Or just advance it a couple of degrees and see if it gets better under load?
I can't drive 55
- Thread starter MatthewMcD
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I got a spring kit for my old 60 series dizzy, I chose the springs that, reportedly, we're all in at about 3k RPM. I haven't looked at my new dizzy springs. I don't think my springs are all in at idle, I have good acceleration up to 3500, can go to 3800 with little effort. There's not a lot of ported vacuum, it's got to be the mechanical advance working.
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pb4ugo
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In your case I wouldn't change a thing. You gotta to get it running correctly 1st, and I don't think timing is the issue.
My engine is different. You can find your mechanical advance # with the adjustable light. Typically most engines mechanical advance is all in around 3000 rpm. Disconnect the vac line and plug it. Use the light, tdc mark and pointer. Rev to about 3000 rpm and adjust the light so tdc and pointer line up. Your number will be total advance.
Total - base timing=mechanical.
You might notice that the mechanical comes in sooner than 3000 rpm, if it does note the rpm. Fyi, You've already checked mechanical operation by twisting the rotor.
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Sounds like your tank vent is plugged. Leave your gas cap off give it a try. Could be the problem.
MatthewMcD
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- #165
It's a new gas tank, hoses and gas cap. I assume you mean the separator (or something in that circuit)? The one-way valve is working. (At least it was when I redid the fuel lines.) The valve should allow pressure to pass out from the fuel separator, right? (Another thing to check isn't ass backwards.)
I'll try it out today.
Just my perspective. And by the way, this thread is really entertaining. Static timing has to be compatible with starter-cranking, and unleashing the torque-beast at rpms below idle speed (where normal engines tend to stall with inclines and no throttle). Avoiding a situation where the compression-stroke is working against combustion chamber pressure will work in favor of performance (keeping the engine rotating clockwise) and reducing wear. Engine and ambient temperature plays a big role in how atomized the fuel-charge is and how fast that fuel will burn, as does the introduction of EGR. Ported vacuum addresses driving using an intake charge above idle, but not much throttle. Ideally, combustion chamber pressure works in concert with the leverage that the connecting rods can exert on the crank, and the crank needs to be in a particular position, or angle.
I observed nothing by removing ported vacuum advance. Also, it seemed a bit harder to hot re-start at 14 btdc, than at 7 degrees. My conclusion is, without a dyno, who knows? Therefore, keep it closest as I can to factory. I've installed a new factory distributor, which isn't saying much as the original 2F vacuum retard system was complex with a computer-controlled vacuum source, and it had to also function for EGR. With the new dissy, I've insured that the centrifugal weights and springs aren't rotten. Also, focus on the dwell-setting, check cable-resistance, the cleanliness of the cap and rotor. My plugs foul kinda easy, so I gap them with the narrower F-engine setting, and I clean them at the frequency of oil changes.
I observed nothing by removing ported vacuum advance. Also, it seemed a bit harder to hot re-start at 14 btdc, than at 7 degrees. My conclusion is, without a dyno, who knows? Therefore, keep it closest as I can to factory. I've installed a new factory distributor, which isn't saying much as the original 2F vacuum retard system was complex with a computer-controlled vacuum source, and it had to also function for EGR. With the new dissy, I've insured that the centrifugal weights and springs aren't rotten. Also, focus on the dwell-setting, check cable-resistance, the cleanliness of the cap and rotor. My plugs foul kinda easy, so I gap them with the narrower F-engine setting, and I clean them at the frequency of oil changes.
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MatthewMcD
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- #167
Tried to pull the muffler yesterday. The way the PO installed the muffler, I cannot get it off the truck without grinding off a welded mount. (That weld is right next to the unused OEM muffler mount that is removable!) I'll add that to the list.
I did tap around the body of the muffler and didn't hear any dead spots that might indicate an issue. Looking in the tailpipe I don't see any evidence of critters. So, for now I'll move on.
Today I'll take another look at the distributor and see if I can ensure the mechanical advance is working.
I did tap around the body of the muffler and didn't hear any dead spots that might indicate an issue. Looking in the tailpipe I don't see any evidence of critters. So, for now I'll move on.
Today I'll take another look at the distributor and see if I can ensure the mechanical advance is working.
I am sure hoping it’s just a fuel thing…!
RevISK
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Well make a race tractor out of that thing yet.
A suggestion. Not sure if you can swing it.
1. Confirm your fuel pump is delivering fuel at idle and when you rev engine. Disconnect fuel line to carb and use a paint cup to measure quantity of fuel for 5 seconds of flow at idle and at 3000 rpm. Latter should be a higher.
2. If above checks out, find someone with a good working carb and switch it in. Try to see if speed improves. If it does, its your carb.
3. If it is not your carb, find someone who us willing to switch out their good working dizzy to yours and see if speed issue resolves.
4. If above fails, its in your driveline somewhere.
Not the easiest route, but process of elimination will get you off analysis paralysis.
1. Confirm your fuel pump is delivering fuel at idle and when you rev engine. Disconnect fuel line to carb and use a paint cup to measure quantity of fuel for 5 seconds of flow at idle and at 3000 rpm. Latter should be a higher.
2. If above checks out, find someone with a good working carb and switch it in. Try to see if speed improves. If it does, its your carb.
3. If it is not your carb, find someone who us willing to switch out their good working dizzy to yours and see if speed issue resolves.
4. If above fails, its in your driveline somewhere.
Not the easiest route, but process of elimination will get you off analysis paralysis.
Simple stuff, is the choke-butterfly opening fully? Is the throttle and cable or linkage working like it should? There is a fuel-inlet filter on the carb that could be restricted. This is one of the more desirable alternative carb options, in my opinion.
Stock mechanical fuel pump? Not clogged fuel filter?
MatthewMcD
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- Thread starter
- #172
The choke is opening fully. Throttle cable works correctly (now).
I'll check the condition of the filter. I assume you mean the one pictured in this post: I can't drive 55 - https://forum.ih8mud.com/threads/i-cant-drive-55.1347969/post-15664287 I don't think this is a serviceable part, but I'll see what I can see.
Yes, stock fuel pump.
Fuel filter looks good, but I can replace that easily enough.
MatthewMcD
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- #173
I wouldn't say "paralysis", I am actively looking at all possibilities and ruling out items that could be issues. This truck sat for a LONG time before I bought it. There are systems, like the exhaust, that I haven't gotten into.
I have a replacement carb on the way.
I'll have a look at fuel pressure today or tomorrow.
Every carb I've worked on has a screen at the fuel inlet. Typically, they come with rebuild kits, however, they usually only need cleaning. Something like part number 14 - Rochester B, BC, BV Diagrams and Exploded Views - https://www.carburetor-parts.com/diagrams-exploded-views-rochester-b
In @RevISK photo, what is the abbreviated metal fitting, at the valve cover-side doing? Is it capped? On a Rochester carb, it appears to be a vacuum source for the distributor, or choke-breaker.
MatthewMcD
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- Thread starter
- #175
This carb does not have an internal filter, it uses the external one labled #1. (I am picking up a replacement today.)
I think #3 is the hose you are talking about. It is vacuum to the distributor advance. #2 has been plugged, in true '40 style, with a torx bit for as long as I have been driving it.
I will try a new carb this weekend
Carb just landed on my doorstep!
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There are occasions, now that i am home more and older , I’ll watch “ The Bold and The Beautiful” to keep my wife company during lunch. That is some soap opera…who is doing who, cheating with whom, etc etc…
@MatthewMcD THIS SAGA IS SO MUCH BETTER… I can’t wait to find out the fairy tale ending
@MatthewMcD THIS SAGA IS SO MUCH BETTER… I can’t wait to find out the fairy tale ending
77mustard40
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She's probably pregnant... seriously lets see a photo from the other side of the carb where 2 originates
MatthewMcD
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- #178
fyton2v
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When you put a new carburetor on there, your rig will be capable of doing wheelies.
77mustard40
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Wow the base of that carb where it attaches to the adapter plate is tiny, I wonder if you just cant enough fuel / air to feed the motor? What's like shifting up through the gears, does it seem to want to pull to a redline or does it run out of steam in the shorter gears before the rpms get all the way up?
