Starting problem

[ochretoe]

The engine is a 79 200cid in my 74 Bronco. It has a weber 32/36 and adapter as well as duraspark II. The head has a 3 angle valve job and back cut ex. valves. The engine is a very recent rebuild (3,000 miles or less) builts stock. Everything was the same in the old engine except it was built 30 over. I busted a piston with crap getting in it is why I put new engine in it.

Now the problem;

Since I put the new engine in, when I go to start the truck it turns over hard and a lot then has a small backfire. As soon as it back fires it will start right up. It runs great after it starts. It even does this when its warm. The engine soulnds like it has a bit of cam lope to it but the man I got the rebuilt engine from said he thought it was a stock cam. Could a mildly agressive cam and higher compression cause the starting problem or is it something else?

 

[page62]

What is your timing set at? Could be too much advance....

 

[ochretoe]

It is set at 8 above.

 

[BIGREDRASA]

When you say "above," are you talking about the physical picture as seen from the driver's side? In that case, you're @ 8* BTDC (Before Top Dead Center). Otherwise, 8* After Top Dead Center puts you about 18* retarded. Not good at all, and not usually what you can see without a Degree Wheel.

If you're reading 8* BTDC with the Dizzy hooked up to any vacuum source, you're still way retarded. I personally only connect to the Ported
Vacuum on the carb. Others prefer the manifold. Either way, initial timing is set with vacuum plugged.

Hope that helps.

 

[ochretoe]

You are right about it being 8*btdc. It is above as I look at it. I have been setting timeing with the vacume removed from the carb. I thought it was suppose to be unplugged to set timing. I will check it with vacume attached and see if it does better. I use the vacume port on the base of the carb.

 

[ochretoe]

You are right about it being 8*btdc. It is above as I look at it. I have been setting timeing with the vacume removed from the carb. I thought it was suppose to be unplugged to set timing. I will check it with vacume attached and see if it does better. I use the vacume port on the base of the carb.

 

[BIGREDRASA]

Vacuum needs to be disconnected from the carb, and plugged/capped to avoid a leak. Try cranking timing up to 12* BTDC.