Worn cylinders?

[ronan]

Was the engine burning oil or rattling from the top end ? If an engine is running ok it can be a dilemma weither to pull it down or leave well enough alone. The bsa a10 (a sort of two wheeled tractor) when i bought it first, started easily , ticked over lovely and didn't burn oil, i took the cylinder head off for a look and was amazed it could run at all the bores were so worn.

 

[Tengtooltom]

You use a Hone to remove any Glaze that has built up on the bore/inside of liner. When the bore gets glazed up (lack of oil changes/Cheap sh.t oil) you will get blow by. The compression blows down by the piston rings and builds up pressure in the sump which blows out the oil up by dipstick and out through oilseals etc.
You get the lip at the top of liner where the top ring on the piston stops. You need to remove the lip to fit new rings down into the bore. If the lip is too big you will break the new rings.
The bore wears oval due to the rotation of the crankshaft/conrod and the explosion of the diesel....

 

[Lawnmowerboy]

If it isn't that bad then just give it a good hone and re-ring the pistons.

 

[johniban]

Has the piston got much movement in the bore?

 

[Tengtooltom]

Clean up the block with 500grit wet and dry paper and water - cover the crank journals with oily rags and use a rotary motion.
Clean the new FINISHED liners with parrafin inside and out. Wait until the Kitchen is vacant before putting liners into the freezer.

The liners should almost slide in by hand but the bit of wood is used to make sure they are seated home. If not pushed home evenly there is a fear of snapping off the top lip. So clean and clean again and then clean everything again, making sure that the groove in the block where the liner lip sits is CLEAN and I mean CLEAN. Use an old broken ring from an old piston to clean any built up carbon in the groove.

 

[normspanners]

What engine /tractor is it petrol/diesel, if a diesel did it start ok? if was off the button then it was prob good , did it burn oil, look at the carbon deposits on valves n piston tops, sometimes an engine will burn oil when brand new. You can get stepped top rings to stop the catching. Honing has to be 'cross hatched' to work have a look to see if you can still see the honing marks 1/4 of the way down the bore, if so, it cannot be worn too much because of the 'depth' of the hone scratches are minimal also the wear at the top is usually caused by the 'digging in' of the top ring as it changes direction. Also get a torch to look down the side of the piston to see the ring gap and do a 'guestimate' having a vernier close by to 'measure' with your eyes can be a good aide to working out if it needs a rebuild. Usually a new set of rings transforms an old engine, especially if its not going to work hard. You can make it worse by re-linering and not 'working ' the engine after.

 

[Welderpaul]

The pistons are tight in the bores. Its stood for a year, doesnt look stuck, but no movement.

This the bit of kit i need then?

 

[Welderpaul]

What engine /tractor is it petrol/diesel, if a diesel did it start ok? if was off the button then it was prob good , did it burn oil, look at the carbon deposits on valves n piston tops, sometimes an engine will burn oil when brand new. You can get stepped top rings to stop the catching. Honing has to be 'cross hatched' to work have a look to see if you can still see the honing marks 1/4 of the way down the bore, if so, it cannot be worn too much because of the 'depth' of the hone scratches are minimal also the wear at the top is usually caused by the 'digging in' of the top ring as it changes direction. Also get a torch to look down the side of the piston to see the ring gap and do a 'guestimate' having a vernier close by to 'measure' with your eyes can be a good aide to working out if it needs a rebuild. Usually a new set of rings transforms an old engine, especially if its not going to work hard. You can make it worse by re-linering and not 'working ' the engine after.

Its a Dexta tractor with a diesel Perkins 3.144 engine. It started ok, not off the button, but without too much cranking. There are carbon deposits, but not too bad, I'll get a pic in the morning.

 

[Tengtooltom]

http://v2.gb.sparex.com/ItemDetails/ItemDetails.aspx?ItemNumber=66597

Here is more info. This kit has unfinished liners.

Its not a big job to fit the engine kit especially if you have the block out and the crank removed.

Do not forget to check the combustion chambers http://v2.gb.sparex.com/ItemDetails/ItemDetails.aspx?ItemNumber=41567. Fitted on side of cyl head.
They sometimes loose the cup section which make the engine run very rough

 

[Tengtooltom]

Ok. Its a Standard Dexta and not a Super Dexta. Ignore my links but search them for the 3.144 and not the 3.152 engine. Not a lot of difference really. 3.144 has a vaccuum injector pump. 3.152 has a mechanical piston pump.

Yes, that is the kit for your engine.

Silly me for not asking re standard or super Dexta.
I have a sales brochure here stored someplace safe - you know the place!!!

 

[Welderpaul]

Ah, good stuff. I took the combustion chamber caps off earlier. Just looked like blanking plates to my uninitiated eyes.

Is that where the fuel ignites?

 

[normspanners]

Sometimes modern oil is too 'good' for older engines and causes glazeing of the bores and with the oil being thinner it can get pushed up too easy and burnt.
If it started ok the compressions must be reasonable have alook at the honing marks tommorow and report back

 

[Welderpaul]

Sometimes modern oil is too 'good' for older engines and causes glazeing of the bores and with the oil being thinner it can get pushed up too easy and burnt.
If it started ok the compressions must be reasonable have alook at the honing marks tommorow and report back

With new liners/rings etc will modern oil be suitable?

 

[pete23]

The bores wear olive due to the piston rotation in one direction on the con rod

i wore olive once she were a loverly girl just a tad minty though.

 

[normspanners]

Ah, good stuff. I took the combustion chamber caps off earlier. Just looked like blanking plates to my uninitiated eyes.

Is that where the fuel ignites?

Yes that where the injectors n heater plugs go into, it is called a pre-combustion chamber they make a diesel quieter. but not as easy to start, unless your heater plugs are def working.

 

[Welderpaul]

Hmm, Heater plugs. I don't think i've found them. They would be electrical then?

Why is the gasket between the head and the rest of the block copper when the rest of the gaskets are asbestos/fibre?

 

[brightspark]

Hmm, Heater plugs. I don't think i've found them. They would be electrical then?

Why is the gasket between the head and the rest of the block copper when the rest of the gaskets are asbestos/fibre?

solid copper cylinder head gaskets are far superior than fibre copper ones . i have one on me norton bike

 

[normspanners]

I had a mitsubishi industrial engine the other day which I replaced with a new engine,because of cracks etc , the engines give 56hp but the pump it drives requires 30 hp max, it ran ok but used oil like it was eatin it ! it was not burning it, it was going into the exhaust as neat oil, the engine was under worked and with modern synthetic oil it was not doing enough to run in /roughen the bores, so we ran it with cheaper more basic oil and increased the revs of the engine and forced it to work hard for a solid week!! obviously kept checking oil levels etc. now the oil consumption has gone down to a more reasonable level. So in that case it proves 'better oil' is not allways better !! If she is not going to work hard then a cheaper oil may be better.

 

[normspanners]

Hmm, Heater plugs. I don't think i've found them. They would be electrical then?

Ah perkins, could have a fire start system in the inlet manifold which has aglow plug that drips diesel onto it till it catches fire therefore heating the inlet charge for starting from cold only if you didnt have that working then your compressions MUST be good

 

[Welderpaul]

Elsewhere on tinternet it says that the liners are an interference fit and therefore need boring/honing after installation as they will distort slightly. Other sites say not?

I'm confused now