New 455 Engine Overheating

Hey guys. Well I have had the engine rebuilt in the Rivi and now I can't enjoy the ride very long before it overheats. It overheats idling and running down the road. It has boiled over one time already so I am trying to be more careful. I am losing my mind with this thing. It is a 73 block with 70 heads, 284-88h cam, B4B intake, factory exhaust manifolds, Qjet carb, MSD ready to run distributor, and a new water pump during rebuild. Dyno'd the engine before installation into the car and air fuel looked good (386 hP and 494 ft-lbs).

So since this problem, new hoses, new thermostat, new radiator (production replacement), and new electric puller fans. Total timing is at 34* at 2500 rpm. I don't know what to do next. I want to get on the road with this beast. This is driving me crazy.

Also, the exhaust sound on the driver's side sounds a bit funny, muffled or "fuzzy" but different from the pass side. Not sure if that is important but just wanted to mention it. Wasn't like that before the rebuild.

You guys have any ideas? I am working two jobs and coaching my kids so I get to work on this thing about 20 minutes a week. Thanks for any and all advice.

Eric

 

Since you mentioned a funny sounding exhaust, a plugged exhaust will overheat an engine. Are you sure something didn't get into the pipes while it was apart? A new pack rat home would do it.

What is the actual temperature it is running that you are calling overheated?

 

Perhaps the heat riser valve on the outlet of the left exhaust manifold is stuck closed or partially closed? Guessing it could contribute to both the overheating and odd sound.

It looks something like this:



Devon

 

Vacuum advance working?

 

Electric puller fans? What brand? I tried several before going to the ford/Lincoln single fan.no others would do the job. And on my convertible, had to work through some relay issues to get it to run all the time. If you have it set on a thermostat, when does it turn on? And is it turning on and running like it should be?

Also check that exhaust for restriction like mentioned.

Hope you figure it out soon.

 

Guys,
Thanks so much for the advice so far. Let me try to respond to you questions.
1.) Not sure that there isn't a plugged exhaust but I will see.
2.) It has boiled over once so far. An old temp gauge that I question said 260* when that happened. That equated to a little more than half way on my C to H gauge inside. I have shut it down before that temp since hoping to avoid that boiling over.
3.) The heat riser valve was removed when we rebuilt the engine.
4.) Vac advance is plugged off right now.
5.) Electric fans are running all of the time without relay currently.

Thanks again guys. Any more thoughts?

Eric

 

What fans do you have? Many, and possibly most electric fans are not sufficient to cool as well as a stock original fan with shroud. To go to electric fans and have them work well, you need to spend the dollars for good quality fans and the electrical system to operate them, which includes alternator, relays, thermostats, etc.

 

The engine was overheating with the original fan and shroud, so I wen to the electric. Can't remember the brand name but I will figure it out and let you know.

 

Vacuum advance plugged off = very prone to overheating.

 

X2...that and maybe insufficient initial advance.

Devon

 

There are lots of cars out there with no vacuum advance or disconnected vac advance including my on..if his initial timing is anything above zero that's not his issue in my opinion. Air pocket or plugged radiator is more likely

 

Yep - but confirming that the VA is not the source of his overheating issue will take him about 10 seconds plus a drive. Always check the easiest to fix, possible solution first; or perhaps spend a grand on a new cooling system that does no good because the VA was the source of the problem.

 

I definitely wouldn't be spending any money without a diagnosis first. Checking initial timing is kwik and easy. Checking for a plugged radiator is too if you have access to an infra red temp gun. The fact that overheats at idle is what made me think ai lock or radiator issue.

 

I had two crap thermostats in a row from autozone, one stuck closed and the other stuck open. I'd pull the thermostat and put it on the stove in some water to be sure it opens at 180 or 160 whichever you have.

 

I agree with the ignition advance theory, especially since its so easy to check. I once had a severely retarded timing setup on my old 350 and it would run hot. I didnt realize it until i reread the powertime thread larry posted and reset my ignition timing. Also, the plugged exhaust situation seems odd. Definately look into that as well. Not to change the subject, but what type and compression ratio pistons are in your engine with the rebuild? Completely unrelated to your issue, i was just curious with your dyno numbers as to what CR your engine is at with your cam.

 

Do you really think that a car is going to overheat a idle just because of timing? Not likely if everything else is up to par

 

Ditch the electric fans. Get a new HD clutch and put the shroud back on. I went through all of this with my car and that solved the issue. 3 yrs later I noticed the temp starting to creep up on hot days. Replaced the fan clutch again and its back to normal. When you have the stat out to check it, Drill a 1/8"th - 3/16" hole in the outside edge and place that on top when you reinstall. It will help eliminate the air lock.

 

Not at all what i said. What i said was I really think he should check his timing. Just like I think you should read his first post that said he overheated idleing and running down the road. Cheers...

 

Well it doesn't take a rocket scientist to figure out that if it overheats at idle it will obviously overheat going down the road. I may be new here but I know a whole lot more about engines and mechanical systems than you probably guessed.

There is virtually no load on an engine at idle. So if it is overheating fairly quickly at idle you have a water flow issue.

 

Sorry if I came off as abrasive, that wasn't my intention