Holley 650 DP Flooding

[1965 R]

Blue Oval.

Your right it sounds like the mechanic just isn't going to get it sorted and a good mechanic will sort it easily. I was told by a mate who restored a GT Falcon that had an engine fire, causing the previous owner to sell, put an extinguisher in the Mustang. Sure enough through lack of use a gasket in the carby dried allowing a fuel leak, a fire started. Luckly it started in the garage when I had just started the motor and not on the road. So little damage was done.

On a different note what ratio diff are you running and tyres to pull 11.4 on the strip. I was thinking of getting some drag radials to try to hook up the rears as my street 17/40/255's Potenza are good enough on the road but fry at the strip even with the Detroit locker. So a soft launch is the only way off the line for now.

[mal67]

Hey Ron,

Yep, I agree.....its time for a change.  Little they have done in the whole process has given me any cause for celebration, and they have certainly floundered with this flooding/tuning issue.   Fire is something that has concerned me too, so I will sort the extinguisher thing immediately.

:banghead:  

As far as the pressure gauge is concerned, I doubt it was ever really 2.5psi, as I reckon the thing was dickie right from the start.


Thanks mate.....  

[Blue Oval]

Blue Oval.

Your right it sounds like the mechanic just isn't going to get it sorted and a good mechanic will sort it easily. I was told by a mate who restored a GT Falcon that had an engine fire, causing the previous owner to sell, put an extinguisher in the Mustang. Sure enough through lack of use a gasket in the carby dried allowing a fuel leak, a fire started. Luckly it started in the garage when I had just started the motor and not on the road. So little damage was done.

On a different note what ratio diff are you running and tyres to pull 11.4 on the strip. I was thinking of getting some drag radials to try to hook up the rears as my street 17/40/255's Potenza are good enough on the road but fry at the strip even with the Detroit locker. So a soft launch is the only way off the line for now.

I am running 3.9:1 ratio diff gears. I have 2 sets of wheels I use on the street. One set of 14" magnum 500s which gives me a total tyre height of 25 1/2" and a set of 15" centrelines with Mickey Thompson ET Street 235/15-60 tyres on. These are 26.1" high. I run these at the strip but I get a better time out of a set of 23" high 9" wide M+H drag slicks on 15" steel rims.
This 23" high tyre gives me an effective diff ratio of 411:1 which is the optimum for my engine at the strip.
  I cross the finish line at 6800 rpms in top. Max power is 6300 rpms.

Then the higher tyres I use on the street just cut the revs down a bit at cruise.
On the street I am doing 3150 rpms at 100klms/hr
What are your engine specs and horsepower etc ?
Where is your maximum power at ?
Those low profile tyres would not help you at the strip.

I have some great calculators that'll easily work out the optimum tyre height and diff ratio for the strip if you're interested ?

[shaunp]

You could just buy a holley pump from Hume performance it will have the correct pressure. Also line pressure and volume are too very different things, don't get hung up on low pressure if the pump can deliver the volume. Line pressure is more of an issue with injection as it effects the amount fuel delivered per injector pulse, but a carby is a calibrated bucket, so as long as the bowls are full that's all that matters.

[69candy]

I had a similar problem with a 650 Holley but Vac sec. Mine turned out to be a small hole in the float. Pull the floats out and put them in a jug of boiling water and look for air bubbles. My float was slowly filling with fuel, sinking and letting in more and flooding at idle. Fine if you drove around normaly or gave it a hiding. Might be worth a look??

[mal67]

Hi Guys, thankyou for your ideas.  

The carby is behaving ok right at this moment.  But this is usual after a visit to the mechanic.  The problem usually surfaces after a couple of hours driving, sometimes I get longer, maybe up to 4 hours (in total, not constant).

What I have decided to do is this.  Tomorrow night I will drive the car to Melbourne (300k's).  Sunday night, I will drive it home.  This should be a good test.  If it is still behaving after that, all good.  If its flooding again, I will take it to someone more experienced in Albury.  Unfortunately, I don't have the tools, knowledge, or workspace to do much myself.

[mal67]

Hi Guys,  

I thought I would provide a bit of an end note to all this saga as described above.  In doing so, I would like everyone to know how much I have appreciated the help and advice.  I know it would have been a far longer road to a resolution without the information provided by the good folk here.

My car is now running well.  I have suffered no flooding issues after about 12 hours of road time.  I think it is now safe to say the issue was solely down to too much fuel pressure (originally 9psi at idle, now regulated to 5psi).  The mechanic working on the car for me, really had no idea, and I have no doubt that had the possibility of high fuel pressure not be raised right here, and passed on to him by me,  he would never have looked in that direction.

Just to make matters worse, he never had the tune right either.  I will make special mention here of Blue Oval.  In 20 minutes on the front lawn at my house, and with one dodgey screw driver, he had it running better than the mechanic after multiple attempts.  When the rear needle and seat gave up the ghost because of the previous high fuel pressure, and it was replaced by said mechanic, the car once again came away from his workshop tuned very poorly.  Unfortunately, Blue Oval lives about 4 hours away, so I was not able to get his help in this instance.  After his constant urging (yes, I am a slow learner!!), I actually took the car to someone different to have it retuned.  It is now back to the level of tune it should have and he attained !!  It starts easily, drives off without coughing even when cold, and accelerates smoothly with no bogging or flat spots.

Okay, so bottom line..... Thankyou everyone for the advice and help.  Hopefully this whole drama is now just part of the history of the car !!  lol

[mattp]

Can I suggest getting a 600 cfm Edelbrock?