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1931 Oakland V8, does it have a condenser?


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Hi all,

 

I've been working on a lovely 1931 Oakland for a customer and in the process of doing a systems check, I noticed that there is no condenser.  I've checked in the cap, near the coil, and around the distributor, but I can't find one.  So I have 2 questions;

 

1. Did a 1931 Oakland V8 have a condenser?

 

2. If not, should I add one?

 

I read the ignition part of the 1931-32 Oakland Pontiac Service Manual.  It states that the gap between the rotor and the cap terminals "serves the same purpose as the spark intensifier"  Does that statement mean that there is no condenser?  That doesn't seem right to me but someone here should know!

 

Thanks,

Flying W Forge

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13 minutes ago, FlyingWForge said:

1. Did a 1931 Oakland V8 have a condenser?

I can't imagine it could run very well if at all without it. Does it run? Could the condenser be hiding somewhere?

15 minutes ago, FlyingWForge said:

2. If not, should I add one?

If you do, it goes from the points wire to ground.

16 minutes ago, FlyingWForge said:

I read the ignition part of the 1931-32 Oakland Pontiac Service Manual.  It states that the gap between the rotor and the cap terminals "serves the same purpose as the spark intensifier"  Does that statement mean that there is no condenser?  That doesn't seem right to me but someone here should know!

A "spark intensifier" is just a gap to raise the voltage. It is unrelated.

 

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It does run albeit not well, hence why it's in my hands now.  It's been the victim several shade tree mechanics over the past 90+ years and I'm following their witness marks to figure out what's going on. 

 

It definitely doesn't have a condenser on it right now.  I've been going through "for sale" pics of other Oaklands and spotted where it should be.  Any recommendations for a condenser?  Or better yet, are there measurements like voltage, resistance or otherwise, I can take to match up an appropriate condenser to this ignition system?

 

Thanks,

Flying W Forge

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Hi Flying W Forge, there are three slightly different Oakland/Pontiac V8 distributors, one for each year 1930, 1931 and 1932. The first one in 1930 had a four lobe cam and two sets of points. One set of points was mounted to a separate plate that could be rotated about the centre of the distributor so that the two sets of points could be individually timed as one set fires the left bank and the other the right bank. In 1931 this changed to an eight lobe cam but still with two sets of points that were expected to be set to open simultaneously, a ridiculous expectation. The 1932 version in the 1932 Pontiac V8 deleted the redundant second set of points.

 

In a Kettering ignition system such as this, the points are considered to open too slowly for a DC current flow and there is a tendency for an arc to exist as they open, causing the points surfaces to burn away. The condenser is actually a capacitor and provides a separate short term current path to earth, by charging and discharging the condenser, that prevents the damaging arc. The condenser is essential. On the 1930 and 1931 distributors the condenser is fastened to the outside of the distributor and the wire is connected to the terminal on the outside where the wire from the coil is attached. I’m not so sure about the 1932 because removal of the redundant set of points might have made enough space inside the distributor for the condenser.

 

The problem with automotive ignition condensers is that the capacitance value needs to match the requirements of the distributor. I’m not aware of a tabulation of various capacitance values for various condensers so it is a bit of a black art. Probably any condenser is a lot better than none. If the car is driven a lot, eventually the remaining arc will cause a cavity to appear on one point surface and the missing material will form as a matching cone on the mating surface. At that time, the “minus, minus, minus” rule applies. Minus (low) condenser capacity cause minus material (crater) on the minus (negative) point.

 

So just find a condenser with a suitable bracket that will fasten with a screw into the tapped hole in the distributor body and a long enough lead with an eye terminal that will reach the terminal. Then enjoy one of these wonderful cars.

Hugh Venables

Melbourne, Australia

1930-32 Oakland Pontiac enthusiast 

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Thanks Hugh!  That information helps a ton!  The Oakland currently has an eight lobe cam and only one set of points, though the provisions for 2.  I can clearly see where the other set of points were.  My guess is either the previous mechanic or owner took out the second set and it ran well enough without a condenser for parades and such, that it didn't matter to them.  I'll see if I can find a part number for the 1932 pontiac v8 condenser as that will hopefully be closely rated to the current system.

 

Thanks,

Flying W Forge

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Posted (edited)

Both the moving points are the same but the bases are mirror image. One is much easier to find than the other. The easy one might have carried on in other vehicles.

 

Does this car still have its original Marvel DO carburetor? There are a few tricks to them too.

Edited by hugh.venables
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It does still have the marvel DO carburetor and I would love to know more about them.  I've been studying the service manual and so far have only cleaned it and reassembled, with the main goal of getting everything back to stock.  They are a strange carburetor to say the least, so I'd love to know if there's some tips and tricks!

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As you are finding out, one of the challenges to keeping these old cars going well is undoing the misguided modifications from dumb folk who thought they were smarter than those who designed them, but weren’t.

 

The first problem with Marvels in general is that many seem to think that the purpose of the air valve spring is to stretch it and cut coils off it, unless they decide that they have a more suitable spring altogether. It is found inside the large brass knurled adjusting knob and should have a relatively soft few coils in the centre, wound at a slightly larger diameter. If that is visibly correct and the rest of the spring has uniform coil pitch and closed ends it is at least a Marvel spring and may be correct. The correct spring is important in a similar way to the needle in an SU carburetor in that it affects the fuel mixture throughout the engine’s operating range.

 

The next common problem is that the zinc alloy die cast air valve flap tends to distort and sometimes disintegrate. This leads to two problems: firstly the flap rubs on the die cast bridge above it near the pivot and secondly it no longer seals in the bore of the body. With the carburetor removed from the engine and the air horn/ choke housing removed the fit of the flap in the bore can be visually gauged by looking through the bore of the main body. Just how well it needs to fit is unknown but if you can get it to fit within 0.010” I would think that very good but not easy. You can get it to fit by marking up the edges and dragging a feeler gauge through the tight spots to rub off the mark and filing off the excess. If it is rubbing on the bridge the same technique can be used and probably only 0.002” or so of clearance is necessary.

 

If it floods the float needle may have worn a groove around the conical seal surface that needs to be remachined and hopefully the cork float is still functional.

 

Enjoy, cheerio, Hugh 

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That is incredibly insightful Hugh.  It reminds of a quote, "Only fools and watch makers open the back of a watch."  I'm hoping the fools kept their hands off the spring you mention.  I purposely avoided it in this initial phase as I prefer to work incrementally and address one system at a time, so I can back track my steps if things get worse instead of better.  I've only I cleaned out the old fuel in the carb and am working from there.  Your tips will be invaluable in things are as out of whack as the distributor is!

 

I have another question for you Hugh.  Before the Oakland was put away about 6 years ago, the owner mentioned it was overheating.  Considering the amount of "work" done to the distributor, my guess is it was from timing being off, but is there anything else that Oaklands are known for in respect to overheating? 

 

Flying W Forge

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Flying W Forge,   I been following your post on the Oakland.  I do have points in stock for your car if you are interested and a condenser with the correct microfarads of capacity.  Attached a picture of the point bases.

 

Tom

20240531_150517.jpg

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Simple answer the cooling system is very good, the water jacketing in the block is cavernous, the cross flow radiator surface area is enormous with the top tank an extension of the cold side tank minimising evaporation and if everything is as it should be it works very well.

 

1930 cars originally have a two blade fan that is well known to break blades so I mostly drive my car without any fan at all. As long as I’m sure I will be doing more than about 30 mph with not too frequent traffic light stops that works well. I am alert to stop/start traffic jams and veteran car convoys up steep hills and pull over to fit the fan if I think necessary. A temperature gauge is necessary for this sort of micro management. There are threaded ports in the backs of the cylinder heads with originally impossibly corroded plugs in them that are best drilled out in a milling machine to find the centre of the thread, where a temperature gauge can be fitted. There is also a 3/4” Welch (freeze) plug in the back of the block on the left side that in a pinch can be replaced and then tapped for a gauge. A gauge will only read the temperature of which ever bank it is fitted to as the two banks have separate water jackets.

 

The original (1930) water pump impeller is cast iron and can corrode badly over the years and might have been replaced with something unsuitable. The original is identifiable with 6 very short radial vanes on the back face as well as the usual 6 spiral flutes on the pump side. Oakland claimed that the back flutes created an equal and opposite axial force on the pump shaft to prevent thrust wear. The length of the impeller is not much shorter than the installed distance from the pump face to the bottom of the counterbore in the block. As with any pump, the spiral vanes must run very close to the pump face.

 

The head gaskets seem to be very reliable and fortunately they still appear on eBay at various prices. My engine is recently rebuilt with NOS gaskets that were supplied pre-bent, then an attempt was made to flatten them with a hammer so I had to re-bend them for them to fit. One of them has now been re-used for the rebuild and both of them seem fine despite a few hammer marks that they would have been better without. It seemed a shame to throw them out.

 

The cylinder head bolt holes are tapped through into the water jackets and tend to corrode badly making them possibly unsuitable for properly clamping the gaskets. In Australia, Holden “red motor” main bearing bolts are suitable for the upper and lower rows and Falcon pre-crossflow head bolts for the longer middle row. You can buy commercial bolts but over here they have 5/8” hex heads instead of the original 11/16” and don’t look right. 

 

Prior to the recent rebuild (for all 8 big end failures) it did seem to be getting a bit hotter and I was able to dislodge a very large piece of corroded material from the cylinder head on the left bank, where the temperature gauge is fitted. Perhaps coolant flow was being restricted although I had the radiator re-cored at the same time as the core had several leaks and I’m embarrassed to admit it now has a modern core. Prior to the rebuild I had done about 15,000 miles under all sorts of traffic conditions without the fan.

 

There should be a thermostat fitted at the radiator inlet end of the water manifold between the heads. It is a larger diameter than most modern ones but NOS ones from International trucks, early Toyota Landcruisers and similar fit well.

 

A healthy engine with a healthy cooling system is very unlikely to overheat in my experience with my own sedan and a friend’s roadster that we have done 75,000 miles in, also with a modern core and at times without the fan and much more than occasionally at 70 mph.

 

Fabulous motor cars in my opinion.

Cheerio, Hugh 

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I have a lot of spare parts . Just sent wheels and drums to a freind out west who is doing a 1930 sedan  Howard

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Thanks for all the advice everyone!  This is helping me solve the mystery of this Oakland. 

 

Tom, it looks like Oakland used 829092 (early) or 829107 (later) and some other users of this forum have used napa ECH RR174 with success to replace it.  I've got that on order and should know if it works soon.

 

In the mean time, I did get the Oakland running on a random condenser and it is running incredibly rich.  I fear that the adjuster with the spring in it has been messed with, hopefully that spring isn't too far out of shape.  It's running rich enough that when it warms up, it will start for a sec or two, then die.

 

kings32, I was hoping you'd see this thread!  I am in Frederick, so not far from you.  I am also not ashamed of leaning on someone with way more knowledge than me!

 

Hugh, if it's still rich after making the adjustments you recommend, what would be a likely culprit?

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I would rather take the optimistic view that when you have worked through the carburetor and know it is right that it will no longer run rich.

 

The air valve flap has a short lever on the back of it with a cute little con rod to a thin walled brass piston that acts as a damper inside the large knurled adjusting screw. If you unscrew that screw all the way you can inspect the spring and stick a finger in the piston and try to move it up and down to operate the flap. I’m guessing that you will find it sticking mostly shut.

Timing is everything and unfortunately I’m away from home for the next two weeks so I can respond but not interrogate my collection of stuff. We can have a much better discussion if I have the same stuff in my hands as you do.

 

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Well all, the Oakland now runs like a top thanks to everyone's guidance!

 

Following Hugh's advice, I checked the piston in the air mixture screw and it wasn't budging.  It ended up that the air valve was stuck shut and was incredibly difficult to move.  Following the witness marks of previous work, it seems that someone knocked out the pin the air valve pivots on, bent it out of shape some how and also then tried to removed the air valve and marred the interior walls of the carb itself before giving up and putting everything back in place.  Some patience with some high grit sand paper, a thorough cleaning and a drop of lubrication in the right places, now everything moves freely and smoothly. 

 

To those familiar with the Marvel DO carb, the pivot pin for the air valve was so stuck in place that the previous person didn't even use a pin to hold it in.  It was literally wedged in place. 

 

As far as the overheating problem goes, I think it may be solved at the moment.  I got the engine idling well at what sounds like 500 rpm or so.  I'm familiar with tuning idle air/fuel ratio by ear with motorcycles, so I believe I got the air knob close, but I'll hook up a vacuum gauge to be certain the next time I work on it.  It was getting a bit hot, 190 to 195, so after getting the idle right, I advanced the timing a bit and the oakland cooled down and idled at 180 during a 80F day for 10 to 15 minutes without a problem.  I haven't gotten a chance to drive it, so I'll still have to adjust timing after that, but I'm pretty pleased right now.

 

I'll probably still put in a new set of points and a new condenser as I don't know what the current condenser is and the old points are wearing on one side.  Hopefully I've matched up the new ones closer.

 

Thanks all for the help!

Flying W Forge

 

 

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The timing marks are on the circumference of the flywheel and visible through a cast hole in the bell housing on the left side which should have a domed cover clipped into it. For each bank there are two sets of marks; DC 1-7 for TDC and IGN 1-7. DC and IGN are above the line and 1-7 (or 2-8) are below it. Easier to see if the flywheel is black and the stampings are painted white when it is in bits.

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