Jag gets a visit from the engine doctor.
A look inside:
With the spark plugs removed, we were able to look into each cylinder bore in turn. The Borescope picture is showing the domed head of the piston. The vertical lines are where he gently stroked the piston head with a screwdriver to check for carbon build up – there was none at all.
Further observation revealed concentric honing lines still visible on the bore lining – this reveals that the engine has had little use since its claimed re-condition.
Today we invited Chris Morgan from Specialist Vehicle Services to conduct an assessment of the Jag’s engine condition.
All we’ve had to go on up to now is that we were able to get the engine running a couple of months ago, and that there was a hand written note (no receipts) stating that the engine had been re-conditioned / fitted with a new clutch back when the car was sold to Maurice.
What we needed was a proper measured test of compression (comparing each of the six cylinders), a more accurate reading of oil pressure (cars gauge is unreliable) and a look at the cylinder bores / pistons with a Borescope (a tiny camera).
Compression test:
We then tested each cylinder in turn for compression by screwing a compression gauge into each spark plug position and turning the engine over on the starter. The gauge needle then ticked up until a maximum level was reached and that reading was recorded.
The six chambers returned the following set of psi readings:
1 – 195, 2 – 180 3 – 180
4 – 185 5 – 215 6 – 185
These readings show that all the cylinders have good compression pressures, proving the piston rings and cylinder bores are in good condition, as well as the head gasket of course.
Oil pressure test:
Finally we wanted to gain a more accurate reading of oil pressure. This shows the engines ability to pump oil from the sump up through the engine to the oil galleries in order to supply lubrication to all the moving parts of the engine. Without this an engine would seized.
We removed the oil pressure sender (O/S of engine block below the inlet manifold) and directly attached an accurate oil pressure gauge. The engine was turned over on the starter and a reading returned – watch the video.
Just turning the engine on the starter and not running it, you would hope for a reading of between 20-40psi and we were getting 38psi, so we were very happy with that!
So in conclusion, a day of good news. We have discovered that the pistons and bores are in good condition, all six cylinders have good compression and that there is good oil pressure. This basically indicates that the engine has been reconditioned at some stage as stated in the history file and will not need a full and very costly rebuild. However, as we will still be removing the engine, a general work over and refresh will still be undertaken.
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