hot weather and UNHAPPY 48IDAs (I am getting tired of this)

[Jim Ratto]

Just to mention......   I did try a completely separate pair of carbs on my car last summer... same jetting and vents, but different carbs.... SAME PROBLEM

 

[Rocket Ron]

I had a similar problem with my much smaller 40idfs there was some sort of vacuum in the fuel tank and got only got cured when I increased the vent size to the fuel tank.

[Jim Ratto]

sounds like I am chasing my tail with the carbs.... need to look upstream. Thanks...more ideas? Please share.
Beers for all!

[Frank LUX]

Just to mention......   I did try a completely separate pair of carbs on my car last summer... same jetting and vents, but different carbs.... SAME PROBLEM

 

If you already swapped out carbs, why don't you try to Swap Cars...   

Maybe it has a Bad Karma...try talking to her in a different way, always helped with my Car...

Do I get a Beer Now Jim...

Frank

[Jim Ratto]

Just to mention......   I did try a completely separate pair of carbs on my car last summer... same jetting and vents, but different carbs.... SAME PROBLEM

 

If you already swapped out carbs, why don't you try to Swap Cars...   

Maybe it has a Bad Karma...try talking to her in a different way, always helped with my Car...

Frank

oh brother   


 

[Frank LUX]

Or you can Ship Your Motor over to me...I'll Test it in my Car this Summer...

Frank

[Jon]

Just to mention......   I did try a completely separate pair of carbs on my car last summer... same jetting and vents, but different carbs.... SAME PROBLEM

Then it must be the engine... as in heat...
My guess

[redbluebug]

Deadhead or bypass regulator?

[Jim Ratto]

dead head red Holley

[Tony Wilkie]

Didn't you have a problem with the msd box the last time this happened?

tw

[redbluebug]

Could very well be a vapor lock issue.  I run a mallory bypass unit, really takes the load off the pump and insures cool vapor free fuel to the engine.

Didn't you have a problem with the msd box the last time this happened?

tw

Good point!    It can be a real bitch determining is it a fuel or ignition problem.  Hell sometimes it's both

[Casey]

JIm, I curious if when you let the car sit for 10 min, do you have the deck lid OPEN or CLOSED?

Next time you park it, just take the manifolds and carbs off and keep them in the cooler with all the beer. Problem solved.

I am watching this thread to see your out come. Alot of cars do this after sitting. I know of v8 too. I always thaught vapor lock. Maybe do a test and sit bags of ice around the manifolds when you let it sit. See what happens then.
See ya.

[dirk zeyen]

i think the carbs are geting to hot, put a 7-10mm pertinax spacer between mainfold and carb.

dirk zeyen

[Jason Foster]

Hey Jim,
   Could it maybe be an intake leak? possible different cooling characteristics between head and manifolds? does that make any sense? I have been having lots of intake leak probs myself lately and the issues arise after the engine has warmed up. It could be worth a shot to spray a little brake cleaner at the base of the manifolds while engine is running to see if RPM's change, or just pull the manifolds and do a check of the gaskets. Give it a little rub and a kiss and talk nice to it too....  and keep the IDA's. you'll get it.  Jason

[ugly duckling]

i 2nd what fdk/hurry said  espealiy in an extra hot engine compartment. what is it jim with your hot running engines  what are you running one of them rappid roast behind the fan  try the phonolic of coarse it would have to be some what thin if you had tall scat tracks. good luck to ya my freind. UD.

[Harry/FDK]

Hi Jim, I order my phenolic spacers from Custom & Speed Parts here in Europe. Let me know if i can help.

[Jim Ratto]

well I appreciate all the suggestions. Honestly the carbs and manifolds don't get that hot. I have a milivoltmeter with temp sensor I will go take a reading next time it gets warm out around here.
I think I need to look upstream though.... pump, filter, regulator, gauge.... 

what I may try is next time I re-start on a warm day, and it starts this crap, is crank open the regulator, above and beyond what the carbs will take, and see if it send the problem the "other" way (Rich)

thanks again... if I figure it out I will let you know.

[Peter]

So Jim,
some progress?

[Jim Ratto]

Hi ruff, thanks for asking... and the answer is "maybe"

I did what i said I was going to do in above post....  last week I resorted to 70 idle jets (!) just to experiment and see it if i could "outrich" the issue. As I expected, the car ran horribly on the 70 idles no matter what I did with main jet size (of course, too large of jets with 70's would probably be optimum for "correct" idle jets"). Anyway, I did take car on a 40 mile trip on freeways last weekend, then stopped to get haircut, then restarted car and it still showed signs of being leaner (popping at idle, very slight hesitation again). No way I was going to keep running around with 70 idles (you cannot believe how horribly it ran during the overlap of idle and main circuit...  ). I thought I would try a spare set of old idle air holders, and drill them open to 135... still way to sluggish and rich, and still that was going to nothing to cure the warm start up and idle.
Last night I did do some more snooping around. First I went back to stock 120 kair idle holders, and 60 idle jets. Idle is better, of course, transition to main circuit is much cleaner, and i did drive it this morning to work, as another "test session" (main reason I drive my Bug to work and on errands so often is to "test" mods and service work on car). The other, more important change I made last night, was I turned fuel pressure up to an "indicated" nearly 6psi on VDO mechanical pressure gauge @ regulator.... which resulted (unexpectedly) in no foul running or dribbling from nozzles in throats. Reason I did this was...well reasonS were the adjusting screw on regulator was nearly screwed out all the way to get indicated 3.0psi, which seemed odd. Secondly, I have had numerous issues with Holley pumps and regulators over the last 17-18 years, never been stranded, but i have had pressure and volume issues (maybe kafercup remembers my regulator/gauge issue that hot day we went to Point Reyes? ). I think, at this point, the culprit is the gauge is lying to me. I don't think stock Weber needle valves can withstand "6 psi" without flooding bowls. Before I closed the decklid last night, I lowered the regulator pressure to an "indicated" 4.5psi and left it. In about a half hour I am going to take my lunch and go warm the thing up on a test and try things out. Will let you know.
Thanks 

[Peter]

lets hope its just the gauge then ..
i ll keep my fingers crossed 

[Harry/FDK]

Any (good) news Jim ?

[Martin]

You can get the holley regs that return to the tank, (Bypass) so the fuel isnt stopped. when the pump is on the fuel always returns to the tank, this will help keep the fuel cool. so and vapour locks get pumped out.


Might be worth a try.


Theres always fuel injection

[Allen Wiess]

Jim,

I can't stand it anymore................... EFI 

[Jim Ratto]

ok, update

found one float is the later type with the down-travel limit tab. After looking at this for a half hour or so tonight I saw what "might" be happening. When the carb cover is bolted up, the needle valve jerks float "back" (which is actually "up"), closing needle valve partway, though I can't see by how much. I swapped this float out for an older type, without tab there. Also RESET floats again

6.0mm above carb body (crest of float)
0.953" (24.2mm) from body to needle valve tab
25.0" needle valve height.

Spent about an hour getting the floats as close to perfect as I could with depth mike.

It's 1:20am so I am not about to go fire it up.

More tomorrow.

[Bruce]

Next time you're in there, check to see if the float can drag against the wall of the float chamber.  I have seen a couple like that.

[Jim Ratto]

I am very pleased to report..............


after 8 fricking years of fighting this and chasing my tail...... the goddamn thing is FIXED!

it WAS the float tab against the needle. Drove the car today (92F out) for a good 30-40 min, got oil to 180-190F, went shopping for beverages, come out from store, and no more lean idle, no more huge hole and lean snag in transition.... it runs well. What a weight off of me..... I was ready to take drastic measures....

My last suspicion before I found the float....  that hot air off Setrab fan-cooler was cooking AN-6 fuel hose under car, so I was sizing up making an air dam for the cooler.... which I still might anyway 

Now I only want to finalize emulsion tubes, F11? F2? F4? which one enrichens accleration at mid rpm?

Thanks to everybody.... 
Jim

[Diederick/DVK]

Glad to hear that Jim!
Nice one

[redbluebug]

Good job Jim

[Rick Meredith]

Great Jim! So I should put away my catcher's mitt then?? 

[Jim Ratto]

More driving and no signs of the dreaded hot-start miss.