Just got the rod bearings out of the 408 alc engine. Noticed that the lower shells on the right bank are either brown or have some purple burning. 2 things come to mind on this. Either not enough oil pressure to cool the bearing or not enough oil in the pan. A mellings volume pump is used and never has had over 55 lbs of pressure.I would like to see 85 lbs,but dont know if i can find a stiffer relief spring or not.This engine was built by someone else,so this is the first time ive seen it apart.The crank and rods were bought frm scat as a package with the bearings(4340 crank,H-beam rods,small block chev bearing size).My brother says the bearings were included frm scat.They are 8-7100 ch f/m.the kicker is they are .001 instead of stds.Havent checked the clearance yet,but that also could be an issue.Filter is always cut apart and no metal has ever been found.Crank journal looks fine.Mellings uses a soft plug in the end of the bypass and im wondering if its ok to just up the pressure their unless someone makes a gd adjustable pump.Am using 50w Penn Grade oil.No milking issues.Compression is 13.8.Using a canton pan with 3 traps and scraper.Also found a little bit of black in the bottom of the pan.This is a stroked 351 W.
02-05-2006 02:12 PM
Something i just found out frm my brother. The end plug behind the dist in the oil galley has been drilled. Now i know where the pressure has gone if its a large hole.Is this oilling hole necessary?
02-05-2006 08:48 PM
Update.No hole drilled in end plug,so thats not it.Mains to come out tomorrow.
02-05-2006 09:44 PM
something sounds weird to me , you say just the lower half of the bearings are discolored? All the pressure is on the upper half. Look at the mains post then we will get into this.If the mains get progressively worse rear to front then you have pressure problem. Never heard of the lowers burning, ill bet your mains are bad.
02-05-2006 09:56 PM
Yea,Ill be checking em tomorrow night as i was checking the p/v today on the old cam and then the new one.
02-06-2006 02:27 PM
ACL? I assume you mean on alky?
What's the application?
02-06-2006 02:53 PM
has this crank been cross drilled?
02-06-2006 04:19 PM
Yea its on alcohol,and yes the crank is cross drilled.4340 steel crank. Its in a frt engine dragster.