Lister Engine Forum

How to / DIY => Engines => Topic started by: Farmer on February 02, 2023, 03:32:24 AM

Title: Rebuilding ST1
Post by: Farmer on February 02, 2023, 03:32:24 AM
I'm in the process of rebuilding an ST1 that ran for a short time with low oil.  The two main crankshaft bearings show signs of damage, but the crank journals look good with no damage.  The crankshaft rod journal bearing has more damage and the crank has some discoloration.  I can't feel any damage to the crank surface, but I'm wondering if I need to do something to clean the surface of crank journal?  With the tools I have I can't accurately measure the crank to determine if it is out of round.  Thoughts?

Also, I have a parts and shop manual for the engine.  Is there an operator's manual available for this engine?

Thanks in advance for comments and advice.
Title: Re: Rebuilding ST1
Post by: cobbadog on February 02, 2023, 04:49:00 AM
G'Day Farmer.
If you dont have the tools to acurately measure the journal then a pair of outside  calipers could do a good enough job. If you have a large enough spanner to be a snug fit try it on the journl in a few places. I would simply clean the journal with a length of fine emery paper not to remove any discolourisation but to clean it up ready for assembly. I would replace the main bearings because if you can see sings of wear then its time to  replace.
AS for a hand book / operators manual I dont know but if you do a Google search you may find one. Is there anything in particular you need to know about start ups etc?
Title: Re: Rebuilding ST1
Post by: ajaffa1 on February 02, 2023, 05:08:36 AM
Hi Farmer, I think the crank will be fine unless it already had a lot of wear in it, bearing shells break down without oil much faster than crankshafts. Did the engine seize? If it did the chances are that it was the aluminium piston seizing in the bore. The camshaft has brass/bronze bushes and should be ok, as should the governor mechanism.
I would take a good look at the condition of the small oil pump, it is situated under a plug in the bottom of the engine and driven off a lobe on the camshaft. It is a simple piston pump and could easily be damaged by lack of lubrication. No point in rebuilding an engine that will restart it`s life with low oil pressure.

Bob
Title: Re: Rebuilding ST1
Post by: Farmer on February 04, 2023, 04:08:36 PM
Thanks for the comments.  I had some crocus cloth and I went ahead and lightly cleaned up the crank journal.  There was no roughness, but with a bit of careful effort, I was able to remove much of the discoloration from the bearing journal.  While at my local NAPA store, I rediscovered plastigage.  I checked the clearance and it's between .0055" and .006".  The maximum spec is .0055, but I think I'll go ahead with the rebuild (any concerns?).  Good comment re the oil pump.  I took it apart and found one of the o-rings was broken, but the clearances appeared good ok so I purchased the two required  o-rings along with a gasket kit for the engine.  I've also lapped in the valves as there was evidence of leakage.

As I've never been around one of these engines, and I'm replacing the piston and cylinder. I am looking for any break-in information as well as starting and operating information.  This unit has an electric starter so it should be easy to get it going.

Thanks for your comments
One last question, what is the oil reservoir and plunger that is screwed into the intake manifold?
Title: Re: Rebuilding ST1
Post by: ajaffa1 on February 04, 2023, 08:34:51 PM
Hi Farmer, I think the crankshaft should be OK, unless you are going to be relying on this engine as your primary mover. The crank could easily be reground, bearing shells come in under sizes of 10, 20, 30 & 40 thousandths of an inch. What condition is the little end bush in? Not a difficult/expensive replacement, some need reaming to size after fitting.
Diesel engines are a little different to petrol engines, when running them in it is essential to have a sizeable load on the engine or the bores will become glazed and you will not get good compression.
The plunger mechanism is exactly what it looks like: a syringe. You fill the reservoir with engine oil and push the plunger down, this oil then sits on top of the piston increasing the compression ratio for easier cold starting.
Starting these is relatively simple, especially with an electric start. Check the injector pump rack is fully open, bleed the fuel system at each point, there are little bleed screws on the fuel filter and etc. Work your way from the fuel tank to the injector pump, once you have fuel flowing from the top of the injector pump fit the high pressure pipe, do not do up the nut at the top where it fits onto the fuel injector, leave it slightly loose. Crank the engine over until you get fuel squirting out around the loose nut, now do it up. Crank the engine over a few times and it should start.

Good luck.

Bob
Title: Re: Rebuilding ST1
Post by: Farmer on February 17, 2023, 07:03:45 PM
Thanks for the useful information.  I'm in the process of putting the engine back together and I don't see how I can press the bearing out of the main bearing housing?  Are there any special tools or techniques to get this done??
Title: Re: Rebuilding ST1
Post by: Farmer on February 28, 2023, 01:54:44 AM
I've got all the parts from Gary Jones, and I need to hone the new cylinder that I purchased.  Any advice on technique, etc. I've been reviewing youtube videos, and have an idea as to what I should do, but am open to any recommendations

Title: Re: Rebuilding ST1
Post by: cobbadog on February 28, 2023, 10:49:15 AM
Hi Farmer, if it is a new cylinder then it does not ned to be honed. If it is a 2nd hand one then yes it will. Unless you have the appropriate hone to do the jiob an engine reco shop will do it for you cheaply. Are you certain that the piston is the correct size for the cylinder?
If doing the hone yourself I use kerosine as the lube. You can use a 3 arm hone with stones or a ball hone both will do the job.
Title: Re: Rebuilding ST1
Post by: ajaffa1 on March 02, 2023, 07:39:14 AM
Hi farmer, if you are honing a cylinder the most important thing is to clean it properly afterwards! The mixture of honing grit and abraded steel is death to any engine. Clean it, then clean it again, if you can wipe a white tissue soaked in kerosene around the bore without any sign of dirt it is clean enough, if not clean it again!

Bob
Title: Re: Rebuilding ST1
Post by: mobile_bob on March 03, 2023, 02:45:21 AM
amen on cleaning!

i use ATF (auto trans fluid) because it is really good as a cleaning agent and when used with white paper towels
it shows when the bore is really clean

the atf will float out super fine abrasives out of the crosshatch, and the white paper towel will collect it
when the towel comes out red with no sign of gray color, the bore is really clean.

it is amazing what appears to be clean is really hiding a lot of fine abrasive grit

it makes a difference for sure.

i just finished an inframe overhaul of an isc 8.3 liter cummins, the cylinder liners were all packed in sealed plastic and appeared to be perfectly clean, but were dirty as all git out when i used the above method

it is amazing how many mechanics assume the factory clean is really clean and just either use as is, or think that cleaning solvent will be enough prep to use them.  when the reality is they are installing nasty parts, which shorten the life of the end product.

bob g
Title: Re: Rebuilding ST1
Post by: cobbadog on March 03, 2023, 10:19:39 AM
Very true Bob, I have bought some rebuild kits from the UK and the last one came from Spain I think, Bepco. Anyway the Bepco was surprisingly very clean
Title: Re: Rebuilding ST1
Post by: RachelColeman on March 13, 2023, 02:27:36 PM
When the crankshaft main bearings have damage, it is also important to check the condition of the crank pins and connecting rod bearings as you have already done. If the crank pins look good and without damage, they can continue to be used. However, if the crank pin bearing has more damage, it should be replaced. As for discoloration of the crank pin surface, this can be caused by heat or surface oxidation. If this is the case, the surface can be cleaned and polished to remove the discoloration. However, if the surface has any imperfections, deep scratches or cracks, the surface should be replaced or repolished with a professional tool to keep the molar neck smooth and accurate.