40 HP exaust valve question

[danny gabbard]

I'm building a hopeful long lasting stock motor. Well the question is, I got heads apart and going to lap valves. The intakes look good. Would, or should I replace exaust valves or just lap them in also. They look good with no hot spots or burn spots. Do exaust valves go bad or get brittle from the heat.

[kingsburgphil]

Way back when, the shops that I worked at we always replaced EX valves at overhaul time. It was cheaper and faster than gambling on an unknown quantity.

[TexasTom]

X2 ... replace them, they're cheap insurance!

[danny gabbard]

Thats what I thought, Now is there any that are better than the other? Like ATE or ? And get from who? I've never did a 40 HP motor before. And thanks guys

[Fastbrit]

The original factory 40hp exhaust valves were two-piece, with the heads friction-welded to the stem. In Europe especially, they had a reputation for dropping #3 exhaust valve due to the oil cooler blocking airflow to that cylinder, allowing it to run hot. It was generally reckoned that exhaust valves were ripe for replacement at anything from 60,000 miles – we used to fit stainless valves as a matter of course in every stock engine that got rebuilt. No more dropped exhaust valves after that.

[danny gabbard]

Great Idea keith, Thanks