Tuning post 1990 vs pre 1990 b230ft

[Bungcheezy]

Originally Posted by classicswede

The 85-88(89?) main bearing journal is only 55mm and uses a centre thrust washer. The centre thrust washer system is not great but can be improved by machining the centre cap so that both the block and cap have a thrust washer. You are still left with a 55mm weaker crank but still good for 3-400BHP at most before becoming a high risk of failure

89 on has 63mm main bearings and is back to the original end thrust setup. The crank is safe to around the 500BHP mark with failures starting to be seen in the 600bhp+ region. All the aftermarket upgraded cranks are for these blocks

The 85-88 bottom end once fitted with better rods be it the later 13mm rods or a set of H beams is prefectly fine for a typical build upto around the 300bhp mark. The original 9mm rods are a risk every time you drive. I have had 6 failures and some in NA engines so its not down to boost level. I know of a lot more that have failed

Are the 63mm main bearings and better crank and thrust set up on all b230fts 1989 and later or do specific later models have inferior set ups? Also, would I be able to use the lower end of a non turbo engine but still use the turbo head and manifold? I can’t find any turbo lower blocks for sale sadly, but I want to use an aftermarket crankshaft.

[classicswede]

Post 1990, ideally look for a 95 or later. You can use a B230F(and FB/FD) engine