| sally | -- 10-08-2012 @ 10:38 AM |
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Greeting to All, I'll try and keep this short as possible. A while back I blew a head gasket on my '35 Ford. I pulled the heads; block surface looked okay; had the heads resurfaced; of course new gaskets; reinstalled the heads following all the correct guidelines etc. Here's my problem... Now the car has a horrendous ping any time the car is under load. Fast acceleration, pulling a hill etc. What I've done so far... I rebuilt the distributor; new points, condenser, rotor, cap etc. Once back on the car, I adjusted the vacuum advance brake every which way 'til Tuesday and I retarded the timing, advanced the timing, but still the loud pinging. I did a vacuum test and all the valves checkout okay. Question? When I had the heads off I discovered that the engine had been bored 60 over. Do you think that between that and having the heads resurfaced that an increase in compression is the root of my problem? Please share your thoughts Richard H.
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| ford38v8 | -- 10-08-2012 @ 11:00 AM |
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Richard, your problem stems from the resurfacing of the heads. One or more of your pistons is touching the head and causing the loud ping. Remove the heads and you'll see the contact area, and can decide whether to increase the thickness of the gaskets or to buzz the spots with a dremel. Alan
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| supereal | -- 10-08-2012 @ 3:31 PM |
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If too much was removed from the heads, it is possible one or more valves are making contact. If it is a piston, that sound is usually more than a ping. If it only happens under load, as you say, look for any projections into the combustion chambers, such as a gasket or any sharp corner. When these get hot, they will pre ignite the fuel. Same is true of a spark plug. Try changing them to see it it cures the problem. Also consider if the plug wires are old, causing crossfire inside the metal conduits. I've seen these problems. As to whether or not the resurfacing of the heads could be at fault, the answer is yes. Years ago. one of the most common practices was "milling" the heads to increase the compression. If overdone, the higher compression would cause pinging, as well as the interference mentioned above. As it isn't possible determine by sight whether this is causing your problem the best way is to "clay" the heads. This involves filling the combustion area of the heads with modeling clay, reinstalling the head,then turning the engine over at least once, then pulling the head and examining whether the valves of pistons have enough room to operate. At our machine shop, we always check these clearances, as the owner usually doesn't know what has been done. Milling the heads seldom improved performance, and often did the opposite, including pinging and overheating. This message was edited by supereal on 10-9-12 @ 10:32 AM
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