I bought a DD51T with a broken timing belt. It was a bit sketchy towing it behind my Dodge Grand Caravan: The car trailer was really too heavy. I had booked a 6x12 utility trailer but when I went to pick it up I found that the tailgate was less than 5' wide and there was no way I was getting the Carry into it. I told U-Haul I was only carrying an ATV and they were able to get an override to assign a car trailer to me. I drove slow - it was fine. I was able to get it into my "garage" with the help of a neighbor with a front end loader on his tractor: It's not heated, but at least it won't get full of snow. It's pretty dirty but I don't have a pressure washer and I wouldn't be spraying water around at these temperatures anyway, so I'm working on it like this: I have the bolts out of the centre panel so I can push it aside as needed for access, but I can leave the cables attached. The box is also off and I have access from outside. It looks pretty nasty: but there are no bent valves, so it's going back together. I have ordered head gasket, inlet and exhaust manifold gaskets, timing belt, timing belt idler/tensioner pulley and a set of valve stem seals. I have the head and valve cover cleaned and after closer inspection of the distributor cap and high tension leads I've decided to order replacements for them as well. I have a copy of the Yokohama translation of the factory service manual and it's a bit "thin". As far as I can tell it's missing: procedure to set valve timing procedure to set ignition timing tightening sequence for head bolts Am I just a bad reader? If this detail is not in that manual, do anyone have a pointer to where I might find it?
The Danko translations covers valve lash and ignition settings. It may seem to cost a lot but its worth it for t he basics.
I can help a bit with these. Valve timing - the camshaft pulley has a timing mark, unfortunately that's all you really get. Set the crank so cylinder 1 is at TDC (there is also a timing mark on the crank pulley that lines up with a mark on the engine), then line up the timing mark on the cam pulley with its corresponding mark. Install the belt and go. Ignition timing - there is a rubber plug on the top of the bell housing so you can see the flywheel. There's a few lines on there, a "T" for TDC and then some timing marks. Hook up a timing light to the cylinder 1 plug wire and check timing at base idle. Make sure the truck is fully warmed up before setting final timing, OEM spec is 7 degrees at 950 RPM but many folks find that the trucks run a bit better at 8-10. Mess with it a bit. There is a vacuum advance line on the distributor, if you're setting base timing at the correct idle speed it doesn't matter if you disconnect it or leave it. Head bolts - I have not been able to find an official sequence for this engine, but other engines that are similar torque from the center outwards. I do know the torque spec is 45 ft-lb (technically it's 600-650 kg-cm). Other than that, I would recommend setting valve lash when the engine is cold. 0.003" on the intake, 0.004" on the exhaust. I'm curious to hear what condition your valves are in if you lap them, and how smoothly replacing the seals goes, please keep us posted!
As expected - progress is slow. I have the valves out and the old valve stem seals removed. It looks pretty nasty, but there is no deep pitting in the valve seats - they will clean up ok with some lapping. I'm now back to waiting for parts. I bought a valve lapping tool from a local car parts store - the smaller suction cup looked small enough, but it's not. I also ordered the wrong valve stem seals - I did some research and found a Felpro part number, but when they arrived they were too big. I now have some on order from Japan.
