The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Greybeard on 11.01. 2019 11:19

Title: Another sludge trap warning
Post by: Greybeard on 11.01. 2019 11:19
Facebook post. Triumph crank, showing the muck in an engine that was described by the previous owner as 'rebuilt'
Title: Re: Another sludge trap warning
Post by: Topdad on 11.01. 2019 11:50
always thought Triumphs were full of crap  *red* *whistle*
Title: Re: Another sludge trap warning
Post by: Klaus on 11.01. 2019 12:46
`rebuild`means shiny, ping ,ping and most buyesr are blinded.
Title: Re: Another sludge trap warning
Post by: Swarfcut on 11.01. 2019 13:52
 FAKE and STAGED....

   There is not room in a crank for that amount of detritus. Look closely and you will see the metallic golden brown of high quality rust.

 The sort that the sills/rocker panels are made of when the yearly test on your old car comes with bad news. You don't get flakes of rust in sludge.

  Quality sludge is much finer and  has a consistent look, not angular chunks.

 Its a crank, some sludge and an added  pile of unrelated rust.

 Swarfy.
Title: Re: Another sludge trap warning
Post by: Black Sheep on 11.01. 2019 14:58
The worst sludge trap case I have seen had the oil still going through a wormhole to the drive side big end. I have never seen one blocked completely.   
Title: Re: Another sludge trap warning
Post by: Greybeard on 11.01. 2019 15:09
Here is another one of the same crank
Title: Re: Another sludge trap warning
Post by: Servodyne on 11.01. 2019 19:16
Hi there,
I looks like the crank is either a Sunbeam S7/8 or possible BSA Sunbeam/Triumph Tigeress scooter. Its owner must have been running it on lawnmower oil.
Title: Re: Another sludge trap warning
Post by: lawnmowerman on 11.01. 2019 23:10
Agree Servo. This is a shot of my Sunbeam S7/S8 crank showing the crap which came out. I agree that there is too much sludge shown in the first picture to fit inside the crank journals but mine were over half full and enough to starve the oil to the big ends and neccesitate a regrind and new shells.

Jim

Title: Re: Another sludge trap warning
Post by: Colsbeeza on 11.01. 2019 23:59
I remember when I had my A10 crank rebuilt by a very respected company, I had doubts about the sludge trap, so after they had balanced the crank I removed the plugs and they were about 70% blocked - took ages to get the crank clean. I dunno how the balance will be affected, but sofar great up to middle revs.
Col
Title: Re: Another sludge trap warning
Post by: Greybeard on 12.01. 2019 16:00
I remember when I had my A10 crank rebuilt by a very respected company, I had doubts about the sludge trap, so after they had balanced the crank I removed the plugs and they were about 70% blocked - took ages to get the crank clean.
A very respected company? Not any more!
Title: Re: Another sludge trap warning
Post by: nimrod650 on 12.01. 2019 17:43
my old fella from new always drained oil hot poured in 3 pints of parrafin let bike tick over for a few minutes drain and refill with oil did same with his car
Title: Re: Another sludge trap warning
Post by: ellis on 12.01. 2019 19:43
The price of paraffin nowadays that would be an expensive oil change.   *eek*

ELLIS
Title: Re: Another sludge trap warning
Post by: stev60 on 17.01. 2019 06:48
Everytime I look in this site I read about the horrors of the sludge trap, not knowing whats lurking in the bowels of my bike is starting to give me nightmares, so ive decided it, runs good, dosent burn oil , good compression, I just ride and enjoy it
 
Title: Re: Another sludge trap warning
Post by: Peter in Aus on 17.01. 2019 07:07
Everytime I look in this site I read about the horrors of the sludge trap, not knowing whats lurking in the bowels of my bike is starting to give me nightmares, so ive decided it, runs good, dosent burn oil , good compression, I just ride and enjoy it

That the way to go *beer*
Title: Re: Another sludge trap warning
Post by: Swarfcut on 17.01. 2019 08:25
Peter,  You can sleep easy.  OK, this is a known problem now, back in the day the bikes where not expected to survive to anything like the half century that some have achieved. But like Mark Twain said, some things were certain, like death and taxes, and sooner or later the bike will  require attention. It is inevitable with any internal combustion engine. However, it may not be at a time of your ownership.

  But when that time comes, a complete strip and a clean out make sense. In the meantime frequent oil changes are by far the most cost effective method of engine preservation for any engine. Oil changes are a whole lot cheaper than major mechanical attention.

   On all my vehicles over the years I have always changed the oil and filter at half the recommended service interval. The insides look as clean as the day they were made. How many are running round with valve gear, the bit you can see, covered with a black greasy oil  blocking tarry sludge?    Too many.   Long service intervals are specified by the marketing men and the sellers of replacement engines.

 No doubt the thread will change to views on the virtues of oil choices.... straight, detergent, multigrade and additives.

 Swarfy.
Title: Re: Another sludge trap warning
Post by: RDfella on 17.01. 2019 09:51
Swarfy - you are right. Back in the day, engines used non-detergent oils: for engines little or no filtration, an  oil that dumps out the muck as a deposit is actually the best choice. I've seen engines wrecked by people who wrongly decide that their engine will be better running on a modern oil. Why? Because modern detergent oils hold the muck and products of combustion in suspension to be taken out by the oil filter but, without an oil filter (such as our bikes) this oil keeps circulating as a grinding paste
You should use the oil the engine was designed for and just be aware of the places where sludge is likely to settle. For example, my Riley car, despite having a full-flow oil filter, is supposed to have the sump dropped every 10,000m to clear sludge. In our case, the problem is the crank acting as a centrifuge - a mechanism used on some cars as an actual oil filter - think it was some Renaults which had a centrifuge built into the crank pulley especially designed to filter out solids from the oil.
Sun's shining here today at last, so must get on with some outside work.
Title: Re: Another sludge trap warning
Post by: Black Sheep on 17.01. 2019 10:05
Don't try the parrafin trick with a diesel. My mate did this with his old Land Rover. When he tried to stop it, it wouldn't. Paraffin was being drawn down the worn valve guides and being burnt. It just went faster and faster until the inevitable explosion. Oops! 
Title: Re: Another sludge trap warning
Post by: RDfella on 17.01. 2019 17:11
Black Sheep - I wouldn't recommend it for any engine. Although an oil, paraffin is actually a pretty poor lubricator and you risk scuffing plain beaings by using it as a flushing oil.
Title: Re: Another sludge trap warning
Post by: Triton Thrasher on 17.01. 2019 18:01
The price of paraffin nowadays that would be an expensive oil change.   *eek*

ELLIS

Number 2 kerosene sold as heating oil.
Last 20 litres I bought was 60 pence per litre.

But don’t flush running engines with it- that would be silly.