I love it when a plan comes together, especially a long-term project car like g/28. It was just yesterday I scraped up the $2,300 to buy this '76 Camaro, and now it's almost complete. The interior's done, the engine's nearly dialed-in, and the suspension, trans, steering, brakes, and rolling stock are good to go. It still needs some exterior stuff, but when you get down to the wire, tracking down the gremlins (and killing them) becomes the priority, and that's what makes this hobby fun.
I think the technical term for it is "nut and bolting." When you throw so many parts together, it's inevitable that problems arise. It doesn't matter how many small-blocks have been hoisted over the fenders of Camaros, there's always some goofy problem nobody's heard of. Right now, the biggest monkey on my back-or maybe I should say gremlin-is the cooling system.
Some days, g/28 motors along with the temp gauge on 180. Other times, it rockets to 260. When it does, I drop a gear and run it to 3,000 rpm, and it comes down. If I get stuck in traffic, the temp might stay at 180, or it might go through the roof. If I speed up, it might rocket up, or it might cool off. On hot days, it can run cool. On cool nights, it can run hot-or sometimes not. I should probably just order a big ol' $500 radiator like everybody's telling me, but what's the fun in that? I wanna figure out a low-buck fix.
When gremlins arise, a gearhead will game it out in his head, grab at simple, low-cost solutions, then work his way up. In this case, it could be something as simple as drilling a small vent hole in the thermostat-or maybe not. Every time it overheats, the overflow bottle fills and the radiator empties, so now I'm thinking blown head gasket. But there's no water in the oil and the valve covers don't have green scum inside 'em-both telltale signs of a blown gasket. So I'm still thinking on it.
Everybody else thinks the radiator is too small, which I would be willing to admit-if the engine were putting out 500 hp. Here's the thing, an engine's a heat machine. Put more fuel in, make more heat. Put less fuel in, make less heat. If I'm driving on the highway, loafing along with plenty of airflow through the radiator and the throttle barely cracked, there should be no overheating (little fuel in, little heat out). And this is exactly the way it runs mile after mile-when the radiator is topped off.
When things aren't mechanically kosher under the hood, I'm not one to drive around like a wild man. Lately, I've been driving g/28 like there's an egg under the gas pedal, just to mentally catalog what happens in different traffic scenarios. One thing's for sure so far: coolant is leaving the engine without my permission. It doesn't appear to be leaking externally anywhere from the radiator, hoses, engine, or water pump. And since I don't have a heater, it can't be escaping from there either. There is, however, plenty of coolant coming from the overflow can.
This, I believe, is a telltale sign of combustion pressure in the coolant system. The "pro radiator" camp around here says I'm overheating because the radiator isn't up to the task and the loss of coolant is simply a result of boiling over. But the current radiator is a double-core unit for a 350 (not the original single-core 305 unit) and was installed just two years ago. It's got a good mechanical fan and is properly shrouded. Yeah, its size is marginal, but my feeling is that it should be serviceable in most normal traffic situations, as long as I don't start doing burnouts in the parking lot.
Right now, I'm looking into a low-cost aluminum radiator from Summit (PN SUM-380455, $285.95). It's supposed to be for later '82-92 Camaros and Firebirds, but it's dimensionally identical to my '70-81 unit. I'm still waiting to hear from Summit why it isn't listed as an application for Second Gen F-bodies, but if it fits, I'll probably try it. Even if it doesn't fix my overheating, I'll still need it when I start racing g/28, so no harm done. If that doesn't work, I'll pull the heads and change the head gaskets.
My money's on the head gaskets. Why? Because I think the smallish emission-legal cam (216/228 @ .050) coupled with a 112 LCA and a compression ratio of 10.6:1 (with aluminum heads) has rattled the gaskets a few too many times. If I do put new gaskets in the 383, I will also put in a bigger cam with tighter lobe centers. That will lower the cranking pressure, reduce the detonation, and build more power. Got an opinion on the problem? Fire off the e-mails to john.hunkins@primedia.com. I need all the help I can get!
Got Something To Say? I want to hear from you. Drop me an e-mail at john.hunkins@primedia.com.