[JohnnyK]

Ok, now I'm getting discouraged.. replaced the thermostat on a whim.. On a 5.0, that involves removing the upper intake manifold.. Also installed the 5.0 EFI heater lines.. None of this should have made a difference as the coolant doesn't have a chance to heat up yet.. Installed upper intake. No vacuum lines are left unplugged... Have a coolant leak from somewhere (hose, hopefully) but that seems like a small concern now.

Within 3-4 seconds, literally, the headers started smoking.. Touched them, instant burns (Although not major.. May seem stupid to you, but the headers don't get that hot that fast, even if it is just high temp paint).. And it's been brought up to temperature a few times before, so it's not the paint just cooking for the first time..

When I first started it, it dropped to about 500rpm or so for a few seconds, then went up to about 1200-1300.. That's not normal for it.. Shouldn't be any vacuum leaks. Even replaced some of the vacuum caps that looked bad. Also I did remove and reinstall the throttle cable bracket, but it seems to be closed properly. Timing hasn't changed from the marks I have on my distributor and my engine..

Any ideas?! I can't really think of anything, nor at this point can I think of how to diagnose without doing some damage.. Also had the valve cover off to install the heater lines, but both headers seem to be too hot too fast, not just the one (Although it, passenger side, seems worse)..

Thanks guys.

 

[JohnnyK]

Timing definitely not changed.. Could have bumped it I suppose, but this thing seems to be running lean (I assume).. Don't see how the plenum gasket could be damaged, but perhaps it is a good idea for me to start with that.. Would a tiny air leak there cause this problem? As I said, I'm too worried to run it for any longer to do tests that way.

 

[JohnnyK]

Well I can't physically SEE anything amiss.. I was hoping for a missing vacuum line or something.. Any way to check for vacuum leaks without firing? I logically can't think of any, but.

 

[JohnnyK]

Well I'm close in the sense I'm sure I can get it running nicely, but far in the sense it'll be a long time until it's on the road.. But I appreciate the encouragement.. haha

I agree with your diagnosis.. It definitely seems like the RH side is heating up more, but the lh seems to be heating up more than usual.. 4 seconds definitely doesn't not seem correct.. used to run much better before this little heater tube incident.. I COULD get the car running, but I don't want to toast the valves or anything.. I guess I'll pull the upper tomorrow and see if anything seemed amiss on dissassembly? Seems the best way to start at least? Vacuum leak would cause this severe of exhaust heat though (before I dive in)?

 

[JohnnyK]

Ok, I'm at a loss.. First thing. Heater tubes, thermo.. No matter WHAT is up with them (Back heater hoses are kinked in a 180 temporarily) that would have no affect on this, correct.. I mean, 4 seconds.

PLEASE tell me I haven't screwed up my lower manifold somehow, would that account for this? I did flush with a hose through the upper rad hose.. Hopefully I didn't blow a gasket (Sealed the hose in there, with a t-shirt, but didn't go full blown with the hose).

Put upper on again with a new gasket (no problems with the old ones though).. Didn't attach throttle cable or bracket or anything so nothing is touching anything.

I am running with probably 3-4 gallons of fuel in there.. EFI.. Could that cause this problem? I mean, it's low, and not reading on the fuel gauge, but it seems coincidental to start happening right when I pulled the upper for the heater tubes.

Where should I go from here? Fuel pressure check for 3 seconds? Manifold vacuum check for 3 seconds?

 

[JohnnyK]

I went gung ho and let it run.. Fires up to 1400rpm.. stays there for a bit.. Then it stalled. Started it again.. Idle settled to 800-900.. Unfortunately without exhaust I can't tell if I'm hearing a knock or just the engine bouncing around.. Valve covers getting pretty hot after a minute. Frankly, I can't remember what is normal and what is not. The smoking stopped.. I Guess the paint had enough.. But I swear I never got any grease or anything on there. How long should it take for uncoated headers to be boiling hot (Blisters.. spit evaporates in a second).. Longer than 5 seconds?

 

[JohnnyK]

Yessir.. Oil pressure is at 40-50 at idle (Err, at 1300, the 'new' idle.. )

 

[JohnnyK]

Any ideas before I go back to the car in a couple days? If FP is good, timing is still at 10 base or so, and manifold vacuum is good (What should I be shooting for on an EFI with a B cam), should I Just chock it up to "Headers are supposed to get that hot within a few seconds, even though I don't think they did before". I assume the vacuum will be the telltale if I have a vacuum leak? Or is there something else I can do?

 

[JohnnyK]

Well just concerned because they never did that before.. And now all of a sudden they started to, after I messed with the intake.. Maybe I have really greasy hands or something..

 

[JohnnyK]

Yeah, thought it might have been the 'salt and pepper' shakers, no codes though, but i can squeeze the terminals closed a bit more I guess..