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'86 5.0 Ticking Noise


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Just did an R&R on the lower manifold and valve covers. She fired right up after putting it all back together and sounded good. Let her warm up, and pulled the shorting bar on the ignition harness so I could check the timing. Truck had a high pitched ticking sound with the shorting bar removed. Set the timing to the factory white line on the balancer and reinstalled the shorting bar. Ticking went away.

Driving the truck this morning, no ticking at idle or when revving up the motor out of gear. When under load ticking noise is back and doesn't not change as the motor warms up. Volume of the noise increases with accelerator pedal position. If I take my foot off the gas, even in gear, the noise just about goes away. Foot to the floor and the tick is the loudest.

I'm assuming it's timing related since it changes with the shorting bar installed or not installed, but wanted to get your thoughts. I haven't had a chance to try and pin point the location other than it appears to be up top and probably drivers side.

Anyone experienced anything like it before?

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Strange that it changes with timing. What about a spark jumping some place? That could change with timing and with throttle.

Use a rubber hose to find the sound's source. Put one end to your ear and run the other end around the engine listening for the sound.

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I have and it is always an exhaust leak at one port which gives it the ticking noise rather than a rumble. Look for carbon trails around the exhaust ports.

It's just really weird that it started after all the work when the manifolds weren't touched. Didn't have time to do much listening last night, but I did try adjusting timing slightly this morning and while I think it got a little better, it didn't change much.

Hoping to have some time to listen tonight. Also noticed I still have a coolant leak under the water neck even after installing a new one. Going to try and check the bolts tonight to make sure they are tight.....

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It's just really weird that it started after all the work when the manifolds weren't touched. Didn't have time to do much listening last night, but I did try adjusting timing slightly this morning and while I think it got a little better, it didn't change much.

Hoping to have some time to listen tonight. Also noticed I still have a coolant leak under the water neck even after installing a new one. Going to try and check the bolts tonight to make sure they are tight.....

There's an exhaust passage in the head that meets the lower plenum. Or, at least there was on earlier heads and I think it was still there when they introduced EFI. So, the leak could be there.

On the thermostat housing, the naturally-aspirated manifolds had two different bolt lengths on the Windsor. So make sure you got the right ones in the right places as you can't tighten the long one down in the short spot enough to stop a leak. Don't ask how I know. :nabble_smiley_sad:

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There's an exhaust passage in the head that meets the lower plenum. Or, at least there was on earlier heads and I think it was still there when they introduced EFI. So, the leak could be there.

On the thermostat housing, the naturally-aspirated manifolds had two different bolt lengths on the Windsor. So make sure you got the right ones in the right places as you can't tighten the long one down in the short spot enough to stop a leak. Don't ask how I know. :nabble_smiley_sad:

I'm not certain about the bolts on the water neck, I'm pretty sure my uncle swapped it out, but I saw the old bolts laying on the table later and I'm pretty sure they were the same length. It had a leak in the same spot previously so maybe that was the issue? I'll have to do some research and find out what the lengths are supposed to be.

The exhaust passages are still there. I was actually thinking of that this morning. One of them feeds the EGR tube and the other just dumps under the lower manifold from what I could tell(I could be wrong) but the underside of the lower manifold sure looks like it gets hit with it.

I just really don't want to pull it all apart again.....That was a ton of work for zero performance gain.:nabble_smiley_unhappy:

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I'm not certain about the bolts on the water neck, I'm pretty sure my uncle swapped it out, but I saw the old bolts laying on the table later and I'm pretty sure they were the same length. It had a leak in the same spot previously so maybe that was the issue? I'll have to do some research and find out what the lengths are supposed to be.

The exhaust passages are still there. I was actually thinking of that this morning. One of them feeds the EGR tube and the other just dumps under the lower manifold from what I could tell(I could be wrong) but the underside of the lower manifold sure looks like it gets hit with it.

I just really don't want to pull it all apart again.....That was a ton of work for zero performance gain.:nabble_smiley_unhappy:

If the lower plenum is corroded you may have problems sealing to it. Check the casting closely.

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If the lower plenum is corroded you may have problems sealing to it. Check the casting closely.

There were some corrosion issues, but only around the coolant passages on each end. Everything in between was in great shape.

I should also note that the corrosion was all internal to the mating surface, meaning nothing that went from the passage all the way across to the outside of the gasket. What was there, I would consider minor pitting.

EDIT: After doing a little research, I'm pretty positive I installed the gasket upside down. Correct side facing the head, but rotated 180*. SMH. I REALLY don't want to do all that work all over again without a performance manifold going in.... Which no one makes for the EFI motor that I have found.

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There's an exhaust passage in the head that meets the lower plenum. Or, at least there was on earlier heads and I think it was still there when they introduced EFI. So, the leak could be there.

Gary hit the nail on the head! Not sure if I got the gaskets upside down or what. That passage actually extends up past the top of the lower manifold and the gasket isn't covering up the little bit that is exposed. The old rubber hose let me right to it.

Guess I'll have to pay more attention to gaskets the next time.... For now I'm just going to have to deal with it or figure out a temp patch of some kind to keep stuff from getting in there and into the valve.:nabble_smiley_cry:

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There's an exhaust passage in the head that meets the lower plenum. Or, at least there was on earlier heads and I think it was still there when they introduced EFI. So, the leak could be there.

Gary hit the nail on the head! Not sure if I got the gaskets upside down or what. That passage actually extends up past the top of the lower manifold and the gasket isn't covering up the little bit that is exposed. The old rubber hose let me right to it.

Guess I'll have to pay more attention to gaskets the next time.... For now I'm just going to have to deal with it or figure out a temp patch of some kind to keep stuff from getting in there and into the valve.:nabble_smiley_cry:

Glad you found it, but sorry that's what it is as that's not an easy fix - as you already know. I thought perhaps there's a difference in the gasket for EFI vs NA, but checked the catalog and there isn't. Don't know what to tell you.

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