Technical Another SBC 350 Noise Question

Hi All,

I have a shoebox ford with a 350 motor (and 350 trans). The previous owner showed some photos of the engine rebuild but I don't know the much of the history as I got it in April. I hear some noise from the engine bay that I don't know how to diagnose further (if I need to).

I hear a bit more of it from the passenger side and am not sure if its an exhaust leak, piston slap, lifter noise, etc. What I do know is I drained maybe 2 to 2.5 quarts of oil (I suspect another 0.5 in the oil filter) and I put in 5 quarts this past weekend. I hope the previous owner didn't run it low on oil for long! This car has given me a bunch of headaches already ugh!

The noise changes a bit once it's warmed up which may give some clues.

Video 1: Shot when the engine was somewhat cold



Video 2: Shot 2 minutes later maybe warmer



Video 3: Shot 3 minutes later



Video 4: Shot way later in the day after I worked on door seals and had let the engine warm a lot more to see whether the sound changed much.

 

I am not hearing much that sounds wrong. If you got a friend get them to hold a rag over the ends of the tail pipes. Listen to it. If it is an exhaust leak it will become really evident.

I do hear a slight miss, I think.

As for low oil, when I first screwed the Timex 355 together in '97 I had my oil pump fail and had to limp home about 2 or 3 miles. Zero oil pressure. That was 150,000+ miles ago and several bodies. I probably should freshen it but it is still going strong or would be if I put it in yet another car.

 

I’d drive it

 

yup drive it and if it breaks fix it.

 

To me through my computer speakers it sounds like header gaskets. Get a stethoscope from the auto parts store, run it with just a hose around the flange (upper and lower).



Stock exhaust manifolds, point type distributor and a 3 wire alt will make it almost bullet proof .

 

I'd bet that the headers are leaking where the four pipes are welded together at the collector.

 

Wow crazy story. When I drained low amount of oil, I had driven it once prior to the DMV and I did see the oil pressure seemed fine. Maybe it's ok and its a header gasket leak as others suggested. Thanks!

 

Awesome thanks I'll give that a try!

 

That's true! I need to drive this thing its brought me a fair amount of frustration and I haven't even enjoyed it since I got it in April!

 

Long screwdriver works great to pinpoint internal noises. Handle held to ear and tip against engine.
Make sure to keep clear of pulleys, belts and fans.......



No, that is not me.......

 

Sounds like the header collector gasket is leaking or maybe the bolts loosened up. The noise sounds like multiple cylinders puttering..not a rhythmic singular sound...if that makes sense. Try tightening the collector flange to exhaust pipe flange bolts..see if the noise changes.

 

Get a length of garden hose (3 -4 feet), hold one end to your ear, and float the other end around the engine/headers, you'll hear the noise, and being a hose, if it's coming from the headers, you can get right in between the pipes to locate it and you won't burn your hands..

 

Check the flex plate and see if it has crack...

 

I drove a 327 Chevy that was VERY low on oil. The engine light came on during a turn... this time it stayed on... and it was running rough, but no knock. I was close to a parts store, went in and got 3 quarts to put in it. Got it started again and the oil light was still on and it ran like crap. I figured I would try to get it closer to home so it would be less of a hike. After about a 1/2 mile, it smoothed out and the light blinked, that went out and it ran fine from there. The engine had 200k miles on it and I eventually sold it to a guy who outfits boats. he said that the crank and bearings were in good shape.

BTW, your sounds like a header leak. You can get someone to hold a rag over the exhaust for a couple of seconds while you look at the collector and flanges for a leak. Exhaust leaks show up as gray soot most of the time.

 

sounds like a exhaust leak to me.

 

The small block chev is known as a mouse motor. I think yours wants out

 

Low oil and small block Chevy’s. I worked at a full service station in south Phoenix in the early ‘80’s. Lady came in, one guy checking tire pressure, other guy cleaning windows, my turn to check under the hood. The stick had no oil on it. I said “ma’am, you need some oil”. She says “no, it’s not making that clicky noise yet”.
Ooookay.

 

This will make ya grin. My dad had a genuine engine stethoscope (I got it now). He used a long screw driver unless there was a client in the shop. I do the same, the stethoscope is just for looks.

 

Have you put a wrench on the ha? If they worked loose the gasket is already burnt, and will need replacement. But at lest the check for loose bolts will tell you it's a flange gasket leak.

 

Don’t you love it when you pay someone to take their headache away?

 

Yea I bought this car just looking at photos and vids.. could have been way worse according to many. I did learn a valuable lesson.

 

Thanks so much I will check the tightness of the flange bolts. Next chance I get I'll fire it up and start searching for clues. I'm glad at least no one thinks there's an internal engine issue based on the video but I'll have to keep digging to confirm that.

 

On the passenger side I found one bolt that was moderately loose towards the back. I tightened it. On the driver side I found two that were pretty loose. I tightened them. In the video it seemed the noise from passenger side was louder and towards the rear. Next time I fire it up I'll use a hose to the ear to see if I can find the source of any unusual noises.

 

If the noise is still there, it could've already destroyed the gasket.

 

Leaking header gasket.....(turn the curb idle DOWN some !)
6sally6

 

I've used exhaust manifold gaskets with headers before... I never had a problem with leakage....

 

I’ve been racking my brain to figure out “ha”. I’m sure it’s simple, but please ease my pain

 

Have you checked to see if this guy is hanging around our car?

 

I hope that, just once, a doctor somewhere at some time has used a screwdriver.........

 

What does it do if you give the throttle a slight rap on and off ?

A guy sold you a car 3 quarts low on oil ??? Yikes . my

First question is were did the oil go and why second is what else is wrong ?