unleaded or leaded?

[Arthurdaily]

If the old owner didn't know, how could you tell if a head was leaded or unleaded on a 1098 engine?

[bmcecosse]

It would have to have been 'converted' - so the inserts would be visible if the head was stripped and inspected. BUT - it doesn't matter! Just set the exhaust valve gaps to 15 thou - run it on unleaded fuel - check/reset the valve gaps every 3000 miles. Simples!!

[Arthurdaily]

Valve gaps - i.e tappets yes? As per the MMOC service guide? 15 thou... 15 thousandths of an inch?

[bmcecosse]

Well - the 'tappets' are down inside the block (cam followers really) and don't have 'gaps' on this OHV engine - but indeed it's the gap between the tip of each valve rocker and the valve stem.......and yes 0.015" = 15 thousandths of an inch (15 thou is easier!)

[Arthurdaily]

Thank you BMC.