1933 V8: Troubleshooting...suggestions welcome

[kurt v]

I still say the carb has a piece of junk in it, my carb was doing the same thing running on one and a half barrels. Take it apart and blow and wire it out.

[Bored&Stroked]

You can easily take the air cleaner off and look down the carb to see the fuel being pulling via the emulsion tubes from the fuel well. I would slowly own the throttle plates and watch down the carb to see how the fuel is flowing. I'd also stab the throttle plates to see if the squirters are pumping fuel into the car. You need to determine if it is fuel starved or has some other issue. It is almost always ignition or fuel . . .

Just make sure you're wearing some sort of eye protection and also have a good fire extinguisher and some "snuff out" rags handy. The last thing you'd want is to burn yourself or start a fire. I'm not trying to insult your intelligence, but have seen too many situations where the "unexpected" happens . . . usually to the nicest guys!

[petehoovie]

Originally Posted by kurt v

I still say the carb has a piece of junk in it, my carb was doing the same thing running on one and a half barrels. Take it apart and blow and wire it out.

Yeah, Kurt, I agree. I think he's running on just 4 cylinders...

[torpedo]

Hi B&S, Kurt and Pete. Thanks for providing opinion and tips.
Carb visual test that you suggested was done yesterday with engine running at diff RPM. Plenty of gas flowing, squirters operating when full throttle.

I'm being helped by a pro mechanic (his specialty are flat4/6 VW/Porsche but also services and repairs other engine types with carburetors and mechanical distributors in 6V such as Porsche 356).

We can summarise the problem as follows:
Engine starts and runs smoothly at idle on 8 cylinders. Did the ignition wire test off the plug tip on all cylinders and have a clear blue plain spark.
A smooth and gradual push on throttle will increase RPM almost to the max (we measured 3400 rpm).

The problem arises when throttle is open sudden to the max. At approx 75% of rpm range the engine does not rev up. On the road that manifests by a poor response when full load is required (hill) car not going more than 45 mph.
So far we tested:
fuel filter > new
fuel pump > delivers volume at correct pressure. restored in 2021
carburetor > professionally checked. Accelerator pump OK
Distributor > installed a new unit (supplied by 3rd Gen)
Coil > new Pertronix
Condenser > New (supplied by 3rd Gen)
Ignition wires > New (copper wire)


We are guessing we may have a leak at the intake manifold gasket (I do not know when it was last installed but probably 30+ years).
We plan to work on this next week (I have a new gasket): any tips or recommendations ?
Additionnally and since we have access to the valley, are there any sanity checks related to valve train we can do such as clearance between valve stem and lifter ? Please provide as much detail as you can because this is new territory for us. Also please indicate if any special tooling will be required.
Sorry for the long message and chunky images. All the best

[glennpm]

When you lose power is the engine pinging indicating too much advance? I've read the whole thread and understand you have two distributors from a good source but you may have too great an advance for your engine.

Where is the the pointer on the advance plate? You could try retarding it 2°-4° and note changes. Stock is right in the middle of the side plate providing 4° advance.


Glenn

[torpedo]

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Hi Glenn,
The dizzys are indeed coming from a good source. Michael has knowledge and equipment to set them up properly and i trust him. Actually dizzy #1 was used for about 600k miles and ran perfect. No reason to suspect dizzy #2 is defective. Pointer is half way between middle and first notch.
Symptom does not sound like pinging but more like "choking". I can try to repost video if that may be useful?

[dean333]

If dizzy #1 ran perfect, why did you change it?

[glennpm]

"I can try to repost video if that may be useful?"


Yes please
Glenn

[torpedo]

Hi Tim. I did explain in earlier post. During initial checks we found the hex locking nut for advance brake was loose. After tightening it the symptom was not cured and we mistakenly played with pointer on advance plate. Rather than going blind with setup we decided to use backup dizzy #2.
Running with dizzy2 alas did not cure the problem;-(

[torpedo]

For Glenn and others with interest, hoping the link works:


https://www.filemail.com/d/qhfjwhzabwedvqq

[glennpm]

Link worked fine this time.


Sounds like its not firing on all cylinders. Sorry I don't know what to add now. You have seemed to have checked everything. What was the last change you made before starting this fault?


I'd hook up a timing light and check each plug circuit at high RPM. If you have a TDC mark, you could check #1 with that too.

[torpedo]

Hi Glenn. We are reaching the same conclusion. This is why we decided to investigate the intake manifold gasket. We have no reason to suspect ignition. We did check each plug at high RPM lifting the wire from the plug tip, could see nice bright sparks. Don't have TDC mark on pulley but have found a good method on the tech archive.
The problem did not surface overnight after a specific change. I noticed it on a trip when going uphill the car performing poorly...

[glennpm]

Okay, very frustrating ....


The zip tie method works very well for locating TDC, probably what you found.


Best,
Glenn

[Bill OH]

While you are checking the intake manifold gasket, check the condition of the intake manifold - cracked or hole burned thru? Take a look at the valve springs.

[torpedo]

Glenn,
The one with tube and ATF oil.

[torpedo]

Originally Posted by Bill OH

While you are checking the intake manifold gasket, check the condition of the intake manifold - cracked or hole burned thru? Take a look at the valve springs.

Hi Bill,
We will carefully check the manifold for cracks, surface, holes...
It will be ultrasonic cleaned, sanded and repainted.
As far as valve springs are concerned what should pay atention to ? Are there any specific checks to be done ?

[glennpm]

Originally Posted by torpedo

Hi Bill,
As far as valve springs are concerned what should pay attention to ? Are there any specific checks to be done ?

Look for valves that are hung open. Do two full crankshaft rotations and look for valve stems that remain open or appear sticky returning to their seat. You can also remove all the plugs looking at their condition and looking into the spark plug holes to verify that a valve/s are not closing.


Glenn

[torpedo]

Preparation of intake manifold. Will be repainted tomorrow.

Are the following values correct for valve lash ?


Intake 0.10-0.12
Exhaust 0.14-0.16


Thanks

[petehoovie]

"repainted"???

[torpedo]

Wrong word. I meant sand blasted.