jeffsunzeri

To clarify a bit, "point bounce" refers to the tendency of a points system to become inefficient at high RPMS (typically past 4,000 RPM). The older method to alleviate this is the use of multiple point distributors, typically dual point distributors. Even when multiple points are used, mechanical inefficiency can cause problems. In the early 1970's, BSA/Triumph raced a 3 cylinder motorcycle which had one point per cylinder system. The points were opened by a cam on the end of the exhaust camshaft. At racing RPM's the runout in the cam was found to be enough to make the timing erratic even with the 3-points system. The engines were misfiring at around 6,000 RPM. The solution was an electronic system which was more tolerant of the camshaft movement and thus eliminated the high RPM misfire. Engines which operate in the lower RPM range (up to 4,000 or so RPM) work fine with single point systems, and the benefit of dual point systems generally appear around 4,500 RPM and up. Electronic (reluctor based) breaker systems tolerate a lot of slop and provide consistent timing throughout the normal RPM operating ranges.

The bucks are about the same, but the Gear Vendors units are pretty good at retaining originality as much as possible. Concours judges take no points away for using them. I've got a Laycock OD unit from a Volvo, which is the same starting point as the GV units. I'll be modifying it for one of my trucks, but that $3,000 is actually looking pretty cheap when we factor in the amount of work needed to do the modification and fit-up. For someone who doesn't have the welding and machining shop capabilites, the GV unit appears to be a genuine bargain. Replacing the rear end and trans with modern stuff in a 1 ton... might as well buy a '93 whatever and just paint "Pretend it's an old truck" on the side.

So, Scott - welcome to the 1 ton dually club! I'm with you and your Dad on the desire to get higher cruise speeds, but retain the character and bullet-proof nature of the truck 4-speed. I have the same setup in my 1942 WD-21. One of the main problems is keeping your wheel set, very important for a dual rear tire setup. The other issue is that I use my 1 ton for what it was meant for. I've investigated just about every option at this point. I'm thinking of going with a Gear Vendors solution. They have an overdrive that will permit us to retain the original transmission, brake, and rear end. Has anyone any experience with the Gear Vendors products in this type (vintage medium-large truck) vehicle?

I recently installed a Pertronix, 6 volt Pos. ground unit in a Chrysler industrial engine application. I had purchased the Pertronix unit at a pretty good discount and was planning on using it in a future project. However, the condensor went bad, so I replaced the points with the Pertronix. My reasons for replacing the points was solely because this particular application would be simpler than others that use the coil mounted to the firewall with the armored hot wire, and I was curious to see if there would be any advantages. I have electronic (Pertronix) modules in other applications, and they work well, but this was the first in the MoPar flathead. First off, the unit was meant for another distributor. Either that or you're supposed to rip out the points pivot to install it. I want to be able to revert to points in an emergency, so I elected to 'custom' mount the Pertronix, drilling two holes and locating the unit 180 degrees from the points orientation. On this particular distributor, the fitment is a little of a Kludge, but that wasn't Pertronix's problem. I use the stock coil. Performance is just the same as with the points (and a good condensor). It has always been a good starter, and smooth runner, and no change. In many decades of driving with points systems, I've only been stopped once by a bad component in the ignition system, a failed condensor. I have had one failure with electronic systems in about the same amount of driving. The only time I really dislike points is on the 392 hemi with a rear mounted dual-point distributor located right under the heater/vent box which makes adjustment and replacement a PITA. For me, the only valid reason to use the Pertronix is the expectation that it would eliminate point bounce at high rpm's. Otherwise it really has no advantage, in a perfect world. In this imperfect world however, condensors are of crappy quality (compared to back in the day), so I changed. I also don't mind setting the points once a year or so, and any other "advantage" of the Pertronix is lost on me. Oh yea, one disadvantage of the Pertronix is the warning that leaving the ignition on with the motor not running will fry the unit. With the Pertronix installed, I keep the points and a new condensor handy in case of failure. With other vehicles running points, I keep just a new condensor handy. So, it's a bit of a wash.

Boba - Being nervous about this process is a good thing. One thing I found that has helped tremendously is a DVD demonstrating body filler and general painting preparation techniques. I believe I got one from Eastwood a million years ago (it was on VHS) but there are a couple out there, and they are better than what you will find on YouTube. Play the tape/DVD over and over, and you will be as prepared as ever! Watching some pros helps a lot! Bond-o was used by the factories back in the day, and it is a time proven process. Go for it!

The moral of the story may well be one or all of the following: - Never re-use cotter pins. - Only use high-quality cotter pins. - Fit and bend cotter pins in the correct fashion. Most of the cotter pins (split pins) I've seen in those inexpensive kits seem to be made of the softest, most awful material available. Use aircraft hardware here when possible. Otherwise the wrench-and-nail thing looks pretty cool!

Vintage Power Wagons offers a kit (vintagepowerwagons.com) and you can measure the length of your head bolts and order the individual studs and nuts from a number of sources such as NAPA, Summit Racing, Fastenal and others. I have actually installed the studs on 2 of the 4 mopar flathead sixes I currently operate, as well as a few more for customers. In at least one case, I replaced studs that were already there, and in the others the cost was about the same as replacing all the old, corroded head bolts. It's difficult to justify re-using 60 and 70 year old head bolts considering the overall cost of a failed head bolt or damaged thread. When I look at the wear and tear on the threads in the block due to the usage of head bolts, I am glad I have used the studs.

Yes. I don't think you'll be getting any failure due to the increased CR or power. A good move would be to replace the head bolts with studs to help prevent a possible blown head gasket. Just promise to never use your increased power for evil deeds!

Changing the head is easiest and least expensive way to get a good increase in power on your engine. In 1949, high octane fuel was 88 octane, and your engine was designed to easily run on 77 octane. An increased compression ratio (within reason) from shaving the head does not add a lot of stress to a relatively healthy engine, so I'd say go for it. You should see and feel your hill climbing and cruise speeds change significantly. The whole job of changing the head is much less than an 8 hour day, especially if you are swapping one head for another. I'd say you are on the right track with a head swap. The choice is whether you buy another head and have it milled, and do a swap, or remove your head, send it out for milling, and replace it. To get full benefit you will want to adjust your timing a bit to take advantage of the new compression ratio and possibly run a high octane fuel.

Sounds like nobody has done a strict before-and-after comparison of stock exhaust versus dual exhaust for gas mileage and/or HP. That would certainly be interesting. I seem to recall some magazine people doing fuel consumption test with V-8's in various cars showing that going from single to dual exhaust was just about easiest and most sure-fire way to increase both HP and mileage. Anyone know of any old articles or research done on flathead sixes?

That truck could be a real fun project and learning experience. It would be really helpful to have the model information, and perhaps a few more photos. Look inside the door jambs for plates with the model number and other information.

That plate originally would have been attached to the block just aft of the oil pump bulge. It would have been attached by 2 drive rivets. Paint might be covering up the original holes, but that's where it belongs.

Why get a 1951 automobile? It's all personal preference. My personal preference is to have a 1951 (or any other vintage period) that is actually as close to being 100% of that period as is practical. Some folks don't feel that way. Good for them. The practical reasons for going back to 6 volt include removing the broken resistor. However, if you're dead set on being practical, I would suggest staying clear of old cars and other mechanical things.

My first car was a 1951 Cranbrook 2-door. What a learning experience that was. Compared to all my friends that pushed their Chevys, Fords, Buicks, etc. that Plymouth was outstanding. Made me a lifelong MoPar fan. In your long-term plans, I'd suggest working with your Dad to bring the Plymouth back to a 6 volt system. Looks like you guys did a good job on the carb.

No. It would indicate that the timing is OK, but there are some components in the ignition system that are heat-sensitive when in marginal condition.

I believe you will find that your compression is just too weak. 60 PSI is the lower limit that you would want to ever see, and you're below that. You will probably find that the engine will start in a push-start situation at maybe 5-10 mph in 2nd or 3rd gear, or perhaps under ether with a fast spinning starter. Time to overhaul that motor.

I don't know - I think that front bumper looks awful! It's totally disgusting, and unwholesome. It is so terrible I think you should send it to me for proper disposal. Pack it up nicely and I'll even be so kind as to pay the shipping. You need to get rid of it, and I'll be nice enough to take it off your hands.

If you haven't already, get a factory (copy) shop manual. Buy the book before you do anything else.

What a great car to have some fun with! Don't bother squirting oil down the spark plug holes, as all you will do is bath the valves on oil. After removing the plugs, change the oil, and turn the engine over with the starter to get the new oil circulating before starting. If the engine won't turn over with the starter, put it in top gear, and rock it back and forth to see if you can free things up. Back when I didn't have a lot of money to spare, I'd have used any available spark plug too. There's not much harm to be done with that unless they used a long reach plug and the exposed threads have gotten corroded and that is what is holding the plug from being removed. Just be gentle with them, turning 1/8 turns back and forth to get them extracted. You don't want to exceed about 20 ft. pounds of torque. If you do end up with buggered spark plug threads, replacement heads are inexpensive, readily available and easy to change!

At the rear of the cylinder head, just over the number 6 cylinder is a 1/8 npt threaded plug. When you remove this plug, you can insert a thin rod, such as a welding rod. Set the number 1 cylinder on compression stroke. Using the rod in the timing hole over the number six piston, set the piston to top dead center by pulling the engine through by hand. You can be super accurate by using a dial indicator in conjunction with the rod in the hole. Once on TDC, you can then make a mark using a paint pen, or thin brush to mark your timing cover opposite the marks you made on your balancer. You now have an accurate pointer.

What do you want to accomplish by changing the starter and distributor?

One thing I've found out that applies across all vintage engine types is that multi-viscosity oils don't hold pressure as well as a good single viscosity oil. It's easy to see on the oil pressure gauge in back-to-back oil changes, especially on a warm day. I won't use them in any vintage engine, and I won't recommend them to any of my customers for their engines, and if I've rebuilt the engine and they have used multi-viscosity oils and have troubles related to lubrication they are on their own. Excessively thinned oil will promote smoking. In modern engines, it's a whole other story. 2-stroke engines are another thing altogether. By vintage engines, I mean: Pratt & Whitney, Lycoming and Continental radials, Lycoming and Continental flat aircraft engines, BSA, Triumph, Norton, AJS/Matchless, Ariel, Case gas engines, all older mopar engines up through the LA series V-8's.

A few comments: - If you have a damaged vacuum advance diaphragm, you will have a vacuum leak which will cause poor idling and other issues. - The purpose of the vacuum advance is to compensate for fast throttle opening movement from idle. Beyond idle, it has no function. - A failed vacuum advance will exhibit a lag when the throttle is snapped open from idle. - Industrial engines and other engines which are intended to run at steady throttle openings, without rapid opening from idle, don't need and are not equipped with a vacuum advance unit. If an NOS vacuum advance unit has been in a box for a couple of decades, it may well be good. My experience is that 40-70 year old units operate just fine. The advance unit is easy to test with lungs providing sufficient vacuum for most to operate. A vacuum leak caused by a broken vacuum unit won't cause an engine to lack power or high RPM operation. A bad advance unit (centrifigal) will cause an engine to lack power and not achieve high RPM operating speeds. Incorrect timing and fuel blockage will cause an engine to not rev up.

If you are running one, change the condenser/capacitor first. It is the least expensive of everything you will change, and is the most likely suspect.

After periods of inactivity, these flatheads will experience valves stuck in the open position. This will prevent starting. Check your compression on each cylinder to be sure.