gregchrysler

lead additive ? 49 chrysler spitfire

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All Chrysler built 6 cylinder engines in that era came from the factory with hardened exhaust valve seat inserts and special alloy exhaust valves. You can put a lead additive into your fuel but the only real effect that will be to make your wallet lighter.

 

Any modern off-the-shelf multi-viscosity oil will have more ZDDP in it than was available when your car left the factory. And, being post war, it should have been fed multi-viscosity oil since new unless some cheap SOB previous owner thought they could get by with single weight. You may wish to pull the valve covers and drop the pan to inspect for deposits and clean them out if found. But other than that, I'd use a on sale multi-viscosity oil from my local auto supply in the range that keeps your oil pressure at the factory recommended level. If new or recently rebuilt that would probably be a 10w-30 but with a worn engine it could likely be something heavier.

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On ‎2‎/‎9‎/‎2017 at 10:07 AM, gregchrysler said:

Thanks ply33   I didn't know they had hardened valve inserts

I would really want to check this out.............

My first car was a '52 Plymouth, and it was a "flathead" so no valve cover to pull.

Just the side plate to set the valves.

But seriously, pull the pan and clean it out !!!!! THIS IS JOB #1 !!!!!

How is your oil pressure ?

I would use Shell Rotella 15-40, and a can of STP, just to make you feel better.

As for a lead additive, you can use an ounce or two of CD-2 lead substitute just for insurance.

 

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STP is a viscosifier, which makes the oil thicker. If you want thicker oil, use 20W-50 and leave out the additive. For best performance = minimum wear, use a synthetic oil. If your engine is fairly new, you could try a 5 or 10W-30. The 5 or 10W means the oil will circulate quickly on startup because it is behaving similarly to an SAE 5 or 10 oil. At operating temperature will behave like the second number. If older, a 10W-40 perhaps and see how the oil pressure is.

 

When we dropped lead in NZ, I used an additive in my 1930 Dodge 8. The plugs all failed at the same time 1000 miles later. Apparently they may be able to be resurrected with a light sandblast. So leave out the additive.

 

If you want zinc to protect the flat tappets, use a CI-4 rated diesel oil - it has the maximum zinc allowed in it. If you go for a synthetic, just use an oil for petrol engines.

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53 minutes ago, FLYER15015 said:

. . .

My first car was a '52 Plymouth, and it was a "flathead" so no valve cover to pull.

Just the side plate to set the valves. . . .

 Those side plates are the valve covers. :)

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No additive needed, your car was built to run on low lead or no lead gas of 65 to 70 octane. Today's cheapest regular is 87 way more than you need.

 

You can add an upper cylinder lubricant like Redex, Marvel Mystery Oil, Bardhal or your favorite brand. This is said to extend engine life between overhauls, but is not totally necessary. In very hot weather if you have a problem with stalling due to vapor lock you can add 10% kerosene or stove oil to the gas.

 

Multi grade and detergent oil were introduced about the time your car was built. Chances are it always had 10W30 as that was the default choice at every dealership and gas station from the fifties through the eighties.

 

Change oil every 3000 miles, filter every second oil change. There is a drain plug at the bottom of the filter. New filters are available from your local auto parts store although it may take them a couple of days.

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For older, flat-tappet engines, see Selection of the Right Motor Oil for the Corvair and other Engines,

 

Heavy Duty Engine Oils are a good choice because they have high levels of ZDDP. The detergents in these oils will slowly clean any sludge out of your engine.  I would use a 10W-30 grade in your engine but I would also change the filter at every oil change.

 

As for STP, see the HAMB STP Discussion.

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On 2/9/2017 at 11:19 AM, ply33 said:

All Chrysler built 6 cylinder engines in that era came from the factory with hardened exhaust valve seat inserts and special alloy exhaust valves. You can put a lead additive into your fuel but the only real effect that will be to make your wallet lighter.

 

Any modern off-the-shelf multi-viscosity oil will have more ZDDP in it than was available when your car left the factory. And, being post war, it should have been fed multi-viscosity oil since new unless some cheap SOB previous owner thought they could get by with single weight. You may wish to pull the valve covers and drop the pan to inspect for deposits and clean them out if found. But other than that, I'd use a on sale multi-viscosity oil from my local auto supply in the range that keeps your oil pressure at the factory recommended level. If new or recently rebuilt that would probably be a 10w-30 but with a worn engine it could likely be something heavier.

I personally did not have my '47 251 rebuilt but supposedly they used all new parts. So I am wondering what the likelihood that they would have acquired the hardened valve seats and alloy exhaust valves? The owner was a "spare no expense" type guy and wanted it made better than when new. The work was preformed about 4 years ago. Would a rebuilder have access to these parts?

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Why would any "knowledgeable rebuilder" have to acquire hardened seats when the engine originally came with them.  Of course if one of them was burnt they would/should have been replaced.  Obviously a "knowledgeable rebuilder" with any integrity would have known this.  If you don't have an itemized copy of what was done you really have no idea.  The only way to know for sure would be to pull the head and check.

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Why would any "knowledgeable rebuilder" have to acquire hardened seats when the engine originally came with them.  Of course if one of them was burnt they would/should have been replaced.  Obviously a "knowledgeable rebuilder" with any integrity would have known this.  If you don't have an itemized copy of what was done you really have no idea.  The only way to know for sure would be to pull the head and check.

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You are correct in that this part of the restoration was performed before I received the vehicle. When the owner said it was rebuilt with "all new parts" I assumed he meant those that are normally replaced. Me not being a mechanic, I don't know exactly which these are. I can do a perfect paint job but leave the greasy end to others. LOL I don't recall the shop that did the work but at the time (3 years ago) was told by many that he was a very good and thorough rebuilder. It did run very smooth when we started it but haven't had the chance to drive yet. Thanx for the input. Now if I could only find someone to help with the aftermarket harness I might be able to get it on the road. 

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There are certain advantages to having a vintage auto that has been in the same family for it's entire life and has only had two owners.  Even then sometimes I wonder why my Grandfather did what he did.  Good luck with your Chrysler Woodie.

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Maybe I can clear up some confusion about the valves and valve seats.  All flathead Chrysler engines came from the factory with valve seat inserts for the exhaust valves. These inserts were made of a special heat resistant material. They normally last the life of the car. At overhaul time they can be ground smooth and are as good as new.

 

From the mid fifties on up, car makers dispensed with this nicety. The use of leaded gas allowed them to get away with running the valves directly against the metal of the head.

 

Starting in 1970 unleaded gas was the rule. For a few years cars suffered rapid valve seat wear. Then they learned to harden the valve seat area. This was cheaper than installing inserts.

 

Then it became the rule to put inserts into the heads of 1955 to 1970 models, or replace the heads with newer heads that had hardened valve seats.

 

This is a long winded way of explaining why everyone thinks you need to add valve seat inserts. But Chrysler's engineers already though of that way back when your car was built. Those Chrysler guys thought of everything.

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I'd run Brad Penn or Schaffer's racing oil at a straight 40 weight if it's summer.   In our cars the oil pressure drops to almost nothing with multiviscosity oils at a hot idle.  Straight weight keeps the oil pressure up a little more in a heat soaked engine.  

 

I also run Marvel or Schaffer Neutra fuel stabilizer in our cars.  They both lubricate the valves which is a good thing.   

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In the 70s when I went to the OMC school the instructor suggested that multi vis oils tend to migrate to the center of the weights.

Also suggested that the OMC stern drive engines use straight weight oil.

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Let's back-up a little bit . . .    If this is the Chrysler flat-head engine, the valves are in the block, not the head.  As for oil pressure, I have a '51 Plymouth service manual which specifies oil viscosities and oil pressure.  As flaky as it might seem, the manual states that at hot base idle, if ANY oil pressure shows on the oil pressure gauge at idle speed, that's FINE.

 

The oil viscosity recommendations were highly temperature-dependent.   Even all the way down to !0w-10 for some very cold areas.   Just as with the 1960s motors, generally, 30 viscosity was the default grade as multi-vis 10W-30 oils didn't really come into being until the earlier 1960s. 

 

It was said that the earlier 10W-30 oils did end up more 10W-20 after a thousand miles or so.  That was in about 1961 that I found that in an article in "Motor Life" magazine.  Modern multi-vis oils stay more "in grade" with age and use.  Considering the viscosity range for a given designation, there can be a 10W-30 that is closer to a 10W-20 than not, or a 10W-30 that is closer to a 10W-40 than not.

 

As for STP, I knew of one guy that had a Firebird 400, 1976 or so.  The engine had a lower-end noise, so he did a fresh oil change with 20W-50 motor oil and one bottle of STP.  That apparently helped, but didn't get it all, so he added an additional bottle of STP.  Knock worse!  Time for a new crankshaft!  STP is a "viscosity improver", typically said to increase viscosity by an additional "10" onto the base oil for one can.  He ended up with about 40W-70 or so!

 

Personally, I like the idea of using a good quality 10W-30 motor oil.  It should cover most any conditions you'd encounter.  The modern oils have much superior cleanliness additives too.   Even the SN oils probably have more zddp than the old oils did back then, plus better oil basestocks (which can lessen the need for zddp somewhat).   I concur with removing the oil pan and the side covers to clean things out.  It'll be messy, but dispose of any "stuff" in a responsible manner.

 

Any lead substitute use should be limited, if used.  TetraEthylLead is very poisionous, so even the old "Real Lead" fuel additive had very little "real lead" in it.  Other substitutes are sodium-based and, from my own experience, stuck an accelerator pump circuit anti-siphon "weight" closed.  If you're going to use such a supplement, don't use too much and drive the vehicle regularly!  One benefit can be that if the valve seats have degraded a little, the lead substitute can fill in those little gaps and make for better sealing.

 

Those were neat cars, IF you understand them well.  And understand how to use them optimally for best results.

 

Enjoy!

NTX5467

Edited by NTX5467 (see edit history)
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