'53 B-4TA-190 Fire Engine

[E37Bruco]

Drained the rear tank, filled the front with fresh gas. Fixed a small leak on the rear ....found a leak on the front ??Waiting on new plug wires still, been swamped between work and hunting season. 

 

---------------

 

Once I get her fired back up, what's the best way and order to adjust timing, idle rpm, idle mixture?

 

I'm struggling to understand the timing instructions, it says timing is TDC with mechanical advancement max 16-20* at 2240rpms....so 0* at idle and throttle up to 2240 and be between 16-20*? Then it also mentions +/-4* is acceptable at idle and references the distributor plate markings lol I got timing light with a tachometer on it that works with 6 VOLT motors. Also is it cylinder 1 or 6 haha everyone says different things. 

 

I know 450-500rpm is idle, the idle mixture screws are currently 1 screw rotation out per manual. Then it says to fine tune that with a vacuum gauge, is that adjust until the vacuum reaches its high amount with a indicator steady needle? I assume remove the plug below the carb and screw in a vacuum gauge there. I'll have to make an adapter. 

Edited November 14, 2023 by E37Bruco

[Merle Coggins]

Use your timing light to set the ignition timing to TDC using the markings on the crankshaft damper/pulley. With today's gas many people will advance that some. I run my truck at 5* BTDC. To be able to check the advance at 2240 RPM you either need to have marks on the damper/pulley that you can read at that advance, or use a timing light with an advance setting. The light I have has a dial on the back. As I increase the RPM I can turn the dial to keep the TDC mark in view. The dial will register how much advance you are getting. 

 

Either #1 or #6 will work for checking the ignition timing as they are both at TDC at the same time. One will be at the end of it's compression stroke and the other will be at the end of it's exhaust stroke. I've also heard guys recommend just clamping your timing light pickup to the coil wire to get a brighter light. I've tried it and that works too. It's not really brighter, but it's flashing 6 times faster so it appears brighter. 

[Dodgeb4ya]

Hardest part of timing one of these engines is bringing up the timing marks located on the  center of the dual pulleys....you have to sand this hard to access area between the pulley grooves. Belts are in the way.

Shown is a picture of of the timing marks...

Adjusting the idle fuel mixture is pretty basic..

Engine fully warmed up...you then slowly turn the mixture screw CW inward till engine the engine just starts to slow down/ idles rougher just a bit.

Then back out the screw CCW 1/2 TO 1 turn to obtain the smoothest idle.

Repeat on the other carb.

Might have to repeat this on both carbs again ...Simple.

One thing to note though is both carburetor throttle plates at closed idle need to be set exactly the same for both carbs. Properly adjusted throttle linkages are also critical when setting base idle throttle plates.

If they are not exactly the same opening at slow idle it affects how smooth the engine idles.

These engines normally idle perfectly smooth... smooth...smooth if the carbs are set right.

A Uni-Syn sync tool can do wonders setting up multple carbs but not necessary if you follow the shop manual procedure.

There's a techie learning curve setting up dual carbs 100% correctly.

So for now I think you should only set timing at a slow 450-600 RPM idle speed.

As mentioned above by Merle a bit advanced 2-4 degree's before TDC. Probably 4degree's.

This because of todays fuel.

Then set both idle mixtures for now best you can. Get clean fuel in it and new plug wires...then hopefully get some driving time on it.

You have enough on your plate as is right now.

Get it driving good enough and later go back and do more difficult fine tuning.

Once right it's set for good.

 

[E37Bruco]

That's gonna be fun to clean up so I can read the notches haha

 

I have an timing light with a digital tach and advance indicator. So I can get it to 2240 rpms and check the advancement. Is it still timing light on cyl 1? That's more so my confusion with all the cylinder 6 talk in the book. I'll have to look closely then to find the cylinder 6 peep plug. I think it's hidden under the massive throttle linkage.

 

Also if I'm reading the book correct, the 1 mark on the distributor indicator should mean I'm roughly 2° advanced currently? If everything is right 

Edited November 15, 2023 by E37Bruco

[Dodgeb4ya]

I'd use #1 for no confusion.

I'd also just worry about the timing being checked at idle speed. You can see what you get at higher rpm's but it will probably be in spec...I have never had any issues with these very plain and simple distributors.

I have checkef a couple of mine on a Sun machine...none out of calibration issues. The centrifical weights cannot be stuck and the shaft bushings cannot be worn.

Yes each mark is 2 degree's on the dizzy.

Each mark on the crank pulley is 1 degree.

 

[E37Bruco]

Is this the #6 plug you pull to check tdc and cylinder travel 

[Dodgeb4ya]

Yes it is....

[E37Bruco]

Got all these damn gas leaks fixed haha. I have the motor currently at TDC, will set the timing. Also cylinder #6 is 5" of stroke, so she's a 377

[Dodgeb4ya]

Did you ever try to get the build sheet from Chrysler or who ever they are these days??

[E37Bruco]

No I have not. I started looking into it and I can't remember why I stopped

[Dodgeb4ya]

You probably want to be driving "Bruco" before history searching at this point...?

[E37Bruco]

Ok. I'm idling at 500rpms. Still at 0° timing. Trying to advance it some. The distributor will not rotate at all. The plate on the bottom does if you loosen the 2 bolts into the block and the bottom bolt that looks like a shaft clamp. 

 

My assumption is the bottom clamp bolt is supposed to stay time and the distributor rotates. 

[E37Bruco]

Disregard. Got it broke loose. Set at 3° advanced. 520rpm idle and mixture screws set. 

 

Time for road test. 

[E37Bruco]

Road test went amazing! She has so much power and purrs right along. No issues again with the engine. 

 

 

Also the rear 2speed is still trying to switch to high while you're in 4th and 5th cruising. Should I pull the diaphragm and have it rebuilt? Maybe a broken spring? Can also hear the gears back there occasionally when coming to a stop with the clutch disengaged, like the shift forks bouncing between high and low, or bad backlash on the ring/pinion. It's not all the time tho so i want to rule out the ring/pinion.

Edited January 9 by E37Bruco

[Dodgeb4ya]

Great you have the engine issue fixed!

As for the 2 speedrear end...

When the shift button is pushed down the rear axle should never be able to upshift. It stays in low range.

Pull the button up... vacuum is sent to the rear axle shift diaphram...let off the  gas for a second the axle shifts into high.

If the rear axle shift diaphram gets no vacuum it cannot upshift into high range at all.

So..look at

**A incorrectly adjusted shift button cable that operates the control valve on the firewall..

**You need to check that the shift cable operates the control valve fully both up and down. The Control valve is on the passenger side of the firewall

** The control valve internal seat gasket could be damaged and leaking admitting vacuum to the rear axle causing un- controlled upshifts.

** Check all the vacuum lines and flex hose to the rear axle diaphram for damage cracks and vacuum leakage..

**It is possible the rubber diaphram and or spring are damaged...diaphram might have cracks or is stiff and not flexible, return spring is broken.

**A quick check to be sure it can stay in low range is to disconnect the vacuum hose and plug the vacuum line to the engine...drive it. Should only stay in low range.

If it still tries to upshift or make noise the  diaphram spring is weak/broken or the rubber diaphram is hard and not flexible. Or bell crank/ shift collar issue. Unlikely.

**There are two screws on top of the differential to adjust the shift collar bell crank inside the axle...don't mess with them until all othet avenues are exhausted.

 

[E37Bruco]

Ok. I plan on removing the shift control cable and vacuum valve to go through them meticulously. There isn't a lot of travel going from low to hi, it only moves maybe 1-1.5" up. I wonder if it's never really pushed down enough for low to maintain. I saw a video of a Chevy 2speed rear and that control knob came up like 3".

[E37Bruco]

Going thru photos i found this. If I drove with it like this it would be in high 

[wallytoo]

hard to say, but it might be worth looking into.  that's probably all related to the firewall control, and the adjustment of the cable there.

 

fwiw, here's mine in low position...and the total movement up/down is only about an inch.

 

 

again, could be all about the firewall mechanism adjustment.

Edited January 10 by wallytoo

[E37Bruco]

This is the vavle I have. Not the Eaton one. Part number brought up a Ford one on eBay. There it showed the bottom port plugged. Mine isn't. (Photo is rotated sorry) mines intake vacuum on the left, to rear axle on the right, speedo adapter out the back. 

 

With the adjustments it's definitely an easier movement and can feel the click when pushed in. Drove it a little without issue but really need to get it up to higher speeds to test. 

[Dodgeb4ya]

It is the factory Dodge control valve...

The shift cable on yours has been changed at some point.

Black vinyl covered cable ...

As wallytoo said only an 1" of shift button movement up/down. Should be easy movement too...not sticky or uncomfortable to pull/push shift button.

 

Edited January 15 by Dodgeb4ya

[E37Bruco]

Is the threaded hole on the  bottom solely for securing it to the firewall bracket? Just making sure that doesn't need plugged

[wallytoo]

yeah, as bob notes, that's the factory firewall control.  same one in mine, even though i have a smaller eaton 1350 2-speed.

 

 

[E37Bruco]

Look at you with factory fresh air lol

[Dodgeb4ya]

9 hours ago, E37Bruco said:

Is the threaded hole on the  bottom solely for securing it to the firewall bracket? Just making sure that doesn't need plugged

That control valve bottom hole is a 3/8" X 24 tpi bolt hole.

The 1-1/2 thru 2-1/2 trucks use that bolt hole to  mount the 2 speed rear axle  control valve on a rubber insulated bracket to the firewall... up at the approximate height of the single carb air cleaner as used on most all 1-1/2 thru 2-1/2 ton trucks.

On the bigger twin carb Moly Block 30" long engines the control valve has to be mounted down lower on rigid 1/2" tubing....not using a firewall mounting bracket.

The reason is the rear carburetor is right up close to the firewall.

So that lower threaded hole is not used.

[wallytoo]

9 hours ago, E37Bruco said:

Look at you with factory fresh air lol

 

oh yeah.  for whatever reason, this truck had a host of features that in subsequent years became options for most.  it has twin sun visors, fresh air and mopar truck heater, triple bumper over-riders, extra fishbelly frame plates on the rear of the chassis, vacuum booster brakes, vacuum 2-speed eaton 1350, corner windows, hood ornament, etc.  did not have a radio or ash tray, windshield washer, etc.