2 replies to this topic

[mvahora]

managed to get my hands on a 1275 motor fairly cheap. doing a full strip to see what the condition is and what's hiding inside. was told going with hot cam. turns over smoothly. ID tag is missing so must have had a skim in the past.

 

I've taken off the head and it mostly looks ok. one of the thermostat studs was a real pain to get off (corroded),  rockers are tight. push rods all straight no rust. the head, valves and top of pistons have a lot of carbon deposits so quite black. bores look pretty good. head gasket looks good. no indication of anything getting into the bores. with waterpump off waterways look pretty ok. 

 

I noticed once head was off that 2 of the main studs have a very milky slimy kind of oil on them whilst the others all have normal black oil. is this a cause for concern and what would it indicate?

 

first time doing a light refurb or possible rebuild of an engine. so would appreciate the guidance. 

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Edited by mvahora, 11 June 2025 - 10:55 AM.

[DeadSquare]

The "Slime" indicates that the engine has been run on a high detergent oil.  Detergent oils have been in use for at least 60 years, they allow the water content of combustion that blows past the rings, to emulsify in the oil, and on longer runs when the engine temperature is high enough for a sustained period, to evaporate some of that moisture.

 

It looks, from your photos, although there is no sign of tracking, that moisture has seeped from around cylinders 1 and 2 water-ways, towards the Head Studs.  This shouldn't happen and it might be that the Head Studs have stretched or that the torque setting has not been checked regularly.  

 

Experienced engineers, such as AC Dodd or Spider, who provide so much information on this site, presented with an unknown engine to strip would automatically check the torque of Head Studs or Crankshaft Bolts, before loosening them, because this would give an indication, should a problem such as yours, be found.

 

If I had had your engine in its present state, in my workshop, I would pass the the Head and Block under a surface grinder to reveal any high or low areas and machine both surfaces to 'spark-out'.  (Do not be fobbed off with trepanning / fly-cutting).  Two 'truly ground' surfaces will give you the best Head Gasket seal.

[Spider]

Normally that's an indication of water and oil but where it came from is anyone's guess. There doesn't appear to be a sealing issue at the gasket.