I have a 340 duster that's somewhat built big cam redone heads bored new pistons and rods. My question is I just took it out of storage and was going over a few things and I was checking base timing. I have it set at right around 14degrees btdc I noticed when I disconected my vacum advance the timing did not change. Does this mean that its not working? The car will still break the tires loose but it does feel a bit slower.
timing question
- Thread starter jay dcpt
- Start date
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if your vaccum advance is hook up to the ported vacuum on the carb...it is not getting any vacuum while the engine lines..that is why you see no change in idle speed.
as you step on the gas..the vacuum port in the carb is exposed to engine vacuum..and then you get vacuum advance...
vacuum advance is design to provide addition advance to the engine during light engine loads as in crusing..
as you step on the gas..the vacuum port in the carb is exposed to engine vacuum..and then you get vacuum advance...
vacuum advance is design to provide addition advance to the engine during light engine loads as in crusing..
Mad Dart
Nothing to see Here!
Tony nailed it. When you take the plug off the carb at idle you will know which one is ported or direct manifold vac cause the engine will go into convulsions....... LOL
If you have a vac gauge you can hook it up to the port and see which one is ported and the one that is direct manifold vac. If you get a reading at idle it is the Direct port, not ported.
If you have a vac gauge you can hook it up to the port and see which one is ported and the one that is direct manifold vac. If you get a reading at idle it is the Direct port, not ported.
green1
Well-Known Member
Basically; set timing to highest idle, or vacuum, just by moving dist. then adjust carb. Then see what initial you have, and pull advance out of the dist. Done.
green1
Well-Known Member
Basically; set timing to highest idle, or vacuum, just by moving dist. then adjust carb, to idle back down. Then see what initial you have, and pull advance out of the dis, to keep it around a total of 34 to 36. Listen for knock, and adjust. Done. Know vacuum will run up to 54 degrees, under light cruise. That's how a engine works.
well its a 750 cfm carb edelbrock. and from what ive been reading you hook up the advance on the left side of the carb. I was just wondering because on other motors i have messed with when you set base timing with advance disconected then hook it back up i usually see the timing change with the timing light.
................only on brand X do u run vac at idle...........and with a big cam u may be better off without vac advance anyways............kim......
Thats why i was asking. The past references i was speaking in was setting timing and adjusting a carb on a sbc. However i am going to give this thing a tuneup this weekend and was wondering what plugs you guys would suggest using? The motor is a 340 bored 30 over srp pistons eagle rods 10 to 1 compression 500 lift cam heads redone with 2.02 n 1.60 manley streetflow valves not ported run a tci breakaway converter 4.11,s in the rear. Any suggestions on plugs?
green1
Well-Known Member
Got a pic of the existing plugs? That will tell. Advertised tells nothing, what is actually happening is the start point. Not being an azz; but is it decked? heads and pistons been checked? How much bleed off on the cam?
It all fits together. Lets see them plugs.
It all fits together. Lets see them plugs.
The block didn't have to be decked whwn machine work was done I can post cam specs when I get home and ill post some picks of the plugs.
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