Vacuum advance

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KosmicKuda

KosmicKuda

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1964 225 Valiant, completely rebuilt, 3 speed manual. Points ignition, all new quality parts chosen by what was recommended here. The original vacuum advance can wouldn't hold vacuum so it was replaced with a new one. I also installed a new drive gear on the shaft and set the end play per the FSM. I dug out my old test equipment and the dwell is 43*, right in the middle of the 40-45 spec. Currently set at 8* BTC static. I'll add more but that's at the limit of the adjustment slot on the distributor. (I know about the second slot underneath) It starts so quickly you can hardly hear the mini starter spin.

Future plans include converting to electronic distributor and HEI but I just wanted get it on the road and have some fun before winter starts.

It's running great and I've managed to put 180 miles on it in the last few weeks with the top down 90% of the time.

But.....when I connect the vacuum hose from the carb to the advance can, the engine bucks, misses and becomes undriveable. It backfired so badly it blew the bottom of the old muffler open so it sounds like an old hot rod. So I've been driving without the vacuum hooked up.

I hooked up a timing light and at about 1500-2000 rpm's the timing light stops flashing on #1 cylinder. I have not checked the others cylinders yet.

Anything?
 
You are attaching the vacuum hose to manifold vacuum. It should be attached to ported vacuum.
 
Needs to be hooked to the vacuum port on the carb that does NOT suck at idle. when you pick it up off idle, then the vacuum begins. Vacuum will also fall off at wide open throttle.
 
Yup, I've had exactly this situation before, and the others have probably nailed it: too much total advance at idle because your vacuum advance is receiving vacuum at idle. This may be through no fault of your own; you may have hooked up the vacuum advance hose to the correct port on the carburetor, which may have been deliberately designed to supply vacuum to the advance at idle; that was a frequent difference between the otherwise-identical "With manual trans" vs. "With auto trans" carburetors for any given application. However, you've also advanced your base timing 5.5° more than the spec of 2.5°BTDC, and your vacuum advance unit may not be to original specs, which could all add up to the gasping and skipping at idle when you hook up the advance.
 
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slantsixdan said:
Yup, I've had exactly this situation before, and the others have nailed it: you've got too much total advance at idle because your vacuum advance is receiving vacuum at idle. This may be through no fault of your own; you may have hooked up the vacuum advance hose to the correct port on the carburetor, which may have been deliberately designed to supply vacuum to the advance at idle; that was a frequent difference between the otherwise-identical "With manual trans" vs. "With auto trans" carburetors for any given application. However, you've also advanced your base timing 5.5° more than the spec of 2.5°BTDC, and your vacuum advance unit may not be to original specs, which could all add up to the gasping and skipping at idle when you hook up the advance.
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Read the part about his timing light not flashing
 
Forgot to mention that the carb is the original BBS that I rebuilt. Get this, after the install in the car I looked for the hose nipple on the carb for the vacuum advance hose and I didn't see it. Huh? Referencing a 63 and 68 FSM I saw where it should be but there was just a hole. I measured the hole at .188 so cut a short piece of 3/16 brake line and pressed it in the hole with sealer. I used my vacuum pump on the "new" nipple with the engine not running and confirmed it was not pushed in too far. In other words, it is open to atmosphere. I'll check it tonight with a vacuum gauge at idle to see if it has vacuum.

I will also confirm that none of the internal wires/terminals have clearance with the housing.

IIRC, the replacement vacuum advance unit was stamped 7.5 but it's been 8 months or so since I worked on it. Don't remember if I saved the original.

My best friend's mom passed away so I have to pay my respects tonight so stay tuned. Hey, sometimes life (and death) gets in the way.

I abandoned the Browns on TV last Sunday and worked on the column shift linkage after having to drive if home using only 2nd and 3rd gear. One rubber bushing on the lever arm was just about disintegrated so I used a hunk of sectioned 5/8 heater hose and 5/16 fuel injection hose and made a new one. Wow! Zero clearance and it clicks through the gate. It probably hasn't shifted this well for 45 years.

Over the summer I managed to pick up a correct 65 4 speed trans with the trunnion output and shifter. Can't find a bellhousing though. :-(

Also bought a crusty rusty 4 speed hump.

And....I got a 4 speed OD trans with shifter. And later bought a BH.

Driving around, I think I'd be happiest with the OD. (Currently 3.23)

Did I mention how great this car is to drive?
 
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FIXED!
Saturday, first checked the vacuum at the carb port at idle and it was zero. Speeding up the engine created vacuum so that's normal.

The distributor was at about 8* initial but the adjustment slot was maxed out. I wanted to move the under-distributor slot to center the top slot so I pulled the dizzy. Ah ha! The nut holding the points and condenser lead was very loose so I tightened it. Not sure why it was so loose but im thinking I didn't have my small ignition wrenches way back when I assembled the distributor and didn't go back and tighten it later. (My tools were scattered around 3 houses at the time)

I put everything back and bumped the initial to 10 degrees. Hooked up the vacuum hose and speeding the engine didn't cause a misfire.

So I grabbed a Hoodie and went for a ride. First stop was my son's place about 25 miles away. Of course he's a speed demon and drove it harder than I had up to that point. It definitely is not fast but it's acceptable. My daughter in law sat in the back seat for the ride and she liked it.

Stopped at 2 other friends houses in the next county and got home just in time to watch the World Series game. First time I'd seen my buddy John's new 4 post lift and it's a nice one. He had his 69 GTX on it with the corvette under.

I probably put another 80 miles on the Val without issues.
 
Lift is a Backyard Buddy 4 post made in Warren, Ohio. I think the factory may be an old Packard plant. He toured the plant, robot welders and powder coated.
He has the optional wheel casters that allow the lift to be rolled around with a car on it, though at the lowest position. Also has a movable shelf/drip pan. No floor reinforcement needed and his is the 120v model. Very nice.
 
I was driving the car a couple nights ago and the oil light flickered when going down a long hill (off the gas, just free wheeling). Drove about a mile home and backed it in the garage. No oil on the dip stick. Looked like there was some oil around the sending unit, nothing from the valve cover.

Jacked it up last night and crawled underneath. Thought I'd take off the bell housing inspection plate to check the rear main seal. I noticed there was some black dust coming out the side vent. Clutch dust I wondered? Nope, the aftermarket clutch arm boot had worked its way into the bell housing and a good portion of it was ground into black powder by the pressure plate. That boot never fit correctly from the start. Cheap Chinese POS no doubt. I retrieved the original dried out stiff original from the basement and installed it. Ahhh, good fit. So I gotta say the repop boots are junk.

Anyway, the oil pan was completely dry and so was the rear main seal area. So it looks like I lost all that oil from the original sending unit. I can actually see a trail of oil on the drive from the street to the garage. Going to order one tonight.
 
It may be time to consider going to a full synthetic oil after a long breaking period of you keep blowing out oil system parts LOL

BTW, tell your friend to be very careful with that BYB lift on casters. Not being bolted down presents some dangers. (I sure would not do it.)
 
I think I would drop the oil out of the pan and see how much was actually still in there. Or measure how much it takes to top it off. I hate short dipsticks, cuz you just never know...................
nm9,
I think the casters on that model automatically disengage when the platform rises just off the bottom.They use the platform weight to lift the corners. And they can be disengaged to not engage at all.
IIRC
 
My buddy is very thorough, anal at times, and very cautious. Yes, the casters are disengaged when lifted. In normal lift use the casters are not even attached to the posts but stored away.

It took 2-1/2 qts to top off. I drove the car with the new oil sender in place and all is well.

The exhaust gasket had blown out at the extreme rear of the head (#6 port) so I ordered and received the Remflex set. Bought off Amazon for less than $30. In the meantime I stuffed the leak with copper high temp sealer so I could drive it again and it's holding until I swap it out.

I started with Lucas Hot Rod high zinc oil that may stay in until spring. Full synthetic is probably in it's future.
 
AJ/FormS said:
nm9,
I think the casters on that model automatically disengage when the platform rises just off the bottom.They use the platform weight to lift the corners. And they can be disengaged to not engage at all.
IIRC
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I know, but that is not all of it: not being bolted down puts all the forces keeping the posts vertical at the slide joint between the columns and platforms. That puts higher stress on those joints and the area on the vertical posts where they ride, and with those inexpensive lift systems, a jammed pulley or slide point or a cable off a wheel will put even more stress at those points. These are not heavy duty lifts by any means.
 
I don't get too impressed by the BYB info. They don't give steel gage IIRC, just makes claims of the box shape being superior.... which is nonsense. It all depends on the gage and steel grade, how the slide attach to the platform, how the load gets placed on the column, etc. If you think BYB is expensive, then look at a commerical grade lift....I have just about decided to go for that versus the cheap BYB and other similar types. (But I have some heavier vehicles to service too....)

So much for vacuum advance, eh? LOL
 
AJ/FormS said:
I thought the BYB was an external slide column with full box-section towers.
I was looking to buy one of those boxed column, external slide jobs at one time. It was pretty pricey. I thought it had been this one. Oh well.
Car Lift - portable 4 post - 7,000 lb. Over Height| Backyard Buddy Car Lift[/QUOTE

Yep that's the exact one he has. It's rated for 7000 lbs. You can't sell this stuff without testing and it HAS to have a safety factor of at least 2:1. He has a 69 GTX on it now and a corvette parked underneath. It's made in Ohio, not China. BTW, the wall thickness on the tubing looks to be at least 11ga. If you divide the total supported weight, including the structure, by 4, each tube is not carrying much.

My vacuum advance is working fine thank you.
Click to expand...
 
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