Help-blown head gasket? 67 FE Mustang I think I have a bad head gasket. Here's what is happening:
Starts up normally, runs well for about 15 minutes then it starts to run rough, almost like an ignition miss. I've gone through the ignition system and everything seems ok.
Temperature guage remains normal I don't see any white smoke out of the tail pipes. It's not losing anti-freeze.
I'm going to do a compression check on it. Anything ideas on what else to check before I pull the heads? Thanks
They were famous for two things. Broken diaphragm in the vacuum advance and bad coils. Start there.
Al
A good shop can check the coolant for products of combustion. It's inexpensive, and a lot less work to do the test before taking the heads off.
Other places to look are (1st) the ignition system. Heat causes strange things to happen to ignition components.
Second, check the carb, especially the choke.
"Big Al" wrote in news:465630b2$0$491$ snipped-for-privacy@news.qwest.net:
A bad vacuum advance wouldn't cause this. The coil might. Raise the hood at night, and look for arcing from the plug wires.
Sorry, when the advance diaphragm breaks it allows small amounts of fuel vapor into the distributor. The arcs in there burn it and make carbon. Sometimes it blows the cap off. This is a very common problem. The points will be black and so will the contacts in the cap.
Back to the coil. That would be the first thing I would check.
Al
I've used the following method to check for a blown head gasket.... Remove the radiator cap, and place a pressure gauge on the opening (the pressure gauge I use has a manual pump to pressurize the radiator manually if desired. Start the engine and if the pressure gauge's needle fluctuates, chances are that you have a blown head gasket, (compression pressure leaks into the cooling system).
Best of luck to you!
Dave
"Big Al" wrote in news:465678f5$0$503$815e3792 @news.qwest.net:
Please explain how that happens, since the ported vacuum is pulling air INTO the carb, not from it. There is no way fuel vapor can get inside the cap. I've never heard of this, and I have had several blown diaphragms.
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