HELP ! exhaust overheating GLOWING

[standup616]

My exhuast is overheating long story short bought a car dirt cheap 93 camaro 3.4 that was run hot, blown headgaskets and such. Had to rebuild the engine. transplanted that 3.4 sfi engine wiring computer into a 1984 s10 pickup that was a 2.8 carb setup. the sfi has 2 crank sensors one cam sensor and is distributorless so no adjusting the timing like everyone says. RUNS FANTASTIC but the exhaust is so hot that the pipes and manifolds have a slight orange glow to them at night. Used the infared thermometer off my fire truck and its between 780 and 800 degrees both sides. Everyone elses vehicles at the station run 400 to 450 but they are chevy v-8s and a 4.3 chevy. The temp guage runs straight 180 but after the engine is shut down and restarted a few minutes later its 220 but thats not abnormal. Occasionally after its parked for a few minutes and restarted is spits backfires in the intake when you first crank it over but starts right up. never any problem starting running or anythiung except that occasional backfire and the heat. no catalytic converter to clog has stock manifolds and muffler shop pipes that connect to the original exhaust where the cat was. I did the specs on the valve lash to 1 1/2 turns, ran nearly a tank of fuel through the car with that setting. Melted some insulation on the wiring harness blistered some paint on the oil filter and pan. the machine shop said too valve lash too high, reduced it to about 3/8 of a turn and no real change. made my fuel pressure regulator adjustable and I upped my pressure from 35 (what it was) to 50 (spec is 41 to 47). Put a vacuum guage on the intake and it reads 16 to 17 inches. i think should be a little higher at idle. sprayed brake and carb cleaner and wd 40 everywhere to try to rule out intake manifold leak and no change in idle or vacuum. Changed the injectors with some other ones off an identical motor, no change. Tested the temp sensors and those came out right. my scan revealed nothing major about the ecm or emmissions but has several codes stored and some of them were from changing the air temp sensor while the vehicle was running, checking sensor voltages and resistance, but everything thats happening now has been happening since day one on the rebuild and swap into this truck. The car barely ran when i bought it and I knew beacuse it had been run extremely hot the engine would have the be gone through. havent done a leakdown or compression check have less than 200 miles on the rebuild so that may not be conclusive because the rings may not have fully seated. Im leaning towards a poor vavle job because the truck cranks runs fantastic but the heat is going to kill it and i'm affraiid to drive it any distance (i work less than 7 miles from home). Im stupmed other than pull the heads and get them done again and hope the machine shop did crappy work but thats hours and nearly 200 dollars for gaskets and new head bolts. any suggestions.

[gpse3400]

Check your spark plugs. you are possibly running super lean. bad coolant temp cicuit or map sensor cicuit or MAF if you have that will affect that. If your plugs are white and blitered, you have a lean condition, and if you tranfered all the parts from the '93 Camaro with e the bad head gasket and used ithem, you might've put that cars problem into yours.

[JMo60]

are you sure that you cam timing isnt a tooth off? That can do the same thing

[standup616]

spark plugs are nice and tan color finally got a scanner pluged up. not showing new codes but giving me 42 (ignition control failure) and 43 (electronic spark control) as history codes. hooked a different vacuum guage to it and this one vibrates at nearly all engine speeds (with no load in park) and averages around 15 inches at idle. the guage goes about 2 inches both ways at idle 13 to 17. thats a little low in my opinion. rev the engine and as you close the throttle it goes up to 20 but still vibrates at constant speed but a little less than 2. history the camaro was a police impound I bought from a towing company (about 400 miles away) with 157,000 miles on it. The previous owner was apparently running from the cops, got caught when it blew head gaskets and severely overheated. the car was impounded and sold to pay legal fees. I tore the engine down took it to a reputable machine shop hoping to get away with just rings, cam bearings and valve job. no ridge in the cylinder didnt smoke in the camaro but i never could run it long because of the head gaskets and blowing coolant everywhere. What i ended up with from the machine shop is all new bearings, turned crank, pistons, rings, camshaft and lifters. He said a few valves were warped and put a few used ones in. I let the machine shop put the bottom end together and install the cam, because I dont have a torque angle meter for the mains and rod caps. I remember looking at the timing marks and also turning the engine over by hand to make sure there was a "lobe" for the cam sensor so I could be sure the correct cam was in the engine. I followed the book to the letter with everything else, like heads and valve lash. installed the engine in the 84 s10 with all the wiring harness and computer from the camaro, hooked everything up and the engine fired off in less 10 seconds and runs perfectly except for the heat. as its warming up there is loud popping sounds like bolts are breaking, insulation is melting in the wires, paint is blistering on the oil pan and filter! One thing I did notice is that the original paint was still on the heads where the exhaust manifolds bolt up and I was thinking I after I put the engine in the truck I should have painted and prettied it up a little more. That factory paint is now gone and every time i run or drive the truck a little more of it disappears. I have a friend that works at the pontiac dealer in the body shop and ive been bugging him to get some of the techs opinions on this or to look at it in their off time but I cant get him motivated. I guess either way I'm going to have to either pull the engine or take the heads off either to find a problem or after things crack or seize up. Im still leaning toward crappy machine work. you guys have been more help than the s10 or camaro firebird messageboard thanks and looking forward to more ideas

[sharkey]

what you are describing sounds like the timing is way off. now i know its not adjustable, but the timing being off or rinning exessivly rich is the only thing thats gonna make manifolds glow. if your not smelling fuel, then its gotta be timing. being you have ignition codes, you need to find out why. you may have a ground wire missing or something like that. either way, fix the codes first.

[tractorman]

I had a little ford ranger many years ago when I was a stupid kid- a 2.3L 4-cyl. with a timing belt. Well, being a stupid kid, I liked to tinker with it, including changing the cam timing by a tooth in either direction to see if the motor would run better. It didn't run 'better', but it ran different. If the cam timing was advanced, the engine idled fine, and might have even had a bit more low end torque... but the power dropped off real quick after about 2000 RPM. When I retarded the cam timing one tooth from standard, the engine idled just a little funny- sounded like it had a long-duration cam. It had no low end torque, but it actually had a little more pull at higher RPM's this way. And here's the kicker... the exhaust manifold got smokin' hot when I'd run it that way.

I'd say check and see if some dip$hit screwed up installing your timing chain- might have gotten it a tooth off.