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Hey all I have a 76 that I bought last month and have been driving it back and fourth to work and the other day while on the freeway just all of a sudden stated makin a spark knock sound. It stated loosing power on the way home but thankfully I made it. I checked timing its at 6 degrees btdc replaced vacuum line to distributor, put in new points, cap, rotor, condensor, spark plugs and played with carb quite a bit to no avail. its still making the spark knock like its got really bad gas in it or its out of time. I had a 75 bronco that blew a head gasket between 2 cylinders and did this same sort of thing so Im hopin that isnt it and maybe you guys could point me in the right direction. Thanks!

Uh, that really sounds like a blown head gasket. That's not a huge operation, nothing to be afraid of. You could start by doing a power balance test. To do that, you'll need a long needle (preferrably an embroidery one), a section of wire, and a place you know has a good ground. Start the truck, and one at a time, stuff the needle with the wire solidly attached to both the needle and a good ground, into the sparkplug boot. Listen to the engine. An RPM drop when you ground out each cylinder is a good thing. If you ground out a cyl, and the RPM doesn't change, it means that cyl is producing zero power, and has a serious problem. If two ajacent cyls. put out no power, there's a good chance that you have a blown headgasket between the two cylinders. If it's only one cylinder, check for spark and compression.

The same thing happened to me. Started making a loud whap whap noise, and it turns out that I had blown the headgasket between my #3 and #4 cylinders.

If you need help with the changing the head gasket, Figuarus just fooled around with his, and I think he's got it down to a science.

Good luck and welcome to the site!
-Ret

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1980 4X4 LUV daily driver, as stock as can be.

hehe why thank you kind sir!

If you need help, look up the thread for "blown head gasket?"

I also have pictures and procedures written down that are alot more clearer than the chilton or haynes manual offers. Did i mention i have pictures?

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To the Oquirr hills for awesome thrills! Go-go 4wd, Activate!

ok thanks for the input! I will try grounding out each cylinder this weekend. I drive truck for a living and wont be back home till then. Ive done a few head gaskets before but always on small block ford or mopar. this shouldent be too much different just half the work right!!! Ill take a look at that thread also. If Im not mistaken I believe it was mention there was pics.

indeed there are. i will have to upload them soon.... i had to move them. look out for a new post

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To the Oquirr hills for awesome thrills! Go-go 4wd, Activate!

Hey all, just an update. I finnished up with the head gasket today. That wasnt too bad at all! it was blown between the no. 1 and 2 cylinders. Thank you all for the great advice and pics. the zip ties on the timing gear was a life saver. now to get on with fixin her up!

glad it worked out! didja fire her up already?

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To the Oquirr hills for awesome thrills! Go-go 4wd, Activate!

yep fired her up and she runs like a champ! drove her around all week and runs great. thanx again.

glad to hear it's back where it belongs: on the road!

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To the Oquirr hills for awesome thrills! Go-go 4wd, Activate!