Trying to run down why my new 468 temp keeps slowly climbing and wont come down. Dist. advance is locked at 38 total degrees. Starts and run's great . Could this lock out contribute to overheating? And yes, I know there are numerous other things to cause overheating (Dang, there are so many!). I'm gonna get those items also(LOL).

An overly advanced motor will have a tendency to run COOLER not hotter.
You might need to look at basics like shrouding, water pump speed/volume, good radiator etc...

The following items are all new: 4 row radiator, edelbrock waterpump, march performance serpentine pullies,180 t stat ( with 1/8 hole drilled), 850 holley ( jetted 80 square, plugs show no signs of burning lean), Factory shroud and flex fan ( can't use stock fan and clutch, not enough room), 100% water and one bottle purple ice water wetter, lower rad hose has wire insert, Valves are set properly and as already noted, timing is locked at 38 degrees total.
Cranks and runs great. Temp rises slowly and continues non stop untill I shut engine off at about 220 degrees. Idle or cruising does'nt matter, it's headed for 220 degrees. Soon as engine is cut off it pukes water and begins to cool down. I'm getting frustrated to say the least.

When it's running can you see the water moving through the radiator? I know you said the water pump is a new Edelbrock but it sounds like you have covered most everything else. The one thing that bothers me is the flex fan. They just don't work. I run a stock fan with a severe duty clutch. It's the only thing that has really worked for me. I have essentially the same setup. Why don't you have room?

Like Troy said, check for water flowing through the rad. Although rare, make sure you have the correct rotation water pump as sometimes you get the wrong one???????????????? If it is the wrong rotation you'll never get the flow correct.

Yes, water is moving through radiator (once t-stat opens at about 190 degrees per new mechanical gauge) and flow increases as engine is reved up.
Stock fan and clutch will not fit because I'm running the long water pump. Flex fan bolts directly to waterpump pulley and sits just inside shroud,it's only a couple inches off the radiator (Car is a Nova - core support to engine is closer than a chevelle I think)

I was thinking the same way as LevonH, do you have a reverse flow waterpump with the serpentine belt drive? 505 (.100 over 454), stock waterpump, viscous clutch and fan, 2 core alum radiator, 38* locked timing and its never been over 190* this summer.

my case: 454, 55 chevy was overheating exactly like yours. Heres what I tried, clutch fan , flex fan, recore rad, 18 inch electric fan , 160 t-stat, no t-stat, high flow water pump, moroso cool can , gutted original rad cradle(duh!!) put in 19 by 32 griffen aluminum gm rad.... And what I found was .. a bad intake gasket, easy fix after ya know

How could an intake gasket cause the overheating, unless it blocked coolant flow somehow???????????????????

Leaking intake gasket,,,,vacuum leak, causing lean condition and overheating.

Frequently with a new engine an overheating problem will be something simple. In addition to the above great suggestions: Are you sure that you have the right timing marker on your engine? Is 38 degrees really 38 degrees? Is the thermostat opening properly? Is the fan drawing air towards the engine, or pushing it back toward the radiator? Is the flex fan dinky or not have many blades? How is it possible for a '72 to have too tight a fit between the engine fan and the radiator? Maybe there are some mismatched pieces on the motor mounts or radiator etc?

Since you mention that space is at a premium in the fan to radiator clearance - the reason why you have a flex fan - I'll bet the fan may not be properly positioned in relation to the shroud. The highest rate of airflow happens at the circumference of the fan itself. If the fan is completely inside the fan shroud that will be cause for airflow reversion. Looking down the top of the fan blades the ideal is to have 1/3 to 1/2 of the blade inside the shroud, and 1/2 to 2/3 of the blade outside the shroud.

Did you have your block bored? How much overbore, and was the block checked for core shift? If the block has core shift you may have cylinder walls that are too thin on one side or the other.

Thomas

Factory shroud and flex fan ( can't use stock fan and clutch, not enough room)...

Why not?? :confused:
I run a March serp system with a factory shroud, GM clutch fan, cast waterpump, and large (thick) aluminum radiator under the hood of my '70...plenty of room.
Even have a crank trigger and power steering. Never over 180 degrees...and I'm cooling more cubes and a big stall.

Lots of flex fans have a pretty poor reputation. On recommendation of several at little brothers site, I use a Derale 17xxx flex fan. Darned thing moves enough air to almost blow the hood off, for less than $50.

OK, here goes...Per my timing light and everything I see it is 38 degrees(cranks and runs great),stat opens at 190 per mech gauge in car, air flow is toward engine,flex fan fills stock big block fan shroud and is aprox. 1/3 into shroud , bore is .060, block was not checked for core shift and as I said earlier this is a Nova not a Chevelle. Radiator to engine is closer, fan clutch ain't fit'in.
Thanks for the replies everyone :)

If your lugging the motor or don't have enough gear or convertor its possible your seeing detonation with the timing locked out. If this is a street car I see no benefit to running locked out timing. I would consider an advance curve. My $0.02

Have you burped the cooling sustem? Take your cap off, fill the radiator, start the car with the cap off. Put a bucket or pan under the radiator and let the car run with the cap off until your thermostat opens. Once you have no more air fill the radiator and put the cap back on. Air can cause pockets, or cavitation and lead to heating gremlins.

Motor is 10.2:1 , comp 286h cam ( 2200-6000 power range), stall is a Hughes 2800, TH350 and 3:42 in the rear. I have burped the system(twice actually). I'll get this gremlin eventually(LOL).

Is it possible your new pullies might have slowed the water pump down?

Yes, water is moving through radiator (once t-stat opens at about 190 degrees per new mechanical gauge) and flow increases as engine is reved up.
Stock fan and clutch will not fit because I'm running the long water pump. Flex fan bolts directly to waterpump pulley and sits just inside shroud,it's only a couple inches off the radiator (Car is a Nova - core support to engine is closer than a chevelle I think)

The only other things I can think are 1. make sure you have a fan for a clockwise motor 2. I always had problems when I would move the fan any more than 1 inch away from the radiator. The fan would not draw air through the radiator. Hope this helps.

fuel mixture too lean, wrong head gaskets, cylinder walls too thin, are other items to offer, hoping it wouldnt be the latter two.

I had a BB '70 Nova and there wasn't room for a clutch fan. Factory deal was a non-clutch fan that sounded like a propeller plane taking off. I'd find true TDC with a piston stop to make sure the timing marks are correct and in any case ditch the flex fan. They explode. I know of someone whose flex fan exploded recently and put dents in his SS hood. In the 70's a local weekend racer here was killed while setting his timing and the flex fan exploded and hit him in the chest.

Just a thought and correct me if I'm wrong. If the engine temp continues to rise at cruising speeds would'nt this rule out the fan being the culprit? I mean the air flow at 65 mph is tremendous, if that does'nt cool it down then it should be something else right?

have you checked your timing and fuel mixture yet?

Yes 72BB the problem existing at highway speed should eliminate the fan as the problem, unless the fan is actually flexing to the point that the fan becomes almost flat at speed and blocking air flow thru the radiator. I have never seen this but it seems possible. I have a GM fan that looks like a regular clutch fan blade wise but it mounts with out a clutch, if you could find something like that at least you could eliminate the flexfan.

Well, I'll tell you what the problem is and I'm sure your not going to like it. Sorry for responding so late.
I've seen this on a few cars, but it's usually the first gen camaros that do it worse.
1. Big engine
2. big cam/ compression
3. headers
4. small engine bay
5. 454 .060 bore getting thin on the cyl walls.

All these things combined are causing your problem, that's why it's so damn hard to figure out. You see I work on alot of cars like these so I get familiar with these kinds of problems. Not trying to sound cocky. I'll bet if you pull the hood off and go for the usual drive where the motor starts to get up in temps I'll bet you'll see it dropped down considerably. Your just having a hell of a time getting all that heat out of the engine bay. Header wrap will help some, and might even be the cure but you won't know for sure until you pull the hood and go for a ride. I know of 2 first gens that WILL not run lower than 220 in the summer months. And they both slapped some serious cash into both of them to try and elimnate it. The way I learned about it was my freind totalled his 69 SS BB 468 chevelle and bought a 69 prostreet camaro and then the problem existed. even after a brand new raditator install. NO fan will ever cool better than a stock clutch fan, hands down. His brothers 67 camaro 396 which I helped build did the exact same thing when it went on the rode. Try the hood first and let's go from there. SOME motors just run hotter also.

RandyB..
Paint and Resto 20yrs and still going
69 SS chevelle under full resto now.

31chevy, you may be right but I have a friend with a 502 in a 69 camaro and he has no trouble and this is a nova he is talking about. I have a 71 z and the combo you use for an example and I hardly ever turn my electric fans on except in town. Also there must be 1000's of bbc nova's that have no trouble, I think there are a couple on this site with 496 in them too.

Well, I'll tell you what the problem is

This should read "I'll tell you what the problem might be"

I'll bet theres 1k or so camaros out there also with BBC in them, and I'll lay money down that there are also some that just can't keep cool. Some combos just run hot no matter what you do. The last 71 chevelle I owned with a well built 468 would run 180, no thermostat, and no shroud. stock 4 core radiator. When I added the inner fenders that it previously didn't have it would run 30 deg hotter at whatever speed. All I'm trying to say is the guy has already tried a bunch of ideas from the past 24 post and wasn't getting anywhere. By pulling the hood will tell right away. When everything else checks out, this is almost always the problem. Now if something was overlooked, well then that's something else, but he seems pretty knowledgable.

RandyB..

UPDATE:
Been out of town and was finally able to work on the Nova yesterday. Timing was @ 38 and I bumped it to 42. Car ran fine, but temp still went to 220, only quicker. Dropped timing to 40 and changed jets from 80/80 to 86/84. Made some minor idle adjustments. Got out on the highway, temp peaked @ a tad over 200 and up to 210 @ stop lights. Not only a reduction in highway temp but I could actually see the temp go down slightly after I left stop light and got back to cruising speed. I know 86/84 seems big,but it still ran fine and did'nt really seem to be fat @ idle. Seems like I'm going in the right direction.
Aluminum radiator and electric fan is on the way, will see what that does. :)