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Author
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Topic: 302 with a knock
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FSTBK65
Journeyman Posts: 67
From: Salem, Virginia
Registered: May 2004
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posted 09-10-2004 04:10 PM
   
Alright guys. Here's one for ya. I am putting together a fastback for my brother. I rebuilt the 302, I think it was a 68 model block. I had the machine work done on the block and then assembled it myself. New pistons, mains, and rods, oil pump and shaft, timing set. I am using a set of cast heads that I had on my motor. I had these heads reworked about 2 years ago. They have all new valves, and rockers, new pushrods and cam and lifters. At idle the motor has a knock which sounds like its coming from the front drivers side of the motor and the motor is missing. I adjusted the timing and I pulled the plugs and cylinder 5 isnt firing. The plug looks brand new. What should I do? where should I start. I am going to try swapping a plug and wire, to see if the miss goes away, but what im worried about is the knocking. Any help would be appreciated. Thanks
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capri man
Gearhead Posts: 5526
From: doerun, ga.
Registered: Nov 2000
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posted 09-10-2004 04:29 PM
one of the first things i would do is run a compression test to see if #5 was equal to the other 7.------------------
mike r
racing is real
everything else is just a game.
81 capri-302-7.33 @92mph 1/8
1.54 60 ft. http://www.angelfire.com/ny5/billswebsite/pg06.html
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N266fords
Gearhead Posts: 1196
From: Spokane ,WA USA
Registered: Apr 2003
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posted 09-10-2004 05:16 PM
Could it be a bad wire or plug?
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67nightmare
Gearhead Posts: 118
From: rose hill, ks, usa
Registered: Mar 2004
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posted 09-11-2004 07:46 PM
You may have a stuck valve. I would also run the compression test. If you find that the compression is low in the #5 cylinder you can always try pouring a little bit of tranny fluid in the head through the spark plug hole. This will help free up the piston and raise compression if thats the problem. The tranny fluid will produce a dense white smoke so dont be alarmed if you see that after doing this.
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FSTBK65
Journeyman Posts: 67
From: Salem, Virginia
Registered: May 2004
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posted 09-12-2004 09:16 PM
I ran the compression check on this thing...170 to 180 pounds on every cylinder. I pulled the valve cover on the drivers side and made a deflector shield out of cardboard. I fired her up and pushed on the intake valve on cyl no. 5. When I did the knock quit. When I let up the tick was gone for about 10 seconds and then started again. Sounds like a lifter to me. Im off to pull the intake. Thanks guys.
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FSTBK65
Journeyman Posts: 67
From: Salem, Virginia
Registered: May 2004
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posted 09-13-2004 03:30 PM
Well I fired it up at about 12 last night, after installing the new lifter, and still hear the ticking. I ran it for a while to let the lifter pump up and the ticking would get softer for a few seconds and then tick louder, but it never completely stopped. I pulled the valve cover and backed the rocker arm nut off two turns. Didnt change a thing. I then swapped a push rod and rocker with one that wasnt ticking, and nothing changed. I turned the motor my hand, and when the valves rocked on cyl no. 5 the pushrod over top of the lifter that i replaced was tight, I could turn all of the other pushrods with my fingers. I really stuck now. Any help or suggestions would be appreciated.
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FSTBK65
Journeyman Posts: 67
From: Salem, Virginia
Registered: May 2004
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posted 09-27-2004 11:48 PM
Well I tore down the motor and found that the no. 5 piston was tight on the rod. The block is going to have to be bored. I took it back to the shop that did my work, and we came to the conclusion that the carb has been leaking gas into cylinders no. 4 and 5, and in turn washing the oil off of the walls. The heat actually caused the wristpin to seize up. Who would have ever thought.
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