mike tkach

iTrader: (3)

i had a conversation with a friend about the exhaust valves in a 1990 merc 340 hp engine in a cruiser,he said merc installs inconal valves,i thought that merc buys the engine complete with heads installed,and the valves were not replaced with stainless.anybody got the skinny on this?

wannabe

I'm sure they spec inconnel valves and yes Merc buys complete engines from GM Powertrain.

Wannabe

Black Baja

iTrader: (2)

I've had a few merc engines that didn't have iconel valves. 454 330 mpi had eaton stainless valves $5 a piece.

MILD THUNDER

iTrader: (3)

I doubt mercury installed the valves. GM produced these "marine" 454's, and they were sent out that way. The old peanut port 330/340HP engines were based of the L19 truck engines. They did have different camshafts though. The trucks got something like 194/204 @ .050 cams, the boats got something like 214/218 @ .050. .460/.480 lift, 115LSA But, the Boat cam was a GM grind and came that way. I wouldn't be surprised if at GM, when these engines were being assembled for "Marine", they installed the "marine" cam, Which was actually a late 60's early 70's LS5 cam, and used in some 396's I believe, installed Inconel valves, and probably some other minor changes for the "marine" customers. Gm also used Inconel valves in some of their HD truck engines too.

I suppose though the only way to know for sure if tearing it down. Im sure someone here has been thru these engines and would know.

wannabe

GM batch builds these engines and yes they are "marine" specs. So tolerances are different, cams , valves etc. :]

Wannabe

mike tkach

iTrader: (3)

thanks for the replies fellas,i didn,t think merc took these engines apart to make changes.it makes sense that gm would build them to mercury,s specs instead,im suprised merc would spring for inconal valves because of the expense but i guess a standard steel exhaust valve would fail before the warranty was up so in the long run they saved money by installing the inconal valves.

kvogt

Merc only put inconnel in the blue or HP engines.

MILD THUNDER

iTrader: (3)

If I remember right, back in the day, the old HP 420, 440, 460, 465, cyclone engines, and so on, before things got painted blue, were custom assembled at mercury in their high performance division. Which makes sense, since most of those engines had crane camshafts, crane rockers, weiand intakes, etc. Those were not delievered in crate form from General Motors. Same as the new mercury racing stuff.

mike tkach

iTrader: (3)

so maybe as black baja said,these engines got a cheeper ss valve instead of inconal?

wannabe

Yes that is possible. The black everyday engines they build for Searay, bayliner etc. are built on the assembly lines at Tonowanda or wherever the engines were built. They got crated and shipped to Merc, OMC, Volvo, Indmar etc.

Actually for merc they were buying so many they were often in racks that were returned. Merc would crate them for shipment after dressing the engines and adding the out drive.

Wannabe