Well I have a few questions guys. I have acl race main bearings that are calico coated and my clearances are 1.5,1.5,1.0,1.5,1.5 thou. Do you all think this is ok with them being coated? This is going to be a high hp engine around 800whp is the goal. I have built many hondas and V8s but never a mitsu.

Thanks in advance

 

I know that .008 to .0016 is factory, an that some people do a little over thatlike .002 on the mains and rods , but I dont know what everyone elses thinks.

 

even though your building the engine with forged internal upgrades, try to keep your bearing clearances within manufacturer specs, too much clearance, leaves a much higher chance of spinning a bearing. Too little clearance, and the bearings will heat up a lot more due to oil starvation, and then you can toast a main bearing, which will open up a huge can of worms. So like I said follow manufacturer spec on clearances, and you should be good.

 

anyone else have any input???

 

too tight imo.

for that hp level, running a thicker 15/50 or 20/50 oil, i suggest ~.0025 +/-.0003

what method/device are you using to measure your main bearing clearances?

 

Yeah im at the .002 for mine as well. No way I would want them to be tighter like stock.

 

.001-.0015 to 400hp
.002-.0025 to 600hp
.003-.0025 for 800hp plus.

metals flex more with increasing hp. building tight is not a good idea.

 

yea ^ this guy makes a good point especially if some of the bottom end internals are gonna be switched over to aluminum compared to steel.. aluminum and steel both expand with heat at different temperatures. But in all honesty as long as your using reputable bearings ( im using acl race bearings), some arp main head and rod studs. and everything is torqued properly, it should hold together no problem. But id go a little loose on your internals as far as the specs go to allow for heat expansion, theres my 0.02 take it with a grain of salt.