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

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.

Attachment 3379Attachment 3380Attachment 3381Attachment 3382

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

Quote:

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Originally Posted by content22207

. Apparently his cable is too short.

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

Cross posted from another thread:

Quote:

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Originally Posted by nullset

... 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)

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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

Quote:

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Originally Posted by sean

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

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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

Ok, I'm learning.

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

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

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:
Attachment 3479

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

Quote:

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Originally Posted by content22207

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

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One can never say never around here!

Playing :devil: 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"->:woot:

If you don't want to take my word for it, simply push the plate closed with your fingers and see what happens.

Bill Robertson
#5939

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Originally Posted by content22207

If you don't want to take my word for it,...

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I remember what happened the last time I did that...

Quote:

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Originally Posted by content22207

...simply push the plate closed with your fingers and see what happens.

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That's pretty funny, but it wouldn't be "partially closed" nor prove anything, now would it?

But, since I don't have a hacked fuel system on my D, how about the next time we are at a meet we try it on your car? Now since you said never, I'd choose to do it after you shut your engine off, but while you hit the pedal once (per manufacturer starting instructions mind you), then step back and you start it back up.

Seriously, I just wanted to point out that it is not always the case, even with a perfectly tuned carb, and that it can be used as a diagnostic tool.
I have to admit messing with you is always fun, but you are making it too easy now.

Till next meet....

Quote:

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Originally Posted by content22207

A healthy PRV pulls too much vacuum for the compression spring on the throttle cable alone to reliably close the throttle plates

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Huh? The point of a butterfly valve is that the force required to open/close it is independent of the pressure/flow going through it.

Oh grow up -- K-Jetters have had to tighten their throttle return springs too.

Bill Robertson
#5939

Curious isn't it: I was kicked out of Mike Lund's EFI thread (posts deleted), yet Martin is allowed to come into a thread clearly labeled "CARB" / "Carbed Car" and start slinging disparaging comments around....

I've done a few more carb conversions than Martin has -- chances are I know better than he does what works in these applications (especially Motorcraft specific conversions).

Bill Robertson
#5939

Just FYI, the fittings on the new fuel pump I bought are 3/8" NPT. Bill's carrier has 1/8" NPT fittings. I will seek adapters at the hardware store. This will make the pump sit a bit higher, so it will be necessary to lower the carrier inside the boot a little bit.

Farrar

Quote:

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Originally Posted by content22207

Oh grow up -- K-Jetters have had to tighten their throttle return springs too.

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Yahuh, but it has bugger all to do with engine vacuum, oh master of erroneous (and childish) comments.

Quote:

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Originally Posted by Farrar

Just FYI, the fittings on the new fuel pump I bought are 3/8" NPT. Bill's carrier has 1/8" NPT fittings. I will seek adapters at the hardware store. This will make the pump sit a bit higher, so it will be necessary to lower the carrier inside the boot a little bit.

Farrar

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I had a similar problem with the pump that I got- I needed a 1/8" NPT barrel adapter to put it in place of the one I took out. It's possible that Bill had installed one in the old one too, but it looked like the old pump had a male 1/8" NPT fitting on it vs. the new pump's female one.

Airtex E8012 has female 1/8 NPT threads on both ends.

This is the order of components that made your original fuel pump and carrier:
Attachment 3535

Bill Robertson
#5939

The reducing bushing works fine on the bottom. For the top, I simply used a straight barb and an elbow fitting:

Attachment 3543

Farrar

Quote:

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Originally Posted by content22207

What kind of failures are you experiencing? My epoxy killed pump just sat there like a bump on a log (didn't do anything). I lost one pump to what appeared to be bearing failure (jumped around so much it was difficult to hold in my hand). It is possible my third pump did not die (the car bogged down just as Louie and I were passing an off ramp, so we zipped off the interstate, into the gas station at the top, and threw the spare into the tank -- it could have been a gust of headwind).

The pump currently in my tank got me Alabama to New Orleans, then went to/from Lexington, Pennsylvania, and DC twice, but I won't hesitate for a second to throw my spare in there if necessary.

Bill Robertson
#5939

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The Airtex unit had been making some strange noises the past few weeks. My guess is it was on its way out. Yesterday, 150 miles from home, it started going out intermittently. The car would stall and then start back up (sometimes). I managed to limp around for 15 minutes while I drove around Jackson, MS looking for a place with shade to do some work. I ended up in the ghetto and decided to limp to the entrance ramp to the interstate. Luckily it got that far and then the fuel pump stopped for good.

I honestly spent more time driving around looking for shade then it actually took me to do the work. Since I carry a spare fuel pump I just swapped it out and was back on the road again. After taking a lunch break, and stopping at Autozone to get a new spare (made in china part), I was on my way again.

I think I purchased my spare Airtex unit at Advance Auto. Unfortunately I don't have my receipt (this is why I prefer Autozone) so it might be difficult to get it replaced. I bought the Adance Auto pump less than a year ago, installed it in the car, and kept the original as spare. I'm going to go to the store I bought it from and see if they will honor the warranty without a receipt.

Even if I didn't have a spare fuel pump with me the day still wouldn't have been too bad. I could have stopped at any auto parts store and gotten a fuel pump capable of filling my carburetor bowl. If I had been depending on a K-Jet fuel system I would be stranded in Jackson until a vendor could overnight me a part.

Quote:

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Originally Posted by stevedmc

Even if I didn't have a spare fuel pump with me they day still wouldn't have been too bad. I could have stopped at any auto parts store and gotten a fuel pump capable of filling my carburetor bowl. If I had been depending on a K-Jet fuel system I would be stranded in Jackson until a vendor could overnight me a part.

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So carb owners should expect a 1-2 year lifespan, or even less in your case, out of a fuel pump and carry a spare just in case? Just curious as you and Farrar seem to be having pump woes but I've never heard Bill talk about pumps failing like this when promoting the carb kits.

Quote:

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Originally Posted by sean

So carb owners should expect a 1-2 year lifespan, or even less in your case, out of a fuel pump and carry a spare just in case? Just curious as you and Farrar seem to be having pump woes but I've never heard Bill talk about pumps failing like this when promoting the carb kits.

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Keep in mind our fuel pumps cost about $40 and can be purchased at nearly any parts store. K-Jet pumps cost between $90 and $160. For the price of our pumps we can afford to carry a spare.

It isn't carb owners than should expect a 1-2 year lifespan on the fuel pump. It is Airtex owners who can expect a 1-2 year lifespan on the fuel pump. This is why I am switching to another brand.

Quote:

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Originally Posted by stevedmc

Keep in mind our fuel pumps cost about $40 and can be purchased at nearly any parts store. K-Jet pumps cost between $90 and $160. For the price of our pumps we can afford to carry a spare..

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I wouldn't care if carb pumps were free and stock pumps were $300. If I get 15-20+ years outof a stock pump I'm pretty happy I don't have to make fuel pump replacement a random maintenance item.

Quote:

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Originally Posted by stevedmc

It isn't carb owners than should expect a 1-2 year lifespan on the fuel pump. It is Airtex owners who can expect a 1-2 year lifespan on the fuel pump. This is why I am switching to another brand.

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So it seems it is JUST this this pump that is the issue, was this the recommended pump? Curious that both you and Farrar were using them if they're substandard. Does Bill need to post a carb kit recall?

Quote:

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Originally Posted by sean

I wouldn't care if carb pumps were free and stock pumps were $300. If I get 15-20+ years outof a stock pump I'm pretty happy I don't have to make fuel pump replacement a random maintenance item.



So it seems it is JUST this this pump that is the issue, was this the recommended pump? Curious that both you and Farrar were using them if they're substandard. Does Bill need to post a carb kit recall?

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I want to respond to this so much but I'll shut up and let Bill speak for himself.

Quote:

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Originally Posted by stevedmc

I want to respond to this so much but I'll shut up and let Bill speak for himself.

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Bahahahahahaha, you wanted to respond but by saying you won't respond!?!? By all means, you dont need bills permission to speak I'm just asking serious questions. Future carb owners should know if their are issues with the kit. You've been happy with yours but have experienced some issues, why not let potential carb owners know. The carb kit is not infallible.

I was just going to say that Bill has demonstrated his desire to make improvements to his kits as he continues to develop them. In some ways each kit is a little better than the one before it as he continues to tweak things. I cant speak for another person but I wouldn't be surprised if another fuel pump finds its way into the kits.

This of course depends on a lot of things. I'm going to start testing another fuel pump soon. For all I know the replacement could be better or worse. Lots of factors could be causing the problem such as ethanol, driving on a low tank of gas (I normally buy gas when I have 4 gallons left), or a bad fuel pump as I suspect.

Only time will tell but testing a different pump is a good place to start for determining the problem.

Quote:

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Originally Posted by stevedmc

I was just going to say that Bill has demonstrated his desire to make improvements to his kits as he continues to develop them. In some ways each kit is a little better than the one before it as he continues to tweak things. I cant speak for another person but I wouldn't be surprised if another fuel pump finds its way into the kits.

This of course depends on a lot of things. I'm going to start testing another fuel pump soon. For all I know the replacement could be better or worse. Lots of factors could be causing the problem such as ethanol, driving on a low tank of gas (I normally buy gas when I have 4 gallons left), or a bad fuel pump as I suspect.

Only time will tell but testing a different pump is a good place to start for determining the problem.

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IMO, darn good response to to my initial query. Is it recommended to carry a spare pump when bill installs a kit?

Quote:

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Originally Posted by sean

Bahahahahahaha, you wanted to respond but by saying you won't respond!?!? By all means, you dont need bills permission to speak I'm just asking serious questions. Future carb owners should know if their are issues with the kit. You've been happy with yours but have experienced some issues, why not let potential carb owners know. The carb kit is not infallible.

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Very true. Another perfect example of a fuel delivery issue, further proving my point that no product is a fail safe. That is why I would never praise the almighty carb as a end all be all solution. Youre still prone to problems.

No one has ever recommended that I carry a spare fuel pump. J made my own decision based on Bill and Farrar's honesty. Plus a spare fuel pump is cheaper than some of the tools I carry with me anyway.

If I was stranded without a spare fuel pump I still could have limped to Autozone by manually filling the bowl. You can't do that with Kjet.

Quote:

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Originally Posted by stevedmc

If I was stranded without a spare fuel pump I still could have limped to Autozone by manually filling the bowl. You can't do that with Kjet.

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That isnt my point. My point is you can face issues either way, touting one method is better than another gets you no where. Its just as pointless ad me saying kjet wont deisel when I shut it off. I can pick pros and cons of both fuel delivery methods.

I never said carburetors are fail safe. What I am saying is there is a lot less to go wrong. My fuel system makes it possible for me to survive on my own. I don't need any special part that has to be ordered. I could have a complete fuel system failure including fuel pump, PVC valve, fuel filter, ripped fuel line, clogged jets, broken accelerator pump, etc. and still be able to get parts in any city big enough to have a parts store. Shoot, the carburetor itself could get zapped by aliens with a ray gun and I would still be able to get another carburetor locally. The only thing special about my fuel system is the intake manifold.

Ok steve thats great for you, and im sorry you had issues with kjet. For the record I have owned my car for 13 years and have only had one fuel issue. I dont care if a carb owner fills a fuel bowl every 15 feet it does not make a fuel problem less of problem. You dont directly say a carb is fail safe. You dont have to. Its apparent with snide comments bashing kjet in every other thread. Ive said it again, to each his own, but kjet is reliable, and to assume its garbage falls along the same assumption that carbs are outdated junk.

Quote:

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Originally Posted by Soundkillr

Ok steve thats great for you, and im sorry you had issues with kjet. For the record I have owned my car for 13 years and have only had one fuel issue. I dont care if a carb owner fills a fuel bowl every 15 feet it does not make a fuel problem less of problem. You dont directly say a carb is fail safe. You dont have to. Its apparent with snide comments bashing kjet in every other thread. Ive said it again, to each his own, but kjet is reliable, and to assume its garbage falls along the same assumption that carbs are outdated junk.

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I like turtles!

Turtles aren't the issue -- it's cheese. I like cheese.

Looks like it started to rain just in time for me to enjoy some fireworks.

Apparently Airtex pumps are only assembled in the US. Parts themselves are made overseas (Bangladesh?). Airtex made the change about 4 years ago. I wonder if merely sticking already assembled pumps from bulk overseas shipments into individual resale boxes qualifies for a "Made in USA" sticker?

I had excellent success with my first pump, which predated the manufacturing change. Had it not sucked up a piece of Hervey epoxy, I might very well still be using it today.

The problem isn't carburetion in general, it's crappy foreign made fuel pumps in particular. Absolutely no one has had any problems with their Made in USA carburetors. Or their made in USA intake manifolds (especially now that I have a halfway decent welder and a welding jig). No one has had problems with their Made in Israel throttle cable ends. Or their made in USA air filter housings (lids proudly individually hand made in Laurinburg NC).

The sun just came back, so I am going outside now. You all can continue to wallow in sophomoric and juvenile weenie waving without me. I make what I make. Care and attention to detail should be self evident. If you want a conversion, I will gladly make it for you (I may even drive to your house and help you install it, free of charge). Otherwise, there are plenty of vendors who deal in the stock setup who can meet your fuel delivery needs.

Grow up.

Bill Robertson
#5939

Quote:

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Originally Posted by Soundkillr

You dont directly say a carb is fail safe. You dont have to. Its apparent with snide comments bashing kjet in every other thread.

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I, for one, am above such K-Jet bashing. Good day to you, sir! I SAID, GOOD DAY!



http://www.youtube.com/watch?v=on0W9pO2nwA

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Originally Posted by SamHill

I, for one, am above such K-Jet bashing. Good day to you, sir! I SAID, GOOD DAY!



http://www.youtube.com/watch?v=on0W9pO2nwA

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Thats almost a recreation of the lightning scene in BTTF I.

Quote:

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Originally Posted by SamHill

I, for one, am above such K-Jet bashing. Good day to you, sir! I SAID, GOOD DAY!



http://www.youtube.com/watch?v=on0W9pO2nwA

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Eh, at least the kjet car showed up. I saw smoke in the background. Fire perhaps from an alternative fuel car? :)

Quote:

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Originally Posted by Soundkillr

Eh, at least the kjet car showed up. I saw smoke in the background. Fire perhaps from an alternative fuel car? :)

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That smoke was exhaust from the first couple of cars smoking the delorean.

Lest anyone think that mechanical fuel pumps are all sweetness and sunshine, this is how I had to drive one of my Lincolns home when it got a hole/tear in its pump diaphragm:
Attachment 3600
(Engine is a high compression 460, so I traveled slightly less than a mile before the bottle had to be refilled -- it could only empty halfway before it dropped below the neck -- but on a more fuel efficient vehicle I would have traveled nearly two miles).

Steve is correct that the carburetor itself does not need a fuel pump to properly deliver fuel into the engine. Most high winged aircraft don't even have a fuel pump -- gravity alone feeds their carbs.

Bill Robertson
#5939

Quote:

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Originally Posted by content22207

Cross posted from another thread:

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

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If you actually read the entire thing you'd quoted, you'd see that I was saying exactly that. Start with "If you'll excuse the hyperbole. I know a carb conversion is not nearly as invasive".

I was on your side for once!