Sonett engine rebuild by GeoffC

4 minute(s) of a 9 minute read

Well agreed Derek, if it was "just for an oil leak" - there are other things I hadn't mentioned!! The fact is that the existing engine has just cleared 105,000 miles, the sump is dented so the flanges aren't true and have always leaked a bit, but now the oil seals are going all round, clutch starting to slip etc and on top of that one cylinder is down on compression. Blow by is pretty bad too judging by the haze under the bonnet - so it's time for a re-build. It used 2 litres of oil to get from Warwick to Neo's open day - the only good thing being that the front end of the car and half way down underneath are well and truly rust proofed!!

Trouble is the car is performing better than it ever has, probably due to the lack of friction in the engine!!! So for that reason I'm keeping it going as long as possible hence my idea of using the castings in this salvaged engine (even if it looks as if it's been at the bottom of the sea!) for a re-bore and a chance to modify the heads which I wanted to do anyway.

Anyway I'll take the other head off strip the internals and then see what the block is like when cleaned a bit more. If both heads are too badly pitted then happy to use my existing ones. It's only the re-bore that requires professional services I'll do the rest myself.

1-28-2015

Bit of an update but I didn't get anything done over Xmas as I expected. Anyway took the front cover off and the timing gears are all in good condition, no play in the balance and camshaft bearings either although they will all be replaced.



Bit of a surprise when I turned it over to remove the sump, clearing all the crud off the bottom of the sump (probably where it had dragged over the sea bottom in it's role as an anchor!) I found a hole!



Not amused as the sump pan was the only other thing I wanted apart from the castings as my current one is so battered.

Anyway off came the sump to reveal this



A clean set of innards with no evidence of bearing wear - not what I was expecting!



The oil ponged a bit but it's done it's job and kept the bearing faces rust free. No grooving or noticeable wear on any of the shell bearings and the crank looks almost like new!





The big ends were also in good condition and the only problem I have is getting No 2 piston out, as that is well and truly seized. The others came out with a light tap once the crud on the head interface broke away to let them out. I have left it soaking so will have another go tomorrow, and I also need to push the cam followers out which are a bit stuck. I want to send the cam to Newmans as they are going to provide an exchange fast road cam.

The cylinder heads are also stripped, I got the exhaust bolts out, one had already sheared but left just enough to get a pair of stiltsons on it and with some heat and a long tube they are all out and in the bin. Always replace those with hex cap heads anyway.

Next thing is to bite the bullet and find out how much the machining is going to cost me - there may be another long pause in progress!!