Daytona Carb problems

[Steve Meltzer]

A quick look at the debris on a gauze pad, using a magnifying glass, shows metal shaving and bits, as well as some brown stuff that looks like parts of an insect wing! s

[Steve Meltzer]

Wrenched and winced a bit last nite. Drained the tank completely and the fuel from it was clean...no debris and none of the metal shavings I'd seen in the bowls. The little filter in the glass bowl had some metal in it, as did the bowl, per se. The bigger, spin on filter was clean. Running clean fuel from a bucket, forward produced more of the metal shavings in my catch basin. I think the metal bits are coming from the fuel pump(s), tho' not sure how to tell which one. (The bottom filter of one had a sl. amount of debris, not too impressive, and the other, none.) Does this make sense? Replace all hoses with the pump R&R? Use correct, expensive, fuel line hose or O'Reilly hose OK? Thanx. steve

[tyang]

Wrenched and winced a bit last nite. Drained the tank completely and the fuel from it was clean...no debris and none of the metal shavings I'd seen in the bowls. The little filter in the glass bowl had some metal in it, as did the bowl, per se. The bigger, spin on filter was clean. Running clean fuel from a bucket, forward produced more of the metal shavings in my catch basin. I think the metal bits are coming from the fuel pump(s), tho' not sure how to tell which one. (The bottom filter of one had a sl. amount of debris, not too impressive, and the other, none.) Does this make sense? Replace all hoses with the pump R&R? Use correct, expensive, fuel line hose or O'Reilly hose OK? Thanx. steve

Hi Steve,

I'm trying to imagine what part of the fuel pump diaphragm could cause metal shavings to end up in the filter!?!

You can use O'Reilly hose clamped to the barb end of the fitting, but it sure looks like crap in a Ferrari engine compartment!

Tom

[DWR46]

Tom: I do not think there are any rubber diaphragms in a Bendix pump. I have never seen one of them come apart like Steve is describing, but it could be possible. As to fuel line, if he doesn't want the expense and complication of the original leather wrapped line, he should at least buy "fuel injection" hose as it is much longer lasting and higher quality.

[tyang]

Tom: I do not think there are any rubber diaphragms in a Bendix pump. I have never seen one of them come apart like Steve is describing, but it could be possible. As to fuel line, if he doesn't want the expense and complication of the original leather wrapped line, he should at least buy "fuel injection" hose as it is much longer lasting and higher quality.

I stand corrected! I got my Steve's 365GTB/4 problem confused with the other Steve's 365GT 2+2. It's hard to keep track of all this troubleshooting! Thanks!

Tom

[Steve Meltzer]

In trying to make a diagnosis in medicine, I hate ambiguous data, and I sorta have that here. I spoke with another Ferrari expert, Terry Myr (no relation to Jim...I already asked!), who, like you guys, very seriously doubted that the fuel pumps could be chewed up like that. I blew out the main fuel line after the glass filter and before the carbs. I blew it out 3X in each direction, with compressed air, always with a nice clean white surgical pad to catch the crap...no debris, nada. Then I ran a 4-5 gallons of clean fuel through only the pumps and the glass bowl and into a clean bucket, got a couple of specs of debris, small, didn't look metallic, seemed minimal...much less than I had seen in a single carb bowl. Then I ran 4-5 gallons of clean fuel through the pumps, glass filter and all the way to the carbs, but caught the gasoline in a clean bucket before it got to the carbs (sorta like the air compression test I'd done earlier, but with fuel). Again, a few small pieces of trash, nothing too exciting. So, I'm not sure what the source of the debris is, but it's not the pumps. My plan: replace the main line, new filters carefully seated (I understand that sometimes they don't seat well and thus don't properly filter the junk), clean all of the jets and emulsifiers and see what happens. Comments?

Is there a way to do any good at cleaning the tank, without pulling it out?
Would a boroscope help in viewing the inside of the tank?
Hints on replacing that long fuel line?
Best source for replacing the fuel line? The usual suspects? (Ohland, McCann, GT parts, etc)

Guys, thanx so much. steve

[zac]

Hello Steve,

I have been reading along, I think you are headed in the right direction with the long fuel line. I have replaced a couple of them and let me just say they are bit of a pain but a necessary evil to change out. Ferrari used a mild steel pipe to go from the rubber hose out of the fuel pumps to the engine bay where another rubber fuel hose takes the fuel to the back of the carburator fuel rail. Since the fuel rail is steel and located in the drivers side rocker panel that is prone to moister and rust to begin with you can only imagine what happens to the fuel line inside of there. You have to remove the drivers side wheels and remove the splash gaurds inside the fender, the fuel line is tack welded to the ouriggers deep down inside the rocker so a takes some patience to get the whole line out. I have been running 10mm cooper fuel line in place of the steel to prevent the rust issues in the future, without doing major body work you have to come up with an alternate way of attaching the line inside the rocker. I think using the original Aeroguip 2556 3/8" fuel hose is only a $30-50 expense so I don't see why you would use anything else, the cloth wrapped fuel hose is much better quality and will last for another 30+ years so it is always my opinion to do it right and do it once.

While your there you may also want to take a look at the long brake lines, they also will rust over time.

Zac

[B24Spider]

For the sake of diagnosis, is any of the metallic debris magnetic?
-Steve

[Steve Meltzer]

I started to put a magnet to it, then got sidetracked on this project and never got around to it. I'll check this PM when I get home. If it's not Fe, then it must be Al and coming from ?? the tank ?? I'm confused about the fuel lines. Zach, are you saying that the line that feeds the carbs is steel as it passes through the rocker panels and rubber are on either end? How 'bout the line that is the return line to the tank? I assume the run in tandem. thanx. s

[Steve Meltzer]

Some of the debris from the carb bowls was Fe (magnetic) but most wasn't. Not a big sample, so not certain if that helps. s

[250GT]

Hi Steve,
After strugggling through this thread, I am a bit surprise that all experts and tips goes into the direction of carb-problems.
You wrote in the opening statement " Sometimes it will idle fine and then just die. Dies are nearly every stop light."
Debris alone cannot produce this problem IMO simply that engine will not DIE .
it will run on 6-8-or 11 cyl. name it, but not starve !
This is an electric problem without doubt.
You wrote"New plug wires and brand new MSD boxes. (The entire exhaust system was completely replaced by the previous owner.) Still no success"
I did severl "upgrades" on my Maserati engines with those electic ignition boxes, and did have several problems with them especially under the very hot engine bays with those boxes. I returned back to org. configuration and every thing was fine again
You wrote: it dies at trafficlights, that could mean also at hot envirements and stop and go.
Tip :For me the best way to clean Carbs is to drive for 10-15 min 160km(100 miles/H).
Get OFF the trottle suddenly, and after 5 sec press agian the trottle to the bottem.
You will create such enorm underpressure and can test the synchrosring at the same time , well maybe with some blue smoke in the back.
But yeah ,I must have some pity with those who lives in Japan or US.
Its like having ONLY a Pre-ejaculate with those speed limits in my eyes.
without reaching a real orgasm.

Keep us informed about the progress.

Best

C.

[250GT]

Typo.
Sincrorings should be read as pistonrings of course.
the gearbox has nothing to do with this test.

ciao
C

[Steve Meltzer]

As always, I appreciate everyone's input and Cornellis' sense of humor. Let me recap this deal, because even I'm getting confused. I got this car in June; it had a PPI by Patrick Otis, who said it had good compression in all cylinders and that it ran a little flat through the 3K-4K range. No mention was made of difficulty idling. The car now has only about 100 miles and 100 hours of frustration in it. As noted. the ignition system has been completely redone with new MSD boxes (that are in the trunk, BTW, and thus out of the heat) new coils, wires, plugs and the distributors were checked by Dyke, so we know they're innocent.

The car has ALWAYS suffered from:
An inability to idle with any stability for more than a few minutes
Poor response at 3-4K and up
Blowing smoke R>L, at least in the garage
Tho' probably not a big deal, but even after a good warm up, the oil temp doesn't seem to go beyond about 140. I've done nothing to investigate this.

I've checked several times for vacuum leaks and found none.
This thread started with crud in the gas that you could see in the bowls. I drained the tank, blew out all of the lines (no debris in the main line), new filters for both the main canister and the glass bowl. And, for good measure, I put a Jaz bronze sintered filter just before the carbs. All carbs have new acc pumps, super clean jets and emulsifiers, floats checked very carefully, new needle and seats . Fuel pressure is 4PSI. All of this did clear up the" popping" that was occurring because of excess gas getting past the needle and seat. Because it won't idle reliably, I've made no attempt to balance the carbs or set the idle mix.

I drove the car today with fresh gas. Still feels like someone put a weight on the car at 3K and while idling upon my arrival at work, the car's RPMs slowly dropped to zero. (It's never been a sudden death, always a slow decline to zero.)

One thing's for sure: ain't quittin' my day job.
Not sure if this really an engine problem, like valve timing, lash, etc, or maybe it's just time for a real mechanic. I just hate to quit. Thanx for all of your help. s

[DWR46]

Steve: I know you have checked for vacuum leaks, but:

1. Pull the carbs, and level the bases on a surface plate. You will be amazed how "bowed" they will be.

2. It is time to set up the carbs. Do not forget to follow my write ups in setting the Bypass Screws when balancing the carbs.

3. Before you start to set the Idle Mixture. Record exactly how many turns out each Mixture Screw is.

Stay in touch.
Dyke

[Steve Meltzer]

Hey Dyke, Thanx again for the suggestions. If I take the carbs off and true the bottoms, should I take the opportunity to drop them in a bath of carb cleaner? Also, as you suggested, I've closed all of the bypass screws in preparation for the tuning. As you know, it's tough to open and close those little nuts with the car hot and running. Can I A) loosen the nuts with the car cold, then B) warm it up and make the necessary adjustments with those pesky bypass screw and finally C) let the car cool down and tighten the nuts?

Finally, what is the ideal fuel pressure on the Daytona?

As always, thanx for your interest and advice.