Mr D.

Does anyone know what the difference is between a Sun Distributor Machine model SDT, 404 and 504.

From what I have researched so far the SDT stands for Standard Distributor Tester and was produced in the mid to late 50's.

Is there an advantage over a SDT, 404 or 504 when it comes to testing 60-70's distributors?

Thanks, I have nothing else to do on a Sat night.

Plasticman

My dist. machine is a SDT and requires a separate 12 volt battery (as a power supply) for the ignition current, so it has to be at least Lawn Tractor or Motorcycle size. It also has 2 separate "D" size battery cells (1.5 volts each) that are covered by bakelite plates on the front angled surface. These 2 "D" cells power the Tach and Dwell meters.

Newer units have integral power transformers that supply those voltages, rather than my older unit that requires the batteries.

As for function, I know of no difference between the older machines and the newer units in testing of points type distributors.

I have also made an adapter so that I can test HEI distributors (early non computer type with mechanical and vacuum advance).

I also (today) tested a ProComp electronic trigger distributor (not a good sample dist., due to .020" lateral runout at the bottom bearing/shaft, but I could check the curve and output just fine).

Plasticman

62Jeff

Mine is a model PDT-5D. The operator's manual lists a 1975 publish date, but internally my machine has ink stamps from the mid 80s.



I've got the transformers for power, instead of a separate 12v source.


Plasticman became quite familiar with the insides of mine in August, helping me get it working

Mr D.

Thanks for the info and pictures, I'm guessing it would not be all that difficult to convert a SDT over to a 12V power supply for the ignition current and step down the voltage for the Tach and Dwell meters or like Plasticman says buy a lawn mower batt and 2 D cells.

Plasticman

I did convert my 2 "D" cells over to 2 separate DC power supplies. 2 were used, since the SDT uses one of the "D" cells for a 1.5 volt supply to a meter, but then uses the 2 "D" cells in series for a 3 volt supply for the other meter. Yes I could of used one supply for both, but it was "easier" this way, and they are very stable as well. That is something that could not be said about the "D" cells. Every time I would use the Sun Machine, I would have to go through the calibration procedure, since the "D" cells were constantly decreasing in output.

I have not converted the 12 volt battery, since I did not have a transformer or power supply adapter sufficient for that amount of current. Yes, I could purchase one, but I always have a spare 12 volt battery somewhere anyway.

Plasticman

Mr D.

Well I ran across a DT 404 machine that has 3 issues;

1. The machine rubber drive wheel has a flat spot, should not be that big od a deal to fix.

2. The vacuum pump is a little on the weak side only pulling 8" HG, worn pump, leak?? Who knows but I do have a vac pump I could plumb into it.

3. The 3 jaw Buck chuck has no jaws, the chuck works fine. Seller thinks he has located a set.

Plasticman

Mine had a flat spot in the rubber drive wheel (happens if someone shuts down the machine and leaves the drive engaged for a long time), so I made a new aluminum drive pulley with a groove for a large "O" ring. If I ever forget to disengage the drive wheel, I can replace the "O" ring easily.

Have not had any issues with my vacuum pump, and all my jaws are good.

Seems to me that 62Jeff had to replace the rubber hoses to fix his vacuum pump output.

Here is a pic of my well used, but in good shape SDT.

You can see the 2 "D" cell (batteries) covers in the lower right, but I added small rectangular labels on them to remind me they were replaced with power supplies (and how to adjust them - if needed).

Plasticman

62Jeff

I was getting 11" of vacuum the first time I cranked mine up. But I snipped the hard ends off of all the vacuum hoses, and re-attached the hoses, and get over 21" now. For now this was the lazy way to "replace" my hoses - just getting rid of the old ends with the well-worn holes.

504man

A SDT is from the mid-1950's. 404's & 504's were made from 1969 to 1978. A SDT has three meters- tach, dwell & vacuum, all on the right side of the machine. An ok machine, but old. A 404 is like a SDT but newer with upgrades - no batteries and spins faster, 0-4000 RPM. It too has tach, dwell & vacuum on the right side of the machine. A 504 is a four meter machine with tach & dwell on the left and condenser & vacuum on the right. No batteries and 0-4000 RPM. I would go with a 404 or 504 depending on your needs. By the way, I have 35 Sun distributor tester machines for sale.
Mark Saunders
Ph. # 616 878 9734
I'm in Michigan.

504man

A SDT is from the mid-1950's. 404's & 504's were made from 1969 to 1978. A SDT has three meters- tach, dwell & vacuum, all on the right side of the machine. An ok machine, but old. A 404 is like a SDT but newer with upgrades - no batteries and spins faster, 0-4000 RPM. It too has tach, dwell & vacuum on the right side of the machine. A 504 is a four meter machine with tach & dwell on the left and condenser & vacuum on the right. No batteries and 0-4000 RPM. I would go with a 404 or 504 depending on your needs. By the way, I have 35 Sun distributor tester machines for sale.
Mark Saunders
Ph. # 616 878 9734
I'm in Michigan.

Joel 67

504 man,

Do you have a website? Where in MI and How much is shipping typically?