Post by
themadscientist »
https://forums.nicoclub.com/themadscientist-u2806.html
Wed Jan 14, 2004 3:28 pm
If the valve coveres are ribbed and red it's an R31 RB20, walk away. If they are silver with dimple at the halfway point proceed.
If he has it tore down this gives you the opportunity to inspect the cylinders for scoring or rust if you see nothing scary proceed. You can check the crank now for spun bearings which would be heat discoloration or some kind of damage on the crank that makes you say "Holy **** what the **** happened"! if all is well go to the deck and check for warpage with a machinist's rule, RBs run hot and often overheat this could warp the block and head at their mating surfaces. Now the head, look in the ports for signs of worn valve guides, sludge and carbon encrusting the back of the valve. Don't worry if the intake ports behind the secondary butterflies look like that, they always do to some extent. look for sludge in the top use your judgement on what you are comfortable with. A properly maintained engine won't have ANY but some is not bad. check the cams and lifters for uneven wear and the whole engine for broken bolts or studs. I'd tell him $800.00 because of the being tore down situation but I would actually prefer this over a running engine as i firmly beleive most of these motors are in need of an overhaul anyway.