Sonett engine rebuild by GeoffC

By diyauto
( 2 )

3 minute(s) of a 9 minute read


Sonett engine rebuild 

Compliments of GeoffC @


After complaints about the amount of oil my Sonett is depositing wherever it goes and stops, I am finally starting an engine re-build program. However due to budget issues this may take some time so don't hold your breath anyone!!

I acquired a sadly neglected mid '70's 1500 V4 engine sometime ago which looks as if it has spent most of it's time outside! Anyway I removed the flywheel a few weeks ago and cleaned it up ready for machining. I want it lightened but not quite as much as I did years ago with my rally car. The idea is to build a performance 1700 spec engine but still maintain flexibility for normal road use, i.e I don't want a tick over in excess of 1000 rpm.

A bit scabby but should clean up OK.

The engine is seized up due to the length of time standing so yesterday I removed the RH cylinder head. Not a pretty sight:

My idea was to machine these cyl heads and block and get it all ready with new pistons, bearings etc so that when I finally get to remove the front end of the Sonett and take the engine out, the off the road time will be limited. I will of course need the 1700 crank from Sonetts existing engine to complete the build which may or may not require a re-grind.

So having got one head off and seeing the state of the waterways and exhaust exit flange I'm wondering whether or not it has gone back to nature too much? I would obviously shot blast and clean out the waterways as much as possible and machine the head face and open out the combustion chambers, replace valve guides and seats etc - just wondered what anybody who may have done this on an old stored engine before thinks? I don't need to use this engine as I can re-furbish my original, but as I say I just wanted to minimise off the road time and it seemed like a good idea to get machining done a bit at a time as and when given the limited budget.

So what do you reckon worth cleaning up or scrap it?