Timing Question/SB Mopar

What would cause the timing mark to "jump" around, if the distributor and timing chain are both new? The engine is a 360, and the other night, we set the timing to 12 BTDC, and it ran great for the night. Set it with the advance disconnected. Reconnected it, it was fine. Let it sit 2 days, went to start and move it, and it wouldn't run worth a darn. So we checked it yesterday, and it was at about 7 BTDC! What gives? Please help!

BTW, the symptoms were that it was running like crap, backfiring and heating up real quick. We took care of all those problems but now they are back.

Thanks guys!

Jay

 

Is it points or electronic?
If it's an electronic dizzy check and make sure the magnetic pickup didn't come loose and touching the commutator. That can cause all kinds of goofy shit to happen.

 

In the "way too obvious" catagory, was the engine at a hot idle when you set the timing?

If it was running fast (like as if on the choke or fast idel cam) when you set the initial timing, your setting of 12 degrees may have been affected by the engine's speed. Back at a 'normal' hot idle, it could very easily be 7 degrees. (Due to the centrifugical advance, ya know!)

Also, if your carb picked up a piece of dirt, making the needle and seat stick, or if the float sunk or something, you could be running rich and choking the engine with fuel.

(Ummm...you DID re-connect that vacuum line to the distributor, right???)

A vacuum leak will creat erratic idle and mess with ya, too!

One more tip...save the Fosters till AFTER the tune-up is done!!!

 

We were at Matt's, so it was Bud Light.

Yes, we let it warm up, actually, he was doing do-nuts in his yard, and it went to like 220, and he has a 160 t-stat. He had been told that advanced timing would make it run hot, so he wanted to check it while I was there. So we did. Yes it is an electronic distributor, I didn't know about the commutator thing, we'll hafta check it. BTW, it is an Edelbrock 600, electric choke. I thought about the vacuum leaks too, but we didn't find any. Thanks so far, I'll hit him with this info after work.

Jay

 

Holley carb...points distributor...problem solved!!

Bud Light??? Eeyyaacch! You didn't get any on the MOTOR did ya??? That would piss it off fer sure!

 

Maybe we can do a late Tech article this weekend on rebuilding a Holley, and do that one I found, hint hint. I mentioned that to him and he seems willing to try anything, he just wants it to run RIGHT...

Jay

 

Ha Ha...I'll be glad to school ya on the ways of Holley!!

He'll drop kick that Carter into the middle of next week after he sees how good that heap's gonna run once I lay the fine tune on it for him!!!