Timing? Help

Hi,

My car keeps popping and stalling when I put it in gear if I let it idle. The RPMs drop, it backfires and dies. I can keep it running and I can move it around if I stay on the gas to keep the RPMs up, but as soon as I let off, it stalls.

I know the guy I got the car from retarded the timing so the engine would run on pump gas and I'm thinking that's the problem.

The engine is a 355 SBC with 12.5 to 1 pistons with old double hump heads that are stock/rebuilt - no porting etc. The carb is a 750 double pumper. The manifold is a Weiand single plane. The distributor is a Mallory dual point with mechanical advance.

I checked the static timing and it shows about 14 degrees BTDC. My timing tab goes to 12 BTDC and the mark on the balancer is off the tab, just above it. So I'm estimating that it's about 14 degrees.

I'm not sure what the total advance is. I followed the timing light's instructions and I got 8 degrees BTDC at 2,500 RPMs. I know that can't be right.

Anyway, the car seems to run fine otherwise when it's idling. I have it idling at 1,500 RPMs. It'll go a little lower, but the engine gets a little rough. I haven't driven it anywhere yet. I still have to register it and get it inspected. Of course, I can't drive it anywhere if I can't sit at a stop sign or red light if it's going to stall. It seems that it would drive just fine except for the stalling though.

So, if anyone's got any advice, i could use it.

Thanks.

 

it may be just too hot of an engine to make it idle at the speed you want it to. single plane intake , 12.5 to 1 can make for a fast idling engine

when you say "put it in gear" do you mean an automatic tranny? if it's an auto , does it have a higher stall convertor? high performace engines and stock convertors don't mix to well together

what cam does it have? big duration cams don't like to idle slow either

 

Yeah, it's an automatic. A full manual Turbo 400. I can't tell you cam specs. I don't have them. It's an Elgin cam, but I don't know what one and they can't tell me without me taking the cam out and looking at the back of it for numbers. I don't remember for sure, but the guy I got the car from called it either a "Z28 Experimental" or a "LT1 Experimental". I think he said "Z28".

I don't know the stall speed, but I'm sure it's not a stock convertor.

Speaking of "hot" I just backed it into the garage. It actually did OK. But I had POPs the whole way. And the temp went from about 180 to 220 in the 5-8 minutes it took to back it up the driveway and get it positioned in the garage.

 

I called Mallory and they said it sounded like the carb and I should call Holley. Holley said it sounded like the carb was rich and I should check the plugs. I pulled three and they're all used looking, but spotlessly clean, so the Holley guy was right.

So now I need to check the float levels and probably as he suggested, get a rebuild kit.