base timing question

[farmerman96]

I know similar questions have been asked thousands of times but seem to be engine specific so here it goes...

I just did an engine swap on my '93 ECSB z71. The motor was a 0 miles rebuild with an Isky 256/262 cam and an RPM air gap intake. I swapped over the tbi after rebuilding and all other internals are of stock specs. It has new World S/R torquer heads though.

My question is with regards to base timing. I understand the processes for setting it, just not sure how to dial it in. I have played with it from 10 to as much as around 20 degrees, but haven't seen much indication as to where to set it. I have it set around 16 degrees now, but it seems to run very well from 12 up to 18. Is there something specific to look for? It has great power, no obvious flat spots on acceleration, no backfiring, maybe seems to smell as if its a bit richer the higher I set it (obviously). My concern is fuel economy and exhaust temps I guess so I'm not sure how to dial it in to ensure engine longevity. My truck will be pulling a trailer from here in nevada to Alaska in a couple weeks so wanna get it sorted out.

Any advice or insight is greatly appreciated.

 

[copernicusd]

i believe you want it at 0, i dont think your supposed to do any advance on these engines, not sure if that changes after you start making changes to engine and computer

 

[DRAGGIN95]

Do you know the compression ratio of the engine, and have you tried running the engine in the 0-8 BTDC range?

 

[farmerman96]

I don't know the compression ratio for certain but I think it would be close to stock. I actually set it at 0 initially and crept it up slowly but it runs very poorly until its near 12

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[dirtridinz71]

Are you setting the timing with the esc wire unplugged?

 

[farmerman96]

I am... last night coming home from work (7 miles away) I noticed a lunging while driving then the cel came on. I expect the light to come on because I haven't tuned out the egr yet, but it has run fine prior. I stopped to check the mail and it almost died in park. I came out this morning and put the timing light on it and with the esc wire attached it was at like 25 degrees advanced but was jumping around. I unplugged it and it settled in at about 10* so i advanced it to around 16 which it seems to prefer and when I plugged it back in it jumped up again and was again sporadic. Should this be expected or are there likely other issues? Brand new dist by the way, new cap, rotor, plugs wires, etc.

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[DRAGGIN95]

Another question did you install the cam straight up?

 

[farmerman96]

It was installed when I bought the engine so I'm confident its in right. It's now very drivable but occasionally has issues with the timing retarding too much when it warms up. It doesn't happen often but when it does it starts backfiring through the intake and runs like hell. What would cause this? The distributor is new. The timing is only erratic when the esc is plugged in, not sure if this is normal


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