Quote:
Originally Posted by AIR RAM
Ok... I'm all ears on this. In your opinion, what would be the down side to running a .0045 on a daily driver if any? What would be the best oil pressure with such clearances? It just sounds awfully loose to me... Would I need to prime the oil system every time i start the engine?
Thanks for the input.
SPEED SAFE, NICK
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I dont think there is a down side to it. No you would not have to prime the engine every time you start it .
If you think about it and put it into perspective, a human hair mearsures .004" . Thats not very big at all. Now split that hair in half and its .002" right. So when the crank journal is floating in the bearing shell the space between the two is half of the thickness of that hair. Thats hardly any kind of big space at all. The oil is the only thing keeping the two surfaces from grinding together . Thats why the big horsepower engines need lager clearances .. Just for example , My engine now that i drive all over the place is a street car. It makes over 4hp per cubic inch. This is one of those times where i settled for a clearnce that i wasnt happy with just so you know. The front #1 main clearance is .0042" #2 .0032" # 3 .0032" #4 .0035 and #5 .0045. I would of been happy if the front was .0032" but after checking it like 10 times and it stayed the same i just left it. That night i didnt sleep that well . Was thinking that maybe i shouldnt of left it like that . But the next day i continued putting it together. Long story short when i got it running and broke it in it wasnt any different then it ever had been. Oil pressure was 70-80lbs at idle cold and hot was 35-40lbs . So my main point about this is if i knew all of this when i was building it i never would have lost sleep over it . lol Oh and this is a 3" main journal crank..
A bigger journal needs more clearance . So think of it this way. In your case with my clearances it would be in a more tighter relationship with the manufacturers bearings recommendation..
So you're good if you ask me man..