ST1 cylinder head gasket

[ajaffa1]

Hi Guys, some of you will have seen that I purchased a small dumper truck. It has a Lister ST1 diesel engine, it is an absolute prick of a thing to hand start (no electric start).

My first thoughts on this was that the injector was dirty. Stripped it and cleaned it, I get a good spray pattern from it. Still a prick to start.

My second thought was lack of compression, so I took the head off it, followed by the cylinder and piston. The cylinder bore is OK, it has a couple of water marks in it where it has been sat idle for a time. The piston and rings look to be almost new, they are original Lister parts but have the numbers 040 stamped into the bottom of the piston. I believe that this indicates a +.040" oversize piston indicating that this unit has had a re-bore. There are also a lot of other indications that someone has been into this engine before me, silicon sealer rather than proper gaskets and etc.

Cylinder head looks to be OK, slight pitting in the valve/seats, I will lap them in the morning.

The cylinder and piston are now cleaned and reinstalled.

My question is a simple one: tomorrow I would like to fit the cylinder head and set the bump clearance. The problem I have is that these generally have a set of shims and a gasket between the cylinder and cylinder head. I have only one steel shim and no gasket. I am happy to make my own shims but I do not remember what the gasket should be made from. Is it paper, or some other material? How thick should it be? could I use a gasket sealer as an alternative? I could order a set of gaskets from the UK but delivery from the UK could take weeks.

Help/advice please,

Bob

[cobbadog]

Hi ajaffa1,
Did you happen to check the ring gap while you had it apart? This could be an issue if it is too wide, everything else is good but the gap too wide is not.
As for the head gasket, what type of head gasket came off?

Where abouts on the earth are you as there is bound to be a supplier of Lister parts near you or at least in the same country.

[ajaffa1]

Hi Cobbadog, I`m still in Nymboida, NSW, Oz. Nearest town in a straight line would be Coffs harbour, nearest town by road is Grafton. I did phone the nearest Lister agent, they had no gasket set in stock and could not give me a realistic estimate as to how long it might take to get one.

I wish I had checked the ring gap but I was in a hurry to get this thing running. Hope that won`t come back to bite me in the arse! That said the problem wasn`t lack of compression, it was too much compression. I am no longer a young man but would have struggled to pull this one past compression when I was! Crank as fast as you can and drop the de-compressor lever and the thing nearly stops dead.

Some muppet with no idea of what they were doing has been inside this machine! Once I had lapped the valves and reassembled the cylinder head, I fitted it back as it was and did a bump clearance test. It came back at 23 thou clearance, it should be 35 to 38 thou, no wonder I nearly broke my wrist!

It has been a long time since I rebuilt my ST2 startomatic but I remember the bump clearance was adjusted with a stack of circular steel shims with a circular copper gasket at the top. I did not have copper of the right thickness to make a replacement so I opted for annealed aluminium. I think this should be OK as it is tight up against the aluminium cylinder head with steel shims sandwiched between it and the steel cylinder. I redid the bump clearance test and came in at 34 thou. This is still slightly under the specifications but with a little gasket sealer and the 40 thou re-bore should be close enough.

On assembly I found both of the valve push rods were bent! I do wish people who don`t know what they are doing would leave machinery alone.  Push rods straightened, valve lash set and she turns over sweet as. A very slight compression hiss from somewhere, could be rings or valves but nothing to worry about.

My biggest worry is that the same idiot who got everything so wrong may have played with the injector pump timing. On single cylinder ST engines the timing marks on the flywheel line up with marks on the flywheel housing and can not be viewed from outside. Since this engine is close coupled to a clutch, gearbox and transmission accessing the timing marks would be a big pain in the arse! Lets just see what happens tomorrow.

I`ll let you all know how it goes,

Bob

[cobbadog]

Well done Bob. I have never been to your neck of the woods only along the coast road many times and will be hitting Coffs again soon.
I thought of Listeroids at Nambucca or is it Mackville somewhere.
Not sure of where the compression leak would be comming from. Did you use any spray sealant on the head gaskets? Or maybe a valve adjustment. Anyway hope it all goes well tomorrow

[mike90045]

I think the cyl base shims are just thin paper, you put a stack on, and torque, test, loosen and tear a sheet out, until it's right

[ajaffa1]

Hi Mike, I found a copper gasket at the junction between the cylinder and the crankcase, it has been annealed and reused with a little gasket sealer.

So where are we with this pig of a thing that won`t start? Everything has been adjusted and now appears to be within or very close to the original specifications. Valves ground, injector cleaned and tested, bump clearance set, fuel lines bled, but it still won`t light up! I do get smoke from the exhaust but no ignition.

I`m thinking there are only a few possible problems left and they all relate to the fuel injector pump. firstly is that the fuel delivery valve is leaking allowing fuel pressure to return down the high pressure line. Easy to remove the valve, I will do it tomorrow and report back.

Second is that the rack is sticking, I believe that this is a common in engines that have not been run for a while: the volatile components of the fuel evaporate leaving a nasty cross between wax and varnish which gums things up. I will check  it in the morning and if it is sticking I will apply a little heat to it with a hot air gun.

Third is that the injector pump element has been damaged by dirt or water ingress. generally this is easy to diagnose as fuel leaks past the element and ends up in the sump. A rising oil level is a dead giveaway. Sadly without it running I cannot do this check.

Fourth is that someone has messed with the injector timing, I can see no visible signs that this has been played with, it all looks exactly as it would have when it left the factory.

Fifth is that the camshaft is out by a tooth or more, this engine has had work done but the paint on the governor housing bolts looks to be intact.

I hope I will get this running tomorrow, I let you all know,

Bob

[Willw]

Hi Bob, I recently fixed an ST2 which had a stuck injector nozzle; maybe you could give that a check.

[ajaffa1]

Hi Willw, I have had the injector apart, cleaned it and reset the pop pressure to 190 atmospheres, just a little less than 2700 PSI. I have an injector testing rig, the injector works fine and fives a good clear spray pattern.

I have found an old injector pipe and have connected the injector to the injector pump externally so I can see the spray pattern. When I crank it over I get no spray and only a very little bit of a dribble. The injector pump must not be delivering enough pressure. I have checked the rack movement and it is all OK. I also took out the delivery valve and cleaned it.

I am now going to remove the injector pump and examine it, I suspect that either the element is worn or the piston that lifts it up and down is sticking half way up/down it`s stroke. I`ll let you know what I find.

Bob

[ajaffa1]

Hi Guys, mystery solved: the plunger element in the fuel injector pump is history. I have never seen one so badly worn, how this ever ran remains a mystery. I guess this dumper has seen a lot of building sites in it`s time and been run on a mixture of diesel and cement dust.

I suspect that the oil in the sump is now contaminated with a lot of diesel from the leaking injector pump so I will now have to change the oil and filter.

I have already flushed out the fuel tank and fuel lines. Phoned the local tractor parts place today to order a new fuel filter and plunger element for the pump, hope they get back to me soon.

Bob

[cobbadog]

At least you have identified the issue and your well on the way to fixing it.

[ajaffa1]

Thanks cobbadog. I can buy the parts I need, online, for about $60 but they all need to come from overseas. Covid has severely slowed down international postal deliveries so I have contacted my local dealer. It will be interesting to see what price he comes up with, I am expecting to have to pay at least double locally, if he is asking too much I will just buy online and wait for delivery, it`s not as if we don`t have anything else to do around here!

Bob

[cobbadog]

Sometimes our local suppliers get too greedy. I always prefer to support the locals but not be ripped off by them. When this happens I politely ask if they have made a mistake on the price as I can buy it for less elsewhere. By doing this it gives them the opportunity to look at their price and offer similar price. If it upsets them I have not lost anything and would be prepared to wait for delivery.
The McDonald I have under restoration took me months to get the ring set and valves but they are here now.

[ajaffa1]

Hi Guys, further to my starting problems with the ST1, the new injector pump element arrived yesterday from the UK. The price was about a third of what I was quoted in Australia, delivery was about ten days, not bad in covid times. So hat off to the Supplier, Royal Mail and Australia Post.

Fitted the new element, bled the fuel lines and injector. Had to hand crank it twice before she ran but not bad for a 40 year old engine. No smoke from exhaust and no oil leaks she`s a goodun!

Bob

[cobbadog]

Great news Bob. It is satisfying when they finally do start after all your hard work.
We had last weekend at Coffs to escape work and had a great time up there as we usually do. Still good fish n chips at the Co-op.

[ajaffa1]

Thanks Cobbadog, we know the fish co-op rather well, been going there for eleven years now, much better now the walk along the breakwater is open. Sadly they are not a source for waste vegetable oil, they cook everything in animal fats from the abattoirs. Still tastes bloody good, to hell with my coronary arteries!

Bob