Moparts

340 timing settings

Posted By: 71SCAMP

340 timing settings - 07/21/12 04:35 AM

JUST COMPLETED A 340 REBUILD (1970 VINTAGE) FOR MY 69 VALIANT. MOTOR HAS BEEN BORED 0.030, PORT/POLISHED 340 HEADS, MP .484 CAM, STOCK CRANK AND VALVES, ELECTRONIC INGNITION, EDLEBROCK DUAL PLANE MANIFOLD AND EDLEBROCK 600 CFM CARBURETOR,STOCK 340 MANIFOLDS, 727 WITH 2400 STALL CONV AND 8 3/4 WITH 3.23 SURE GRIP. WHAT IS A GOOD STARTING RANGE FOR TIMING SET? HOW ABOUT VACUUM SETTINGS? THE MP DISTRIBUTOR HAS A BUILT IN ADVANCE AND I'M NOT SURE HOW MUCH VACCUUM TO USE. ANY THOUGHTS?
Posted By: RobX4406

Re: 340 timing settings - 07/21/12 04:43 AM

16-20 initial and limit the mechanical in your distributor to hit a total number around 34-36.
Posted By: radar

Re: 340 timing settings - 07/21/12 04:48 AM

Unplug the vac advance and get the total in the 34 deg range if the initial is up over 10 you can probably run it just fine. You have a mild setup. If you want to tune the curve then you would start with the initial then set the mechanical (by welding up or lengthening the slots in the plate inside) to get your total, then mess with the springs to set the rate, then tune the vac. can with a little allen thru the nipple.

Good luck!
Posted By: 340SHORTY

Re: 340 timing settings - 07/21/12 08:24 AM

unlock your caps button... :flamePeople think your
Posted By: Challenger 1

Re: 340 timing settings - 07/21/12 01:18 PM

Quote:

Unplug the vac advance and get the total in the 34 deg range if the initial is up over 10 you can probably run it just fine. You have a mild setup. If you want to tune the curve then you would start with the initial then set the mechanical (by welding up or lengthening the slots in the plate inside) to get your total, then mess with the springs to set the rate, then tune the vac. can with a little allen thru the nipple.

Good luck!



He has a MP distributer...so no welding slots, a 484 cam is not mild imo and he is gonna need a lot more 10 degrees intial timing.

Don't worry about the vacuum advance at this point, no adjustment will be needed to begin with if ever!
Learn how to tune your distributer, it will pay big dividends.
Those torx screws are what you loosen to limit your total timing.

I run a 340 with a 474 cam and need about 20 intial timing, only I have eddie heads with a 340 victor intake, I tried the dual plane and hate it. Give me a single plane with no heat passages. I tune mine all the time beause I take all over the country and drive it, I'm a lucky guy. I drive mine, it ain't no show poddle.
Good luck with your new motor!

The day I put it in.
Posted By: RapidRobert

Re: 340 timing settings - 07/21/12 02:13 PM

If you're getting ready to fire up a new breakin I'd set the initial at 15 then have a helper twist the dist to 35 when it starts (vac adv capped) as you'll be in the 2500 rpm range. Make a mark on the dampener 2&1/4" clockwise from the TDC slit which'll be 35.5 degrees. After breakin What Radar said, initial (vac gauge method)/total(35 w vac capped)/springs/then hookup/tune vac adv IN ORDER
Posted By: 340727dart

Re: 340 timing settings - 07/22/12 04:26 AM

What kind of pistons are you using?
If they happen to be KB hypereutectics, the manufacturer says to limit total advance to 34*.
Posted By: Challenger 1

Re: 340 timing settings - 07/22/12 06:29 PM

Quote:

What kind of pistons are you using?
If they happen to be KB hypereutectics, the manufacturer says to limit total advance to 34*.



Got a link to that?
Posted By: RobX4406

Re: 340 timing settings - 07/23/12 12:43 AM

Quote:

Quote:

What kind of pistons are you using?
If they happen to be KB hypereutectics, the manufacturer says to limit total advance to 34*.



Got a link to that?



I remember seeing something about running 2-4 degrees less timing, but never a top side limit for timing.
Posted By: MY340

Re: 340 timing settings - 07/23/12 02:46 PM

On my old 340-4spd Spaceduster with the MP 508 cam I ran 22 degrees intial and 36 total with vacuum advance disconnected. Timing all in at 2400rpm.
Posted By: 340727dart

Re: 340 timing settings - 07/23/12 04:35 PM

Quote:

Quote:

What kind of pistons are you using?
If they happen to be KB hypereutectics, the manufacturer says to limit total advance to 34*.



Got a link to that?



http://www.kb-silvolite.com/article.php?action=read&A_id=32
http://kb-silvolite.com/article.php?action=read&A_id=7
http://www.riveraprimoinc.com/catalog/ca...k%20Pistons.pdf
Posted By: Challenger 1

Re: 340 timing settings - 07/23/12 04:38 PM

Thank you
© 2024 Moparts Forums