Three issues with my 460

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Old 08-09-2014, 10:24 PM
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Three issues with my 460

I decided to start a new thread since the casting numbers are not important I guess. I posted this in another forum as well.

This is what I know now. I got the truck a couple months ago. 67 F100 with a 460. The previous owner told me, without me verifying, the engine was a rebuild in 2000. I believe it to be true since the truck is flawless in every way except the motor. The motor was pulled from a 1971 Mercury. The block has no casting numbers. The truck was supposedly put in a dealership showroom after its restoration and engine rebuild. Sitting for nearly ten years after being sold to the person I bought it from. The odometer had 2560 miles on it when I bought it. Was told it was a balanced and blue printed engine but couldnt get any papers since they burned up in a house fire. Was told it had a mild cam. I got home and thought the truck was a little weak for being what he said it was. I rebuild the carb and still has a little bit of issue. So here is what i have done. I re-measured the stroke since it was brought to my attention 4.59 was an odd stroke. I pulled the spark plug on #1 and measured from the top of the stroke to the bottom of the stroke with a wooden dowel rod. I did this twice in a row and got 4.15 and then 4.18 the second time. I think the dowel rod was a little flimsy and may have moved on the second one. So I believe it is stroked to 4.15. I do not know if is is bored. I assume it is some. The heads are D3VE heads and I do not know if they have had anything done to them. My distributor was stuck in place and i couldn't move it. So after reading some other threads I soaked it in PB Blaster for days and tapped it back and forth till it moved a little. Finally it wouldn't move back and forth any more without me really banging on it. I was afraid of breaking it so I tried prying up. Well, it worked. But unfortunately it popped way up and out and I didn't have anything marked. Luckily I did look at the rotor bug and see which direction it was pointed. So I put it back in same spot best as I could. I took the 1-4 cylinder valve cover off tonight and see that all the parts appear original to me. Doesn't look like anything custom under there.

First issue, obviously timing is a little off. I think it was off some before I popped the distributor but not sure. Anyway, I bought a timing light. Have never used one before but watched some videos online so I am obviously now an expert at using it. I know for a fact the harmonic balancer is set to zero on TDC because I verified this 3 times. The last time I checked for stroke length and tonight, twice, when I checked for stroke length. So it runs ok at 10 degrees Advanced. It runs better as you get closer to 20. This is with the vacuum advance OFF. Now, I cant take it to 0. If I do it dies. If I get less than 10 it gets really chokey and suputtery. So I set it to about 18 which is where it seemed to not get any better or worse. Then I plugged the vacuum advance on and it shot up to like 30 plus and ran a little better. What can I do to make this better?

Second issue, When I was turning the engine over with a large socket on the crank nut, the engine constantly hissed as if losing compression. Is it supposed to hiss or should it be quiet? I'm thinking quiet. How do I find which cylinder is hissing and from where?

Third issue, I did a compression test on all cylinders and got between 90 and 105 on all cylinders cold and between 100 and 110 on all cylinders hot. From what I have been reading this is way to low. I should be well above 130 right? Especially since it only has 3500 miles now. What can I do to fix this?

There are other issues but these are my main ones right now. I appreciate your help and any advise you can give me. I apologize in advance if this is in the wrong spot or if it is too many questions.
 
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Old 08-10-2014, 06:51 AM
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Hissing is normal.
The engine isn't going to really hold compression unless it is running.
Valves should seal tight so it is likely coming past the rings.
A leakdown test could tell you more.

Did you hold the throttle wide open while cranking when you did your compression test???
Yes, your numbers seem low.
 
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Old 08-10-2014, 09:46 AM
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Originally Posted by ArdWrknTrk
Hissing is normal.
The engine isn't going to really hold compression unless it is running.
Valves should seal tight so it is likely coming past the rings.
A leakdown test could tell you more.

Did you hold the throttle wide open while cranking when you did your compression test???
Yes, your numbers seem low.
I did not hold the throttle down.
 
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Old 08-10-2014, 09:54 AM
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Originally Posted by AberrantGenus
I did not hold the throttle down.
you need to wedge the throttle plates wide open and make sure the choke is open too.
Give it another try.
About 150 and no more than 15% deviation is okay.

If you want to check ring seal you can add a teaspoon of engine oil to the cylinder and compare the readings.
 
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Old 08-10-2014, 10:14 AM
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Originally Posted by ArdWrknTrk
Hissing is normal.
The engine isn't going to really hold compression unless it is running.
Valves should seal tight so it is likely coming past the rings.
A leakdown test could tell you more.

Did you hold the throttle wide open while cranking when you did your compression test???
Yes, your numbers seem low.
So I guess that is why you are supposed to disconnect the fuel pump. It said to disconnect the fuel pump but didn't say anything about holding the throttle open. That makes sense to me now. I will redo it and let you know.
 
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Old 08-10-2014, 10:20 AM
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I always disconnect or disable the ignition coil.
A simple hemostat on the fuel line should stop the engine from flooding.
 
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Old 08-11-2014, 04:54 PM
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Originally Posted by ArdWrknTrk
I always disconnect or disable the ignition coil.
A simple hemostat on the fuel line should stop the engine from flooding.
Oh Yea. First time I've done any of this stuff. I disconnected the coil wire and all the spark plug wires. Does it matter if i remove all the spark plugs or not?
 
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Old 08-11-2014, 05:10 PM
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Taking all the plugs out will make it much easier to crank the engine over while testing.
It should not affect the compression reading of the cylinder being tested.

Do make an effort to blow or vacuum out any rust or debris in the plug wells.
You don't want to suck it into your cylinders.
 
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Old 08-13-2014, 11:52 AM
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Originally Posted by ArdWrknTrk
It should not affect the compression reading of the cylinder being tested. Do make an effort to blow or vacuum out any rust or debris in the plug wells.
It will not only not affect them, but make the readings more accurate with the plugs out.

+1 on the vacuum job. Around here there is always some grains of sand or small debris in the plug ports just waiting to fall in. That's the way it works on the farm!
 
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