Daytona Driveability Problem

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DWR46
Posts: 539
Joined: Tue Sep 22, 2009 8:23 pm

Daytona Driveability Problem

Post by DWR46 » Sat Oct 18, 2014 10:07 am

I have a problem with a Daytona that has resisted all my efforts to solve for many years. I would like to hear from others with experience with Daytona's, especially Timo. This car, when driving off from a standstill, will "bog" if the revs fall below about 1,000 rpm. This is not a big problem on level ground in most situations, but when trying to start off up a hill, the car is very hard to get to move off without using lots of revs and having to slip the clutch more than I would like. Most cars, including 275's and 330's will "lug" off smoothly with minimal amounts of throttle needed. I have tried numerous combination of idle jets, mixture screw settings, and progression holes, including converting the carbs to full Euro Specs. I suspect this may have something to do with the old US carb specs for these cars, but I have little actual driving experience in a Euro Spec Daytona, so I do not know how they respond to the same conditions. This Daytona acts like cars do when somebody installs an aluminum flywheel and then the car is hard to start from a stop due to not having enough energy stored in the flywheel at low revs. However, the drivetrain has never been out of this 23,000 mile car.

250GT
Posts: 968
Joined: Wed Oct 15, 2008 7:41 am
Location: germany/holland

Re: Daytona Driveability Problem

Post by 250GT » Sat Oct 18, 2014 10:49 am

Dyke,
Sounds to me a clutch problem .
maybe caused by a wrong overhauled clutch(springs)
or bent disk.
but you probably renewed this as first possibility.

only an idea.

Cornelis

DWR46
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Joined: Tue Sep 22, 2009 8:23 pm

Re: Daytona Driveability Problem

Post by DWR46 » Sat Oct 18, 2014 11:10 am

Cornelis: I also thought about this, but clutch is very normal, smooth and progressive.

250GT
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Location: germany/holland

Re: Daytona Driveability Problem

Post by 250GT » Sat Oct 18, 2014 1:25 pm

Did you check the ratio of king and pinion in the back?
this all sounds to me like a flat race prepared car.
those must almost pushed by hand to get the swing.
I did once placed a 9/32 ratio in the back to see if the 250 kmh border was possible
on a 250gt engine and it DID on the german autobahn.
I must somewhere have a picture of my tom-tom-gps- the odometer was on 310 kmp.
this must be around 160mph .
But to dangerous nowadays with drums.
but with this ratio in the city/ hills it was awful.
I use it only 3000km : no fun

C.

afwrench
Posts: 398
Joined: Fri Jan 28, 2005 9:13 am
Location: upstate new york

Re: Daytona Driveability Problem

Post by afwrench » Sat Oct 18, 2014 2:23 pm

Hi Dyke, any chance you have brake drag? One or more of the wheels or E brake.Can the car be pushed with little effort on level ground and can the drivetrain be rotated with ease by hand? Good luck,Mike
72,365gtc4,14681,2007 599 GTB

DWR46
Posts: 539
Joined: Tue Sep 22, 2009 8:23 pm

Re: Daytona Driveability Problem

Post by DWR46 » Sat Oct 18, 2014 2:54 pm

Cornelis, Mike: Stock ring & pinion, and brakes are free. I have to believe this is related to carburetion. I hope to hear from other Daytona owners as to how their cars react to the same situations.

kare
Posts: 547
Joined: Sun Sep 22, 2002 11:34 am
Location: Helsinki, Finland, Europe

Re: Daytona Driveability Problem

Post by kare » Sat Oct 18, 2014 4:59 pm

Long shot: could something be loose/collapsed in the engine/clutch housing/drivetrain/engine trans-axle set-up/mounts so that the drive train binds up when the enormous torque is used at low revs killing the engine as a result?
250 GT 2+2 3197/GT

DWR46
Posts: 539
Joined: Tue Sep 22, 2009 8:23 pm

Re: Daytona Driveability Problem

Post by DWR46 » Sat Oct 18, 2014 5:39 pm

Kare: Interesting idea. I will do some investigating. Had not thought about that.

Timo
Posts: 215
Joined: Thu Apr 13, 2006 8:56 pm
Location: Riverside, California

Re: Daytona Driveability Problem

Post by Timo » Sat Oct 18, 2014 6:47 pm

Thank you for the vote of confidence Mr. R.,
Most of the 10 or so Daytonas I've driven, tested or worked on over the years have been U.S.-spec. examples and I do recall couple of similar instances in the past. I'll have to revisit my notes, but if I remember correctly, one of them I was able to solve despite committing cardinal sins by NOT approaching the problem(s) methodically (= one step at the time) and NOT documenting/recording the process addequately. I also may have Euro car stopping by within next few weeks for initial introduction/work assessment and if I remember correctly it too might have some running "issues".
You're also saying this issue has been present for a long time. Always or did it develop over time ?
Has it gotten progressively worse or...?
Sorry, I always seem to have more questions before daring to offer any advise/answers.
I'm sure you've ruled out any cam timing/distributor/ignition related possibilities.
Timo

Steve Meltzer
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Re: Daytona Driveability Problem

Post by Steve Meltzer » Sat Oct 18, 2014 7:28 pm

Dyke, I've not noted that with my American Daytona, but as you and I've discussed in the past, I do notice a sl. "bogging" or transient loss of power about 3K RPMs. Neither noted in my Euro Spec Daytona Spyder (conversion, don't get too excited). You are welcome to come to Houston; I'll take Sue and you out for a great steak dinner and you can drive my car all you'd like! steve
steve
meltzer, "“With a Ferrari, whatever it is, it’s a $1000. If that’s what it is.”"
'66 330 GTC, '72 Daytona-red, did they make any other colors?

DWR46
Posts: 539
Joined: Tue Sep 22, 2009 8:23 pm

Re: Daytona Driveability Problem

Post by DWR46 » Sat Oct 18, 2014 10:10 pm

Timo: The problem has always been present in the car. I have been able to improve it with jetting changes, but cannot make it go completely away. In normal driving on flat roads, it is very manageable. However, if you have to start up an incline, it is very noticeable. I can share my solutions so far, but would prefer to hear others experiences first.

Jumprun
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Contact:

Re: Daytona Driveability Problem

Post by Jumprun » Sat Oct 18, 2014 11:30 pm

Have you considered the accelerator pump circuit? I'm suggesting this based only on general carburetor experience.
--Tom

DWR46
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Re: Daytona Driveability Problem

Post by DWR46 » Sun Oct 19, 2014 10:03 am

Tom: Yes, I have investigated the pump operation. On the 40 DCN 21 and 21A carbs, the pump cams start to feed fuel only after 5 degrees of rotation. I have modified the arms to begin pump action immediately upon throttle movement. Mike Pierce and I came up with this plan. This assures additional fuel immediately upon any opening of the butterfly's. It probably helped a little.

DrewA
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Joined: Wed Sep 04, 2002 10:15 am
Location: Tuscaloosa, AL

Re: Daytona Driveability Problem

Post by DrewA » Mon Oct 20, 2014 10:30 am

I have a euro Daytona and have not had that issue. I owned a USA car previously and do not remember the car bogging down when starting off.

I would think it has to be something in the carb circuit. Even something like a partially fouled emulsion tube. What a pain. Good luck.

Drew

Steve Meltzer
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Joined: Mon Sep 06, 2004 10:31 am
Location: with Barney the Beagle boy and Enzo 8995

Re: Daytona Driveability Problem

Post by Steve Meltzer » Mon Oct 20, 2014 1:41 pm

For the love of my American Daytona and, in the interest of research and obtaining up to the minute information, I drove the car to work this AM. Paying extra special attention to that moment when the car first moves from idle, I detected no hesitation, no "bogging". I did however have a very exciting trip in...just as I was about to pull into our parking lot, I could feel a loss of steering, followed quickly by the sickening sound of thumping... don't know if my tire failure is due to a nail, or that somehow the inner tube blew, but the tire is about 2/3 off the rim!! Fortunately, the rim appears to be undamaged, but I'll know more this PM when I return with a spare that actually has air in it and a jack, etc.

To the problem at hand: in a million years I wouldn't tell Dyke Ridgley how to make a tough mechanical diagnosis. However, my '67 'Vette had a similar problem..."bogged down" off idle. It was constant, it was annoying and it went on for several years. Of course most of the advice I got was aimed at (I resisted the temptation to say "geared toward") the accelerator pump, its jet size and its cam timing. Went through ignition, etc and ultimately did a compression which was fine, but the leak down was bad! Post mortem exam showed small cracks in two different cylinders. Lost my "matching numbers" block, but the car ran great (and still does) thereafter. Weird, but I did get the car to run right. steve
steve
meltzer, "“With a Ferrari, whatever it is, it’s a $1000. If that’s what it is.”"
'66 330 GTC, '72 Daytona-red, did they make any other colors?

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