Katy’s engine gets done
Our T grabs itself a rebuild
Katy’s power plant needed some serious work. The engine fitted to the Ford Model T had to be a strong and reliable unit capable of powering four people at 40mph using only a two-speed transmission. The in-line ‘four’ of 2.9 litres or 177 cubic inches is a robust design with side valves and capable of producing a healthy 20hp. It has no oil pump, no fuel pump and no water pump… I kid you not! Oil is circulated by being thrown from the deep sump by the flywheel magneto, caught in a funnel and piped to the front of the sump where it lubricates the timing gears and runs back to the sump via the big ends. The oil vapour produced makes its way into the valve chest to lubricate the valve gear. Fuel is gravity fed and the water circulated naturally by thermosiphon.
Katy’s engine was not in a good state. The cylinderhead was badly frost damaged and all the pistons were stuck – FAST. So I soaked the engine very carefully in oil and gradually it came apart leaving the pistons stuck in the bores. I have a mandrel for this purpose and numbers 4, 3 and 2 came out with about 3-4 tons on the press.
Stubborn customer
Number 1 did not want to come out – no surprise considering it probably hadn’t run for 50 years. I carefully cranked it up over 10 tons and then jumped out of my skin when it moved with an almighty BANG! After a change of underwear I went on to remove the last piston.
Astoundingly, the block and rods were all reusable.
I checked them for wear and they had survived incredibly well. More astoundingly, the bores were standard, as were the big-ends and main bearings. It then became apparent that there was no wear at all in any of the white metal bearings either! This was great news and meant avoiding having to re-white metal the rods and especially the block, which isn’t an easy task.
All new aluminium pistons, valves, adjustable tappets, gaskets and fasteners were ordered from the Model T Ford spares scheme – an invaluable service for members. I also like the fact that spares controller Rob Lorch takes the mail order packets to the local post office in his Ford Model T Pickup – brilliant.
Machining the metal
I faced the block, recut the valve seats and took the bores to plus 20. Number 1 bore was quite bad, so I fitted it with a liner. I used pistons made of aluminium, which is recommended as a replacement for the original iron as it reduces strain on the original crankshaft.
The engine was assembled and all the main bearings and big-ends were polished and re-shimmed. A later and larger internal oil funnel was fitted and also an accessory outside oil line for backup. The cylinderhead was badly damaged and also incorrect for 1916, so I found a correct replacement which raises the compression slightly as well.
It was at this point that I could have upgraded the engine to facilitate an electric starter… but I want to keep Katy totally authentic and correct, so decided against it. I stripped the carb and found it full of rust, dust and lots of things that
shouldn’t be there. The carb and manifolds were all bead blasted and restored ready for final fitting. The Beaulieu Autojumble deadline was looming and, with Katy due to appear on the
Practical Classics stand, the pressure was on. I approached the last jobs with a sense of foreboding. I checked the large sump for straightness as they are often bent beyond repair. Thankfully, it was excellent with only minimal damage. I sorted a couple of frame ball cup studs, drilled them and replaced the originals. This engine had to hand-cranked in front of a live audience at Beaulieu, so this had to be perfect!
Next time: transmission and time to drive.
‘My Model T parts are taken to the post office in a Model T pickup!’