Author Topic: Exhaust seats and leaded/unleaded fuel  (Read 8183 times)

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fe66comet

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Re: Exhaust seats and leaded/unleaded fuel
« Reply #15 on: July 28, 2014, 12:34:21 AM »
Maybe it is the fuel used? I always run good gas, the little extra in using good fuel saves in mileage and repairs in the long run. Tune ups last longer and less sludge in the engine.

manofmerc

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Re: Exhaust seats and leaded/unleaded fuel
« Reply #16 on: July 28, 2014, 09:04:16 AM »
What happened with me goes along with RJPs statement .I owned a 66 f250 with a nice 390 without hardened ex seats .I used this truck to pull a welding trailer and a car trailer that weighed 4500-5000 with car .Long story short my exhaust seats receded .(c8ae heads ) I had hardened seats installed and no more problems .Bottom line if you use a vehicle for serious pulling or for long intervals of driving exhaust valve seats are cheap insurance . Another possibility are d2 truck heads with their induction hardened ex. seats .I don't know if the these are as good as having hard seats installed though .Doug

ScotiaFE

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Re: Exhaust seats and leaded/unleaded fuel
« Reply #17 on: July 28, 2014, 10:35:35 AM »
Maybe it is the fuel used? I always run good gas, the little extra in using good fuel saves in mileage and repairs in the long run. Tune ups last longer and less sludge in the engine.

That one always makes me laugh. Good Gas. You get what ever comes out of the pump. ::)
Gasoline does not cause sludge.
This causes sludge.
Poor or no PCV system.
Running the engine to cold.
Water in the oil.

HiPower

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Re: Exhaust seats and leaded/unleaded fuel
« Reply #18 on: July 29, 2014, 06:48:20 AM »
One correction about lead, it does not cool the valve, it lubricates the valve and seat preventing the transfer, on a microscopic level, of metal from seat to valve face. It is also not uncommon for a much cooler running intake seat to "sink" as does the exhaust seat from lack of lead as a lubricant.  Burnt valves are not a direct result of unleaded fuel but may burn as they are no longer in firm contact with the seat and can't cool properly.
[/quote]
I didn't say it cooled the valves, I said it promoted cooling.  We're saying pretty much the same thing, different words.

HiPower

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Re: Exhaust seats and leaded/unleaded fuel
« Reply #19 on: July 29, 2014, 06:59:55 AM »
Maybe it is the fuel used? I always run good gas, the little extra in using good fuel saves in mileage and repairs in the long run. Tune ups last longer and less sludge in the engine.
Whether the tank truck says Shell, Chevron, Mobil, or Beacon, 7-11, or Mom and Pop, they all fill from the exact same spigot at the refinery.  Doesn't mean there aren't differences, because there are...in the additive package, not in the base fuel.  The additive package is put in to spec when the truck is filled.

Ratbird

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Re: Exhaust seats and leaded/unleaded fuel
« Reply #20 on: July 31, 2014, 10:35:36 AM »
The guy that built my engine (I have c4 series heads) put in CJ size intake valves. His name is Doug Anderson out of Albuquerque and he has 40 plus years experience and is considered by many to be quite the expert on FE's. (Ask Bud, bn69stang)
He said that it usually isn't an issue if the head is well seasoned. Like RJP said, they self harden with leaded fuel. He also told me that the c4ae-6090g heads didn't really have enough seat to put in hardened seats. He advised me to use a lead additive if I was concerned, and I do.

Correct me Bud if I'm wrong, at least according to what I remember Doug telling me.

Dave J

1959 T-bird - rat kind of a thing
FE 410ci bored .030 over, 4 sp toploader
pure fun

bn69stang

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Re: Exhaust seats and leaded/unleaded fuel
« Reply #21 on: July 31, 2014, 05:14:06 PM »
Yeah Dave he s told me the same thing , he is really old school and been an fe guy forever , 67 comet 427 , and he also has an original t -bolt , and i really like dealing with him but there is things his shop just does nt do .. but he is 70 now and im feeling he will retire in the next year or so .. Bud
69 mach 1 , 428 C J  Blue Oval Performance BBM heads -T@D rocker s- Blue thunder intake - Comp hydr roller - MSD ignition - FPA headers- Holley 850 hp double pumper - TKO 600 - 9 inch 3.89 Detroit Locker . ride tech coil over conversion - power rack @ pinoin steering - 13 inch drilled @ slotted 4 wheel disc brakes ..

410bruce

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Re: Exhaust seats and leaded/unleaded fuel
« Reply #22 on: May 18, 2019, 08:07:37 AM »
Hello gentlemen, reviving an old thread here.

I'm about to start a build on a 410 using CJ heads. This engine will be going in a 1989 F-150 2wd short bed and will be used as a daily driver.
My questions are: Is there enough material in the CJ heads to install hardened exhaust seats? Also, it seems I read somewhere that installing stainless valves alleviates the problem of metal transfer from seat to valve--any truth to this?

Thanks.

Bruce

gt350hr

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Re: Exhaust seats and leaded/unleaded fuel
« Reply #23 on: May 20, 2019, 10:38:37 AM »
   My experience is similar to RJP . Many '60s heads have no seat recession at all despite years of unleaded use. When I see that , I don't change them. In the early '70s "new" production Ford heads were notorious for exhaust seat recession until induction hardened versions were introduced. Seat recession was rampant in '72 on 351C/400 2V heads.
  Randy

Falcon67

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Re: Exhaust seats and leaded/unleaded fuel
« Reply #24 on: May 20, 2019, 11:20:01 AM »
Running stock valves in a stock 68 SBF head I noted some seat recession in the exhaust pockets.  On the 351C-2V heads that I updated to stainless, bronze guides, etc - zero recession despite racing on pump gas for several years.  Pump fuel has become so much crap that I now rather pay $9.50/gallon for VP 110 leaded in any race car/fun car with higher HP and is abused.

cjshaker

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Re: Exhaust seats and leaded/unleaded fuel
« Reply #25 on: May 20, 2019, 12:20:19 PM »
 I can't say I've ever had seats sink in any FE I've ever ran, but I put hardened exhaust seats in my old 390 that I used in my '68 F-250 Highboy (25 years ago), only because it was going to be used to pull/haul heavy loads. I've seen sunken valves plenty of times in small blocks from the early to mid '70s; sometimes so bad I'd swear the exhaust wasn't flowing any air!

The heads I used for my Highboy were C4-G heads, and yes they lose quite a bit of support when cut for seats, but the guy who did the work was an old Ford guy, and he just made sure the interference fit was tight enough. Those heads are in use on my '65 Galaxie now, with nothing more than a light valve lapping before putting them on, so 25 years of use now with no issues.
Doug Smith


'69 R-code Mach 1, '65 427 MR, 2x4, 4-spd, 4.30 Locker
2 1965 Galaxies with 390s
1970 F-350 390
1958 Ford Ranch Wagon 390

410bruce

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Re: Exhaust seats and leaded/unleaded fuel
« Reply #26 on: May 20, 2019, 08:03:27 PM »
Thanks guys. I'm kinda on the fence about which way to go but I'm leaning towards having the seats installed.
I have a pretty competent machinest who has installed them in some early 460 heads for me and they're doing just fine. I'll show him the CJ heads and see what he thinks. 

gt350hr

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Re: Exhaust seats and leaded/unleaded fuel
« Reply #27 on: May 21, 2019, 10:28:08 AM »
    FEs are tricky because a good portion of the replacement seat is poorly supported. I too subscribe to cast iron work hardening. My 68.5 CJ heads have zero seat recession. Of course they began life on leaded and then were subjected to unleaded after 74 ( or so). I am leaving them "as cast". Since it has been relegated to "sunny day" or race track status , I can always add some race gas or lead substitute without having to take out a loan. LOL
    Randy