1968 Engine running hot and overheating

[DaveLev]

Also saw Rotella at Auto Zone store today when looking for the PCV gasket.

 

[DaveLev]

As promised here is a photo of the fan and the edlebrock water pump. Not high quality photos, but these are what made the biggest difference in keeping mine cool:

 

[DaveLev]

Went on a road trip with the hood installed and a GPS. In my rig when speedo says 60 mph it is going 66. When it reads 70 mph I'm going 80. At 73 on the speedo I'm doing 85 and was asked to slow down.

All was on level ground. At 80+ we saw temps rising to 210. Otherwise over 65 we were around 205 degrees. Anything from 55 to 66 we were at 195 or so. In town we were anywhere from 165 to 180. Remember our thermostat is removed and high volume water pump.

I think our troubles are far from over however. When driving the car would hesitate, or stop and restart in sub-second times just long enough for us to notice.

It feels electrical in nature or maybe fuel delivery. No idea what is happening. Open to suggestions. Did not happen a week ago and only thing new is ballast resister and hood back on. Solid connection and ballast resistor.

 

[blubuckaroo]

Does it die out randomly, or hesitate under a specific condition e.g. light acceleration, hard acceleration, over bumps??:?

 

[DaveLev]

Ooh that's a great question, thank you. We noticed it under light acceleration and heavy. Not bumps, and when just 'cruising' at 70+ MPH, we didn't notice it at all. I say we because I was with my wife who was holding the cell phone GPS to get accurate readings on MPH. The fact that she even noticed it - just a millisecond delay/hesitation - tells me it wasn't just my mind playing tricks on me. I was thinking maybe cam float or something ridiculous like that, but RPMs were 3100 or less most of the time.

Carb completely rebuilt, new fuel filter, new fuel pump, new hoses, new sender, new sender filter in tank, stock rear tank cleaned (awaiting budget to upgrade to 23 gallon), Seafoam & premium in every tank since I bought it 4 months ago, no side tank or fuel selector installed (bypassed with new 3/8 line).

It certainly may be dirty gas or clogged carb filter. 2 barrel factory intake & carb, FYI.

Do you think fuel or ignition/spark related? Hesitant to put in the new electronic points (petronix) until I find root cause of this issue. I have good digital volt meter, and can take readings at coil, ballast, etc., if you think that would help.

Thanks again for asking. I should also note this happened on a relatively cool night - 75 degrees or so - and engine temps weren't too hot. Wondering if new MSD ballast or MSD coil is the problem. Not certain.

 

[blubuckaroo]

You could try adjusting the accelerator pump lever for a bit more stroke.

 

[Jdgephar]

Check your documentation and see if the coil is supposed to have 12V or not. If it is a 12V coil, you should not use the ballast resistor. That was the issue I had, but my symptoms were loss of power and misses at close to 4000 rpm.

Check your distributor cap for any cracks or breaks. Check your plug wires for any burns or cracks.

 

[DaveLev]

The coil itself does support 12 V. It is an MSD blaster. The documentation online, however, states that when using with points you must use a ballast resistor. I am using an MSD ballast resister that has a different Ohmic resistance then the one I removed that was broken. Although I guess it makes sense. I will go ahead and do the electronic points and remove the ballast resistor and report back results.

 

[Rustytruck]

If you fear intermittent ignition issues, if you have an electric tach do a test run with the tach disconnected. Electrical issues inside a failing tach have been known to cause misfires and or ignition failures. Running with out the tach connected will verify if it is the source of those troubles. Of course you will be stuck feeling the problem instead of seeing it on the tach.

 

[Rustytruck]

You may want to test your ignition by swapping the condenser. If you changed it to a new one try swapping in your old one. You do have your points set on the wide side of spec? dwell 26 to 31 best set to the high side 30-31. Points gap.017 Make sure they are not set too close. Points too close wont load the coil properly and you start getting misses. setting the dwell on the short side will mean you will be resetting them frequently as the points follower starts to wear down.

 

[DaveLev]

Thank you RustyTruck - will check out the points, condenser, and dwell. The electric tach I have is fluctuating all over the place, so I suspect that either the signal it is getting from the coil it does not like or the coil is failing (at the same time I replaced the ballast resister - very odd, but I've learned not to be surprised any more). I will first try running with wires disconnected from back of tach, then I will try disconnecting the tach wire (white) from negative side of coil to see if that changes things. Wonder if tach bad could fry condenser, points, etc. Mysterious. I'm learning how to diagnose engine troubles quite a bit in the past 4 months, and not how to enjoy the Bronco.

 

[nvrstuk]

Ahhhh, don't lose the faith cause after your trusty steed is up and running and you're a Certified Mechanic due to all your experience fixing your Bronco... you can help others here on the list... : )

 

[DaveLev]

Always looking for opportunities to pay it forward...will do my part!

 

[DaveLev]

My next task is to put a 1 3/4" fan spacer in, replacing the 1" I put in, so that it clears the silicone upper water hose.

 

[Moon's74]

cooling update?

Any update on the cooling issue after the thermostat and hood were installed? Did I miss it, didn't see it? Thanks, I'm having the same issue.

 

[DaveLev]

Removing the thermostat and putting in a high-volume Edelbrock water pump seems to have done the trick. I also put in a seven blade fan at the same time, and put the hood on as well. Working like a champ. So what exactly fixed it I'm not sure because I did so much at the same time.

 

[bronconut73]

I'd really like to hear how it would work with the thermostat back in it, but I understand if you do not want to tear back into it, lol...

 

[nvrstuk]

For helping the masses who are looking for a fix to their cooling issues...I'm wondering if, big IF you could put in your old fan and see if just the Edelbrock WP was the fix... for winter and engine life you'll want to stuff a t-stat back in there some time...

A good t-stat really shouldn't make any difference if you ran your successful test long enough. Eventually (if all things are working properly) the engine won't care if the t-stat's in there or not...it will basically just bring everything up to temp and keep cooling... the fan and waterpump made the difference for you imo... if it won't cool with the old fan on then it's the new large diameter fan...if it'll cool just fine with the old fan then it was the waterpump...

Thanks for doing all the posting...

Just wondering... : )

 

[5001craig]

For helping the masses who are looking for a fix to their cooling issues...I'm wondering if, big IF you could put in your old fan and see if just the Edelbrock WP was the fix... for winter and engine life you'll want to stuff a t-stat back in there some time...

A good t-stat really shouldn't make any difference if you ran your successful test long enough. Eventually (if all things are working properly) the engine won't care if the t-stat's in there or not...it will basically just bring everything up to temp and keep cooling... the fan and waterpump made the difference for you imo... if it won't cool with the old fan on then it's the new large diameter fan...if it'll cool just fine with the old fan then it was the waterpump...

Thanks for doing all the posting...

Just wondering... : )

That request would make me want to eat a bullet...

 

[nvrstuk]

HA!!!

I totally understand... something about just wanting to "drive the dang thing" for a bit before opening the hood with a wrench in hand...

Glad it's working good for ya!