so should I get a 79mm forged crank 9.2:1 shortblock by cosworth? I am sort of confused..
Will building my current engine be more affordable or would buying a shortblock?
I read further into the building up the heads, can you bullet point me everything I need to do to make the engine less destructible?
- heads
- pistons?
I don't ever trust anything already put together least of all cosworth blocks. :tup: I like my motors built in some very specific ways and none of the OTS builders do it quite the way I like it done so I managed to befriend a local machinist and now he knows exactly what I like and machines my blocks to my exacting specification.
Fuji makes some key points about smart part selections. He mentioned Compression Ratio (8.5:1), Looser oil clearances, and some points on strengthening the cylinder walls. All of which you will have to communicate to your builder/Machinist.
Compression... Depends on power goals and driving style and cam selection. If you are staying with stock cams then stock level compression (8.5:1) will probably serve you well. This will require more boost but you will cover that with a bigger turbo. There are a whole bunch of strategies that dictate the static compression ratio but they are to numerous to mention. (I smell a new writeup!)
Bearing clearances should be looser so get yourself some ACL extra clearance race bearings... This serves three purposes. 1 you get more flow to the journals thereby increasing lubrication and promotes the removal of heat. 2 It allows a thicker oil to be used. The significance of this is thicker oils have a higher resistance to shock and shearing actions. 3 Now the oil clearances of the bearings match the oil clearances of the piston so there is no conflict with using an oil that may be compatible with the pistons but is not compatible with the bearings and vice versa.
Strengthening the block... Previous mentioned strategies apply. I have been working with my local machinist and he employs a method called "pinning". What he does is he welds in connection points in the block between the outer cylinder wall and the inner block wall where the head bolt locations are. This adds four more supporting points to each cylinder making it a total of eight per cylinder. Just one idea.
Modify and clean the oil galleys
Torque plate bore and hone.
surface the block and the heads
center line hone
Use the stock oil pick up tube but have it reenforced at the flange.
The moral of this story is the key to a successful reliable build is in the machine work and the proper and smart selection of parts :tup:
