[JS5D]

Hi all,

I am just going to log my latest adventures modernising my ancient 84 3.5 original carb engine. I myself have been looking for information on the internet and found limited information available so I will just explain my experiences here for anybody who is considering similar ideas.

So a little bit of background: I found this low mileage 84 4 door RRC parked in a corner at a junkyard in Texas. It had been sitting in a garage for 20 years after the owner opened the engine, bought a whole bunch of parts and then it seems gave up. Otherwise the car was in good shape.




I bought the car (for cheap obviously) and found that with the parts was an intake manifold that allowed for the installation of a standard US 4 barrel carb (Offenhauser JWR 7001). So rather than install the orginal carb setup I decided to buy a Holley 4 barrel carb instead.


After a full rebuild of the engine (which was very clean and definite the 41k miles on the odometer) I drove it with the carb and it worked ok-ish but in the Texas heat I had some vapour lock issues, apart from a few hundred other issues that come with this sort of adventure.


So then a few months later I found out I could just swap out my carb for a Throttle Body Injection unit (Sniper EFI in this case). All cool and works very nice indeed! (needless to say this is no longer a budget build)



The Sniper EFI does allow for ignition timing control as well as fuel, but this is where it gets a bit more tricky as you cannot do this using the standard Lucas distributor. So so far I have not use the timing feature and ran the timing conventionally. So my next adventure is to swap out some parts to make that happen (next post).

 

[JS5D]

So the way the EFI system works is that you tell it the engine volume (and type of cam shaft), you provide it with a speed signal (in the simplest form from the coil) a temperature signal from a newly fitted temp sensor and a O2 signal from a wideband O2 sensor. It will then start off with a preset fueling plan and tune the setting using the O2 loop. Within the throttle body there are sensors for Manifold Pressure, temperature, throttle opening and a idle circuit.

You can then tune forever the fueling based on tables that are based on manifold pressure and RPM

Key is that the speed signal can come from the coil (+12v/0V) or one step better is to get the speed and timing signal directly from the distributor. The EFI can then take this signal for speed but also to generate a spark signal based on a time delay and you have full ignition control as well (more tables to tune!).

Holley has a whole range of fancy electronic distributors to provide this option which CRUCIALLY DOES NOT INCLUDE THE ROVER V8. That market is not very big so they don't offer much help either.

But they do provide an integration path through the venerable MSD brand (Holley owned) using their MSD Pro-billet distribute range which features the required magnetic signal, mechanical advance lockup and phaseable rotor. This type of distributor is available for the Buick 215 engine (part nr 121-8548), which we all know is the block that Rover bought from Buick and developed into the long lasting Rover V8.

'Developed into the Rover V8' is key here since there are differences that make fitting this distributor not without risk (at a purchase price of about $500 and no documented evidence this works)

 

[JS5D]

So fitting the MSD Pro Billet 8548 into a Rover V8:

Does it fit? The distributor has a few things going for it which is that the part that inserts into the engine is exactly the same as the standard Lucas unit. The diameter and length are the same. What is different is that the top end including cap is quite a bit bigger, but mercifully I found it does not clash with the back of the water pump housing or the intake manifold (which I must add is no longer the standard Land Rover Item remember). So no cutting required here.



The cap fits nicely but touches my cooling water hose which is of the raised type part nr ERC3138, not sure how this would work with a standard cooling water outlet.

Then for the gear at the bottom of the distributor, there are changes there. The Rover (later style I believe) has a male oil pump shaft and female distributor coupling, while the Buick (and early rover V8's) have a female pump and a male distributor drive. So the MSD has the male distributor drive which needs modifying. I will report on this next since I plan to do that today..

 

[95classiclwb]

First and foremost excellent outcome, it promises to be a great conversion.

hose clearance over distributor during service has always been a factor in my experience, so you are not alone. gates used to have a hose which came with an extra inch or so of height from water jacket but due to this height it would rub on the hood. lesser of two evils, fix one clearance concern and create another.

I have learned of a few rover owners using the sniper set up, do not know if install and or tune was performed on driveway or professionally, reports have been mixed but mostly positive. as for distributor my current classic is a 95 which from factory is a mixed bag of parts cobbled together and some unique to model year. I could not find a direct install replacement for it thus, I overhauled and eventually decided to go with megajolt distributorless conversion (it is not complete as this moment) from trigger wheels, they offer a similar overall solution with megasquirt which is efi and coils.

In the past, I have used pertronix and dui (Davis Unified Ignition) on customers conversions. as good as they are over factory they still require timing set up and continuous monitoring plus extra parts and service, pertronix became unavailable and davis cost more than DIS, coil system just plugs and wires.
once your project is up and running, try and drive a standard 3.9 equipped unit and compare it to your modified 3.5, I'm sure other than displacement, the extra mods on your 3.5 will yield similar power bands and driveability.

 

[JS5D]

Hi 95classiclwb, thanks for the encouraging words. I have been working (or shall we say playing) with this rover for more than a year now and it has been very driveable indeed. The idea with adding the EFI controlled ignition is to improve the idle stability (with AC kicking in etc) and to tune the engine better for more economy. Of course the main reason is just because I like a challenge.

Got a little further today. As mentioned earlier the MSD distributor shaft has a male oil pump engagement while I need the female version. Not hard to reconfigure, but it means cutting the shaft so that is the end of any return and I am committed to make it work, or accept a loss of ~400USD. I checked the physical fitting and now I have also connected the distributor to the Sniper EFI, changed the settings and spun the distributor with a drill to check I am getting a reliable speed signal. That all seems to be well as I got a nice steady reading.

There is some concern on the Holley forums that the magnetic signal is weak end easily disturbed by EM interference. I have bought some stainless braided sleeve jacket which I plan to put around the signal cable. Also I will be using noise suppressing plugs and plug wires.

Feeling confident I set out to modify the drive end of the MSD:


As illustrated above I made the following changed:

The shaft on the Lucas is 12mm while the MST is 1/2" so the gear wheels are not interchangeable. I could either ream out the lucas gearwheel or instead I found it easier to drill the missing hole in the MSD gear to accept the pin for the female drive end. That done all remaining was to cut the MSD shaft shorter to allow for the female drive end. Altogether took about 30 min. complete.


No way back now! It should fit but before I can start playing I need to buy a plug wire set as the Rover cap terminals are different (female) compared to the MSD male terminals. Popped over to O'reilly who advised I try the '72 Oldsmobil set which they did not have in stock so will go back tomorrow.

In the mean time I have been browsing the web for suggested timing tables. Exciting stuff!

 

[95classiclwb]

best of luck, what I liked about the pertronix, it had a model which used laser trigger best if you used their epoxy coil. it shocked me during testing and made the muscles and tendons on my hand hurt for a good part of the morning, lol I felt the jolt to the soles of my feet.
great modification, from pictures it seem it will work after all measure twice, then again and just once more to be sure...then cut once.

after all is done you may have to widen plug gap due the stronger spark.

 

[RRLondon]

Very interested too in your changes and to see what results you get.

I've a setup with std parts on my 3.9 with interesting results, interested if you have any emmisions figures for your spec as it is to compare.

The point about resisted wires and plugs is interesting and to see how you get on with that.

My current figures for HC = 87 ppm, CO=0.320% it's full tank range (plastic tank) is max of 327miles it'll be interesting to see if you have anything to compare. It's also non catalysed.

 

[JS5D]

Well I got my ignition leads (or park wires as they are called here in the USA), removed the old Lucas distributor and fitted the new MSD distributor.

I Set the crank at 45deg and lined up the trigger this sets the base timing of 45 deg from which the Sniper EFI calculates the desired timing. Then turned the crank to 25 deg to set the rotor (phase the rotor) to point to nr one pole exactly so that a spark in the range of 10-40 deg can comfortably jump from the rotor to the right pole (since the rotor is now static without the weight advance).

Made all the connections set the timing to static 12 deg and fired the engine. Yes it started just fine. With the strobe I checked the timing which was at 10 deg so I adjusted the distributor to make it match the 12 deg static timing set. I played a little with the Inductive Delay and then reset the system with my provisional timing table, which is basically the Lucas mechanical and vacuum advance combined in the table.

I never really used the ported vacuum which is just a silly emission workaround. I already had worked on a AFR table with works well, but I plan to tune further for economy.

Then a short test drive. Well I must say it is MUCH more responsive. Much better drive and more stable idle as I had hoped. no pinging at all so that's good. I think the difference must be that it is more direct and much quicker to react compared to the mechanical distributor.

I need to so some proper motorway (freeway) driving and test the economy. Sure more tuning, but so far it seems that yes you can fit an MSD distributor to a rover V8 and get all the benefits of the Sniper EFI!

 

[bhoult]

Did you consider the Sniper 2300 in addition to the 4150? I'm building a 4.2 and I'm thinking the 4150 would be overkill for my application.

-.b

 

[RRLondon]

Nick work and very interesting project.

The left/vertical scale on your maps, is that derived from throttle position sensor?

 

[JS5D]

Nick work and very interesting project.

The left/vertical scale on your maps, is that derived from throttle position sensor?

No the left scale is the manifold pressure. There is a confusing mix of metric and imperial used in the Holley step up. This manifold pressure however is surprisingly metric in kPA (kiloPascal) and of an absolute value with 101 kPA being normal atmosphere pressure and 0kPA being absolute vacuum. At idle in Neutral and with the AC off I get about 38kPA manifold pressure with is about 10 in Hg absolute or 20 in Hg and inverse.

I think they used kPA as it allows turbo applications where the pressure goes above atmospheric.

Below table shows the pressures in different form which I used to calculate the vacuum advance for documentation I found for the Lucas distributor (start at 5 and end at 17 in Hg with a max of 16 deg). I made my starting ignition table from this together with the mechanical advance data

kPA	Hg in	Vac HG in	Adv
100	29.53	0.00	0.00
90	26.58	-2.95	0.00
80	23.63	-5.91	0.00
83	24.51	-5.02	0.00
70	20.67	-8.86	5.14
60	17.72	-11.81	9.09
50	14.77	-14.77	13.04
43	12.55	-16.98	16.00
40	11.81	-17.72	16.00
30	8.86	-20.67	16.00
20	5.91	-23.63	16.00
10	2.95	-26.58	16.00
0	0.00	-29.53	16.00

 

[JS5D]

Did you consider the Sniper 2300 in addition to the 4150? I'm building a 4.2 and I'm thinking the 4150 would be overkill for my application.

-.b

When I purchased it about 1 year ago there seemed to be just the Sniper EFI 4150 4 barrel (BBL) which is good for 600 hp, I did not see the 2300 2 BBL, which I think would be more suitable for the much smaller power application of the rover V8.

However the Offenhauser 7001 intake manifold which was part of the parts stash of the car is a 'dual plane' design which means that it splits the 4 barrels into two tracts, one top and one bottom which means that only using two of the 4 barrels would have resulted in only half the opening. In reality you don't need such a fancy dual plane intake manifold and you can probably get a Buick 215 intake manifold (cheap) with 2 barrels and use the Sniper 2300 (good for 350 HP?).

I can't say I get the feeling the rather large capability of the 4150 4BBL Sniper is causing me issue in the lower power and idle range, but yes I probably overpaid for the 600HP capabilities.

If you go that route I STRONGLY RECOMMEND you do NOT to get the full installation package. The fuel pump is cheap and rubbish (noisy as hell), much better to get a Bosch pump for $120 or so. I replaced the rubber hoses with nylon by now which is are much neater and easy to route and secure and the filters are just filters you can buy loose. My carb setup had a return hose so I did not use the parts int he kit for that either.

Assuming you have an automatic you need to also connect the shift linkage to the throttle. I played around to make the linkage work for way too long until I gave up and just bought a Lokar universal cable which is very good quality and easy to install. Has worked flawless since.

 

[JS5D]

No the left scale is the manifold pressure.

I forgot to mention that manifold pressure basically represents the engine load (at that RPM), while throttle opening (which the system measures and uses no doubt) I presume does not factor in the engine speed correctly.

Since the manifold pressure is measured at the throttle body and very quickly I think this might explain the crispness of the engine response after converting the timing to electronic. The timing adjustment (using the table) is instantaneous.

 

[JS5D]

Just an update and some info sharing for other potential Rover V8 SNIPER users. I've completed my tuning for now and enclosed are the configuration file I settled on as well as quick screen shot of the key Target A/F Ratio and Base Timing table.

The tuning was primarily aimed at good and practical daily use, not performance, and some attempt to improve fuel efficiency. The main considerations are:

-Strong and stable idle. Following advise from this forum (thanks, especially Danny!) I kept a flat AFT and timing table around a broad idle zone. I tuned the AFR value using the USB cable to allow 'live tuning' I probably could go a little leaner if I wanted but picked stable over economy for now. Since I have now Sniper controlled idling timing (magnetic, never caused any issues) which combined with a flat timing table works really well to stabilize the idle, barely notice the A/C Kick in and out now.
-Open throttle timing AFR setting following the Rover documentation (advance) and safe/power AFR.
-For cruise economy I analyzed roughly where cruise takes place on the table for 30-40-50-60-70 steady MPH (3-speed Auto box) and then set the AFR at ~15.3 and timing at ~25-35 depending on RPM on those places to get the best economy. Any lower load I consider deceleration which can have higher settings (but little economy gain) while any higher load I considered acceleration where I picked safer setting to avoid high combustion temps (lean) or pre-ignition (pinging). So basically a fairly sharp diagonal change in the tables.

The result so far is a beautifully running car, never stumbles, plenty power and extremely usable. Economy so far still not great estimated at about 15~16 USMPG, but will run a few tank fills and then see if I can improve a little later.