47-55.1 Eliminate draft tube options

[geezer#99]

Whenever I needed to find tdc #1 I’d use my compression tester, hang it up high enough to see from the cab and bump it over with the key until it showed compression. Then moved the crank by hand to line up the marks or the bb in your case.

[leegreen]

if you take out all the plugs it turns over easier, if you leave #1 plug in you will know when it is on compression stroke

[TX3100Guy]

Originally Posted by geezer#99

If you use a factory side cover then an hei fits. They’re indented compared to your ribbed cover.


https://www.ebay.com/itm/324321238128

I know, but I like my chrome Chevrolet one.........lol

[TX3100Guy]

So, I inserted three silicon stoppers in cylinders 6, 2, and 4 (leading up to #1 being at TDC on the compression stroke). I used a remote starter to bump the starter and one by one those silicon stoppers popped and shot across the shop........ Top Tip, make sure you aren't standing anywhere near the spark plug holes when the stoppers POP.

[TX3100Guy]

I gave up on the idea of an HEI distributor since I want to run the magneto in the long run. In the mean time, I purchased an electronic (optical) distributor and coil. Now I need to complete the wiring and attempt to fire the engine up again. Fingers crossed.

[TX3100Guy]

Question: The gap on my NGK spark plugs is .020 for the Vertex magneto. What gap should I reset the plugs to for an optical distributor with a 1.5 ohm coil? I don't know for sure, because under my ownership this engine always had the magneto.

Also I found a reference that suggested tightening the plugs to 25 ft/lbs. Does this sound right?

[leegreen]

you have a unique setup, what is compression ratio and boost expected?

.035 would be typical for a 235/261
Electronic ignition can spark a wider gap, bigger spark for cleaner burn. 045 for HEI SBC

high compression & boost may need smaller gap for if the spark can't jump a big gap in a high density charge, but I doubt your going to be driving this beast that hard in the near future. I wonder if 020 is more to make it easier for magneto to spark?

030 to 035 should be pretty safe
25 foot pounds sounds about right, I just snug em up with a 3/8 ratchet on iron heads

[TX3100Guy]

Originally Posted by leegreen

you have a unique setup, what is compression ratio and boost expected?

.035 would be typical for a 235/261
Electronic ignition can spark a wider gap, bigger spark for cleaner burn. 045 for HEI SBC

Compression is very close to 9:1 and boost will likely be up to 8 psi, but that's driving it harder than I will likely run the truck. While its styling is that of a hot rod, I have no plans to take it to the drag strip.....LOL

[dsraven]

your spark plugs likely have a crush gasket on the seal surface against the head. if so tighten enough to crush the gasket sufficiently. if you look up the spark plug manufacturers site with the part number it will likley give the recommended torque
if replacing the plugs with new, the crush washer wont yet have been squashed yet so a new plug usually kinda feels a little soft as you torque it up. kinda like the threads may be starting to strip. just be carefull and you'll be fine. I suggest to try a new set of plugs with the same heat range as the old ones had, assuming they weren't fouled, because the old trucks usually ran a colder plug than, say, a car application would because the trucks were usually ran with a load so they got a harder use and generally ran hotter, requiring a colder plug. your application with the supercharger would hopefully have had that all figured out already so go with the same plug as it had rather than what the parts book says.

[dsraven]

https://talk.classicparts.com/thread...-torque.22193/

20-25ft/lbs or finger tight plus 1/2 turn with new gasket

[dsraven]

with electronis ign and a hot coil I would also say .035 is a good starting point for gap

[TX3100Guy]

Originally Posted by dsraven

with electronis ign and a hot coil I would also say .035 is a good starting point for gap

Exactly what I gapped them at last night.

I'm helping a buddy today with the carb (original) on his 1950 Chevy sedan. We rebuilt it a while ago and it will not start unless he squirts starter fluid (I use carb cleaner) into the carb. We replaced his fuel pump and he's gets plenty of fuel at the carb. I suspect either a stuck needle vavle and/or misaligned float. Hopefully, its that easy to fix.

[dsraven]

see if the accelerator pump actually squirts fuel. some rochester rebuid kits had leather pump parts and they would shrink if not used regularly. some had rubber and some had neoprene. if there is fuel in the carb it should squirt and if it squirts the flow should shoot at the edge of the throttle butterfly valve for best results. if it doesn't squirt then either the bowl is empty or the pump needs work. if it starts after having gas or whatever dumped down the carb then possibly the carb is fine but leaks or evaporates the fuel out if left sitting for extended periods. if it's not left for long periods but still has trouble starting possibly a fiber gasket under the carb would help as it may be evaporating the fuel out from the hot manifold transferring the heat to the carb. before working on it and touching or cleaning parts on it check for dirt/dust that has clung to what could be wet spots on the carb gasket surfaces etc as that would mean a possible leak. pull the top off before starting it and check to see exactly what is in the bowl, check the inlet needle to ensure it isn't allowing the fuel to drain back after the engine is shut down, and check the float level to ensure it is proper. if you have a plastic bottle with a tapered lid, like some gear oil bottles have, you can put some fuel in that and use the tapered part inserted into the fuel bowl vent (that large diameter tube protruding into the carb throat) to fill the float bowl in order to check the pump operation before pulling the top of the carb off, but that wouldn't allow you to see how much fuel is in the bowl when you first get there, if you wanted to check that.
here is a site with some info on the old rochester carb, if thats what he has. includes info on the accel pump plunger and a video I think.

https://www.carburetor-parts.com/roc...-aM8gxC72RM05d
sorry, you probably knew all this already, just trying to help.

[TX3100Guy]

I asked him about the accelerator pump and he wasn't clear on what I was asking him to look for (he's not the car guy). that's why I need to drive to his place to see for myself.

Thanks for all the things to look for. Could it be a vacuum leak too?

[dsraven]

With a vac leak they will usually at least fire but then run crappy and choke needs to be used.
Check intake manifold bolts for tightness too, since you're there.
Check heat riser operation, since you're there
Check fuel pump pressure and output, since you're there
Check fuel filter and all soft parts in the fuel supply for integrity, from the tank forward
Check steel/hard lines for damage/integrity
Check choke operation

[leegreen]

you say there is fuel at carb but no start without prime. Does it run once started or die?

Maybe he just needs to know to pump the gas pedal 3 times before starting it after it sits for a while

runs but wont idle without choke, look for vacuum leak (check wipers!) or a timing issue

[1project2many]

Question: Does your friend know he's supposed to pump the gas 2-3 times before starting the car? It sounds silly, but I've helped more than one person who's either forgotten or never known this was a part of starting a carbureted engine. EFI has eliminated most driver input during startup.

If he's pumping the gas then I'd expect dsraven's "dry accelerator pump" to be the main culprit. My '36 Plymouth carb has a leather pump cup. First startup after sitting all winter requires adding fuel through the carb. It takes a few miles of driving to before the pump starts working normally. I try to drive the car at least once per week but if it sits for 2-3 weeks the leather starts to dry out again.

[TX3100Guy]

Originally Posted by leegreen

you say there is fuel at carb but no start without prime. Does it run once started or die?

Maybe he just needs to know to pump the gas pedal 3 times before starting it after it sits for a while

runs but wont idle without choke, look for vacuum leak (check wipers!) or a timing issue

To clarify, when the fuel line is disconnected from the carb and a bottle put on the end of the fuel line and my buddy cranks the engine, the mechanical fuel pump fills the bottle rapidly with gushes of gasoline.

Pumping on the pedal and using the choke results in nothing. When he sprays starter fluid in the carb, the engine with turn over and run until that spray is used up. With a second set of hands, I want to see if it will continue to run if I spray a bit more after the initial start.

In no particular order I suspect 1) float issue, 2) needle valve stuck, 3) accelerator pump inoperable, 4) vacuum leak, 5) ?

[TX3100Guy]

Originally Posted by 1project2many

Question: Does your friend know he's supposed to pump the gas 2-3 times before starting the car? It sounds silly, but I've helped more than one person who's either forgotten or never known this was a part of starting a carbureted engine. EFI has eliminated most driver input during startup.

If he's pumping the gas then I'd expect dsraven's "dry accelerator pump" to be the main culprit. My '36 Plymouth carb has a leather pump cup. First startup after sitting all winter requires adding fuel through the carb. It takes a few miles of driving to before the pump starts working normally. I try to drive the car at least once per week but if it sits for 2-3 weeks the leather starts to dry out again.

Good points, but he's had this car for a long long time. I watched him when we installed the fuel pump, pump on the accelerator and use the choke, so I doubt this is the issue. The car does sit for long periods of time unused, so having the fuel evaporate from the fuel bowl and dry out the accelerator pump is highly suspected, but the bowl should fill back up, which makes me suspect the needle valve and/or the float adjustment.

[dsraven]

In that case I would fill the float bowl from either cranking the engine or filling through the bowl vent. Then check accel pump operation with a full bowl of fuel. No squirt means the pump isn't working so fix that first, and do other checks for vac leak etc, then try it again. Like previous posts are saying, if the old car doesn't get driven regularly then the eather accel pump cup can shrink down and bypass fuel rather than pump fuel.
If it starts and runs ok with choke, till it warms up so choke can eventually be taken off, then that's normal.