340 timing questions?
#1
Mopar Fan
Thread Starter
340 timing questions?
Ok guys, I just bought my first 72 dart with a built 340. And I'm new to mopars! (ex ford guy)! So the guy I bought it off of didn't know the cam specs, but it does have a nice lump to it. The car has a pretty good hesitation when you hammer the pedal. I tried to play with the timing but can't seem to get it rite. The stock balancer is on there so the timing mark is under the water pump when I go to time it? Any suggestions would be great, thank-brandon.
Motor specs as I can see the-
340
x heads
Comp L/T headers
750 Holley
Victor intake
Auto trans/stall ???
Motor specs as I can see the-
340
x heads
Comp L/T headers
750 Holley
Victor intake
Auto trans/stall ???
#2
This sounds somewhat like you may have an early balancer on a late engine, IE late timing cover/ water pump
The timing mark tab on the timing cover is on the driver's side?
The lower hose to the water pump is on the passenger side?
FIRST thing to do is find out if your timing mark is correct, and if not you can MAKE one
So get/ make a "piston stop" like this:
http://img.villagephotos.com/p/2002-...onStopTool.jpg
You can make one from an old spark plug
Remove no1 plug, make sure the piston is "down a ways" and remove the battery ground
Install the stop. You may have to play with the length. Rotate the engine with a wrench until no1 piston stops on the device. You are NOT trying to stop it at the top (TDC) but rather "down a ways."
When the piston is against the stop, make a temporary mark under TDC on the timing tab onto the balancer
Now rotate the engine counter clockwise, until it stops again, and make a second mark.
TRUE TDC will be halfway between the two temporary marks, and if the original is correct, that is where it will be
Now do one of two things. CAREFULLY measure around the outside of the balancer with a small flexible tape. Take care to be accurate
Now either buy "timing tape" from one of the speed shops, or calculate how many "degrees per inch" and scribe your wheel.
I usually start with 40* and figure how many inches for than, then use your tape to mark the wheel. Take your time, and be accurate. Do NOT use dividers for this, you MUST use a tape to measure "around" the wheel.
Now that you have TDC and 40*, you can use dividers to divide this in half for 20*, divide in half again to get every 10 *, etc
You can also use a "dial up" or "delay" timing light to measure your advance, but I do not trust these things.
If you mark the wheel out to 50* you can measure your mechanical AND vacuum advance.
I would start by revving the engine and setting the distributor so that with (vacuum disconnected) the mechanical advance goes out to about 35-38*, and then idle down and see where your initial timing "ends up."
WIthout experimenting, you have no idea how much is "in the distributor," etc.
For a performance engine, a "starting figure" is about 20* in the distributor mechanical advance. This means that say, with 36* total at high RPM, you'll have 36-20 = 16* initial IF that's what is "in" the distributor.
If you run vacuum, you can expect "around" another 10*, so with the vacuum hooked up, and the engine "held" at a simulated cruise/ highway speed, you should then have around 36+10= 46 absolute total, that is, initial+mechanical+vacuum
BUT YOU CANNOT DO THIS without
A checking your timing mark for accuracy
B then using either a "dial" timing light, a marked balancer, or timing tape.
The timing mark tab on the timing cover is on the driver's side?
The lower hose to the water pump is on the passenger side?
FIRST thing to do is find out if your timing mark is correct, and if not you can MAKE one
So get/ make a "piston stop" like this:
http://img.villagephotos.com/p/2002-...onStopTool.jpg
You can make one from an old spark plug
Remove no1 plug, make sure the piston is "down a ways" and remove the battery ground
Install the stop. You may have to play with the length. Rotate the engine with a wrench until no1 piston stops on the device. You are NOT trying to stop it at the top (TDC) but rather "down a ways."
When the piston is against the stop, make a temporary mark under TDC on the timing tab onto the balancer
Now rotate the engine counter clockwise, until it stops again, and make a second mark.
TRUE TDC will be halfway between the two temporary marks, and if the original is correct, that is where it will be
Now do one of two things. CAREFULLY measure around the outside of the balancer with a small flexible tape. Take care to be accurate
Now either buy "timing tape" from one of the speed shops, or calculate how many "degrees per inch" and scribe your wheel.
I usually start with 40* and figure how many inches for than, then use your tape to mark the wheel. Take your time, and be accurate. Do NOT use dividers for this, you MUST use a tape to measure "around" the wheel.
Now that you have TDC and 40*, you can use dividers to divide this in half for 20*, divide in half again to get every 10 *, etc
You can also use a "dial up" or "delay" timing light to measure your advance, but I do not trust these things.
If you mark the wheel out to 50* you can measure your mechanical AND vacuum advance.
I would start by revving the engine and setting the distributor so that with (vacuum disconnected) the mechanical advance goes out to about 35-38*, and then idle down and see where your initial timing "ends up."
WIthout experimenting, you have no idea how much is "in the distributor," etc.
For a performance engine, a "starting figure" is about 20* in the distributor mechanical advance. This means that say, with 36* total at high RPM, you'll have 36-20 = 16* initial IF that's what is "in" the distributor.
If you run vacuum, you can expect "around" another 10*, so with the vacuum hooked up, and the engine "held" at a simulated cruise/ highway speed, you should then have around 36+10= 46 absolute total, that is, initial+mechanical+vacuum
BUT YOU CANNOT DO THIS without
A checking your timing mark for accuracy
B then using either a "dial" timing light, a marked balancer, or timing tape.
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a.johansson84
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05-27-2012 03:30 AM