Aston Martin Engine Rebuild
At oselli the Aston Martin engine is rebuilt to the same exacting standards as when new. Crankshafts can be re ground several times and selective main bearing shells make it possible to select from three clearance variables with in a journal size to obtain optimium clearances
The rear main seal on the DB and V8 engine is of an oil scroll design and inevitably leak! But by inline boring the main caps during rebuild the normanl clearance ot three thousanths of an inch can be reduced to improve this short fall.
Cylinder blocks generally corrode badly on both the six cylinder and V8 alluminium engines and to salvage the block it is necessary to bore out and replace the corroded areas of corrosion which has been carried out sucessfully on many occations at Oselli
The cylinder block of alluminium has a steel cylinder liner fitted which is retained in place withtwo rubber O rings at the base. The O rings are basically used to seal the water jacket and crankcase oil area.
The O rings fitted to the liners are approx 1" apart and between the O rings is a 'dry area' when once fitted to the block a small drilling through the block can be found from which when new during manufacture sealing of the O rings to the block was tested.
It is this area of the block that inavitably corrodes. Externally on an engine you can see these tell tail holes and if water or oil is leaking out then this is a good indication of corrosion being present.
Likewise if an engine has been overheated at some time, the O ring matterial can fail and this will also cause leakage at the holes.
Of course once the block is stripped and liners removed the water jacket is clearly visible and the liner sealing area and corrosion is obvious!
The only solution to this problem during major rebuild and with considerable saving over a new block, is to bore out and replace the corroded area in question. And because the block is alluminium this can be achieved very sucessfully.
In the same manner over the years we have sucessfully repaired both cracked and porous cylinder heads, converting heads to hardened seats as a matter of course.
Apart from the problems of corrosion and cracking of blocks and heads the rebuild of the V8 engine and the six cylinder is quite straight forward.
We do however recommend the six cylinder be rebuilt to the more popular 4.2 litre specification with lightening and balancing of all rotating parts a must!
On the V8 range options from Oselli include an upgrade to 6 litre or the ultimate spec of 6.3 litre using billetted crankshaft and cosworth forged pistons!
Any doubts please call or email, we are always pleased to discuss the finer points of engineering!