Testing Helmet On Sun Machine

[v8fordman]

I’ve been doing distributors for close to 40 years using a KRW fixture to set the initial timing, an Allen machine to rotate only and a Ford-Heyer machine to set the dwell. I use a charged 6v battery, and an original ballast resistor so any pre-41 distributor is running on my bench just as it would have been checked on a car brought to a dealer back in the day. Those who don’t set the initial timing by whatever method normally set it on the center mark so they are only guessing. If those who say it doesn’t matter want to find out if it matters, adjust your timing mark to an extreme one way or another and see what your performance and/or temperature gauge does. Don’t say “he said move it to an extreme.” Yes I did, because your initial timing is determined by where that timing plate is when you start the set-up process. Secondly, I have always had the coil on when setting a distributor up. Every distributor I have set up will change if the coil is not on there. Ford, in later service bulletins told dealers to make sure to install the coil when setting distributors up on the KRW timing fixture. Originally, this was not the case in the instructions. I guess Ford had enough case studies to make that declaration but yet it doesn’t apply today? Let’s think about that one? Seems to me that 1935Fordtn knows what he’s doing because he’s at least setting the initial timing and the others are only guessing. By the way, I have either version of the KRW fixture (wooden or metal) for sale if those who skip that step would like to start using it. I’ll even get throw in the instructions which I believe says to install the coil. I also sometimes love sarcasm.

[philipswanson]

This looks to be a pretty good video on the Sun 504 testing a helmet.
https://www.youtube.com/watch?v=8EqUH2ZnSSY

[Hoop]

First, thank you to those who posted responses ... don't know why there is never a lot of discussion on Sun testers. Maybe it's because some guys want to avoid arguing.

Sadly some of the advice offered on Ford Barn is not correct. Some so incorrect that it's embarrassing. Sometimes it comes from guys who have spent years in the auto repair business and consider themselves to be unimpeachable sources ... and who are unlikely to admit they are wrong.

One of the first things I noticed when starting to learn about Sun machines and early flathead distributors was that some of the stuff didn't make sense. "v8fordman" mentioned that setting the index to the middle was probably guessing.

I noticed that a while back and it was the first clue that a lot of distributors were being set wrong. Another clue was how often guys said that there was not much adjustment to be made for the initial advance. There's plenty enough and needs to be carefully set. On a 68 distributor with 16 degrees advance from the weighs, an addition 4 degrees initial is large ... especially when you consider when it comes in.

I hope there will be more posts on Sun techniques.

(One issue that has always interested me is why 22 1/2 degrees is so critical on a Sun when other specs call for .014 to .016 for point gap. I have my suspicions but wonder if anyone else has ever been bothered by that.)

[marko39]

One thing regarding dwell is its a good idea to calibrate the dwell gauge with a modern one. These are old electronics. I checked my 2 Dist. Testers and master motor tester with the same Dist. and they all were slightly different. I averaged the readings and set all meters to that. They then matched my brothers expensive dwell meter

[philipswanson]

Originally Posted by 35fordtn

Not understanding your question?

If that was supposed to read "how can you read dwell by .8 anyways", then the answer would be a digital dwell meter.. I did the same coil on/off test on another distributor today (a 68 series) and it made no difference on the digital dwell meter.

My question relates to: If it only changed the dwell .8 degrees when you took the coil off/on, who cares? You probably wouldn't move it again anyways. That's probably well within the tolerance of that meter. I doubt if the .8 degrees was even caused by the coil being removed and installed. Probably the machine moving slightly between tests would even do .8 degrees.

[35fordtn]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by philipswanson

My question relates to: If it only changed the dwell .8 degrees when you took the coil off/on, who cares? You probably wouldn't move it again anyways. That's probably well within the tolerance of that meter.

Well, good point as that is a minimal amount.. But, to me it matters.. Besides.. Having a coil or adapter plate (what I use) makes it easier for me as it gives a post to connect the lead to.. And it was definitely the coil affecting it as I had the machine spinning as I sat it on there. I have noticed this same affect on hundreds of distributors and it usually is only a minimal amount but there usually but not always is a change.

All in all it's just my preference to set the distributor up that way as recomended by Sun, Ford and others and it's easy so I figure why not set them up the way we are supposed to?? I can assure the first 100-150 distributors I rebuilt were setup without a coil, and none came back for a dwell issue, but in the last several years I use a coil plate as it does affect it and utilizing it makes it easier for me at least.

We each have our own thoughts, ideas and methods and I can live with that. Some ideas stated on here such as the discussion on initial timing I would argue till I'm blue in the face, as just guessing is not good enough in my book. At the end of the day we are all stubborn car guys (me especially), and will always be stuck in our own ways.

[v8fordman]

By the way, the Ford-Heyer machine doesn't even use degrees for dwell like the Sun machines. It uses % dwell with a +/- of 2% from the mean.

[philipswanson]

Originally Posted by 35fordtn

We each have our own thoughts, ideas and methods and I can live with that. Some ideas stated on here such as the discussion on initial timing I would argue till I'm blue in the face, as just guessing is not good enough in my book. At the end of the day we are all stubborn car guys (me especially), and will always be stuck in our own ways.

When you have a helmet on the Sun machine and remove the coil, are you able to wiggle the breaker plate at all? I can't on mine. Maybe the plates are just fitting too tight?

[35fordtn]

When you have the distributor apart you can usually just set the breaker plate right into the housing without the use of a hammer or press. Some have a few thousands of wiggle room and some have pratically none.

Now, if you imagine one with .005" play, once you install the coil, you are moving the breaker plate downwards which will cause the points to open slightly farther.. We are talking small amounts here, but also as we know changing the gap a few thousands makes a difference..

Certainly not arguing, as for a while I thought this was BS when I read it in service bulletins and manuals. But.. After I did notice a difference , even though it's slight, I could see why they recommend it... For me its easier as well using a adpater coil pate as I have a place to connect my tester lead to safely.

I love these discussions as we always learn something new. For example, recently a vendor I build distributors for sent me in a Distributor built by Bubba. It didn't have a problem just had a lot of miles and was time for a freshening and the vendor likely did not know it was his.. I knew it was by the painted black plate, and adjusters.. I noticed when taking the weights apart he uses shrink wrap on the shaft.. Stupidly I never thought of that.. I have used electrical tape to insulate the shaft all this time.. Heat shrink makes more sense... learned something new.
PS the few times I have had any of Jim's (Bubba's) distributors here, they are always fine units and he clearly takes a lot of time and care to service them.

[Hoop]

You are right about Bubba ... generous with his knowledge, helpful and a model for a guy you'd want do business with. I never heard him respond negatively or try to "fluff" his own reputation or guard his "trade secrets."

Learned a lot from Bubba's posts.