Opel GT Forum banner
1 - 1 of 1 Posts

· Über Moderator
6,671 Posts
Hardened Valve Seats

Bob should really answer this question. But I will take a whack at it.

My '71 Owners Manual says that low-lead or unleaded gas is actually recommended, but that regular leaded gas may also be used . I bought it in 1978 with 58,000 miles on it. I used leaded gas for at least 2 years after that. It probably had 80,000 miles by then, and a pretty good coating of lead oxide, or whatever compound that forms and deposits on the valve and seat that protects them from undue recession. I then switched over to unleaded gas, and racked up another 20,000 miles in the next three years, without causing any significant damage to the valves or seats. And from what I have read, it did NOT have flame or induction-hardened seats, which came in late '72 or '73 (Bob???). Now, did the early models have more severe valve recession when using unleaded gas? Probably, at least on a statistical basis. Do you HAVE to install hardened seats to use unleaded gas? Not likely for the kind of use that most of our Opels experience.

From what I have gathered from a number of articles I have read, the use of unleaded gas in virtually any vintage engine will NOT cause severe premature valve or seat damage, so long as the car is driven moderately, and especially for the duration that most vintage cars are driven. If you expect to use your Opel as a high-mileage, daily driver, then by all means have Tribaloy or Stellite or some other wear resistant seat insert installed on your next valve job. But don't waste your money and get it done before you need to.

1 - 1 of 1 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.