Stuart No 1 - Problems


A number of problems were found during the making and testing of this engine. The problem and solutions used are listed below.

The flywheel rim did not have a constant thickness especially when view as shown above. Additionally the casting had some sand in it which meant the rim has an imperfection. This was the second flywheel which was machined up and both seemed to have the same problems although this second one was a good deal better in terms of having the casting halves matched.

The sole plate was not symmetrical about it's long axis. This meant that the bearings had to be machined to compensate for the off-set of the top half of the engine.

The lower, rear corner of the connecting rod had to be chamfered to stop it hitting the bolt heads which held the slider plates in place.

In combination with the con-rod modifications the heads of all the bolts had to be halved in height to avoid a clash with the con-rod.

The threads in the gland studs were not long enough and had to be extended to give a suitable clamping force on the gland packing, extra gland packing was also used.

I couldn't get a satisfactory fit with the valve guiding rod. This was missed off altogether.

The lower face of the steam chest had a crack on the inside. This could have been a casting fault or could have been caused my me over tightening the 4-jaw chuck. This was just left as is.

The valve didn't operate when first tested. The steam chest had to be machined to get the valve block to mate with the port face on the cylinder. The valve block was also made a looser fit on the valve rod so that it could seat itself under steam pressure to give a good seal against the port face.

Initially the piston hit to top cylinder cover at TDC. This was corrected by shortening the piston rod and also by skimming the top of the piston.

The top face of the standard was still not square despite being machined twice. In the end filing and shim washers were used and the mounting holes at the top were opened out to get everything to line up. 

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