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1967 Mercruiser 120 hp 25L cylinder head

T

txgalzdah

Regular Contributor
"I am in the process of a comp

"I am in the process of a complete rebuild. I have the engine torn down and at the machine shop. When I talked with the shop owner about what I needed done he interjected into the conversation that the exhaust valve seats would have to be replaced without even looking at the head. His view was that "hardened seats and valves" would have to be installed because of todays unleaded gas.
I have never heard of this. Am I being hoodwinded?
If this gets posted twice, sorry. Coffe is just now kicking in."
 
"He is absolutley correct.....

"He is absolutley correct...........

It should be done. The reason is as he says, unleaded fuel. When lead was in the fuel it left a coating on the valves and seats that help lube/cushion the valves to the cast iron in the head. Today with the crap fules and additives the valves take a real beating. Newer motors and valve combo's use much better materials then the old stuff."
 
"Thanks for the update. I have

"Thanks for the update. I have learned my one thing for today. I will make note of this.
It is also good to know that ones local machine shop is watching out for their customers.
Now if they can just go a little easier on my wallet. Haaaaaah!
lol.gif
"
 
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