I have checked everything I can on the upper engine, so the only thing to do is put the inlet manifold back on. I decided to go over everything everything again to help reduce the chances of removing it again. I use a steel ruler and feeler gauges to check how flat the flange surface was. It looked good when I had the ruler in the middle however the ruler was about 1″ short of each end. As soon as I slid the ruler to one side I was able to put a .006″ or .008″ feeler gauge under the divider between the two ports. If this was leaking between the two ports it might explain the slight miss in the engine and also the high idle speed.
I checked all four spots, and they all had the same problem! I used a large file to flatten out each end, which didn’t take long as cast iron files pretty easy. In no time I couldn’t even get a .002″ under the divider. I then turned my attention to the heads and cleaned them up with acetone.
I did some research last week trying to find a sealer that was resistant to gasoline and could also handle reasonably high temperatures. Most of them fail on the gasoline however I found Permatex PermaShield and Hylomar were both OK. I found some Hylomar M at the local auto parts store. What makes it more cool is Hylomar was developed by Rolls Royce apparently.
To use Hylomar you smear a layer on both surfaces and then wait for the solvent (acetone) to evaporate. You can then bring the surfaces together. It still stays flexible so you can move them around a little if needed. I put some Hylomar on the heads and the new inlet manifold gaskets, and then once they were together I put some more on the top side of the gasket and also the inlet manifold. I assembled it all together and torqued it down.
Once the manifold was installed I spent the next hour re-installing the carbies and other items. Once everything was in place I turned the key and it jumped into life. Straight away I could tell it was running smoother, and after letting it warm up I was able to reduce the idle speed and also lean out the idle mixture. It finally sounds like a normal engine. Tomorrow I will drive it and see if all is well…….stay tuned