I have a set of heads that have already had a valve job done from a race engine that I never fired. I didnmt have hardened exhaust seats installed because at the time they were going to be used with 110 octaned race fuel. Well, now they are going to be used on a pump gas ( 92 octane ) street engine. I have to take them to the machinist today to get the guides milled for viton seals and I need to know if I should have him install the hardended exhaust seats since they will be on a pump gas street engine. His opinion is don't worry about it, go ahead and run the seats the way they are. He said if I wanted it done he would gladly take my money but he didn,t think it is necessary, especially for just a weekend cruiser.
should i have hardended exhaust seats installed
- Thread starter duster360
- Start date
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Lifsgrt
Well-Known Member
I'd run them like they are until it needs a valve job. Unless you're going to drive the wheels off of it, I wouldn't waste the money on scrapping a good valve job...but you will have the cost of pulling the heads (gaskets and such) when you need a valve job, if ever.
:burnout:
:burnout:
68gtxman
I used to reMember
I had two very experienced machinists tell me the same thing. One even said that is what he always does for his own cars (leave the original seats alone except for grinding them for the valves).
I took their advice and now 12,000 miles later I still have me detectable problems. Use your money for better improvements/parts.
I took their advice and now 12,000 miles later I still have me detectable problems. Use your money for better improvements/parts.
abodyjoe
Well-Known Member
I've always heard arguments for both sides. Me I always put the hardened seats in. They don't cost much and it's not like the gas is getting any better.
younggun2.0
Well-Known Member
im with Joe on this one. the heads are already off and getting take apart for machining the guides. now is the best time to do it. why wait for the problem to happen latter when you can prevent it now?
Without lead in the fuel the seats wear out real quick. You can run top lube in the fuel. We mix it with our Methanol. It slows down the seat wear.
10 races per set of titanium valves. Without top lube 5 races Max
10 races per set of titanium valves. Without top lube 5 races Max
skrews
Well-Known Member
IMO not worth the bother on a 500 mile a year cruiser. Now if you intend to put on 30,000 or more miles then its a good idea.
fishy68
Tyr Fryr's Inc.
I have always heard non hardened seats don't last but I've got a buddy with a Challenger that he rebuilt a 69 440 magnum for in the early 80's. Since then he's put nearly 40,000 miles on those original non hardened seats without as much as adding a lead additive even once and it still runs fantastic. I'd say if they weren't freshly done have it done but since they are and you only put 500 miles a year on it run em like it is. Spring pressure also affects how quickly they'll wear out so that's something to keep in mind.
abodyjoe
Well-Known Member
Like I said. Every one has their own story
I have a friend with a 71 Polara. Original 60,000 mile car. 100% stock 383. Motor was running like crap. Had it rebuilt. Seats were beat to hell and valves were sunk into the heads.
To me it's not that expensive, it's apart and now is the perfect time to do it. Even if you are only driving it 500 miles a year why half *** it?
I have a friend with a 71 Polara. Original 60,000 mile car. 100% stock 383. Motor was running like crap. Had it rebuilt. Seats were beat to hell and valves were sunk into the heads.
To me it's not that expensive, it's apart and now is the perfect time to do it. Even if you are only driving it 500 miles a year why half *** it?
I've heard both arguments and agree with both sides to a point. That said, I think if I were rebuilding an engine, I would do it. Mainly because of the ethanol added in today's gas. Why? Ethanol acts as a drying agent. Without lead in fuel, seats and valves are already running hotter than their leaded counterparts did years ago. Couple that extra heat with the extra dryness of ethanol and IMHO that makes things even hotter. What actually happens to the exhaust seats is, they get so hot that they weld small particles of themselves to the valves and then those particles are blown out the exhaust. That's called valve seat recession. Used to be, before unleaded fuel, a dirty air filter was the main cause. Minute particles of dirt would act like sandpaper and grind the seats and valves away. This is the whole reason I like my engines running a tad rich than lean. It helps keep things cool.
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