N47 head

[grannyknot]

P/U a whole engine yesterday from a 77-78 280z, the head is a N47 with steel liners.

Is there anyway to remove those liners without destroying the head?

From my first look it seems that the valve guide is the only thing holding that sleeve in.

[tlorber]

Everything I have read stetes that it is not worth the effort and damage risk of removing the liners, and that any gain in flow is questionable, or negligible at best.

[Diseazd]

The liners aren't that restrictive, if at all. I wouldn't mess with them. I run P79 heads with liners.....I don't notice any difference whatsoever.

[Jeff G 78]

+1 Leave them alone.

[240260280z]

I have seen ~4 heads with cracks in-line with the location where the runners are anchored into the head. My speculation is these cracks result from thermal cycling of the steel and aluminum and their different thermal expansion rates. Or, from overheating (high exhaust gas temp) and their different thermal expansion rates.

Nothing you can do about it.