360 Six Pack lots of initial timing!!!

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polara1974

polara1974

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Buenos Aires - Argentina
Hi all, I'm having odd things with my initial timing in my freshly rebuild 360 Six Pack engine, I'm set at 28º initial now but I'm able to go to 40º without any kickback on the starter or pinging!!!! At 40º that thing shouldn't even start .... but it does and sounds mechanicaly correct ...
We have checker timing with two strobe lamps, one Innova with digital dial back and one old school no dial back. Both gave the same readings. Mopar timing tape on balancer.

I have read this situation here in the forum but most of the went back to MSD+new dial back strobe light= error or to "if it sounds good and drives good leve it alone" ... well not my case I NEED to sort this out!!!!

Just a few fact for you to know:
- Brand new 360 +0,30 engine rebuild everything new parts except for engine block and mains
- RHS LA Heads 2,02 / 1,62
- Comp Cams Mechanical Flat tappet 20-231-4 282/290 244/252@050 .520/.540 LSA110
- At assembly TDC was checked with a dial gauge and Balancer Zero mark lined up straight with timing cover scale
- 10,3:1 SCR
- Ignition is a Mopar Chrome box + Mopar Oem distributor + MSD blaster2 coil

One thing I like to point out is that just after firing this engine for the first time I was able to set initial timing at 14 with 10vacuum, since my total was too much I ttok the distributor to weld the slot and change springs, when I went back all the high readings startes on the initial timing and at the same moment I found two bent pushrods, retainers hitting valve seal, pushrods hitting pushrods holes in head, you can read about it here:
My 360 Six Pack build!!!

Now all of that has been solved!!! put everything back together, rechecked TDC with a piston stop before putting the head back in and it was spot on (no damper ring twist) the engine sounds perfect!!!! But I can have 40º initial....

I'm missing something for sure, so I need to pick your mind on this. What Am I missing here?

Regards! Martin
 
Are you sure you have the timing light hooked to #1 plug wire? (I'd bet you do) Maybe you're getting some cross fire from another cylinder? Bad cap/rotor, or wires? Just thinking out loud. Where are you for total advance now?
 
yep 100% sure that I'm hooking #1. I have tried two different distributor one aftermarket like OEM (with 15º mechanical advance in it - 30º at the crank) and one Mopar Performance unit (with 10º mechanical advance 20º at crank). Rigth now it has the Mopar unit operating.

For total advance I can tell that it wil be 20º more (all in at 2700/2800) of what i set the initial to. But I didn't mind about total timing since I wasn't able to get a decent initial reading.
 
I ran my 340 at 40deg at the drag strip and it ran great, only did it a few times.
Had no problem starting it, dropped 1 tenth off e.t. and added 4 mph.
Set your crank on 40 deg, pull your dist cap turn your rotor to full advance by hand and your reluctor should line up with your pick up. If it does your timing light is right.
 
take a compression test on 2 cylinders.

for timing at any rpm you basically increase it until the rpms no longer increase much as you turn the distributor then try it there but you may need to back it off around 2 degrees.

you "can" run a lot of advance in a low compression engine but that does NOT mean you should . typically a high compression engine will start to run slightly eratic/rough once it has too much timing
 
Brian6pac: I will perform this test soon and report back. by the way I already used two different strobe lights with the same result on both. One dialback Innova and one old without any adjustment and just reading my timing tape. Both same #.
When you say you ran your 340 at 40º at the strip, you meant 40º initial timing? or total?

If I time by RPM or Vacuum I can go as far as 40º or so, that when I got the higher RPM and vacuum readings. Still my engine has 10,3:1 Static compression ratio, so no low number here, not big number either.

Still do not understand how it can crank at 40º initial timing without kicking back on the starter or pinging!!!
Something is wrong and I can't find it ...
 
Run a compression test, It's a quick easy test, should be around 175psi.
Is your cam set 0, +4, -4.
 
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