W58 head... Any value

[Eric P]

I have a good but dirty W58 head: closed chambers but steel lined exhaust ports. Worth much? I'm in Ohio so probably have to ship to most folks...

[okayfine]

Worth much? No. Worth something? Yes. Most people avoid the round exhaust port heads, but they aren't terrible. Mostly it's avoided just because you'd need a matching header/exhaust manifold, and those aren't very common anymore.

[datzenmike]

The 510 square exhaust will fit and work on the round port, not ideal, but will work. A round exhaust manifold from a W58 does not work on a square port head though.


I suspect these closed chamber heads came here on import engines that were cheaper to buy than a valve job here. The thing is a close chamber head only works properly with a flattop piston like in the L16/18 SSS engines. So this begs the question... in Japan did the L20B come with flattop pistons or not? A closed W58 on dished L20B pistons has a compression of 8.9. I was told that all W58 heads were closed but mine ('78 620) was open and 8.4 compression. All '78-'80 engines had the same Nissan part number. No way they would allow 8.9 compression heads randomly. The emissions would be through the roof.

[Eric P]

Thanks fellas. Sadly, this is probably going in the scrap pile. Probably more expensive to ship than it is worth.

[datzenmike]

It will fit a stock L16 engine and only lower the compression to about 8.2 but it could easily/cheaply be milled down to raise it back up. The W58 is basically a U67 but with round exhaust ports. Big valves and ports. The exhaust liners could be cut out but they don't (or won't) bother an L16. I've had both heads on L20Bs and can't tell the difference. The square manifold will cover the round exhaust ports. In addition the W58 has an L20B cam which has roughly the identical specs as the L16SSS cam. 0.413" valve lift and 248 duration.