1993 5.0

[Notchin]

Hello I have a mustang with a small cam, equal headers,x pipe, and no cats .

Bought the car as a shell with block long story short finally got it started but it has a horrible popping sound I havnt been able to locate. Put a stethoscope all over the engine but nothing noticeable through it coming from inside the engine. I have posted a link to the video. Thank# for any help or tips given.

 

[Notchin]

View: https://youtu.be/KFdWCDik8mo

 

[Mustang5L5]

Sounds almost like a open cylinder or exhaust port.

It keeps pace with each engine rotation so i'd suspect it has something to do with one of the cylinders.

 

[Notchin]

New head gasket/exhaust gaskets.if the smog ports at the rear of the head aren’t plugged we’ll do you think it can cause the popping? . I installed the smog tube but I’m not sure if it was installed correctly(completely sealing the port hole). I’ll have to check

 

[Notchin]

Good compression in all cylinders. Pistons were new old stock .30 over. Timing 10 btdc . New coil,wires,distributor,solenoid.

 

[Mustang5L5]

If the ports on the back of the heads aren't plugged, you will get exhaust leakage there. You need to plug those

 

[LX Dave]

That doesn't sound like the ports at the back of the heads. Sounds like a single cylinder doing that. Like a valve not closing. Intake valve? Anybody else?

Eta... Did you do a compression check before or after discovering the popping?

 

[Wayne Waldrep]

What rocker arms are on the car? And I see stock valve covers. Is the baffle removed inside the valve covers?

 

[Notchin]

I did compression both before and after. All cylinders have good compression.

 

[Notchin]

Stock rockers. Stock heads. Stock pushrods. Stock lifters

 

[Wayne Waldrep]

What about the baffle in the valve cover?

 

[Notchin]

the valve covers are stock. Could the baffle come lose?

 

[Mustang5L5]

Does sound like it's a single cylinder venting out somewhere.

 

[Wayne Waldrep]

Here's what I'm getting at on the valve cover. Just from the video which is hard to compare to actually being there, it sounds like something is tapping. It doesn't sound like rods or anything like that. It sounds close to the top to me. It could be an exhaust leak like some have said and that's good advice. If it is though and it's that loud, you certainly could find it with your hands or a tube in your ear. If it's that loud in a vid, a tube in your ear moved around the engine would find it quickly. If it is something tapping under the valve cover then just pull them off and see what's shiny from being rubbed against....example would be that baffle in the way. The different cam may be too much for lift to run the baffle. That's just my thoughts. I heard that sound once before.....about 2 minutes before the engine broke a valve and shoved it thru the head. The timing chain was put on in a very inappropriate manner (don't even ask....lol) making things interfere with other things. New engine lasted 10 minutes. Just saying.

 

[Mstng93SSP]

Check to make sure your #6 and #5 plug wires are not crossed up. Easy to do and will misfire. Firing order 1 3 7 2 6 5 4 8 . Specifically check #5 and #6

 

[Notchin]

appreciate all the suggestions guys. I won't have time to take a look at the car for a week. But i will do my best to try and trace it down with the stethoscope again. i have placed it on valve covers, heads, block, oil pan, intake, and even transmission lol. But nothing abnormal coming fromthose places.
A bit more info for anyone else that sees this post.
heads are stock 5.0 heads nothing fancy, valve covers are stock, b303 cam. pistons .30 over. stock lifter, 7 quart oil pan, high volume oil pump, stock pushrods, stock rockers. new timing chain/set. new water pump . equal length headers. still has 02 sensors. x pipe. t5 world class,

installed timing set a couple days ago following the manuals steps and a youtube video to confirm visual placement/parts. torqued it down.etc

compression good, exhaust doesn't smell or produce any color. no oil leaks. 10-30 oil 6 quarts.

new distributor, coil,wires,solenoid,battery,ignition switch, plugs

As someone mentioned before i installed the crossover tube for the smog because i was initially trying to run a smog pump but have since decided not to. I was thinking maybe the gasket and tube for it aren't aligned and could be causing a leak. i will remove the crossover tube and plug it and hopefully that does something

 

[Notchin]

Check to make sure your #6 and #5 plug wires are not crossed up. Easy to do and will misfire. Firing order 1 3 7 2 6 5 4 8 . Specifically check #5 and #6

I will chceck that aswell thank you

 

[nelzfoxes]

Turn the crank by hand and feel and listen for interference. You can also run it without the accessory belt to eliminate those components. But the noise does sound like engine internal.

 

[Rdub6]

Right after vid starts with engine still in view, there are a few puffs of smoke from right rear of engine. I guess it could be from something else, but has that cause been identified?

 

[Notchin]

so i cranked the engine over no plugs and knock isn't present. Plug wires are routed correctly. oil still clean no shaving. drain plug has no metal shavings. rechecked compression all good. plugs were on the rich side. confirmed timing at 10btdc. motor from the cylinders up is rebuilt. theres lots of oil/grease from assembly still burning off all of that stuff.

again i went all around the motor with a stethoscope and nothing was making noise. injectors are ok, plenty of fuel pressure.

there was only one place where i was able to feel a bit of the knock with my hand. while adjusting idle, i noticed I could feel the knock. as i ran my hand all around the intake nothing there, only on the idle adjusting screw bracket. Is there anything there? maybe a detonation in the intake? anyone ever experience this?