Oh Bottoms!

Pootle's Owner

Pootle's Owner

Active Member
Couple of weeks ago we took Pootle down to the New Forest. Helen was driving and I took my Celica. Helen then went off to S.Wales with youngest son in Pootle and I returned home for work.... Pootle then became 'unhappy' on the way home on the M4 on monday and arrived back at Pattison-Towers in shame...

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Only had an hour looking at the problem before we had to travel to Norfolk for a few days but fear there is a holed piston - engine starts and runs (on 3 pots I think) but exhausting out of breather pipes. Need to contact Rootes Parts in NV for another piston and rings once I check what size I fitted back in 2020.... Hoping that I can remove sump and fix it by popping bust piston out the top without a full engine-out performance!
 
Will look closer when back home on Sunday. From Helens description sounds like it started pinking and overheated and holed a piston.... Hoping it's not too bad when head comes off - on plus side H reports oil pressure was OK at 40psi but temp went into red so might be fixable in situ...
 
As feared the biggest PITA is I can't get the sump off at the moment. We did lift the engine up off the mounts and lower sump enough to remove No1 bottom cap and remove the piston from the top. Martin not supplying parts now and Speedy on holiday but Sunbeam Spares in Shepperton have all bits for collection tomorrow. Can anyone confirm if sump will come off if I remove one/both steering arms? 20220815_155206.jpg
 
It will. Then a wiggle to get the sump pan around the oil strainer.
Any idea what caused the piston damage? I've got a very similar looking piston that came out of Harvey's original engine.
 
Not sure of cause. Three pots fine and bore and head on No1 perfect. Only problem is bust No1 piston. I wasn't there but sounds like engine started pinking and got hot before P1 died. Could have been a weakness in the piston (new 2,000 miles ago) or pinking caused it. Three good plugs seem good brown cover so not lean. After rebuild will time well retarded and ensure no pinking!
 
Ooooh. That's nasty. :( That piston looks to me like it's been hit very hard from above at that point. 2nd and third lands (between the rings) appear to be broken and displaced downwards squashing the oil control ring.

I suppose it could be the bit that broke out of the piston causing the breakages lower down, but difficult to see exactly how.
 
I would agree with you totally and I really don't understand really. The bore is unmarked and so is the cylinder head so no evidence at all of an impact.
 
Someone asked me if perhaps my rebuild had created an engine with too high a compression ratio? The engine should be fairly standard Alpine spec I think. Standard cam, dished piston tops, 30 thou oversize, standard ali head. The three 'good pots all showed 170psi before I removed the head. Does this seem sensible
 
Defo looks like a melt so some kind of fault, nothing could’ve smashed it or you’d have evidence and more damage I reckon. FI - I’ve been running 190 psi for 4 years due to an over skimmed head and +40 pistons and without anything like this happening - I have just blown the head gasket but was half expecting it at some point. Moved to a new head now with more sensible compression ratio.
 
Speedy is closed for holidays so I bought a set of Pistons from Sunbeam Spares which is just down from us in Shepperton. With all the gaskets and stuff the bill was about £500 which seems a lot until you realise it's about 4 tanks of liquid gold these days! Bloody hell - I remember my father ranting about the price of petrol on a Cornish camping holiday because they were ripping him off at 36p for a gallon! How long before we get to £2.22 per litre (£10 per gallon!).....
 
Have now done about 20 miles with ignition well retarded (5 degrees advance at cold idle) and running well with no hint of pinking. Management is set on a trip to Kettering for the weekend so we need all your prayers I think! :)
 
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