Lucas Petrol Injection

OK, I've aquired a TR6 engine and am starting the teardown/rebuild. I'm also starting to look at possible enhancements as I put it back together. I'm seriously considering the Lucas P.I. system. Can anyone give me the pros/cons, caveats, sources, detailed info for this system?

Other systems I'm considering are the triple Stromberg setup (thought about doing TBI with that, but that didn't look doable), or one of the Revington TR EFI setups. I don't want Webers because of the finicky nature/poor gas milege issue.

Anybody have any other sugggestions to consider?

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I'm seriously considering the Lucas P.I. system. Can anyone give me the pros/cons, caveats, sources, detailed info for this system?




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How deep are your pockets???? /ubbthreads/images/graemlins/nonod.gif

not very, but my initial checks didn't make the price look that over the top - a little more than a Weber system. Did I miss something?

The lucas system is pretty well sorted out now, but parts and info are scarce here. I sourced a complete system from a company called Auto Gear in the channel islands, but that was over 20 years ago. The TR was fast with the PI, but even with the bosch fuel pump upgrade the pump would overheat on long trips in summer. We drove from Richmond to DC with a bag of ice taped around the pump. It sure drew a crowd at shows though.

Do you still have the PI system? Did it have any flaws other than the overheating one? Any other advice you could pass on?

I sold one last year.
They are a bugger to find and not cheap when you do. Spares can be awkward, and rebuilding costs are not inexpensive.

You could possibly also consider the vespertino type s/c as an enhancement - assuming you didn't already - single 2" carb, gen3 M62, about 2k all up istr. That and a cam will give you a nice kick in the butt when you press the loud pedal. Looks nice too.

Why did you sell the PI, if I may ask? I'm trying to understand why everyone that I know who's gotten it has gotten rid of it also. Several fuel injection sites (mostly V8)seem to think the world of the Lucas system, so I'm trying to figure out why the TR folk doesn't feel the same way.

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Several fuel injection sites (mostly V8)seem to think the world of the Lucas system, so I'm trying to figure out why the TR folk doesn't feel the same way.

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Hi,

That's comparing new apples to old apples. The TR P.I. system was fine, in its day. But, it's a pretty early automotive fuel injection design and not nearly so refined as today's iterations of EFI (be they from Lucas, Bosch, or whomever). Scarcity of parts and lack of good info about the original Lucas P.I. would be my biggest concerns. I suspect most modern systems would be superior in terms of overall reliability, too.

I bet you'll find the aftermarket EFI systems are about the priciest option. Luminition and Webcon (Weber) are the primary brands I'd consider, personally. These will really make the car go, if used along with other general tuning improvements and matched up with the right cam. Just add a full electronic igntion for a nearly complete modernization of that old TR6 motor!

One alternative is to pull a fairly modern used EFI out of a late-model car that has about the same 2500cc displacement as the TR6, then figure out how to adapt and graft it onto the TR. I suppose it depends on how much you like fiddling with this sort of thing and your knowledge and skill level. You might be able to use Goodparts or Weber intake manifolds as a starting point, modified to accommodate EFI. Some difficulties will probably include figuring out the rest of the fuel system (tank, filters, pump, feed & return lines, etc.), not to mention the wiring, sensors and computer controls.

This is where an already sorted out aftermarket kit such as those sold by Revington TR, already tested and tuned for a TR and with full, detailed installation instructions, might start looking very attracttive in spite of the extra, initial expense!

The triple carb setup is an interesting less expensive possiblity, although unlikely to approach the same level of performance. Goodparts' manifold might be used with SU carbs, too, if you wished to do so instead of ZS.

Don't know too much about the conversion of three ZS to act as TBI other than what I've seen on the I'net, but it's also a very interesting idea.

Both the ZS/TBI and the triple carb setup above give the benefit of a throat feeding two cylinders, rather than the less effective stock 2-carb setup with a throat feeding three cylinders. (Previous posts here talked about this.)

Other options might include the PRI approach that I've seen installed on both Spit 4-cyl. and GT6 6-cyl. engines. On the GT6, a total of six individual motorcycle carbs all lined up in a neat row looked (and sounded) pretty impressive! I don't know if PRI has a kit for TR6, yet. Might be worth asking! www.prirace.com is their website.

Actually, the basic principle of the PRI approach isn't all that different from the triple Weber DCOE... One carb throat per cylinder.

I'd suggest you not dismiss the Weber sidedraft carb option, too quickly. I wouldn't call them finnicky carbs, just the opposite in fact. They require some fuss initially to be tuned really properly, but after that there is almost no way for them to go "out of tune". That's because fuel/air is nearly all controlled by fixed jets and venturi's. What makes them more complicated is that they are so incredibly precisely tunable, even for slightly different altitudes and differing air density/temperature, if you wish. Even if changes are needed later, it's usually a five minute swap of jets to make the adjustments. I have used them on the street for a number of years and can tell you that they can be set up to be flexible and usable there, too. Gas mileage doesn't need to be a very big issue, either, if the right Webers are chosen and used. We usually hear about 40 and 45DCOE Webers, where the size of the carb's throats are determining important factor. However, all these models have another number as a suffix, too. (Example: "40 DCOE 18" are installed on my TR4). There are a bunch of these suffixes, indicating a number of variations, which can be looked up in most Weber tuning books. One key differences between the variants is the length of the stroke of the acceleration pump. Shorter pump stroke carbs models will use less fuel (and are actually usually better performing on Triumphs). Plus, it's possible to customize the pump stroke even more with some simple modifications, too.

Weber gas mileage is also greatly effected by the size of the primary and secondary venturi, and the jets used to match, so can be tuned by going to smaller ones that give better low- to mid-rpm performance (street), rather than the usual approach of tuning with the largest venturi and jet possible for max power at the highest rpms (race-style). By the way, SU and ZS carbs that are modified for racing will also get significantly worse gas mileage.

Hey, there's an Eaton supercharger with a Holley carb, shown on the back of the current Moss catalog.

Or, get with AlanA (sorry Adrio) about his custom project, which combines fuel injection with a supercharger!

It really comes down to your $ budget balanced off against how much you want to work on sorting things out, either yourself or through a shop.

If you want an easy bolt-on kit, the top choice would probably be one of the EFI kits from Revington. While also at the top range of cost, one of thsee would be the most flexible and fuel gas efficient, but still providing very impressive performance. (Incidentally, the Webcon EFI system generally cannot be "mapped" or fine-tuned by the shade-tree mechanics, need to go to a Weber specialist for that. The Luminition system, on the other hand, allows some tuning via a standard laptop computer and, I think, some relatively affordable software. Either system from Revington comes set up with a map, initially, though.)

For originality's sake, the Lucas P.I. is about the only option, if EFI and it's improved performance is wanted. Might be cheaper than the aftermarket kits, but also might not be, once everything is tracked down, bought, sorted and done!

Certainly a used system from another car appears the least costly form of EFI, but may end up being more expensive than first thought, if individual parts need replacement or sevice, and a lot of fussing and tuning needs to be done to make it work.

Less costly would be a triple carb conversion from Goodparts, either ZS or SU. This should give a very nice performance improvement, but I would think won't be anywhere near as refined as EFI can be.

A TR6-specific triple Weber DCOE kit is more expensive, but is probably the closest to EFI-precision a carb system can get (possibly a PRI/MC carb setup is equal), just needing a little more fuss to get it fine tuned initially.

Heck, strictly in terms of fuel economy, a less expensive Weber dual downdraft carb kit is probably the very best choice, but would most likely be the least desirable in terms of performance.

Whatever you choose, you probably already know that well matched changes in terms of ignition system, exhaust system, camshaft, compression, valve size, porting and possibly more may be necessary - or at least very desirable - to get the full benefit of any intake improvements you make.

Keep us posted on what you do!

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When (if) I get the car back running right I want to do a multipoint sequential fuel injection setup with sequential ignition and a supercharger.

I built the engine (ok paid to have the engine built) to support that and had a custom manifold made to do the FI. That said, the car is on triple zs right now - and I'll run it that way for a bit if it ever gets out of the shop. I want to get a little entertainment out of it before it goes off the road again.

Drifting back to the point - I bought the Lucas setup hoping to adapt it to do what I wanted. The problems for me were the inability to pressurize the plenum and the waste of the rest of the setup, since I didn't need anything else. I decided to sell it on rather than mess with it. It was taken off a european car some years before, and would have still required a ton of work (and $$$) to refurb and install.

A semi-custom efi setup - Patten's TBI setup for example - seems less expensive and less trouble if you want FI. You'll pay through the nose for anything from the UK right now so I'd try to source local if at all possible.

I have to ask, why Lucas - unless you are an originality buff you have a ton of other options, most of which seem easier to install.

I found the Lucas stuff to be pretty straightforward. It is definitly "cave man" injection though. It was developed for power, not emissions or fuel economy. The only scary thing is that it has real high operating pressures( Around 100psi if I remember correctly). My business partner died, and the car was sold off to settle the estate. The next owner removed it, and sold it on. I have lost track of the car and the injection system in the intervening years.

Hello all,

I run a Lucas injection 2.5 engined car (Triumph 2000 saloon/sedan) and have done so for many years.

Weak points are the original throttle system which is difficult to set up. (throttle settings i.e balance is critical to good running) I made up a simple cross shaft with triple links with adjustable (S.U. carburettor) ball joints.
Fuel pumps are mentioned but one common cause of overheating is lack of voltage due to poor (deteriorated) wiring and earths. Mine have a relay and heavy gauge wire feeding them.
(I have a run\stand by set up as a belts and braces approach)
Another problem in fittin the P.I. set up is that the U.K. manifolds don't match some U.S. spec heads as the port spacing is different.

For a knowledgeable and reliable, albeit in the U.K. specialist :- www.prestigeinjection.fsnet.co.uk/

P.I. parts do come up on E-Bay.co.uk (i.e. the U.K E-Bay site)from time to time and not too expensive, certainly far less than the DCOE Weber option over here.

Alec

P.S. I just checked the link and if you look at the overhead throttle section, note the accepted best performing exhaust manifold on that head which is a 6-3-1 set up.

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I have to ask, why Lucas - unless you are an originality buff you have a ton of other options, most of which seem easier to install.

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Good question - I guess to be honest a lot of the appeal of that system is it's mechanical instead of electrial. My comfort level is MUCH higher with the mechanical aspect of things. With electrical things I feel like a fish out of water most of the time - weird since I'm a computer programmer by profession, huh? I pretty much take my modern cars to a shop for anything other than basic maintenence.

Also, I've always liked to be a bit outside the mainstream, which is another reason I'm not that attracted to Webers - seems like everyone has or wants them. Plus, in an effort to honestly look at how the car will be driven (commuting, scenic drives, maybe some light autocross) I didn't think the Webers were a good match. If I don't go with a FI system I'll probably use the triple ZS setup as an acceptable compromise for drivability.

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Whatever you choose, you probably already know that well matched changes in terms of ignition system, exhaust system, camshaft, compression, valve size, porting and possibly more may be necessary - or at least very desirable - to get the full benefit of any intake improvements you make.

Keep us posted on what you do!

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Hey Alan,

Thanks for the very well-reasoned and thought out response. Yours and everybody else's is exactly what I was hoping for when I brought up the subject - I know nothing I can think of that hasn't been thought of before, so I try to tap into that experience and wisdom to avoid what could be painful and costly mistakes. I have looked at most of the options you've suggested, and certainly will check out the remaining ones. I guess part of the appeal of the Lucas system is knowing that with the original cam it was capable of 150bhp factory tuned, which seems like a much better starting point than the 102bhp for the twin carb setup.

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I guess part of the appeal of the Lucas system is knowing that with the original cam it was capable of 150bhp factory tuned, which seems like a much better starting point than the 102bhp for the twin carb setup.

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The PI cars used a different cam and had higher compression than the US cars as well. So it wasn't just the PI responsible for the extra hp. The original cam that the US cars came with doesn't stand a chance in getting to 150hp without forced induction.

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Sorry, should have worded that a bit more concisely. What I meant to say was with the original PI cam, it was rated at 150bhp. Thanks for clarifying what I was trying to say /ubbthreads/images/graemlins/thumbsup.gif

FYI in case anybody's interested, an inquiry to an Australian Triumph PI specialist came back with a quote of US$3500 for a complete setup, refurbished and factory set, complete with Bosch fuel pump and improved throttle linkage. I also sent inquires to a British firm and haven't received a response yet.

Thats quite a lot...
Especially since you have import duties on top. Unless you have deep pockets, I'd be looking at other options.

jooi - Did you talk to the guy who does controllers from 80's GM cars (the one who reckons he can build anything pretty much) about a controller for triples with the drop in TBI setup. That and a cam sounds like a really nice easy fi setup for around 2-3k all up...

I thought so too, I had been expecting $2500 - $3000 based on the sum of individual components prices I had found. Now that I'm looking at almost $4K complete, it puts it out of my range of doable options.

I checked out Rick Patton's website(https://topshamautoparts.com/tr6/tbi.htm), and someone else had asked him the same question - his response was that he could so the TB for it, but that the software/wiring harness provider (https://www.customefis.com/) can't or won't do the setup for it.

odd - his website is a lot more enthusiastic

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I can build a custom GM EFI system for any car. See the links below.

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I know he does batch fire, so why he cant add another injector is a mystery. Did you try asking him direct to find out why? He seemed pretty flexible when I emailed him last year. The big reason I didn't want to use his stuff is because he can't do sequential, but you don't care about that...

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The big reason I didn't want to use his stuff is because he can't do sequential, but you don't care about that...

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This is true if I do the triple ZS conversion - I'll contact customEFI and see. I know others have asked in the past, but I've not heard of anyone who's gotten it done.