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old engines.....unleaded gas..

THE KING

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I am wondering what all the talk about hardend valve seats is all about.
Does this have to do with the unleaded gas we use now a days?
I have an older engine..........1966......318... what am I suppose to do about
the lack of leaded gas? Will my valves hold up useing the unleaded fuel?
should I add lead?...............will my engine turn to toast without leaded fuel?
On this web site I am all the time reading about hardend seats. Can someone enlighten this man who has a lead foot but not leaded gas!
 
I had a '64 Belvedere with a Max Wedge engine that had the stock heads without hardened seats. I used CD-2 lead additive for off road vehicles. It's concentrated and inexpensive and worked well in my engine.
 
You can't get real tetraethyl lead, which is really carcinogenic. It acted as a cushion as previously stated, but it also acted as a lubricant, which is probably more important (protected the seats AND guides). Personally I've never had any luck with additives, but if you're not in a position to do a top end job then they would be a stop gap measure. When I have my heads done these days I have hard seats and bronze guides (or at least bronze liners) installed
 
In big blocks it would be 71 or 72 when they started using the 452 heads
 
In big blocks it would be 71 or 72 when they started using the 452 heads


Actually I was TOLD that they started much earlier than that by a reputable machine shop that has been around for 40 years. He said that on old Mopars you seldom had to add new seats for use with unleaded fuel.
 
906 heads were used through 70 and they never had hard seats. They were followed by the 346s and I've never seen or heard of them having hard seats. The 452s are supposedly the exact same casting as the 346 but with the induction hardened seats.

I have NO idea what was done with small blocks

but I'm open to learning something new today:HappyNewYear:
 
Actually I was TOLD that they started much earlier than that by a reputable machine shop that has been around for 40 years. He said that on old Mopars you seldom had to add new seats for use with unleaded fuel.

I just tore down 69 383 Bee back in August for a freshen up, I have been using and abusing this car since before 1988/89 when the Leaded disappeared, I have never ran any fuel additive other than octane booster, Valve seats looked good with out any problems, car has the original 906s, Lucky or Not ? you decide.
 
Actually I was TOLD that they started much earlier than that by a reputable machine shop that has been around for 40 years. He said that on old Mopars you seldom had to add new seats for use with unleaded fuel.


I have heard the same thing regarding all makes. My head guy said he could tell by cutting or grinding the seats.

I think the life of the exhaust seat may be subjective on how you drive the car and how you build the engine. A lot of high RPM and racing type activity will most likely pound out the seats sooner as opposed to being the little old lady type driver. One story I heard from a friend was his old Ford lasted one trip from SF to LA (~400 mi) on a fresh set of non hard seat heads and had issues by the time he got there.

The seat material that is commonly used is a nickel alloy and I can tell you from cutting it myself it's pretty soft, but nickel has great wear properties and holds up well at higher temps. Do not run it rich and keep the timing out of the tailpipe, which will help keep the exhaust temps down.
 
i would think spring selection and seat pressure would matter more and maybe the exit ramp of the cam
 
Good point. I think it all matters.

I remember in the 80's when the leaded premium was being phased out and we were all in panic mode.
 
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