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Old 13-12-17, 07:30 AM   #1
AndyMoran
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Default Bamford Z/1 Diesel

I have rebuilt a Bamford Z/1 - I thought it was going to be easy until I got the piston out, broken gudgeon, piston flanges all broken, deep score down the bore (the engine had obviously run with broken gudgeon). Bored and sleeved, replaced piston but how do you time these engines? The block has to drop onto the crankshaft making it impossible to see the meshing of the cam gear (not that there were any markings anyway). I'm all re-assembled but timing is slightly advanced so no go.
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Old 13-12-17, 09:15 AM   #2
Paul_Sterling
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Quote:
Originally Posted by AndyMoran View Post
I have rebuilt a Bamford Z/1 - I thought it was going to be easy until I got the piston out, broken gudgeon, piston flanges all broken, deep score down the bore (the engine had obviously run with broken gudgeon). Bored and sleeved, replaced piston but how do you time these engines? The block has to drop onto the crankshaft making it impossible to see the meshing of the cam gear (not that there were any markings anyway). I'm all re-assembled but timing is slightly advanced so no go.
Hello Andy,

When you say "the block has to drop onto the crankshaft", I guess you are referring to the split crankcase feature? The crank and the top half of the block stay together, so you should be able to see it mesh up with the Cam, before you hinge the two halves back together.

Some time back (within the last 5 years) a chap restored one and did a writeup in the SEM (Stephen Morley I think), and he did mention the timing was tricky, and he ended up having it set up a little like a Lister CS, which he had recently finished restoring by chance.

Paul.
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Old 14-12-17, 05:50 AM   #3
AndyMoran
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After removing the crankshaft from the upper block (had to remove wet liner to rebore) one has to re-assemble the crankshaft to the upper block. The cam gear is fixed in the block so the best i could do was set crank at top dead centre, revolve cam gear till both pushrods were down and pump cam up and lower the block onto the crank - not easy and clearly open to error. After doing it I thought it may have been easier to do it upside down (lower crank - and very heavy flywheels - onto the upside down block) but then the arms operating the pushrods hang down and even though one may have a slightly better view there are no marks to line up.
I'm now considering suspending the block with crankshaft, loosening the main bearings enough to allow the crankshaft to drop and to rotate crankshaft without engaging the cam gear. Each adjustment is trial and error and going to be very tedious. Hope there's a better way.
As i say "If this was easy, everyone would be doing it"
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Old 08-01-18, 07:11 AM   #4
AndyMoran
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Well it worked. I undid the four bolts holding block to base, removed the hinge pin, screwed in four eye bolts where the tappet cover bolts on and used my chain block/girder trolley combo to lift the block with crankshaft/flywheels clear of the base. I was able to count the gear teeth from below and calculated that I had to retard by two teeth on the cam gear. Loosened the main bearing nuts till the gear on the crank dropped clear of the cam gear teeth, gently touched the am gear to see if it was free and it immediately spun round - the pressure of the pump spring pushed the pump cam lobe off TDC. So with no initial timing to work off I went to plan B (probably better anyway), set up a fuel tank and spill timed the pump. Because the pump spring is so strong, it's not possible to manipulate the cam gear accurately (and not possible to hold the position when rejoining the two halves) so I used a socket on the nut holding the cam lobe on the end of the cam shaft. Holding the precise position with the socket, tightened up the main bearing nuts, checked spill timing again and put it all back together. Fine tuned the timing via the lateral movement of the cam follower holder. Engine wasn't easy to start but is now a runner. i expect a few hours of fine tuning governor, pump and valves and what was a total wreck will live on.
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