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can someone edumacate me?

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walshja

walshja

Jedi Warrior
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when I bought my '74 Midget in June, the car was popping loud and often when you took your foot off the accelerator. I posted that issue on the board and the general consensus was the timing was off. not knowing how to adjust it, it was never adjusted.

but as the weather is getting colder in CT, it seems the more the temperature drops, the less it pops, almost being eliminated when the weather is in the low 60's.

would temperature effect the popping noise?

also, is there an idiots guide to adjusting the timing on my car? something with pictures? I am not afraid to try it, I just need a guide. I have all the manuals, but none of them are giving me the comfort feeling I need to jump into this.
 
The exhaust is not staying hot enough to ignite the unburned fuel passing into the tail pipe.
 
It is just an educated guess. I seriously doubt you are hurting anything if it is only popping on the overrun. If it is popping every time you shift, then there is a bigger problem (like timing).
 
Then again it may just be running too rich.
 
I had deceleration backfiring something fierce this spring. Need to eliminate exhaust leaks. In my case it was the header to head connection. The flanges are different thickness compared to the intake flanges. I regasketed and used some exhaust sealer goop and some little shims. That did it for me.
 
the popping only occurs when I let off the gas while in gear, using the engine to slow the car down, and it only happens when I first let off the gas, after the first pop or 2 it stops, the popping does not follow the RPM's as they decrease.

I really need to learn this part of the car, and soon !!!
 
That doesn't sound like any real problem. Exhaust leaks can make it worse.

Timing? Are you interested in static timing (engine not running) or dynamic timing (while car is running).

Do you have a haynes manual?
 
Well...

Normally when a car is within factory spec and nothing is worn out or swapped out, then static timing is sufficient and usually optimal.

There is a good John Twist video on youtube about how to set static timing.

In reality, when distributors are swapped out and the springs grow tired, it may be more optimal to use a timing strobe light and set the timing dynamically.
 
If it's running decent your timing is close. Get a timing light hook it up, shoot it up under the car see where the mark on the pulley appears in relation to the timing marks. Loosen and rotate distributor a tiny smidge to advance or retard as needed. Car all warmed up. Idle low. Advance vacuum line from carb to dist. removed and the carb end plugged. Static timing is setting the timing without the engine running after major work of some sort, just to get close. Dynamic timing, with a light, is to dial it in.
I messed with timing and other things but I highly suspected it was exhaust leak and it was. As soon I sealed it up, no more pops AT ALL. Gasket is cheap, don't even have to unhook the carbs and stuff.
 
It's the Infamous Gulp Valve
 
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