Backfiring after rebuild

As you may know, my old 1600 went bang. We've rebuilt it on another case and all seems to be fine except it is backfiring a lot. It hasn't been driven as yet, it is backfiring when static ticking over.

It's a bit frustrating as I hoped to get it done today so when it started backfiring my brain froze.

Suggestions please to get my mind back in gear.

 

air leak on the exhaust side

 

Mine was doing that too, just after I changed the exhaust, after looking carefully I think Ive disturbed the crusty cracked manifold boot on the left hand side.. I will find out tomorrow if this is the case..

 

I'm pretty sure it's not and exhaust leak of any sort. Gaskets are new and tight, exhaust is stainless and in good condition.

I'll hopefully get back there tonight and it will be something obvious .

 

I had a slight leak in the inlet manifold to head gasket which caused mine. Could be inlet manifold boots too
;D

 

Ignition timing correct? Is the dissy properly seated?

 

mixture too lean, timing out or drawing air in on inlet side

 

It's only backfiring on high revs.

Have tried all above to no avail.

 

Just a thought but is the distributor drive cog in correctly?

 

Is it a vacuum advance dizzy or 009 type, maybe worth double checking gap on points : good luck

 

Checked ponts, changed dizzy, used both SVDA and 009.

 

Im guessing you static timed the bus, double check its correct if theres no air been sucked in, kinda points to timing so check it all again with va dizzy on, sorry not much help :- have some karma to help..

 

I'm clutching at straws really. I think it's probably something more serious like a worn cam shaft. We took a risk using parts without knowing 100% of their history.

 

I think it's something far more simple, mate. Check your ignition timing as above.

 

Timing has been set both statically and with a strobe.

 

Tested for airleaks.

 

This isn't like backfiring I've known with air leakage, it's not the odd bang. It's bang-bang-bang-bang-bang-bang.

Similar to if you get the HT leads on the wrong way (the HT leads arent on the wrong way BTW).