Originally posted by Kuqi
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Since this question keeps popping up, I'll address it here. If we are building the same engine as Alpina did, why are they falling in the first place and how can we prevent it from happening? Alpina used very tight piston to wall clearances 0.01-0.02 mm, stock N62 105°C thermostat and 5W30 oil. Disastrous recipe for a supercharged engine and in my opinion, that's why it ends up with scored cylinders.
To achieve better emissions and fuel consumption, 105°C tstat was used, which means the engine will sometimes see temperatures as high as 110-115°C when under heavy load and when you have such tight clearances, thinner oil, well something has to give and damage occurs. If you look at the high-powered M engines of the same era, S85, S65, S62... they all run 10W60 oil which offers far superior protection under heavy loads and none of them run that insanely hot, they all have 79°C thermostats. Alpina did a good job by beefing up the bottom end on N62 when they developed H1 engine, but using stock N62 thermostat and thin oil on a 500hp supercharged engine with tight clearances... Well, here we are with a toilet plunger in our hands.
When we put this engine together, we'll rock that 95°C thermostat and 5W50 oil. It will help long-term. As for the piston to wall clearance, since this is a used block that's worn, clearances will be on the loose side which goes in our favor. The goal now is to get this turd back on the road and do so without giving millions to Alpina for new parts. If we can get 100k km out of this engine, that would be a win. Given 15 other cars that I have, it'll take me 100 years to cover that distance with one car anyway.
To achieve better emissions and fuel consumption, 105°C tstat was used, which means the engine will sometimes see temperatures as high as 110-115°C when under heavy load and when you have such tight clearances, thinner oil, well something has to give and damage occurs. If you look at the high-powered M engines of the same era, S85, S65, S62... they all run 10W60 oil which offers far superior protection under heavy loads and none of them run that insanely hot, they all have 79°C thermostats. Alpina did a good job by beefing up the bottom end on N62 when they developed H1 engine, but using stock N62 thermostat and thin oil on a 500hp supercharged engine with tight clearances... Well, here we are with a toilet plunger in our hands.
When we put this engine together, we'll rock that 95°C thermostat and 5W50 oil. It will help long-term. As for the piston to wall clearance, since this is a used block that's worn, clearances will be on the loose side which goes in our favor. The goal now is to get this turd back on the road and do so without giving millions to Alpina for new parts. If we can get 100k km out of this engine, that would be a win. Given 15 other cars that I have, it'll take me 100 years to cover that distance with one car anyway.
edit: no joo voi tuon lukea niin, varsinkin jos tietää sellaisen olleen, että 95c termarilla oli jo putkitettukin.
. en usko köyhien noita ostelleen


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