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Old motors and unleaded

SawzSawz Member Posts: 6,049
edited December 2011 in General Discussion
Have an old boat motor that needs leaded I have used lead additive in the past. My mechanic says that if you use the right oil and or oil additive it will take care of the guides anybody heard of this before?

Comments

  • grumpygygrumpygy Member Posts: 53,466
    edited November -1
    Lead was not for the Guides. It was for the valves and valve faces. Lots of old engines have been converted with new valves and seats.
  • 11BravoCrunchie11BravoCrunchie Member Posts: 33,424
    edited November -1
    Just get a new boat motor. My father in law swears by Honda 4 strokes.
  • SawzSawz Member Posts: 6,049
    edited November -1
    quote:Originally posted by Zulu7
    Just get a new boat motor. My father in law swears by Honda 4 strokes.

    This is a sterndrive inline 6 cylinder (Inboard outboard) its the little chevy 6 cyl. 250 or 4.1.

    Seats and valve guides is what I have read maybe more seats but still guides
  • SawzSawz Member Posts: 6,049
    edited November -1
    quote:Originally posted by savage170
    here is a link from chevron
    http://www.chevron.com/products/prodserv/fuels/technical_safety_bulletins/use_unleaded_gas.aspx


    Thanks for that link sounds like If I run Premium or octane booster will be better for the engine

    from that website

    quote:Mercury, who is a major supplier of Stern Drive Engines for marine use, advises that their engines are automotive based and have hardened exhaust valve seats. Most of Mercury's outboard engines were developed with unleaded gasolines, and Mercury's only concern is with octane number.
  • grumpygygrumpygy Member Posts: 53,466
    edited November -1
    quote:Originally posted by dennisnielsen
    quote:Originally posted by grumpygy
    Lead was not for the Guides. It was for the valves and valve faces. Lots of old engines have been converted with new valves and seats.



    Yes seats were hardened so the need for lead was not more. Most times I just changed the valves too.
  • v35v35 Member Posts: 13,200
    edited November -1
    Why not use the motor up before reworking the heads.
    Replace valves, valve seats and guides only as needed after inspection.
    Boat motors don't see the loading (BMEP) motor vehicles put on them.
  • john wjohn w Member Posts: 4,104
    edited November -1
    Just add a lead additive every other tankfull. It will take a long time to hurt the valve seats on unleaded. My 355 olds has the stock leaded seats and was run on unleaded since they quit using lead years ago. Upon teardown 3 yrs ago the seats and valves were perfect. When i rebuilt the motor and upped the compression with new pistons and changed the cam i still used the old heads with a fresh valve job. I use a lead additive every other tankful and i use 93 octane now also.
  • Ford 23Ford 23 Member Posts: 3,129
    edited November -1
    I have three T's I run on unleaded (stainless valves)
    An old Case tractor from the early fifties original valves
    Ford 8M original valves
    International KB5 original valves
    Plus a couple if other old pre lead engines in other units

    These are not sit in the stall units, all are run on unleaded fuel. Usually run diesel lube oil in them for the zinc additive for the lifters, not convinced that is even necessary. Over winter simply turn them off in the fall with no additive to the fuel and they run fine in the Spring.

    I have no problem with unleaded, have no reason to believe lead additive is needed
  • p3skykingp3skyking Member Posts: 25,750
    edited November -1
    I just add a little two stroke oil to the gas and it seems to do fine.
  • gesshotsgesshots Member Posts: 14,186 ✭✭✭
    edited November -1
    When lead was phased out in the 70's, there were lots of machine shops that would replace valve seats with stellite inserts. Don't know if this still being done.
  • spasmcreekspasmcreek Member Posts: 38,925
    edited November -1
    anything is fine as long as it is NOT SYNTHETIC
  • rcrxmike_2rcrxmike_2 Member Posts: 3,275
    edited November -1
    quote:Originally posted by Sawz
    quote:Originally posted by savage170
    here is a link from chevron
    http://www.chevron.com/products/prodserv/fuels/technical_safety_bulletins/use_unleaded_gas.aspx


    Thanks for that link sounds like If I run Premium or octane booster will be better for the engine

    from that website

    quote:Mercury, who is a major supplier of Stern Drive Engines for marine use, advises that their engines are automotive based and have hardened exhaust valve seats. Most of Mercury's outboard engines were developed with unleaded gasolines, and Mercury's only concern is with octane number.


    Better fuel and octane boost isn't really gonna fix it. have to use lead substitute.....
  • 1FMJ1FMJ Member Posts: 1,618 ✭✭✭✭✭
    edited November -1
    I rebuilt the V-6 in my 1965 Evenrude boat in 1989 I call OMC and asked about leaded gas.Engeneer said to switch to premium higher octane fuel.And not to get valves hardened.As it will not be worth the added cost.
    Still runs great.<1FMJ>
  • rcrxmike_2rcrxmike_2 Member Posts: 3,275
    edited November -1
    quote:Originally posted by 1FMJ
    I rebuilt the V-6 in my 1965 Evenrude boat in 1989 I call OMC and asked about leaded gas.Engeneer said to switch to premium higher octane fuel.And not to get valves hardened.As it will not be worth the added cost.
    Still runs great.<1FMJ>



    That was 1989. unleaded fuel require's hardened valve seats. wanna see what happens in one of our racing engines with 'old heads'? they swallow valves......
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