline makes these motors run hotter than the original stuff ever did.  It's sorta "watered down" compared to the older stuff.  I think this is more at fault for the overheating than the overbored motors.  (Lots of modern engines come with cylinder walls no thicker than a lot of overbored old Mopar engines, and they don't overheat like this.  But on the other hand, our gasoline's been getting weaker at the same time that we've been overboring more & more of the old motors we use.)

--  The "Water Wetter" stuff really works pretty well.  It basically makes the coolant into a "thinner weight" liquid so it circulates into the hot nooks & crannies of the motor better.  It won't solve this problem but it's worth spending money on.  Might even buy you 10 degrees on a motor that doesn't have other cooling problems to address.

 

[TylerCharger69]

I know that on the B/RB waterpumps, that they come in a 6 blade impeller  (usually like a 2bbl 383 like mine was)  or an 8 blade impeller used on Hemis, R/T cars, and probably a few others.  When you go to the parts house and get a water pump,  the book says they all fit which is true, but there are those major differences between the two.  I remember getting two different water pumps for my car a few years back....the part number they had was the same, but the impellers were different.   It's worth a good look!!!

[crzyc68]

1970440RT,
When you took off the square shroud, did you leave the fans on or were they one piece like the flex-a-lite setup?

[1970440RT]

     The shroud I had came with the radiator and was aluminum.  The shroud was cut by the mfr. for the dual fans to set in. 

     I was actually thinking of cutting " trap doors " in the shroud to let air pass thru at speed, but then snap shut when at idle to let the electric fans do their work.  The dual fan set up seems good enough at idle but the shroud lets the water get too hot at top end.  I drove to the Nats on friday afternoon and before I got off the Brice Rd. exit,  I was doing 80 to 90 mph.  The water got to 225.  In the bumper to bumper on Brice Rd., the temp climbed to 230 deg but not more.  I think if I can control the cruising temp, the idle temp will follow suit.

[crzyc68]

You know I just recently saw some shrouds like what you are talking about online.  What kind of material would you recommend using for the trap doors and how many would you put into the shroud?

[1970440RT]

     Since the fans are offset, I would offset the doors as well and make them as big as space will allow.  I just haven't figured out a way to fab the doors on some type of hinge that would be reliable enough to open at speed with the wind through the rad and shut at idle when the airflow stops.  Ideally I would like to see how someone else did it first before I hacked into an expensive aluminum shroud.

     I just read a thread on Moparts on how some guys are using electric fans off old ford t-birds and tauruses.  Apparently they work very well as the factory fans move more air than the aftermarket fans.  I probably will try this before I cut up the shroud. 

[Steve P.]

So,,,, Have you pulled the heads off yet??

I just read through the post and didn't see anything about white smoke,(steam), from the exhaust. Have you looked??

How about the pressure test??  Did it hold for a while up near the RED??

Rad. doesn't sound like the problem to me. Sounds like a head gasket or a crack to me.. 

[defiance]

Sorry, gave up on 'fixing' it, and decided on a major rebuild...  Still, when I pulled the heads, there are small water tracks.  It never white smoked, and the oil never really looked milky, but I'm honestly not sure why --  it was definitely a head gasket problem..  Maybe the leaks just weren't enough to get milk-oil, or maybe I just didn't run it enough to make the oil visibly different (I changed the oil every 3 months, and it probably never got more than a hundred miles or two because of the heat problems...)