Question1967 Plymouth VIP. Blew factory 383. Bought '73 Polara w/ '75 440 4bbl. Put 440 in VIP. I hired retards aparently. When I picked it up, the distributor was loose. I will take it elsewhere. Doesn't run w/ correct firing order, but runs and backfires w/ different firing order(I don't get it). 2 weeks ago the air filter(triangle foam Edelbrock)caught on fire, so I threw a bucket of water on it. Before it caught fire, it was backfiring less.I had carb rebuilt, but it still backfires and I smell fumes. Everyone says to fix timing. I am driving it anyway(probably shouldn't be). Obviously, I want it to run smoothly. HELP! What do I do?
p.s. you may post this if you like
AnswerI usually don't try to answer questions on cars which have been changed from the factory setup, as I have no way of knowing what some creative person might have done. But I can tell you, if you are seeing backfiring through the carburetor, a spark plug is firing when an intake valve is open - this means that the timing or firing order is seriously screwed up, or else there is a problem in the timing of the valves.
If I were faced with this problem, I'd remove the #1 spark plug, stick a finger in the hole and bring the engine up on the compression stroke to TDC (you'll feel pressure against your finger - if you don't, you are 180 out with the distributor, a very common error). If you don't feel pressure the first time around, bring it around a second time (remember the cam only goes around half the rate of the crank!) - now you're on #1, so stop on TDC. Of course you have to crank it manually to stop at the right place, so it will help to remove the rest of the plugs to make it easier to rotate the crank. You must crank it in the clockwise direction, viewed from the front.
Now, with the engine stopped at #1 TDC, remove the distributor and reinstall it so that the rotor is pointing to the #1 plug wire, which should be nearest the alternator. Next, with the key on and your test light on the terminal on the side of the distributor, slowly rotate the distributor body back and forth so that the test light JUST comes on as you rotate against the normal direction of rotation of the rotor. Make sure the #1 plug wire is still positioned over the rotor tip. Now lock the distributor down in that position. Now reinsert the rest of the plug wires in the correct order 1-8-4-3-6-5-7-2, around the cap in the direction of rotor rotation. You know, I assume that the cylinders are numbered 1-3-5-7 down the driver's side, and 2-4-6-8- down the passenger side, front to rear.
At this point, the engine should start and run right, although you still need to fine tune the timing with a timing light. If it still backfires, there is a problem with the valve timing - this requires major disassembly to diagnose, but probably the chain has jumped a cog. You don't say anything about the condition or history of the engine, but if it has over 100,000 miles since the last timing set, it's due for sure.
Rebuilt carburetors are almost always problems, the people who do that work are not skilled enough to do it right - I do my own, but if you don't want to do that, either send it to a pro like Jon Hargrove at "the Carburetor shop" or buy a new one - they are readily available at around $300.
I assume you were joking about putting water on it, but in case not, water is the last thing you want near an engine fire. The right way to put that out is to pull the coil wire outof the top of the coil and ground it to prevent any spark, then crank the engine. The suction will pull the flames down into the cylinders, where they can do no harm. A Halon fire extinguisher is also a good cure, but they are getting hard to find thanks to the EPA, who doesn't like them.
If there is a possibility that water went down the intake, there might be serious engine damage.
