Sludge

[tankdiver]

I have just started on the B40 engine with the intention of a  rebuild .       On taken off the rocker cover  the inside was spotless and on one of  the nuts inside  had some condensation rust. 

On removal of the sump inside the lower crankcase  was very clean { SPOTLESS } as if it had been petrol washed  the sump had clean sides but in the base was about a litre

 of thick sludge, that covered the bottom of the sump pan and had not come out when the engine was drained. Further examination of the crankcase and bearings showed good bearing  surface on both the main and big ends.

The con rods had condensation rust on them which was easily removed with a petrol soaked rag.  Pondering the clean engine with good   B /end  & main bearings  I came to the assumption that the engine had been overhauled and a detergent oil  was used which totally removed all of the  old sediment present and dropping it in the base of the sump.

This reminded me of engine failures in the sixties when the detergent oils were introduced  sludge blocked  the intake gauze and starved the bearings.

Again pondering the removal of the oil it did not remove the sludge , so now when I do engine oil removal  after I will refillI  and put a mixture of petrol oil and allow to stand then drain the sump again to remove any deposits of sludge,

Regarding the engine  I will replace the big end bearings as these take the most wear  but retain the original main bearings.

I must be a little out dated with the cost of bearings  as they were over  3 times the amount estimated   I use to pay £50- £80 max  for big end bearings and for todays prices  I would have had a regrind shaft and all bearings throwing in. All they are is a mildsteel shell with white metal on it.

 

[Richard Farrant]

Detergent oil keeps impurities in suspension so that when passing through the filter they leave the muck behind. It is the older type straight engine oils that leave the sludge in the bottom of the sump.

You never know what oil a previous owner has been using.

regards, Richard

[tankdiver]

You are quite right Richard  I think it cleansed all the crankcase and was just about to get to the sludge that dropped into the sump judging by the strainer  pick up . It will be interesting to get to the filter at a later date to see how full of sludge  there is.

I am looking forward to getting it running again with good clean oil  and hope all the oil galleries are clear  .I will give them a good blast with the air line. I think this engine has had little running due to its internal. condensation  It will get a good run when its finished

regards 

Laurence