Technical Unleaded gas will eventually get a leaded gas motor

I have a 1970 302 ford motor in one of my rides for 10 years and 32,000 miles and now #4 exhaust valve is not seating too good,motor had 16,000 original miles when installed and still does not have 50,000 so something to think about when putting a older motor on the road. Not sure if I am going to have the original upgraded or find a later set of heads that will work,I do have a set of fresh 66 289 heads but do not want to do this again.

 

And you believe the unleaded gas caused this issue?

 

Got to blame it on something other then my lead foot,never had this problem with the newer heads with hardened seats and put much more miles on them then with this motor.

 

Have you had an exhaust leak close to the head? Ford has used hardened seats for quite a long time.

 

No this one did not have any exhaust leaks at the headers,I think most manufactures went to hardened seats around 72 so that was 2 years after this motor was made. This is the first motor I had that a valve burnt,I have bought them that way but never done it.

 

I have seen two burned exhaust valves on Ford engines. Both in about 1970 before there was such a thing as unleaded gas. What I'm saying is that there might be something else going on.

 

Could be I suppose.. but engines have been burning valves since the beginning of time for one reason or another.
Like adjusting too tight, or the seat ground too narrow.

 

It should not happen again after it gets hardened seats or later heads,I thought the adding of lead to the gas back in the 40s was suppposed to help this problem.

 

when you have the heads done have them install the seats , problem solved . I have seen valve head recession from a induction hardened head they ground the seat too much and got into the soft Iron , most of the recession is from running it hard and hot or high spring pressures , and also long periods of time ( long trips over 50 miles )

 

Tetraethyllead was originally added to fuel to increase the octane rating, and that it does very well - I believe it is one of the most potent octane boosters there is (and that's why there is still leaded race fuel). The valve/seat lubricating effect was not what they were trying to get, but everybody liked less wear and longer life between overhauls.

Today it's easy to build engines that does not require lead to last long thanks to way better valve/seat materials, and going unleaded is obviously good for the environment.

 

My 71 engine did the same thing, installed hardened seats and its still running great.

 

How are the valve guides? I've seen worn guides cause poor valve seating which lead to burned valves.
Burnt valves at 50K was fairly common in the 60's and early 70's.

 

I worked for a large company that had a fleet of several thousand cars and we drove around taking service calls all day. I remember that in 1971 almost all of the Ford 500 models with 302 engines were recalled for valve problems. My ugly green machine had less than 20K on it when it was towed away. If you check you will find that the early 302s had other problems too.

 

how did you figure out which valve has problems? have motor apart?

 

The reason that you burned your valves can be many. And as well as many other fixes to ensure a lifetime of abuse. And when I say ensure, it's to be taken lightly.

I did a lot of things to prevent valve burns, like at a little diesel, valve or ignition timing.

But the most simple solution could have been lead subliment added to the fuel.

But there is nothing wrong about change to hardened seats.

 

Just throw some E7TE heads on it and be done with it.

The used heads are cheaper than a valve seat repair

 

Mandated for 2016 here in Mn 15% alcohol in the gas Does it ever end ? Yup this is the corn state Money to be made !!

 

For all of the vintage engine guys reading this topic, FWIW, most vintage engines like early Ford bangers, flatheads, for sure almost all Packard engines, and several others share the same thing. Superior metalurgy which DOES NOT require the installation of hardened seats. Henry was proud of his castings, Packard used cast steel (higher nickel content), and many others as well. Hardened seats in those are a bill of goods that only help the engine shop's cash flow. Research your vintage engines before you drop the jack needed to do this. Could save a bundle.

 

Early hemis seldom need hardened seats either.

I am not sure that I am the one to chime inhere, I have run old mills no problem with no lead and for los of miles. If the motor has a burnt valve it is not because of lack of lead in the fuel, what will happen to a motor that has soft seats is that the seats will get hammered out. Burnt valves come from other issues.

Here is a little practiced thing that can be done, all the lead does is cushion the valve when it comes to an engine having a valve problem caused by lack of lead. Alcohol motors have no lead and they don't use lead substitute to over come the cushioning problem. They make oil that you ad to the fuel to cushion the valve. It is along the same lines as Bardahl top end lubricant. The stuff is cheap and a little can in a tank of fuel will go a long ways toward saving your top end if you think that your seats are too soft.

You fellas can keep on buying expensive lead substitute if you like but top oil will do the trick just fine.

 

It has the usual sputter sound out the exhaust when the exhaust valve is not seating and a miss,I thought it could have been the plugs since they have over 30,000 miles on them and the plug from the cylinder in question had some build up where the other 7 were burning clean but worn. I think it was a problem that was starting a long time ago and the trip done it in,I am going to the junkyard saturday for a pair of E7 heads and a set of later pushrods for a flat tappet cam.

 

The motor when installed had less then 20,000 miles so one would think the guides would be good but there was a tick on the other side of the motor that could be heard with a stethoscope on #7 intake rocker stud which got me thinking it could have a bad guide since lifters did not cure the noise and I thought I would had problems with that one valve but its #4 and on the other head so now that there is issues on both heads time to take apart.

 

so, no external noise? had a "good" motor making a noise like a valve heading the head. had a old timer look at it and he slowly poured automatic transmission fluid down the carb and it took care of what turned out to be carbon build up. ran good after that.

 

I thought it could be the valve sticking so I ran a quart of trans fluid through the motor and no change so the heads are coming off.

 

As soon as I get my 37 moved to my aunts garage for the winter its going in the garage for a compression test and if my suspicion is correct will come apart,I got thinking since the plug from the cylinder in question had some some stuff on it but not fouled that cylinder might have been sucking oil from the lifter valley and could have carboned up the exhaust valve making it not close completely. After I installed the aluminum intake this motor started using oil and with the other 7 burning good I suspect that might be the cylinder where the oil is going so what if there is excess carbon holding the valve open can something be sprayed on it through the exhaust port to break it up,I revved it up and the ground was black under the tail pipe on that side so there is some excess carbon in there somewhere.

 

Tearing the motor apart tonight and found out why it was using oil after the change to a 4 bbl,instead of getting Felpro gaskets I ordered a installation kit which came with Mr gasket intake gaskets and they were made too big around the ports which allowed the gaskets to hang lower on the heads so there would not be enough between the head and intake to seal properly and was sucking oil out of the lifter valley. Will have heads off tomorrow to see what happened to the one exhaust valve,the cylinder that had the bad valve was the one with the least gasket on the bottom of the port.

 

When I worked with Ford, I got to see a lot of old training and ad footage. They were advertising hardened valve seats in the 30s. Having ground valves for years I can tell you that most of the Ford seats had characteristics of being very hard (brilliant spark display and a lot of grinding to take a little off compared to other makes). A lot of things can take a valve out like worn guides causing oil carbon, adjustment too tight, exhaust leaks and even saw a flathead seat dislodge due to heat from a restricted exhaust pipe on one side. It is possible that they produced a run that did not get properly treated as well.

 

To be completely honest about this motor it had sat for a few years before I got it and there is a possibility that the valve in question had sat open and rusted but one would have thought this problem would have shown up much sooner then 10 years and 32,000 miles. I will have the heads off as soon as I get moving and out to the garage and decide if those heads will get fixed or get a set of E7s and the pull and pay tomorrow.

 

I'm always in favor of least invasive - least expensive first. I would dribble Seafoam into the carb as you keep the revs up so it doesn't stall. Shut it down, let it sit overnight and repeat the dribble procedure then give it a good run.

 

Its a burnt exhaust valve on #4 and it has a noisy guide on the other head so I am going to have these heads fixed,I will need to have the newer heads gone through and with buying them it will be cheaper to fix what I have. With the intake gasket not sealing around the ports on that side I think that cylinder was running a little lean so I will have to make sure to check that when putting back togather.