The results or todays gas in older motors?

[junkyardjeff]

I installed a 16,000 original mile 302 in my 65 custom 500 10 years ago and have since put 32,000 miles on it and burnt a exhaust valve last sunday,I was going to blame it on the crappy gas we have today but after I tore the motor apart I think I might have found the problem. 8 years ago I changed it over to a 4 bbl since I had to pull the intake to replace what I thought was a bad lifter that was making noise after the 30 storage of the motor,instead of buying a good name brand of intake gasket I ordered a installation kit with the intake and the gaskets are too big around the intake ports and the gaskets were haging a little too low and not much to seal on the bottom of the ports so I think it was running a little lean and also using oil that it did not do until the intake change.

[JamesBulldogMiller55Buick]

I would blame the gasket.

 

A fuel problem would have an equal affect on all the cylinders' valves

Edited December 12, 2015 by JamesBulldogMiller55Buick (see edit history)

[junkyardjeff]

I definately will check how the intake gaskets fit before dropping the intake back on it.

[padgett]

With port injection that is possible but carbs particularly on log manifolds can have significant dfferences depending on the route to each intake. In general end cyls are liable to run leaner than center. Dual plane 4bbl manifolds are worse since few pay attention to primaries and each throat feeds a different bank. Good distribution is why Chrysler stock dual quads over each bank on long tube manifolds.

 

Daily driving does not matter as much but sustained high rpm leanouts can do all kinds of damage.

[junkyardjeff]

Got some bad news from the machine shop,those heads that only have 48,000 miles are worn out and need all new intake valves and guides plus the one exhaust valve and will be around 500 dollars to repair. He told me all the motors of this era were like that and I was told by others it was common to for that era of motors to need a valve job around 50,000 so I am going to pick up a later set of heads to have gone through. I have put over 200,000 on the late 80s and up 302s without any valve problems so its going to get a set of E7 heads.

[padgett]

True, have a couple of older owner's manuals that tell you how to remove the heads. Valves used to have rotators to clean off the lead deposits. Am a bit surprised though, it usually exhaust valves that give more issues unless you get hardened seats installed. Is one reason I run my cars cooler than stock.

'nother point is that back in the '60s, a car was ready for the junkyard at 100k and a new car every year was common.

Better metallurgy, better gasoline, better oils, better tires all make a difference. Heck I remember big cars with drum brakes (Caddys in particular) that to stop from a high speed the best thing was to lock 'em up since otherwise they would fade out before it stopped (of course a fast way to stop a car before disks and ABS was to spin it but that had to be learned).

We also have brake fluid now that is less likely to boil when the brakes start glowing cherry red. Sometimes it seems incredible that I survived my yout but part of it is that I had disk fronts and often 4 wheel even in the 60's. Now all of my cars have disks & Judge is the only one that doesn't have 4WDB and ABS. Of course I have faded disks before also....

Today, most of my cars are over 100k & all are ready for a long drive. None are coffee tables.

Biggest issue with E10 is the lack of the lubrication lead provides and the increased incidence of detonation caused by lower octanes. I always add an ounce of CD2 to the Judge when I fill with 93. Can usually tell a valve that has seen a lot of detonation, surface is kind of pebbled.

Edited December 24, 2015 by padgett (see edit history)

[junkyardjeff]

I always thought those older motors were the best but even though the later motors did not have the power they were able to go more miles before repair,I am a little dissapaointed those heads did not get to 50,000 before wearing out. When it goes back togather I will take the 190 degree thermostat out of it,I was chasing down a lack of heat issue from the heater which turned out to be a bad heater core and never removed it so i had been running it a little hot.

Edited December 25, 2015 by junkyardjeff (see edit history)

[padgett]

Agree with that. I run 160's in older cars and 180s in computer cars. Never had a heat problem (though cars with AC have better heaters) even in Indiana and Michigan, get good heat at anything over 140 if everything else is good.

 

Heads are a different matter and if off, having hardened exhaust valve seats added is a good idea. Enormous impovements in metallury, machining, and oils also has made a big difference in the last fifty years.

 

Finally an observation. In the late '50s and into the '60s 30 psi oil pressure was considered "enough".  By 1970 the advice was 10 psi for every 1000 rpm and my 3.6 Jeep has that to its 6400 rpm redline. OTOH a 3.8 DOHC Jag could do 6400 rpm once & the mantra was 40 psi at 3,000 rpm. My Buick 3.8s run 40 psi at idle and that was increased in '92.

 

Also all of my 6's have roller rockers, something only real racers had in '70, and balance shafts to cure secondary vibrations. Finally the feedback computers today correct a lot of issues such as leaning out automagically.

 

So engines today often go 200k or more with just regular maintenance and the lack of lead in the gas is helping.

 

ps years ago if you got water in the gas, what you added was alchol to make them mix. When was the last time you had water in the gas ?

[junkyardjeff]

I got water in the tank of that car when I gassed up at a station that had recently reopened after sitting for a year or so,I had spent a few years and trying alot of things to get heat from the heater in that car including a new heater core that was worse then the original and the 195 was the first done.

[GK1918]

Got some bad news from the machine shop,those heads that only have 48,000 miles are worn out and need all new intake valves and guides plus the one exhaust valve and will be around 500 dollars to repair. He told me all the motors of this era were like that and I was told by others it was common to for that era of motors to need a valve job around 50,000 so I am going to pick up a later set of heads to have gone through. I have put over 200,000 on the late 80s and up 302s without any valve problems so its going to get a set of E7 heads.

 

$500 ?  Machine shop must be in Las Vegas where there's deep pockets  no way around here

[padgett]

Depends on what is being done to them. That is about 2 skilled hours per head. Hope that includes hardened exhaust valve seats.  Good shop is worth it.

 

Good news is the number of new cars that want premium gas - 93 will probably be around for a while.

 

These are the good old days.

[junkyardjeff]

That quote did not include hardened seats.

[RPrice]

Maybe I missed it, but did anyone recommend adding zinc  (ZDDP) to modern motor oils?    Zinc has been removed from motor oils because it can affect the catalysts that are on modern cars.   Zinc will save the valves in our old cars.   You can also use Valvoline VR-1 racing oil.   It will contain the necessary zinc to protect our old engines.

Rog

[junkyardjeff]

Original heads are being rebuilt.

[MikeC5]

I had a Slant 6 powered Mopar from '65 for a long time and after burning unleaded gas for several years and roughly 100K miles, compression was way down.  Pulled the head and the exhaust valve seats were toast.  I swapped the head for a later model one with induction hardened valve seats. 

Edited January 9, 2016 by MikeC5 (see edit history)

[junkyardjeff]

Just picked up the heads today and now comes the fun part to put it back togather,I was going to get a later set of heads but did not want to drill new steam holes in the block and worry about if I got a set on heads that were cracked.

[Modeleh]

Beware there are two styles of intake gaskets for the 302

I had a similar problem once and didn't notice I used the gasket for the large port water jacket on a small port head. Water leak into the valley

[junkyardjeff]

I made sure I got a set of gaskets that are much closer to the port size this time.

[ted sweet]

how does zinc save the valves?

[Dandy Dave]

Not so much the sealing surface of the valve and seat Ted. Zinc does help with wear on the guides, stems, flat style lifters, and cam lobes. If a stem and guide is worn excessively, then the valve can kick to the side and make the seat wear oblong. Especially with the valve action of an overhead design. Dandy Dave! 

 

 

how does zinc save the valves?

[Guest]

Maybe I missed it, but did anyone recommend adding zinc  (ZDDP) to modern motor oils?    Zinc has been removed from motor oils because it can affect the catalysts that are on modern cars.   Zinc will save the valves in our old cars.   You can also use Valvoline VR-1 racing oil.   It will contain the necessary zinc to protect our old engines.

Rog

The ZINK and Phosphate do not save the valves, it saves camshafts. Blended with motor oils to increase it's high pressure capability.

[junkyardjeff]

It is back togather and running,had a little scare when one rocker arm popped off and a miss developed but it is now running smoother then it ever did. It always had a tick which is now gone so I am thinking it did have one bad guide or a bent valve from sitting 30 years,just have to find the exhaust leak and its done.