Ask Bill about carbing a DeLorean and other K-Jet/Carb tangets

[joebob101]

Here are photos of one of Bill's manifold/carb conversions. It was a simple install. I am so pleased that I can drive the car without worrying about reliability. It starts every time and doesn't scare you by dying at a stop sign like the Kjet did. I can even kill the engine when I stop at a store and know that it will restart. I still have some linkage issues to work out with the automatic kickdown. I'm very pleased with my conversion.

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[content22207]

Clarification: Garin is talking about the shift point cable, not the kickdown microswitch. Apparently his cable is too short. We've been in direct communication about a replacement.

Bill Robertson
#5939

[sean]

. Apparently his cable is too short.

isn't this a standard piece of your kit? Does this cable length vary from car to car?

[content22207]

Cross posted from another thread:

... Isn't this the same argument as modifying the car by adding a carb? I see no difference…. (if you'll excuse the hyperbole. I know the carb mod isn't NEARLY as invasive)

Oh dear, obviously there is educating still to do.

A carb conversion only involves one "permanent" modification to the vehicle -- the throttle cable needs to be cut shorter to mate up to throttle plates in the middle of the engine rather than at the far end. Making a lazy bend in the original length just doesn't work very well -- the cable binds and does not slide smoothly.

All other adaptations either bolt on or are simply stuck in place:
- A low pressure fuel pump clamped in the original tank boot
- A new fuel line from the front of the car to the rear (K-Jet plumbing and components typically ride around idle underneath the car)
- Plugs stuck in the original injector boots
- Carbureted intake manifold mounted with the original head bolt holes
- One additional electrical line (original K-Jet wiring can be coiled up in the corner of the engine compartment, as mine has been for nearly a decade)

Everything north of the manifold is of course radically different, but once you unbolt the manifold all that differentness comes off with it.

Comparing a BTTF conversion to a carb conversion is either an attempt to be inflammatory, or simply displays significant lack of understanding.

Bill Robertson
#5939

[content22207]

isn't this a standard piece of your kit? Does this cable length vary from car to car?

All I provide is a ball end to go on your original cable.

The shift point cable should of course be the same length as the throttle cable. Both need to be cut shorter to mate up to a centrally located throttle mechanism. I don't know what happened to Garin's car, but for some reason his cable is too short already.

Bill Robertson
#5939

[sean]

Ok, I'm learning.

[content22207]

DeLorean carburetion has taken on a mystique that totally misrepresents what it in fact involves.

Carbureting a DeLorean is one of the easiest things you can do to the car. The whole process can easily be completed in one afternoon.

It also is one of the least invasive things you can do to the car. As stated, only one cable needs to be cut shorter (two for an automatic, although as Garin evidences the car is drivable even without the shift point cable attached). The longest part of the procedure is removal of K-Jet. Bolting down the carbureted intake manifold (everything north is already attached) only takes a minute or two. Since I test drive each installation on my own car, the carb shows up already adjusted and tuned -- as soon as it is bolted down (and the throttle cable cut shorter), you can start the car and drive it around.

We do run new fuel lines, so driving the car before a new line is in place will require filling the bowl manually, but it can be done -- a carbureted DeLorean can go from a bare intake valley to a drivable vehicle (within the range of a bowl of fuel) in minutes.

Bill Robertson
#5939

[joebob101]

This was a very simple installation. Like Bill says, the worst part is removing the Kjet. While I had the engine clean, I spent some time putting on new cooling hoses and working in the valley. Putting the manifold on and hooking up fuel lines, etc. took only a couple of hours and the car was purring like a kitten. I have kept and labelled all the removed parts. It would be a fairly easy job to convert back to the K/jet if I ever want to. Right now, I can think of no reason to reinstall unless I wanted a spot-on restoration, but that's not why I have the car. Right now, I want to get in it and go for a drive. It is so much more driveable now than with the K/jet.
I'm going to Bonneville next week. As soon as I get back, I'm going to see what I can do with the shift point cable. I'm sure it's an easy fix, I just haven't worked at it very hard.
Garen

[content22207]

If you need to snap the throttle plates to get them to close all the way, something is wrong with your supplemental return spring (stretched, popped off, etc). A healthy PRV pulls too much vacuum for the compression spring on the throttle cable alone to reliably close the throttle plates, so I add a supplemental tension spring:
SupplementalSpring.jpg

A partially closed choke plate will never cause a warm engine to rev high, but it will indeed cause it to struggle low (the poor thing can't breathe). Take the air filter off and look at it -- if the plate is open, it is working normally.

Converse is of course true for a cold engine: choke plate needs to snap closed, then crack open as soon as the engine is running. Don't pump the accelerator pedal -- just tap it lightly to take the tension off so the choke mechanism can rotate (positions the fast idle cam as well as closes the choke plate).

Bill Robertson
#5939

[Ron]

A partially closed choke plate will never cause a warm engine to rev high...

One can never say never around here!

Playing advocate-

A partially closed choke plate can indeed cause a warm engine to rev high:
-Set the fast idle cam you mentioned (that's its job).
-Compensate for vacuum leaks (a great test BTW).

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They should have named this "$tir$hit" instead of "woot"->