EFI to carb conversion.

[unissamog]

Well, since the other thread started is got me thinking.

My '87's 3.5 is anemic as all hell. I know there are issues in the system somewhere, but I believe that life would be easier for me to have a carb on the engine and not have to worry about TPS, MAF, ECU and other overpriced acronyms anymore.


As old scout pointed out I could get a new intake and a carb for my engine from Summit for about $400. Aside from that the only thing I believe I would have to change is the fuel pump.

Am I correct in what would have to happen to do the conversion?


Is there anything big that I am missing?

Is there any good reason not to do this?

This vehicle is my DD and sees very little trail time.

[Old Scout]

I take it you don't have smog cops?

[unissamog]

smog.....hmmmmmmmm............

nope.

I live in Vermont.

As long as it still has it's catilytic converters (if it was equipped from the factory with them) then we are good to go on pre, 97 vehicles. no tailpipe emissions.

[Old Scout]

Non computer controlled carbs on engines with cats can lead to problems. The carb will tend to dump in more fuel than the cat can deal with, this leads to a poisoned cat. You can add a smog pump to help the cat out with a little oxygen. Most Catco cats have a inlet air tube just for this reason. The Catco universal replacement cats are ~60.00 from summit.

[DooDoo Brown]

I kinda did this conversion on my 87 RR last mar. I still think it is a good idea if you use a Q-Jet or even the new edelbrock copy of the Q jet. Instead of a new fuel pump you could use a presure regulator. as I did. The heater will have to be rigged a little because of the diffent/extra hole location on the new intake. A new thermostate housing will have to be rigged or bought from RPI. kickdown cable will have to be rigged/bought from RPI.

Well I had the engine running /idleing pretty damn good.....BUT it was poping up through the carburator. Had a local shop look at it. Some how I screwed something up. I think it was a stuck or burned valve. I then had RCH look at it and yep I screwed it up somehow. It was idling good when I went to check it out and hear the bad news.......I needed a new engine :barf: ohh well A good amount of money later I had a new to my truck engine, and it ran GREAT... RCH did a really good job. they kinda scolded me for the carb conversion...and they put the fuel injection back on.
Any how, the engine ran great and 7 mo later its running ok, but I still think the electrical system (and the front axle of coarse) is the Rovers glass jaw.

I'm no mechanic but I think next I will put a 4.6 with the edelbrock intake and a chevy TBI system. That would be a simple, reliable setup.

Ohh Yeah one more thing...On the intake...use the new synthetic type gasket and tighten the bolts from the front/back in as opposed to the chevy inner to outer. That will save you a MAJOR headache as I did it from the inside out and it leaked, and had to redo it.

And a Davis Unified Ignition for a 215 buick won't fit (even with a little dremmel help)

Hope I helped

[unissamog]

Originally posted by Old Scout
Non computer controlled carbs on engines with cats can lead to problems. The carb will tend to dump in more fuel than the cat can deal with, this leads to a poisoned cat. You can add a smog pump to help the cat out with a little oxygen. Most Catco cats have a inlet air tube just for this reason. The Catco universal replacement cats are ~60.00 from summit.

Well there is a simple answer to that....clean out the cats. As long as the cat exists for a visual inspection it is ok.

Doo doo,

what happened that killed your engine? was it the carb? or something you did wrong in the conversion?

RCH I assume to be rover club house, but what is RPI?

[Old Scout]

Originally posted by unissamog

but what is RPI?

http://www.rpiv8.com/

[DooDoo Brown]

I don't know for sure but I think it reved to high one time when I was adjusting some linkaging and/or there was an underlying problem that something I did aggrivated it (when RCH tore down and ran the numbers on my old 3.9, one head was from a disco and one was from a RR:mad: )

If anyone knows why it would have been poping up through the Carb post. It might help unissamog (It was timed right)

Rpi has an good Injection/carb page

But I cant stress If I were to do it again I'd use a chevy TBI system swap. Holley makes one for around 850$ - 2004 carb
600 dollar more...not to bad. Or get one from a junk yard and use a painless wiring adpter. All kinda sites on the net about this plus do a search on POR. Ive found all kinda stuff.

[redrangie]

Originally posted by DooDoo Brown
)

If anyone knows why it would have been poping up through the Carb post. It might help unissamog (It was timed right)



Well, it all boils down to the valves and flow. Timing is one piece of the pie. Essentially, there was an openning allowing the explostion to enter the intake tract. There are probably ten things that can cause this, but in fact, it was either timed incorrectly or there were broken parts in the intake tract.

Some discos had valve issues, 96's if I recall correctly.

On a separate note, I would not run a non ecu equipped/controlled carb on a cat motor either. On the 460's from ford, we would see clogged cats ALL THE TIME due to fuel overload. These were even with electronic carbs/02 sensors. The sensors would go into loop and call for full rich, and it would end up melting the cat guts, and restricting them to beat hell. Carbs just can't modify a/f ratio's fast enough. There is a reason they are called toilet boils.

If you want to build a hot-rod, run the carb, put in a bolt in cat replacement pipe and replace it with your cats when you run emissions.

When running non cat, use a tailpipe sniffer to determine fuel to air ration and emissions, keeping a eye on timing and head temperature.

Also, take some sleeping pills at night to help you get some sleep from polluting the air that my kids breathe. :flipoff2:

IMHO, you are openning one BIG ASS can of worms by trying to convert it to carb and maintan any semblance of emissions on a full time basis.

j

[DooDoo Brown]

I agree about the "can off worms" ................................
















































Do a Chevy TBI conversion...(for the children):D

[unissamog]

I am still debating this.

I can attempt to remedy the current EFI problems. $$$$$$
Change to a carb, possibly just as expensive.

or I can sell my 17-20MPG land rover and get a 8-10mpg Fullsize truck.

Personally "for the children" I believe any rover based option is better.

[redrangie]

why not find a crashed rr or disco, no matter what the year, and merge the two or swap completely? Mainly just r&r work, and a little improvisation. Example: 4.6 block, 3.5 ancilaries and heads, or even 4.6 heads, and an 4.2 ecu. (need for the extra fuel rate)

j

[derangedrover]

get a good aftermarket ecu like Motec/Haltech etc or if you dont want to spend as much maybe a Wolf system. Get a full ignition and fuel setup for 1000-2000 AUD, all the lucas crap is gone, your fully programmable and all is well.

Carbs suck, literally.

Cheers
Daryl

[DooDoo Brown]

I agree get rid of the Lucas system. Thats why I like the Holley TBI or any Chevy TBI. With both its go to any parts store and recieve the parts right then over the counter. The Holley ECU is programable through your laptop. The throttle body is bolt on to the edlebrock intake(or the ophenhiemer intake). The few sensors that do have to be connected already have a home to go too cause of the old Lucas sensor places. My .02 cents