ENGINE BACKFIRES WHEN INCREASING RPM - STICKY VALVE??
May, 26, 2006 AT 7:07 AM
It's a little 800cc Renault watercooled engine from the 1960's - a " Gordini" powered Caravelle. It has sat on the blocks for about 2 years with rare startups.
The engine starts quickly and idles pretty smoothly but increasing just a few hundred rpms and the engine starts popping and backfiring, I think thru the exhaust. I've changed the points, condenser and plugs, set timing. The dwell is supposed to be 57 but I can only set about 51 before I reach the end of the adjustment cam.
I was wondering if a valve is sticking and hoping there is a simple solution -- something about Marvel Mystery Oil or a similar product -- I can use before opening things up?
I understand there is a diagnostic involving removing the valve cover and observing the valve operation?
Hi: First, I thought this was a chrysler product. However, the dwell is the problem. The points need to stay open longer. If they are sending spark at the wrong time (at a higher RPM) you will get a backfire. If there was internal engine problems, I think you would notice it at an idle too.
Make sure the points are the right ones for the car. They may be too small.