360 timing, help

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philcollins

philcollins

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Bought a Satellite Sebring with a built 360. Can't adjust the timing, pinking like hell unless i have about 0 advance, then idle not that good, about 5 lbs of vaccum.

Spec i've got on the engine, The PO passed away so i don't have all the spec. What i've got:

Hypereutectic teflon coated 9.5 to 1 pistons, 0.030 over
64cc chambers, 9.7 to 1 compression

MP Purple shaft hydr cam.474 lift, 238 duration at 050. P4452992C
MP lifter, .500" valves springs.
Crane chromemoly pushrods

340 X HEADS, fully ported, stainless pushrod guides, 64cc, 2.02 intake, 1.60 exaust

Edelbrock Performer carb 1405 with choke

headers

Mopar electronic ignition.

l could adjust the initial timing to about 12 degrees (20 degreemechanical ) and have a nice idle at 850-900 with 16" of vaccumm but it pink like hell. So i've reduced the mechanical advance to 16 degrees but no change. I'm lost...

Tried 34 degree total, doesn't work... i've got a FBO total timing limit plate and i use the best fuel available.
 
Have you tried starting from step one?

Pull the distributor and make sure cylinder 1 is at the top on a compression stroke and drop the distributor back in with it pointing at cylinder one.
 
doogievlg said:
Have you tried starting from step one?

Pull the distributor and make sure cylinder 1 is at the top on a compression stroke and drop the distributor back in with it pointing at cylinder one.
Click to expand...
Don't worry about what cylinder the rotor is pointing at on the block. Just make sure its pointing where the number one wire is on the cap. You can put the distributor drive
gear in any way you want, just make sure the rotor is wherever you have the number one wire on the cap
 
Did you verify the total with a light ? Or just go off the numbers on the fbo plate ?
 
Cool, report back with what you find. timing tape will work as well, if you verified tdc though
 
iw378 said:
Cool, report back with what you find. timing tape will work as well, if you verified tdc though
Click to expand...
As said verify the dampener ain't slipped by checking/confirming exact TDC with the tool in the spark plug hole. its somewhat rare for it to slip but your (timing) numbers being reasonable with your good gas it should not be pinging. what RPM does the springs max at? pings at part or WOT? or both. EDIT I reread & saw the 9.7 SCR, if all good you may (highly likely) just need more octane cuz if your dampener ain't slipped your numbers are actually very reasonable unless possibly it is coming in REAL fast, what is your cranking compression. proportioning in some av or race gas works. if you build a monster you gotta feed it what it wants/needs
 
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Springs too light on the dist? That will make it ping with too quick of an advance.
 
It probably has the super light advance springs and no limiting of the slot. Put in at least one medium spring to hold the weight at idle and use a welder or solder to shorten the advance slots on the outside. You will probably want to disassemble the top of the distributor for this which includes the little snap ring under the rotor which can be gotten with needle nose pliers. Solder is easier to work with and holds up despite the softness of the material. Old fuel may also be an issue especially with iron heads.
 
ok here are the number: Mecanical advance set at 14, vaccum advance 21.
Idle 900 rpm, initial advance 18, 12 in of vaccum, total advance 53 at 1800 rpm.

The timing was all wrong before, was using the wrong mark on the damper. PLS, DON'T LAUGH AT ME. Run good now but ping a little bit at part throttle and tend to diesel when shut off.
Had the best vaccum at initial advance of 20, getting 14" of vaccum. But was pinging more. Total advance seems to be too early, should i use bigger spring or reduce mecanical advance.

P.S. new gas, FBO total timing limit plate so it's easy to ajust mecanical timing.
 
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Yes, at least one stiffer spring (they don't need to match). Ported vacuum for advance?
 
Stop using the vacuum advance until you get the base timing and total timing figured out.

IMO that cam will like 20ish+ for initial and then figure out where the total wants to be without pinging. You likely need different springs to get your total to come in slower.

That carb is usually lean in most all areas of throttle position.

Check for a vacuum leak somewhere as well.
 
yes ported advance
IMG_1151.JPG
 
crackedback said:
Stop using the vacuum advance until you get the base timing and total timing figured out.
IMO that cam will like 20ish+ for initial and then figure out where the total wants to be without pinging. You likely need different springs to get your total to come in slower.
That carb is usually lean in most all areas of throttle position.
Check for a vacuum leak somewhere as well.
Click to expand...

That there's good advice.
If it diesels, the throttle is open too far, indicating either it's idling too fast, or the idle timing is not enough, or both.
All sb engines like power-timing to be in a very narrow window between about 32* and 36*. So a good target is 34*. When it gets there and how fast it gets there, YOU the tuner' have to figure out.
So start with the best gas you can find and, a slow curve coming in very late and, work your way back. Leave the vacuum advance off for several weeks/several tank fulls, til you get the mechanical sorted.
After you get that sorted, you can try the next grade down in gasoline, and start all over.
check my sig below
 
Use your advance timing light and map your distributor curve. Start at idle and then to full advance, then go from there...
 
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