69 Dart Hard to Start When Hot, Starts Fine Cold. Vapor Lock?

[slantsixdan]

I have to disagree with your statement.

Go watch a few—or a couple dozen, or a few hundred—carbureted cars running with see-thru fuel filters, then come back and tell us what you saw. Or, shortcut: go lookit what people are saying about this on other-brand forums

The filter like the oil filter

Not quite, no. Similar idea, but different details in how fuel filters are configured versus oil filters. The air/vapour bubble taking up most of the filter volume is deliberate; if it weren't there, the carburetor would tend to flood a lot more and worse because fuel pump surge wouldn't be damped out by the "shock absorber" effect of that vapour/air bubble, and fuel expansion with heat would force liquid fuel into the carb.
(1/2)

 

[slantsixdan]

(2/2)
Here's Chrysler figuring that out for '63:

 

[Bewy]

Whether the filter is filled with fuel depends on it's orientation....
If it is vertical, it will fill with fuel..no air.
If it lies on it's side [ horiz or nearly so ], it will fill with fuel until the fuel level rises to the top of the exit hole. Above that is trapped air, an air lock.

 

[Casca 2525]

Hey guys, lurker here turned member today.

My 69 Dart Slant 6 runs like a top, but has a VERY hard time starting when hot (lots of cranks). I heard it could be fuel vapor lock based on what I've read on these forums. Something about the fuel line being close to the exhaust manifold.

Is this what's happening based on this pic? If so, what is the fix?
A/C car, has been removed and choke functions correctly.
TIA !
had an 86 B250 with a leaning tower of power, it would randomly stall on hot days/nights, and act like it had ran out of gas, my steel fuel line and steel leak down fuel filter went straight up over the rocker cover, I used adhesive pipe wrap and put 3 layers deep and it solved my issue

 

[Brooks James]

That hot start problem is a symptom of a dying Holley 1920 series happened twice to me, on 2 carbs

 

[Casca 2525]

That hot start problem is a symptom of a dying Holley 1920 series happened twice to me, on 2 carbs

was that in ref to what I posted or for op?

 

[AJ/FormS]

My experience with slanties is that they are very difficult to flood.
When mine got ornery, I just pumped the intake full of gas, floored the pedal and cranked it! It never failed to start.
But when the compression goes away, they don't suck no more. Well they sorta do, but if the fuel ain't in the air coming past the throttle-valve, well, whatever is laying on the floor of the plenum is gonna stay there until the engine fires up, and then, the fast idle better be working ...........
In your case, I would start with a valve adjustment, followed by a compression test.
Neither of my smog era slanties ever liked the factory lash settings. I "hot" set mine to .013intake and .023 exhaust, BUT
on every old slanty I ever had, the valve stems had beat grooves in the rocker arms and the lash could only accurately be set with a narrow enough feeler that properly fit into that groove.
I say hot-lashed but, by the time I got the plugs out and the VC off, she wasn't hot any more; so she just got what she got, and the lash I used just flat worked. I went into the job having previously marked my balancer for TDCs of the various cylinders, so, I just used TDC for setting the lash, as each cylinder came up, in the firing order. Thus lashing only takes a couple of minutes.
If I set the exhaust even just a lil tight, I had problems. However, I run all my engines at or just over 195 on the IFR gun, so that might have something to do with it............

 

[Casca 2525]

My experience with slanties is that they are very difficult to flood.

my 225 was terrible for flooding, once it was flooded the only thing that unflooded it, was pull the doghouse, and pull the back 4 plugs, then lite the cylinders off with a propane torch, after that put the plugs back in and it would start right up, as with typical Canadian winters, this got old really fast

 

[RustyRatRod]

(2/2)
Here's Chrysler figuring that out for '63:

View attachment 1715964517

Yall can argue and scoff all you want, but Dan is dead right here. Chrysler didn't waste time on these bulletins for nuthin. They knew what they were talkin about. As usual, thanks for your contributions, Dan!

 

[AJ/FormS]

my 225 was terrible for flooding, once it was flooded the only thing that unflooded it, was pull the doghouse, and pull the back 4 plugs, then lite the cylinders off with a propane torch, after that put the plugs back in and it would start right up, as with typical Canadian winters, this got old really fast

Well I shouldda said that my experience was with well-tuned, well-maintained engines, with correctly functioning parts including the chokes.
I too live in Canada, in Southern Manitoba, and one of those slanty cars was a 1980 Volare fb. Of all the carburated winter cars I have owned since 1969, this had to have been the best starting, and among the best driving, and Boy-O-Boy could she buck snow. certainly the best slanty.
I/we, my entire growing-up family, together, drove that car, until she wanted to fold up in the middle, from 1994 to around 2017, by which time, she was a back-up car, but still a great beater..

 

[SIX225]

Check the heat riser. Mine tends to stick occasionally.

 

[Casca 2525]

Well I shouldda said that my experience was with well-tuned, well-maintained engines, with correctly functioning parts including the chokes.
I too live in Canada, in Southern Manitoba, and one of those slanty cars was a 1980 Volare fb. Of all the carburated winter cars I have owned since 1969, this had to have been the best starting, and among the best driving, and Boy-O-Boy could she buck snow. certainly the best slanty.
I/we, my entire growing-up family, together, drove that car, until she wanted to fold up in the middle, from 1994 to around 2017, by which time, she was a back-up car, but still a great beater..

wow I must have really bad luck if that old b van even thought about snow it got stuck, my next was an other b van but it was a maxi, I had about a half ton of frozen news print I got shafted with and it still got stuck to, it was a lots easier to start though, it had the magnum v6 with tbi

 

[AJ/FormS]

wow I must have really bad luck if that old b van even thought about snow it got stuck

was that an 80s van?
My brother had one of those with a 360 auto in it that ran like crap. He brought it to me, and told me about all the mechanics that had worked on it and nobody could make it any better. Well long story short, he made me a deal I couldn't refuse, Oh boy.
So
I went to check the timing on this pig and could not find a mark. Finally I put the crank up at TDC #1 compression, pulled the doghouse, drilled a window in the BH, and center-punched the convertor, then inked it all up. Then the dial-back told the tale, what a POS that distributor was. So I fixed that and it still ran like crap, just not as crappy as before. So I pulled that big 2bbl off the intake, and started drilling everything in sight. IDK how many time I pulled that stinking carb off, she was sooooo lean.
Finally, she was running not too bad, but none too good either, so I started giving her more and more timing, and she started to perk up. So I pulled the VA out, and started sawing at the tabs to get closer to the timing she wanted.
Eventually, I thought she was running pretty good so called up my brother.
Well, I can't begin to tell you how happy my brother was. And the beast even got waaaay better fuel economy. My brother paid me a ridiculous amount of money for that job, but before too many months went by, he called me and noted that he was coming up on breaking even with the fuel-economy savings, and the power increase together with the better driveability, was a well-appreciated bonus. sand yes, he was a very happy brother.
BUT
I'm never gonna work on another one of those (I think it was a Holly) carbs. Next time, if there is one, I'm just gonna put a 4bbl on it.

How it was in the snow, I never asked. but I noticed that the tires were always newer, and it mustahad a pretty good alignment cuz the tires always looked pretty decent. and a good alignment especially in the winter, is crucial. And no, those tires were not 8-plys lol. I think they were P-types, which is 2+2.

So what is your opinion on that old Chrysler TBI ? I've never had one, and ain't planing on getting one either, lol. I have no opinion on those.

 

[Casca 2525]

was that an 80s van?
on that old Chrysler TBI ?

Yes I had a 1986 with the slant6
They were a bit of a mess right from dodge, it was a B250, so a 3/4 ton but it had the "light" front end which translates to the fact that I broke a lot of upper control arms I delivered a bulk route the the bigger of the 2 flyer delivery companies that meant loading the old girl with bags of flyers, on a busy week there were 4 layers and unlike ford and gms the b250 was a unit body with 5 bolt rims, the other van was a 1990 maxi van, it had the magnum v6 with a tbi, like isaid in another thread it didn't matter how cold it got I could always count on it to start right up, the 86 is the one that flooded ever single cold day, both of them got stuck if they even thought about snow

 

[Casca 2525]

Yes I had a 1986 with the slant6
They were a bit of a mess right from dodge, it was a B250, so a 3/4 ton but it had the "light" front end which translates to the fact that I broke a lot of upper control arms I delivered a bulk route the the bigger of the 2 flyer delivery companies that meant loading the old girl with bags of flyers, on a busy week there were 4 layers and unlike ford and gms the b250 was a unit body with 5 bolt rims, the other van was a 1990 maxi van, it had the magnum v6 with a tbi, like isaid in another thread it didn't matter how cold it got I could always count on it to start right up, the 86 is the one that flooded ever single cold day, both of them got stuck if they even thought about snow

Oh and I was going to say they had a light and heavy front end, the upper control arms are different on the light the thickness the control arms were pressed out of was thinner so once I had depleted all the auto wreckers I had to get my bil to well them up so I could drive it to the scrap yard, and that's when the 1990 came into my life it had heavy front and the rear had 7 rather the the 4 in the 86, the a arms were thicker and they came from dodge with strengthening gussets welded in