Carb Expert needed asap! Holley 4160 1850-4 rebuilt, now load squeling noise!

[thecrazygreek]

I have a holley 4 barrel 4160 type 1850-4. I just kitted it, and when I reinstalled, it now is making a loud screaching/whistling noise as part of the vacuum. It can start and run ruff, but I need to fix this noise issue first. Noise lessons as you give it more throttle.

Need expert carb guy help please!

 

[jtoro]

I had a similar problem with my Weber 32/36. It turned out to be that the base was not tight enough and air was leaking between the manifold and the gasket. Check that all the screws are correctly tightened.

 

[lone gunman]

that is the 600cfm one with vacuum secondaries right. did you maybe forget to replace the cork ring in the vacuum port that actuates the secondaries ?

 

[grant5127]

A vacuum leak check would be a step in the right direction.......

 

[thecrazygreek]

OK, thx guys looks like a bolt was stripped and the carb wasnt tightened all the way down...

BUT...

The whole reason for the carb rebuild was that the engine was bucking under load. It is getting progressivly worse.

So the first step was the carb. I have rebuilt it, and it seems good. But the bucking continues. Soo, I figure it's one of two things.

1. The coil is bad and not working under load or...

2. The fuel pump is bad.

This problem has been getting progressivly worse. The rig was sitting for about 3-4 years as well.

I thought about bad gas etc, but did a stabilizer, and a new filter. But the filter is after the pump, so maybe the pump has gotten gummed up?

Thoughts suggestions would be great.

I plan on Fuel pump next.

 

[Brian in Oregon]

I assume this is on a V-8, possibly a SBC. Just as an aside, I gave up on Holleys and went to a QuadraJet. The improvement in low end response is quite noticeable. My 350 was much more drivable with the QuadraJet.

As for bucking, yes, a bad coil, loose wire or poor fuel delivery could cause the problem.

My 350 started bucking and backfiring really bad. I have an HEI distributor. My tach started acting erratically. As it turns out, I discovered that defective tachs can knock out the HEI brain module. And that's exactly what happened.

Had another problem months earlier. I wanted a locking fuel cap, but no one makes one for the 1971. Cut the end off the tube, and welded on the end from a Chevy, so I can run a Chevy cap. As it turns out, the Chevy cap is not vented, so this caused a vacuum problem and eventually the pump had trouble pulling fuel. This also led to bucking and even killing the engine. Discovered the venting issue when I removed the cap and heard a big whooosh as the vacuum was broken.

 

[grant5127]

What if?

I assume this is on a V-8

Maybe not........

 

[lone gunman]

i had a similar problem when i got my 40. it also sat for several years and water and bad gas in the tank caused rust and crap to build up and as i drove it it would suck chucks of this crap up and it eventually partially plugged the line and didn't let enough fuel to flow so under load and on hills it would buck like crazy. i had to flush the lines and eventually used one of the POR-15 tank sealler kits on it. i havent had a problem since (about 4 years)

 

[thecrazygreek]

OK, I have installed a new coil, and fuel pump.

SAME DAMN PROBLEM...

This is getting ugly... Your guess was correct, its on an old SBC 327.

Could it be a timing issue?

The bad gas thing maybe a possibility, but it seems to pump gas just fine as I smell gas, and I am actually afraid of flooding.

Could I blow the lines back into the tank with air?

Now remember, this issue started off slowly and built up to un-drivable in about 5 days / 150 miles.

Help me Obiwan Kenobi...

 

[grant5127]

Timing chain slack.............

Have you checked cam to crank timing........(chain slack)......?

 

[lone gunman]

blow the lines out with compressed air and put a clear filter in line as close to the tank as you can and see what it traps. i am still betting on crap from the tank slowly plugging the line. and you might also pull the fuel tank sending unit and have a look inside the tank and if need be tie a magnet to a string or get a telescoping one and see how much crap (rust) sticks to it. do the cheap (free) fix first and stop throwing money at it.


it will pump gas fine at idle but under load the flow cant keep up with what the engine needs. if it runs at an idle fine i highly doubt its timing chain. just check the tank first!

 

[car-car]

it will pump gas fine at idle but under load the flow cant keep up with what the engine needs. if it runs at an idle fine i highly doubt its timing chain. just check the tank first!

It can start and run ruff, but I need to fix this noise issue first.

Is it running well at idle, or is it running rough? It could be the timing if it is rough at idle too.

As for the tank/bad gas deal you have mentioned, how long has that gas been in the tank? If the truck has sat for a while with the same gas, it could go bad over long extended time. If that's the case, it wouldn't hurt to drain the tank and put fresh gas in.

 

[thecrazygreek]

I will check the tank tomorrow.

I did do a squirt test and that seemed to go just fine. (making sure the nozzle squirted fuel as I pumped it)

The fuel bowl is at the right level when I check it (not running)

I will have a better idea after I swirl my extendo magnet around the tank a bit tomorrow.

I will keep you posted, as I am very curious as to what the cause actually will end up being...

 

[thecrazygreek]

Strange days...

OK, I blew out the lines, opened up the tank and did the magnet sweep. VERY LITTLE debris was found on the end of the magnet.

Put it all back together, and put the dist cap back on. Started it up and viola!! It ran great. I pulled it out of the garage and drove a bit, then it started happening again.

Sooo, I did the squirt test and she shoots fuel just fine. As a matter of fact, I think it may be flooding. Wouldn't flooding do the same thing as whats happening here? If I pump the pedal and try to start her she wont fire unless I let go of the pedal and keep cranking. The only way she will run is (once she turns over) is to keep doing very fast small pumps on the pedal.

I need a carb man.. Mark or Jim?

 

[thecrazygreek]

PROBLEM SOLVED!

It runs better than evah!

I did so many things, who knows what fixed it... heheh...

Plugs, blew the lines, fuel lines etc. But I think it was me adjusting the float bowl level.