Bad noises

[drooartz]

Okay, I'm *still* struggling with getting the Tunebug running properly. The latest issue is what I can best describe as a "chirping" noise on acceleration. Timing is set at a bit below 30* at 3500RPM or so. I put the mixture back where Hap had it set, and this did not effect the noise (I had leaned it out a bit, using the piston-lift method).

Here's a sound clip of me driving around the block. You can really hear the noise starting at about 18 seconds in.

https://www.drooartz.com/public/tunebug_noises.mp3

I'm also *really* boggy off the line. The poor car is not happy with me at all.

 

[Deleted member 8987]

Sounds like an exhaust leak under load, OR a very bad u-joint.
Hard to tell from the sound file, but seems to be under load, later it was just revving (like it got hot and the exhaust leak opened up a bit) and it really sounds exhaust.

Doggy-pluged exhaust?
Somebody jam a potato in the tailpipe?

If I had to say one thing, it's an exhaust leak.

What I would do, and this is just me, what we did in shops, pull the air claners, and squit some motor oil down the throat while it's running (don't need a lot), and watch for smoke on the exhaust manifold or exhaust pipe packing.

Check the mainifold nuts to head and to exhaust pipe.

Dave

 

[AngliaGT]

Drew,

Glad to hear it's not a mechanical noise -
sounds like it's easily fixable.

- Doug

 

[Billm]

To me it sounds like you have a metal fan that is lightly hitting the PCV tank on the timing cover or maybe the radiator.
BillM

 

[drooartz]

Fan is plastic, Bill, though I'll check that area as well to be sure.

Hadn't thought about an exhaust leak. Gives me something to look for. Thanks.

 

[Gundy]

I'd guess exhaust. Like the pipe is jigglin' in a bracket
or vibrating against a surface.
I had a similar noise in the wife's B. Only when cold.
Annoyed the heck out of us. Found it when we put a new
exhaust system on. It seems when the previous owner had an exhaust installed a small bit of welding had dropped into
the pipe. I was there as the old pipe came off and darn
if a little bit of loose welding fell out of the pipe between
the manifold and muffler. I'd never have found it if I hadn't put a new system in.
I still don't know why it only rattled when cold and stopped
once the motor warmed.


Good luck running down the source of the noise.

 

[PeterC]

Drew, with the car running, just put your hand covering the tailpipe. An exhaust leak will quickly reveal itself.

Peter C

 

[jlaird]

I think the churp muct be the rear tires under serious acceleration, after all you got a Hap engine. LOL

I think I would look very close at the exhaust pipe where it runs throuigh the frame below the carbs and the mount where it attaches to the bell housing.

 

[drooartz]

Thanks guys. I hope to be able to give this some time in the next week or so.

 

[Hap Waldrop]

Sounds like a exhaust leak to me as well, the only other wierd noise I heard was the famous straight cut non syncro whine fo first gear, normal for that gearbox.

Drew get it on jackstand or take it somewhere you can put it on a lift, with the motor running, move your hands around the exhaust, careful not to touch it, see if you feel any leaks, my first guess would be a leak around the headers or where the collector joins the exhaust.

A bad exahust leak can make a car run like sheeeeeet (ok you have to creative here) A bad exhaust leak can also burn a exhaust valve, so it needs to addressed before the car is driven much further.

Oh and that noise isn't that bad, trust me, I know bad noises sound like , you should have heard my MGB, when the engine went it in, now that was a bad noise. PO kinda did a engine refresh without much machine work or measuring, maybe would have held up under normal people, but with my right foot she went kaboom in a big way. I'm building myself, a trick 10.0 to 1 1900CC big bore engine with a trick ported head, and a new T9 5 speed, lots of goodies, hoping to flirt with 125 hp, give them S/C MGBs a run for their money for a few thousands less.

 

[drooartz]

Thanks, Hap. I hope to have it up on stands tonight and I'll give it a good check over.

You MGB motor sounds like it'll be a good one.

 

[Deleted member 8987]

You can check manifold-to-head nuts from topside.
I think you can do the same on exhaust pipe to manifold.
Checking for leaks at manifold can (and should) be done on the ground, first, before you dig out the jack and jackstands and go through all that to find the leak is topside.

 

[drooartz]

I did some checking, and there is an exhaust leak at the header -> pipe connection. I didn't have much luck getting it to stop, but at least I've got it identified. If nothing else, I can take it in to my local muffler shop and have them sort it out. I pulled the pipe off and put on some exhaust paste, but that didn't seem to do much good.

I'll play with it a bit more, but it's nice to have it located. Thanks for the tips, I wouldn't have thought about an exhaust leak.

 

[Deleted member 8987]

I forget how a BE pipe connects, and what kind of packing.

My Jag had a "new" exhaust from DanFast (local chain) and it had similar if not louder noise under acceleration.

I tried all 8 nuts (got them all off, cleaned and anti-seized), and still there. Jags use an odd do-nut, not a gasket, and the MORONS used an off-the-shelf do-nut that was WAY to big, and rested on the edge of tha manifold instead of dropping down into the cavity.

I found on the shelf ones that fit the cavity, but were slightly small on the ID for deopping over the pipe.

I sanded out the inside until they did...and the retainer plate is not oh, less than 1/4" from the manifold instead of an inch.

NOW it's quiet.

Sometimes, if it's a do-nut syle, the manifold is either damaged or there is old material cemented fro heat and exhaust in place.

Is yours a do-nut style?

Is there any spots where there is black strips, like exhaust has passed?

Sometimes, removal of the manifold, inverting same in a vise, and chiselling the old shXt out works (if yer careful), and then take it to a machine shop and have the cavity/surface for the do-nut glass beaded.

Generally that works.

That's what it sounded like, but always good to check the manifold to head nuts, too.

Dave

 

[drooartz]

I'm running a LCB header (Maniflow with Jet-Hot coating) into a 1-1/2" pipe back to the muffler. There is some black at the header outlet -> exhaust pipe connection. I could feel air moving there when the car was running. Definitely a leak there. Head -> header seems fine.

Exhaust pipe is just clamped to the header outlet. That's the weak spot.

 

[Deleted member 8987]

Have you still got the simple flared end pipe that fits to a bell on the manifold, with a two-piece clamp that fits around it like a Model "A" Ford?

If the angle of the pipe isn't right (like, straight up, not angled forward) or crud on the manifold bell, or in the pipe flare, yes.

On Model "A" Fords (and early B/E in the shops), the trick was the clean everything (and sandpaper on the bell end of the manifold using a mirror to make sure you have it smooth, and NO LINES where the old bonded-from-heat buildup stayed), clean the flare, GREASE the bell and flare with wheel bearing grease on your finger, then grease the inside of the clamps, and the outside of tha manifold and pipe flare, clean the bolt threads and anti-seize them, tighten snugly and evenly (look at the gaps), run it until hot, then re-tighten hot (don't burn yourself).

I am confident there is some workshop procedure for doing it differently, but that always works for us in the shops.

To give you an idea, we have had to work over a head and manifold on Ford big-blocks (once you get all them bolts out) with a small ball-peen hammer to break the crud off before sanding, or it won't stop leaking.

Dave

 

[Deleted member 8987]

I red your post whilst I was posting.
So it's a two-piece clamp style?

Parts are new?

Try the clean and grease trick, run till hot and re-tighten hot.

Dave

 

[drooartz]

All parts are new. Header is one of these:

I'll pull everything again tomorrow night and give it all a very good cleaning prior to reassembly.

 

[Deleted member 8987]

Okay.
I had gone the the website, the photos would not enlarge, the one I thought you had used a bell-end, it looked like.

That one is just a clamp.
However.....

How tightly does the pipe fit?

If it was clamped tight, it crimped, and you would NOT be easily getting it off.

Pipe should have been a snug fit, not sloppy.
Otherwise, you will never get a good seal.

How deep does the pipe fit the header?

Any exposed slots in outer pipe?

Dave

 

[jlaird]

Oh, you need a real clamp. Check with the muffler shop as you said of course.