model b intake diagnosis

gotthard

gotthard

Junior Member
I have to change the manifold gasket and took some pictures from the intake and outlet. One intake is a little bit greasy. I can tell, that there was some false air issus since the carburetor flange of the intake manifold was not streight. Is probably this the reason, should I adjust the valves or is there no worries about that? Is there anyone with advice?

best reguards
 

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If your tappets are the adjustable type then it's not a difficult task. If they are original type tappets then the job gets a lot more complicated. The old two piece guides have to be driven out to remove the valves on the original design. Valves would be ground on the stems to open clearance up or the valve seat cut for too wide a clearance. If the clearance is close then I wouldn't mess with it unless it would allow the engine to run properly.

The manifold surface should be completely cleaned off after removal of the last two studs there. It can then be evaluated for condition. This is a spot that can have a little bit of material planed off but it would have to be set up in a mill to do that. If the surface only has some minor wear or impact areas then a new copper gasket could likely still be made to seal as long as the irregularities aren't too deep or large.
 
It is a original engine, so I fear there are no adjsable tappets. I will clean the surface, as soon as I got an other manifold, I was able to buy. The actual one has after maching no space left, to install glands. I have to mention also, that I broke the power jet tube, by searching for the reason for high idle. I drove the car during summer anyway and I now was able to fix that, with a modified model a tube. But the engine never run since. Probably I have to do one by one, because there are coming things together. Is it helpful to measure the compression?
 

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gotthard said:
I have to mention also, that I broke the power jet tube, by searching for the reason for high idle. I drove the car during summer anyway and I now was able to fix that, with a modified model a tube. But the engine never run since.
Click to expand...

gotthard said:
I have to change the manifold gasket and took some pictures from the intake and outlet. One intake is a little bit greasy. I can tell, that there was some false air issus since the carburetor flange of the intake manifold was not streight.?

best reguards
Click to expand...

A reason for your high idle could be your vacuum leak at the carburetor flange.
 
What did the spark plugs look like on that end of the engine?

Here is what I recommend. Put marvel mystery oil in the crankcase, and in the fuel tank. Drive the thing. Then pull the plugs, and look in the cylinder with a bright flashlight. She where you are. Costs virtually nothing, and you are no worse than where you are now. Ya know a valve that is sticky might work itself out.
 
don't assume anything about the tappets.
it's a rare engine that has not been apart/rebuilt in 90 years.
take the valve cover off and see what you have.......
 
Seeing the oily deposits in the front intake port, I think you may have excessive wear on one or both of the valve guides in this port. If it were mine, I would remove the head, rotate the crankshaft to raise those two intake valves and see if you have excessive lateral movement of the valves in the guides. Grab the top of the valve when in lifted position and try to move them horizontally.
You can check this by taking the valve cover off and looking for the same movement, but it is much more difficult to get to the valve stem to apply pressure.
This condition could also be caused by an intake valve not seating well.
Good Day!
 
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