Pre'72 model year cars, pre-76 light trucks and those vehicles without catalytic converters
Pre'78 trucks and motorhomes over 6,000 gvw
Motorcycles (4-cycle)
Farm equipment: tractors, combines, reapers, etc.,
4-cycle utility equipment engines: lawn mowers, generators, etc.
Stern-drive & Inboard 4-cycle boat engines
Fire trucks, school buses, heavy equipment
1. Needs an EVA-A at all times.
2. All trucks used for farm and commercial applications need an EVA- A.
3. Load conditions requiring an EVA-A (any one or more of the following situations can be considered a state of 'load'):
4. Motorcycles: Japanese before early 1970's, pre-1984 Harley-Davidson, pre- 1981 BMW, all Moto Guzzi, Ducati and British motorcycles.
5. Of the 2.3 million farm-use engines, 44% still require leaded fuel. Ford has used hardened exhaust valve seats in tractors since the late 1930s, the big International Harvester engines also have hardened exhaust valve seats.
NOTE: This chart is intended as a general guide to engines that may be vulnerable to excessive exhaust valve/valve seat recession when run on unleaded fuel. Because there is so much variation as to engine design and fuel requirements, it is essential to check the owner's manual for manufacturer's fuel recommendations. For more information or for an analysis of your use, write to the International Society for VEHICLE Preservation. Please be sure to enclose $2.00 and a large SASE with details about the engine as to make, year, model, no. of cylinders, cubic inches, miles driven per year and how it is being used in a car, truck, boat, RV, farm equipment, if and what you tow all details so that a fair appraisal can be made. Send to: ISVP Attn. WWW.796, P O Box 50046, Tucson, AZ 85703-1046.
EPA propaganda referring to use of unleaded gasoline under 'Normal' driving conditions has been picked up by many in the news media causing untold confusion by those whose engines were designed for leaded gasoline.
Normal conditions are those that meet the following criteria: temperature under 68°F, humidity over 65%, max speed of 55, max rpm of 2800, no more than 300 pounds luggage and 2 adults, level ground not more than 2- 3% grade, not greater than 20 feet above sea level, no air conditioner, luggage carrier or trailering.
Any condition in excess of these parameters constitutes a load and puts your engine at risk of exhaust valve seat recession when run on unleaded gasoline.
Dear Car Collector:
We have received thousands of queries regarding recommended fuel and additive use for various engines.
Several questions have been raised repeatedly, which has prompted us to prepare 10 general points which hold true for everyone.
Please review the Society's membership information which describes our purpose and work. We are totally supported by donations and membership dues. Our existence depends upon contributions from people like yourself. Join ISVP so we can keep up this work and service for you and invite your friends to join. If you can't join at this time, please send something even $1.00 would be most helpful.
The 10 general points regarding fuel and additive use may be accessed by returning to the Q&A page and clicking on "protect my exhaust valves."
Sincerely, International Society for VEHICLE Preservation by
Walter R. Haessner, Executive Director
ISVP, P O Box 50046, Tucson, AZ 85703
(Source: International Society for VEHICLE Preservation, Copyright 1987-2003 ISVP)
Phone 1-520-622-2201 or Fax to 1-520-792-8501 or E-Mail isvpinfo@dakotacom.net
Last updated June 27,2003
Made in the USA
Return to Q & A Page