I would like to ask some questions on the bearing clearance decusion. Sorry if this seems to be off topic of the tread, if you wish I will start a new one, just say the word And I will do this & this post can be deleted.
I have built my own engines for years. Although I am use to a engine that has more beef to it ( big block Mopars) My best results have been using .001 - .0015 oil clearance ( prefered .001). This is tight I know, and everything has to be perfectly stight ( with crank torqued in I can still free spin with good coasting after the spin). These have been street/strip build that put out around 800hp (with NOS) and I have put as much as 100,000 miles on them before. After a tear down my cranks & bearings like like the day I put them in ( even with piston,rings & cylinder walls needing redunn ).
Now a turbo engine is a bit diff, and a Buick block doesnt have the beef or strenth of a old school big block. Is this the reason most go with looser oil clearance in the buick( there is alot of give when pushed this hard ). Or is it that most do not go threw what is nessesary to achive what is needed to have the block,crank as stright as needed to accomplish this.
The reason I ask is because I have seen the proof of having things this stright & close on the clearance. To me it seems that there is less room for movment and keeps the rods from beating the bearings & keeps the crank from flexing as much so the end results have always been exellent wear in the bottom end of my engines ( believe me my engines went to H*** and back in my cars) Driving as much as 200 miles to go race & then drive back and then was used as my daily drivers threw the whole years, even in the snow. Running a stick most of the time & shifting at 7200 with NOS on from line to line. They had no easy life but was maintanced very good also.
So what is the reason for this loose of oil clearance that most seem to have good luck with in the buick. Is it the block gives that much and it needs the room for flexing so things dont start binding under the load. Or is it that they are just not getting the Block & crank stright enough to function in this tight of clearance, or is it something to do with being turbo charged that creates this need.
I will be doing a Buick built this winter and it will be my first Buick built. I would have built off my own expierance & results because of my success with the way I had been doing. But it seems that there is something differant going on here that I need to be aware of and will probably need to go with the looser clearances, but I would kinda like to know why.
We use to have to freshen up my engine every year, but after spending the money to get things at the clearances meantioned I would run these engine for as long as four years before they would need a freshen up, and this was the cylinders & pistons and not the crank & bearings that was in need. I could not go against this because as they say the "proof was in the pudding"
But all engines are not the same. So maybe some of you expeiranced Buick builders can explain the reason I need to go looser.
Jess
j/k, pretty much anything thats not synthetic, for break-in, T.A. 10w40 is what we use a lot of, or some rotella.
