scottd

Hello gentlemen, Im new to the site. Ive got a 82 Z28, 350 punched 40 over, headers, carb, intake, mild cam and the rest of the go fast parts. Ive been turning my own wrenches for about 20 years and rebuilt this car from the junkyard. Ive got an issue that needs the collective attention of people with much more experience than I....

My problem.....the car runs great until she gets good and warm. By great, I mean tire shredding, responsive and nimble. Once she gets warm, she looses power. Less responsive and is tough to break the tires loose off the line. Now let me explain in detail.

My temp guage is a bit off but Im guessing once she hits the 215 range, she become less responsive off the line. I say guess because the dash guage reads 220 under light work and 235-240 when she gets warmed up and lil slow. If I was really hitting those temps I would know it... (When I say slows down, she doesnt quite want to break the tires loose, even doing a brake stand). I had some bad pinging (which I resolved with higher octane). She vapor locks. I had to install a phenolic carb spacer to stop the fuel from getting boiled out of the bowls after short stops. I replaced the starter because the stock model suffered from bad heat sinking.....What Im getting too is tht the car has always run hotter than most and Ive been able to adjust for most of the issues. But this general 'loss of horsepower' has me stumped.

My mixture is fine, maybe even on the slightly fat side. Im running a flex fan. Timing is 12-14 degrees....am I missing anything? Somebody suggested my plug heat range may be suspect, Im running Accell Shorty's... (plugs??)

I think I need to bring the operating temperature in the engine compartment down. I think the vapor lock, bowl evaporation, starter and pinging issue show the engine and engine compartment are just too hot. Its not dangerous

My plan is to wrap the headers. Ive heard all sorts of negatives about header wrap but I dont see any other alternatives at this point. I think the headers are adding enough heat to cause these problems.

What do you all think. I hope I gave you enough detail. Im open to discussion. Thanks -Scott

camarokid89

maybe theres not enough air getting to your engine compartment, is your air dam still in tact .

scottd

Most of the air dam parts are intact, some of it may have been gutted as I bought the car from a junk yard. Nothin appears to be missing.....

NINÅ

Fionnla

I had the similar problem when I installed the 350 Vortec in my 85 Camaro. Installed dual fans, 200/185 degree temp switch & 180 degree thermostat. Never hotter then 210 degrees in heavy traffic in 95 degree weather. Good Luck.

84 z28

Loose the flex fan and put the stocker back in.if your using the stock 305 radiator get rid of it and put in a 3 core aluminum radiator.

scottd

Well I just dropped way too much money on header wrap. This is gonna be an ugly job, I cant even reach those pipes.

3 core radiator huh? That sounds like an idea. Never thought a stock 305 radiator would not be enough for a 350.....

TheMonster

Actually I am running a 305 radiator in my 355 camaro.

scottd

Looks like Im back to the header wrap this afternoon.

csmith3

Sounds like you're experiencing "heat soak". I'm running a 350 in my '87 Formula with the three core rad, edelbrock victor water pump, 160 t-stat, and hypertech 176 fan switch, with the stock 305 electric fan. My airdam is fully intact and functioning, and she never goes above 165 whatever the temp is outside. Just some thoughts.

RED86Z28

The header wrap is a good start to control excess heat. You also have to look at the radiator and fan setup. I would get a heave duty radiator and dual electric fans set to come on at 185.

scottd

Well the header wrap did very little. I still vapor locked but just not as soon. That was a waste of 5 hours. Tomorrow Im going to ck the temp guages for accuracy and probably install an aftermarket temp guage. Ill relocate the fuel line (dont know where Im going to route that) also.

I think the radiator may be the way to go but Ill exhaust all other options before I spend that cash.

RED86Z28

a good radiator is cheaper than you think.

mnorton

I think that you could remove the hood seal rubber in front of the windshield cowling and dump some heat that way.

Stevolwevol

iTrader: (1)

How does that work when it rains? I was thinking of removing the rubber seal from my 86 iroc, and my 92 rs, but I am concerned about water dripping on sensitive stuff like distributor cap.

loneroad

iTrader: (3)

im confused , are you talking about the air dam or the front gfx?

Are you running a shroud with the flex fan?
how close is the fan to the radiator?

scottd

Well hows this for 'missing the simple stuff'...........

Yesterday I decided to check the accuracy of the factory guage and install an aftermarket one. Watched the aftermarket climb to 205 before the thermostat opened (factory gauge was reading 225). So this whole time I was running a 205 t-stat and didnt even check it. DOH! Installed a 180, she now runs around 185-195. I may throw an electric pusher in front of the radiator but I think I got this heating issues cleared up. Now to go back and fine tune my mixture and timing......