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1961 - 1966 F-100 & Larger F-Series Trucks Discuss the Slick Sixties Ford Truck

Knocking sound?

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Old Dec 18, 2017 | 05:30 PM
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Knocking sound?

So I got the 66 f100 running. Actually runs decent. I noticed though, at low idle, it make this...knocking? sound. It sounds like it's coming from the back of the engine. But seems to be coming higher on the engine. I don't think it's rods but I'm not sure. It's not very consistent. And so far I only hear it sometimes. It's doesn't seem to make the noise all the time.
 
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Old Dec 18, 2017 | 07:15 PM
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What engine?
 
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Old Dec 18, 2017 | 07:17 PM
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Originally Posted by TheMonson
What engine?
The engine is 352
 
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Old Dec 18, 2017 | 07:18 PM
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I've heard of push rods getting bent but if it's inconsistent I'm not sure. Does it happen more when it's cold? Before it reaches operating temperature?
 
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Old Dec 18, 2017 | 07:19 PM
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What does the oil look like and when was it last changed? It could just be tappet noise.
You might try getting the engine good and warmed up and add something to the oil to help clean up deposits. We had a '64 olds that had a lifter that would get sticky. We would add half a quart of ATF to the oil and drive it a couple of days and then change the oil. It
would get rid of the noise untill the oil got dirty again.
 
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Old Dec 18, 2017 | 09:28 PM
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Originally Posted by john jamieson
What does the oil look like and when was it last changed? It could just be tappet noise.
You might try getting the engine good and warmed up and add something to the oil to help clean up deposits. We had a '64 olds that had a lifter that would get sticky. We would add half a quart of ATF to the oil and drive it a couple of days and then change the oil. It
would get rid of the noise untill the oil got dirty again.
I really think it's lifters. I put my hand on the intake when it was running and it seemed like it was coming from right underneath it. Marvels should work just fine shouldn't it?
 
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Old Dec 18, 2017 | 09:37 PM
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Maybe better, should be a good plan for an uncertain engine that's been hibernating. Replace 1 quart of crankcase oil with Marvel oil and 4oz per 10 gallons of gas, put it in both crankcase and fuel. In the fuel it helps keep valves from sticking in guides and dissolve carbon, in the oil it helps unstick gummy piston rings and lifters. It's made for this, to dissolve carbon and varnish.

Speaking of fuel a lot of guys will run a boat tank or whatever, hooked up to carb to bypass the fuel tank and lines. Old stale gasoline will cause big trouble. Should perform a cylinder compression test to see what you have before getting too spooled up on this thing.
 
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Old Dec 19, 2017 | 08:12 AM
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Try what Tedster 9 mentioned...won't hurt and might help.

Valve train noise is usually a tap at half the rpm of the engine. Connecting rods more or less hammer. Both sounds can/will come and go. And neither sound should be ignored for too long or engine might go ka-powie.

With valve covers off and engine idling you can sometimes make a valve tap go away by holding a wood handle on each rocker until you locate the trouble.
 
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Old Dec 19, 2017 | 09:38 AM
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Another thought to help locate the noise - they do make engine stethoscopes - but a cheaper alternative is to take a piece of something like heater hose about 2 feet long or so and hold one end to your ear and move the other end slowly from one spot to another. You might be surprised how much it can help to isolate the noises.

Chad

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Old Dec 19, 2017 | 09:41 AM
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Could this also be a wrist pin? I heard people talking about that. Also, how can I check how much oil pressure it has? Just get a gauge from the store and hook it up to the oil sender?
 
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Old Dec 19, 2017 | 10:07 AM
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Originally Posted by jwitty
Could this also be a wrist pin? I heard people talking about that. Also, how can I check how much oil pressure it has? Just get a gauge from the store and hook it up to the oil sender?
Could be either end of a connecting rod making noise.

For oil pressure, yes. Unscrew the oil sender and screw in oil pressure gauge. The kit I have has adaptors for various sizes. This gives you oil pressure at the filter. Don't think you can measure it anywhere else on and FE unless you have a sideoiler FE.

I installed an oil pressure gauge and mounted it on the steering column so I can see if there are ever any changes from the normal.
 
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Old Dec 19, 2017 | 10:10 AM
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Could be. Or "piston slap".

Usually a cylinder compression test is recommended before anything else. In my old MoToRs Repair Manual it's on page 1 paragraph 1. The idea behind this is to avoid spending money on a tuneup for a motor that is too worn out. If compression is reasonably good and even across all cylinders it will respond well to repairs and adjustments.
 
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Old Dec 19, 2017 | 10:16 AM
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Originally Posted by Tedster9
Could be. Or "piston slap".

Usually a cylinder compression test is recommended before anything else. In my old MoToRs Repair Manual it's on page 1 paragraph 1. The idea behind this is to avoid spending money on a tuneup for a motor that is too worn out. If compression is reasonably good and even across all cylinders it will respond well to repairs and adjustments.
alright I'll borrow a compression tester from a buddy. Why's is a piston slap?
 
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Old Dec 19, 2017 | 11:15 AM
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Auto-correct must have kicked in there.

Try this link. Just a cool way to search.

LMGTFY

Chad

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Old Dec 19, 2017 | 11:19 AM
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Basically a well worn engine, tolerances get loose, noticeable especially when cold.

We're not trying to beat up on ya, just save time and aggravation. Do a good by the book compression test - remove all the spark plugs first, block throttle & choke wide open all the way, and use a fresh charged battery. Record the compression numbers for each cylinder after the same number of pumps - say 5. Each cylinder should hopefully rise quickly to a high number, and all cylinders about the same.
 
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