1937 ULH low Cylinder Pressure

[Rollo]

Yeah got thinking about it and you do need to guide to center the cut for the seat. My bad! Corona virus got me. So if the guide acts as the mandrel to center things up how would it end up being out of round? Only thing I can think of is guide pressed in crooked? How far out is it? Would think that once you cut the seat and dropped in valves (test fitting) either it would be obvious that the valve was not seating properly or there would be binding on the valve stem? Until it is figured out I wouldn't place blame on any particular person or component. Not defending ACF here as I have had my own issue with them but also know I have had pretty good work done as have others over the years.

Tom (Rollo) Hardy
AMCA 12766

[T. Cotten]

Error is additive, Tom!

The concentricity and alignment of the guide's valve bore will always be subject to production variances, but I only found guides really bad from India.

Then add installation variances (including fitting for the valvestem), and every seat must then be cut piloted to that.

On a veteran, one hopes there is enough meat left in the casting.
On a new production, I would expect to cut a lot just to get to minimum stem protrusion.

....Cotten

[shinedogg]

I just finished a garage made leak down tester with gauges, fittings and a air spray nozzle. Test tomorrow!

[knucklehead 61]

have the rings been broken in & fully seated yet, or are you testing before firing it up?

[shinedogg]

She hasn't run yet with these cylinders

[knucklehead 61]

She hasn't run yet with these cylinders

hard to get an accurate reading when the parts haven't been seated & broken in yet.

[T. Cotten]

If your "leak-down" test equipment, Shinedogg,..

Puts air to the combustion chamber at the sparkplug holes, then you might avoid the bother of calculating the rate.

Just listen at the timing hole, carb, and exhaust as you turn it through.

....Cotten

[shinedogg]

OK so after fine tuning my home made leak down tester, I put 150 psi in each cylinder, which slowly leaked down until about 90, then held. I thought that was pretty good. I turned the engine over until compression started in the front cylinder. Tapped the kicker over until the mark came up in the timing hole, not straight up, but almost. The small cam of the timer was almost ready to start opening the points. With a little coaxing, and the ignition on, I turned the advance and the plugs fired. The pictures show before I turn the timer. Anything wrong here, before I take her down off the lift to start kicking?20200402_201801.jpg20200402_201736.jpg