Engine and Transmission Tech

Hi guys, me again. Me and the carb on the car are not getting along very well as the electric choke doesn't appear to want to work well on its own and I haven't been able to determine if replacing that unit will fix the issue or not. Also it is hard to match it up to this carb looking at the info supplied on the various websites to tell if it would work or not. When we got the engine we also got a complete EFI set up sans the computer. If we were to pick up the Mega Squirt as the husband would like to try, how hard is it to make this switch? Or does someone want to come stay for a week and help me do it? :D I looked at the price of the carb that is in the range of what my 3.5 uses and it looks like the cost for that is around $370, but if the swap isn't horribly tough I thought maybe we would consider going for it. Spring is around the corner and she really would like to get out of the garage some, what do you think? Thanks!

Hi Michelle,

What kind of carb do you have and what is it doing wrong?
Carbs can be made to run very well and there is nothing wrong with using a well tuned one.
Ultimately EFI is a better choice but is certainly more complex to put onto the car. Might be a better project for next winter.

Cheers
Fred

Hi Fred,

It is a vintage Carter AFB from a early Buick that was rebuilt right before I bought it. The electric choke is not engaging as it should which means when doing a cold start you have to use a spray of starter fluid in order to get it going and baby the gas until it warms up. There isn't much in the way of adjustment on it other than the two screws on the front if I remember correctly. I wanted to replace the electric choke but so far the ones I had found do not appear to be a match for the one it has on it. The currently one only has one wire connection and most of the ones I have seen have two.

Are you sure it's a vintage Carter AFB? Buick 215 and 300 4 barrels were Rochester 4GC's.

Dan Jones

Yeah Dan, it is a Carter AFB from a 1964 or 65 if memory serves correct. I have looked it up on a couple sites that sell parts specific to the carb but the electric choke they show doesn't look like mine at all. I do have an old Rochester that came off of the Buick 215 but it needs a total overhaul as it is in bad shape, it came with the intake that I bought when I was doing my build.

Vintage AFBs didn't come with electric choke, so if yours has one, it's been added, possibly incorrectly. Fixing that is MUCH cheaper and easier than converting to EFI, if that's your only reason for converting. Since you have a non-stock installation, you will likely require an aftermarket computer and custom programming for the EFI to run right.

I struggled with the original Rochester on my 215 for months, rebuilt it twice, and still couldn't eliminate accelerator pump problems. I went with an E-brock 1403 (500 CFM, electric choke) and it works great.

Michelle

You should be able to use the two terminal chokestat as a replacement for the single wire one. The second terminal would just need to be connected to a good ground wire.

For EFI a Mega-squirt ECU would work fine with your Rover FI componets. EFI does require fair amount of mods the fuel supply system, including a high pressure pump, supply/return lines, and either fuel tank mods (swirl-pot) or a small remote fuel cell for the high pressure pump. If a remote fuel cell is used, a low pressure supply pump is also required to keep the fuel cell full.

The Mega-squirt web-site has a TON of info on how to convert to EFI. I person could spend weeks reading it all!
[www.msextra.com]

Bill

Some additional thoughts. First, if the choke plate is not closing on a cold start, the black choke coil needs to be adjusted to increase spring pressure when the engine is cold. This adjustment is made by loosening the three screws that hold the choke coil to the housing on the side of the carb and rotating the coil to increase tension in the spring. This is likely a trial-and-error process.

If the choke has been purposely adjusted this way because it doesn't open properly, then either the coil is bad or it's not wired correctly.

Joe wrote:

Quote:

Since you have a non-stock installation, you will likely require an aftermarket computer and custom programming for the EFI to run right.

Check the BritishV8 article archive and you'll find a bunch of articles that contradict this. One of the advantages of the Rover 14CUX EFI is its proven ability to adapt to a nice range of Buick/Olds/Rover engine installations. Imagine a carburetor that automatically selects its own jets to suit the engine it's installed on. As for how long or complicated it is to install... the issue is that it involves skills that are new to most of us. If you're Glen Towery or Jim Stuart, you could have Rover EFI installed in an evening or two. Novices have done it inside a week. It typically requires a machinist's assistance in modifying your plenum housing (if you want to stay underneath an MGB bonnet.) The Rover wiring harness will be longer and will have more wires than you need, so you may like to trim it down for a neater installation. Etc.

Start with these...
[www.britishv8.org]
[www.britishv8.org]
[www.britishv8.org]

For those who have went to the Edlebrock application, I know the 500 cfm is too much for this engine set up so it has to be jetted backwards. Does the out of the box application come with the necessary jets or is that a kit purchase? Either way that sounds like I would end up spending just as much as changing the EFI by buying the Megasquirt.

If memory serves me correctly when I researched the number stamped on the carb, it was indicated it came with the electric choke. Joesph, you mention I may need to adjust the black choke coil, how do I adjust it ? The carb had just been rebuilt by a shop prior to me buying it, I bought it from one of the board members who found he needed the 500cfm for his 302 engine and not this one. So I was thinking that this one would be set and ready to go but we just cannot get the choke to engage properly for some reason, I don't know if on a rebuild that was checked for functionality or not.

The Edelbrock 500 will come with middle-of-the-road jets/needles already installed, but without any alternative jets/needles in the box. If you install it as-is you'll probably be very unhappy with the mixture, but the engine will run. Some local speed shop or parts store will likely have the jets/rods you need. (Changing needles is EASY and only takes a few moments for the pair. Changing jets requires temporarily removing the top of the carb that's probably a ten minute job.) Jets and needles are priced similarly: about $9 per pair. Don't be too surprised if you end up buying two or three sets of jets and two or three sets of needles. So let's see... for the sake of budgeting, 6 x $9 = $54. (Edelbrock secondary jets are the same as the primary ones, so you might possibly spend a little more money there. The needles are lifted by skinny little coil springs. You can buy spring kits with various color coded pairs of springs. They're not expensive, and there's a fair chance you won't need them.)

Now, here's the rub. The jetting that works great for someone else's 3.5 MIGHT not suit yours. To really get the carb dialed in sometimes takes a great deal of fiddling. "Reading plugs" doesn't work well with modern alcohol-blended gasolines! What tools do you need to do the job right? Dyno time is one option. Instead, I bought a wide band oxygen sensor and gauge. It's especially helpful because it helps me tune for changing altitude on long road trips. You might also use it to optimize your ignition timing (curve).

The basic Rover 14CUX system starts looking more and more economical when you consider that it continuously self-tunes.

> For those who have went to the Edlebrock application, I know the 500 cfm is
> too much for this engine set up so it has to be jetted backwards.

Umm, just because the jetting has to be leaned, doesn't mean that 500 CFM
is too much for the engine.

> Does the out of the box application come with the necessary jets or is that
> a kit purchase?

You buy a tuning kit with an assortment of rods, jets and step up springs.
Even with a tuning kit, you can may need to buy individual parts. I've
got probably half dozen different tuning kits (both Edelbrock and Carter)
plus additional parts to be able to span a wide range of engines and AFB
carbs.

Go to Edelbrock's website and download the tuning manual for the 1404 carb.
That will help with tuning. Also, below I've attached an old post of mine
that might help with tuning a Carter or Edelbrock AFB carb. It's a write up
I did on tuning my Triumph TR8 when I first got the Innovate wide band sensor.

Dan Jones

I recently went through a tuning exercise on my Triumph TR8 using a wide
band O2 sensor. I highly recommend using a wide band O2 sensor to check
your mixture. Besides making the process of tuning a carb go much faster,
it's found problems I didn't know I had. When I started tuning the Rover
3.5L in the TR8, it was rich in 1st, 2nd and 3rd but would go lean at the
top of 4th gear and in 5th. I figured there were 3 possible causes:

1. Fuel pump capacity insufficient
2. Carb inlet needle and seat too small
3. Fuel filter too restrictive

Turns out the fuel filter I had (one of those metal mesh filters in a glass
tube) was too restrictive. Holding it up to the light, I could see through
the mesh so it didn't appear clogged but the wideband knew better. By the
time I hit fourth, the fuel bowls had drained enough to cause the mixture
to go dangerously lean. A larger diameter clear plastic fuel filter
(Purolator F21111) fixed the problem. Since the Purolator filter has a
plastic body, I moved it to the firewall to keep it away from direct engine
heat. The fuel filter originally on the car was maybe an inch diameter with
a glass body, a metal mesh filter element and 3/8" inlet and outlet.

I kept a detailed log of my tuning. Here's a summary:

The engine is a stock low compression (8.1:1) Rover 3.5L V8 engine with
the following modifications:

Edelbrock triangular foam air cleaner (needs to be replaced with a real filter)
Edelbrock 1404 500 CFM four barrel carb (Carter AFB clone)
Offenhauser/JWR Dual Port intake manifold
Crane hydraulic flat tappet cam (unknown specs)
New but stock rate TR8 valve springs
Rhoads fast bleed rate lifters
Rimmers tri-y headers and dual exhaust (H-pipe, no catalytic converters)
Mallory Unilite distributor with vacuum advance
MSD 6AL spark box
MSD Blaster 3 coil
NGK BPR5EY11 spark plugs gapped at 0.040"

I installed the Mallory, MSD and plugs. Everything else was installed by
the previous owner and, if I were buiding the engine from scratch, I'd have
picked different parts.

The 1404 Edelbrock carb is a clone of the Carter AFB. The easy stuff to change
or adjust includes:

idle stop
idle mixture screws
primary side jets
primary side rods (controls primary cruise and primary power mode mixtures)
secondary jets
step-up spring (controls when the transition occurs between cruise and power
mode mixtures)
accelerator pump lever hole
float drop

Instead of a power valve for enrichment like a Holley, the Carter/Edelbrock
AFB's use a rod and jet arrangement. A 2 step tapered rod, controlled by a
vacuum-referenced, spring-loaded piston, moves up and down in the jet to
provide a two different area main metering orifices. This allows the carb
to adjust the air-to-fuel ratio for differing loads, as sensed by the vacuum
level. When the vehicle is cruising, the rod is on the lean step. Under
high load, low vacuum, conditions the rod moves to the rich step. The
metering rods and step-up springs can be changed without removing the top
cover but the cover has to come off to R&R the jets. There's a series of
screws that hold the top cover on but you must first remove two small clips
that hold the accelerator pump and throttle lever linkages in place. These
are very tiny and easy to drop, so keep a spare pair on hand and cover the
carb when removing them. I used a very small pair of needle nose to remove
the accelerator pump clip but found a dental pick with curved hook worked
better on the throttle linkage. You should also remove the rod and pistons
(uses torx headed screws to hold the covers on). Unlike a Holley, there's
no need to drain the float bowls when changing jets. Use a screwdriver with
a tip that is the same width as the jet, otherwise it's easy to scrape a
little aluminum of the carb body.

The goal of my tuning was to get it lean of stoichiometric at cruise for
best fuel economy while in the range for maximum power at wide open
throttle. 14.7:1 is the stoichiometric ratio. It's the "chemically ideal"
where there is no excess fuel or oxygen left after combustion. Leaner means
there's excess oxygen left after combustion. Richer means there's excess fuel
left. Generally, you want to run rich of stoichiometric at wide open throttle
(WOT) and a bit lean at cruise. There's no single ideal ratio that applies
to all engines. Some engines make best power at 13:1, others closer to
12.5:1. Note that the air fuel ratio is by weight. 13:1 means 13 pounds
of air are mixed with 1 pound of fuel. The usual target values for normally
aspirated 4 stroke engines are about 12.5 to 13 for WOT, 14.0-15.5 at
part-throttle cruise and 13.5-14.0 for part throttle acceleration (or
climbing a long hill, pulling a load, etc.). If you want to lean out the
mixture at cruise for best fuel economy, be aware that you'll also need to
adjust timing. Combustion gets much slower under lean conditions and if
you don't adjust spark timing, the combustion occurs much later and exhaust
temperature climbs. That's bad for the exhaust seats and valves. However,
if you adjust for MBT spark at each A/F ratio, exhaust temperature will
actually decrease relative to stoichimetric (rich will still be somewhat
cooler). For typical gasoline engines, the range or ratios is:

A/F Characteristics
Ratio
5 Rich burn limit. Combustion is weak and/or erratic.
6-9 Extremely rich. Black smoke and low power.
10-11 Very rich. Some supercharged engines run in this range at full power as
a means of controlling detonation.
12-13 Rich. Best power A/F for normally aspirated WOT.
14-15 Chemically ideal. At 14.6 the A/F is at the theoretical ideal ratio
with no excess fuel or oxygen after combustion. Good A/F target for part
throttle cruise and light to moderate acceleration.
16-17 Lean. Best fuel economy A/F ratio. Borderline for part throttle
drivability (worse than borderline if EGR is used).
18-19 Very lean. Usual lean limit (Driveability).
20-25 Lean burn limit. Varies with engine.

If your engine has a cam with a lot of overlap, your wideband may read rich
at idle, even though it isn't. In cases like that, I usually set the idle
mixture use the RPM drop method. Adjust mixture to yield maximum RPM, then
lean it so the idle drops 20 to 40 RPM. Even with milder cams on engines
with carbs, I usually only get around 13:1 at hot idle if the idle speed is
low enough. Raise the RPM a bit and the air fuel ratio will quickly go to
the cruise value. You can fine tune this by lowering the float level, if
need be. Also placement of the sensor (in collector versus near tailpipe)
can yield different results. Dyno shops using tailpipe probes will often
shoot for a leaner WOT air-fuel ratio in the 13.0 to 13.5 range. Measuring
at tailpipe tends to read leaner than if it was measured at the header.
13.2 at the tailpipe can correlate to 12.5 at the header. The best thing
to do is to correlate air fuel ratio on a dyno with maximum power for your
set-up. You can accomplish the same thing with an accelerometer based G-meter
or at the drag strip.

I started the tuning session by driving the car around to warm it up before
setting the initial idle speed and mixture. Timing and spark strenght had
been set previously. It drove well with no bogs or flat spots but the old
plugs and tail pipes suggested the mixture was rich. The carb was installed
out of the box without any jetting changes by the previous owner. The
baseline specs of the manual choke 1404 carb are:

1423 jets (0.086" diameter) in primaries
1460 rod (0.065" x 0.052", stamped 6552)
orange step up springs (5" Hg)
1426 jets (0.095" diameter) in secondaries
center position accelerator pump
0.0935" needle and seat
11/32" float height (+/- 1/4" float drop)
middle accelerator pump link hole
0.028" accelerator pump nozzle diameter
500 CFM rating

I set the initial hot idle speed to 750 RPM. BTW, with the MSD, it starts
just fine without the choke and will idle down to 400 RPM. I set the initial
idle mixture using the method suggested in the Edelbrock carb owners manual
(richen to maximum idle speed then lean to a 20 RPM drop). I then installed
a wide band O2 sensor in a bung I had welded in previously. It's located aft
of the passenger side header collector with the sensor cable routed through
the engine compartment (zip tied away from anything hot) out the rear of the
hood into the passenger side seat.



The wideband showed the the idle mixture at 13:1. I was initially going to
try for stoichiometric (14.7:1) but settled on 13.5:1. Then I noticed the
representative charts in the Edelbrock catalog show a 13:1 idle mixture. Be
aware that cams with a bunch of overlap can fool the wideband at idle due to
the unsteady nature of the idle (misfires result in unburnt fuel passing over
the sensor). This will go away quickly as the revs rise. Since it's
dangerous to drive and read the gauge at the same time, I had a neighbor do
the driving while I read the meter. It was immediately obvious that the base
calibration was way too rich (2 points across the board) for my engine.
Edelbrock provides nice little charts that correlates the rod and jet
combinations to changes in mixture:

[www.bacomatic.org]

Each step is approximately a 4% change. With the mixture readings from
the meter, it's possible to calculate how many steps are required to get
a desired mixture. Be aware that not all possible combinations appear on
the chart and only the highlighted ones are possible using the tuning kit.
You'll need to purchase additional tuning parts for the other combinations.
I wrote a little program to calculate all the possible rod/jet combinations
and it helped me find a couple of rod/jet combos that worked better in my
application. I'm now cruising at 15.5:1 (lean of stoich for better fuel
economy) with transition mixtures (climbing a hill, pulling a load, part
throttle acceleration) in the 13.5 to 14:1 range and WOT in the 12.5 to
13:1 range. Pretty much ideal. When I started, it was rich across the
board. I've picked up 3 MPG and power to boot. Using the combos on the
chart, I couldn't get the primary power mode lean enough so I had to
compensate by leaning down the secondaries a bunch. Getting the right
primary rod/jet combo fixed that. Depending upon where your cruise mode
mixture is, you may want your primary power mode to go between 15 and 25%
richer.

The initial reading was so rich, I didn't even bother to write the air-fuel
ratios down. Returned home and went three steps (12%) lean on both the
primary cruise and primary power modes:

#10 on chart, #1422 jets 0.083", #1463 rods (0.067" x 0.055")
Effective Cruise Jet Area (sq. in.) = 1.8849555921538760E-03
Effective Power Jet Area (sq. in.) = 3.0347785033677404E-03
3.0348 / 1.8850 = 1.61 or 61% more area
Flow is proportional to area squared
0.61**2 = 0.372 or 37.2% power enrichment flow

That was too lean at cruise (had a mild surge) so I went to #11 on the chart
(2 stages lean on both cruise and power modes):

#11 on chart: #1422 jets 0.083", #1460 rods (0.065" x 0.052")
Effective Cruise Jet Area (sq. in.) = 2.0923007072908024E-03
Effective Power Jet Area (sq. in.) = 3.2868913138183213E-03
3.287 / 2.0923 = 1.571
0.571**2 = 0.326 0r 32.6% power enrichment

That put me near stoichiometric (14.7:1) at cruise but was rich in power
mode which also made WOT rich, even after leaning the secondaries from
the baseline 0.095" jets down to 0.080" (five 4% lean steps). The power
mode was too rich, causing me to try compensate by leaning out the
secondaries. The tuning chart doesn't show any other combinations that
would allow me to fine tune this set-up but using the program I wrote, I
came up with some additional combinations not on the chart that worked
better:

not on chart: #1422 jets 0.083", #1461 rods (0.065" x 0.057")
Effective Cruise Jet Area (sq. in.) = 2.0923007072908024E-03
Effective Power Jet Area (sq. in.) = 2.8588493147667119E-03
2.860 / 2.092 = 1.367
0.367**2 = 1.135 or 13.5% power enrichment

not on chart: #1421 jets 0.080", #1441 rods (0.062" x 0.052")
Effective Cruise Jet Area (sq. in.) = 2.0074777056438778E-03
Effective Power Jet Area (sq. in.) = 2.9028316119169689E-03
2.9028 - 2.0075 = 0.8953
0.8953 / 2.0075 = 0.446
0.446**2 = 0.200 or 20% power enrichment

I purchased the additional rods and jets for these two combinations.
When I went to install them, I noticed the #1461 rods were machined
differently. Both carry the same part number, though it's obvious
they are from different production batches as the stamped lettering
is different. Also, the length of the machined step is different
and the tip of one of the rods was blackened which solvent failed to
remove. I put the micrometer on the rods and they varied more than
I cared for. I also have a Carter 400 AFB here and, as luck would
have it, it was equipped with rods with the power mode of the #1461
rods but a slightly leaner cruise mode. Since the rods are so easy
to change out, I swapped the rods over and took it for a test drive.

not on chart: #1422 jets 0.083", Carter 400 rods (0.066" x 0.057")
Effective Cruise Jet Area (sq. in.) = 1.9894135478857367E-03
Effective Power Jet Area (sq. in.) = 2.8588493147667119E-03
2.860 / 1.989 = 1.437
0.437**2 = 0.191 or 19.1% power enrichment

Cold, without the choke, there was some mild lean hesitation but that
quickly went away as the engine warmed. The leaner rods did the trick.
By leaning out the primary mode, WOT also leaned out without a further
seconday jet change. With the Carter rods, I'm now cruising at 15.5:1
(lean of stoich for better fuel economy) with transition mixtures
(climbing a hill, pulling a load, part throttle acceleration) in the
13.5 to 14:1 range and WOT in the 12.5 to 13:1 range. Pretty much ideal.
I got 19 MPG on the last tankful when I was cruising at 14.7:1, up a
couple of MPG from where I started even though I was mainly WOT tuning
the carb or cruising at 75+ MPH. With the latest carb changes, I think
it'll do 20+ MPG around town. Edelbrock doesn't have a 0.066" x 0.057"
rod listed. The next size listed is #1436 rods (0.068" x 0.057"). That
would be too lean at:

not on chart: #1422 jets 0.083", #1436 rods (0.068" x 0.057")
Effective Cruise Jet Area (sq. in.) = 1.7789268400952206E-03
Effective Power Jet Area (sq. in.) = 2.8588493147667119E-03

With all Edelbrock parts, the best bet would likely be the other
combination listed above that's not on the charts (#1421 jets 0.080",
#1441 rods 0.062" x 0.052")

There are some other rod/jet combos that give similar but slightly different
effective jet areas. If I was really trying to fine tune this combo, I'd
test each on the same day with an accelerometer to see which gives the best
performance. Vizard has gone so far as to put O2 sensors in each header
primary so he could stagger jet to better equalize the mixture distribution.
IIRC, he said it was worth 20 HP on an engine in the 300 cubic inch range.

Some miscellaneous observations. While it starts just fine with no choke,
you don't get the fast idle cam so it idles at 500 RPM cold versus 750 hot.
The Offenhauser Dual Port/AFB combo is very smooth and I could not tell when
the secondaries opened. It will pull 3rd gear idling through the subdivision
and is, in fact, smoother than the fuel injected 5.0L in my 1987 Mustang.
In case you aren't familiar with it, the Dual Port design has the runners
split into top and bottom sections with the plenum split fore and aft (rather
than the usual side-to-side). It's essentially two single plane intakes
stacked on top of each other with the 4 barrel carb primaries feeding the
longer path lower runners and the secondaries feeding the shorter path upper
runners. It's an interesting concept but the packaging required to fit within
a carb intake envelope does compromise the design. The Offy Dual Port has the
reputation of being a good low to mid range intake with excellent throttle
response and fuel economy (probably the best cruise fuel economy based upon
BSFC tests performed by David Vizard... I've got the dyno results here some
place). It's not a high rpm intake but Offenhauser says you can trim the
dividers back at the head flange to pick up some top end power. An Edelbrock
Performer Rover intake will make better power but is taller so hood clearance
may be an issue. The Edelbrock foam air filter has got to go. The air fuel
readings were not quite as stable as the readings I got on my buddy's 428CJ
powered Cobra replica. That might be due to the size of the motor relative to
the carb (750 CFM on a 428 versus 500 on a 215). Also, the accelerator pump
shot and/or clogged fuel filter may have had something to do with it. Make
sure to tighten the fuel line after you've re-jetted or you'll spray fuel on
the hot manifold. Doh! It's tough to read the numbers on the rods and jets
once they get stained with fuel. I resorted to the calipers (for the rods)
and a tapered rod (for the jets) to verify the sizing. I then bagged and
tagged the rods in individual zip-loc baggies (the really small snack size).
I noticed a little sediment in the bowls and cleaned it out. I'll check
again later. I was shifting at 6000 RPM and managed to bump the 6400 RPM rev
limiter once while watching the meter. I bought a dual outlet for cigarette
lighter so I could use the radar detector during tuning. The wideband O2
uses the lighter socket to provide power for the sensor heater. The primary
side venturis of the 600 CFM AFB's are the same size as the 500 CFM AFB's
though the boosters are different. Need to get a G-meter to correlate
acceleration (power) with mixture.

The wide-band I used is an Innovate LM1 and it's very nice. It allows you
to datalog or just watch a hand held display. On most of the cars I've tuned,
we've welded a bung into the header collector but on some we've had to go a
few feet aft of the collector. I typically use zip ties to temporarily route
the cable into the car via the passenger side window. When datalogging, be
aware noise from high power ignition systems can cause an erratic RPM converter
signal. A 50k-ohm potentiometer from Radio Shack will usually fix that problem.

As a follow up, the Offy Dual Port seems to need a richer mixture at WOT.
Even though wide band showed I was in the range I wanted to be at WOT, top
speed was down a bit so I suspect individual cylinders are leaner than the
average reported by the wideband. A recent dyno test of an Offy Dual Port
on another engine showed it to respond to richer than usual mixtures, perhaps
due to poor mixture distribution. The Dual Port is an interesting design
but on the Rover/Buick 215 engine it has very small passages inside and, if
any engine does not need a dual port, it's the small port Rover/Buick.

Further investigtion revealed the pre-load was improperly set on the Rhoads
fast bleed rate lifters by the previous owner. He installed adjustable
pushrods but they were too long to get to zero pre-load. I pulled the
manifold and removed the lifters for inspection and found they were
flat on the bottom, not radiused which indicates premature wear. I decided
to swap out the Offenhauser Dual Port and Crane H-216/285-2S-12 cam
(266/278 degrees advertised duration, 0.456/0.480" lift, 112 LSA) and Rhoads
fast bleed lifters with an Edelbrock Performer Rover intake, standard lifters
and an Erson RV10/RV15 (Wedge Shop custom grind) cam of the following specs:

280/288 degrees advertised duration (208/214 @ 0.050")
0.448"/0.460" lift
111 lobe separation angle
4 degrees advanced when installed straight up

With this combination, I had to change to #1423 main jets (.086"), #1450 rods
(listed as 0.070" x 0.042" but I measure them at 0.069" x 0.041") which is
close to the leanest cruise and richest power mode (#15 on Edelbrock tuning
chart).

The Offy/Crane/Rhoads combo was very smooth at low RPM, like fuel injection
and would pull 5th gear from very low RPM but fell off at higher RPM. Some
of that is probably due to the intake manifold design and some to the Rhoads
lifters. The small primaries of the Dual Port design maintain a high velocity
across the carb primaries giving good fuel economy and throttle response but
the design restricts flow at higher RPM. Also the lifters bleed down at low
RPM, effectively shortening the duration of the cam but testing by David Vizard
has shown they do not give the full duration and lift of the cam at high RPM.

By comparison, the Edelbrock/Erson combo needs a bit more RPM to get into
its working RPM range but pulls harder and the power hangs on past 6000 RPM.
It might be interesting to try a Carter 400 AFB or perhaps an Autolite 4100.
The smaller primaries of the Carter 400 and the higher gain annular boosters
of Autolite 4100 would both tend to increase atomization at low RPM.

Later, I had the new engine combo on a Dynojet chassis dyno. Here's a follow
up post:

Last year, I swapped out an Offenhauser Dual Port intake, tiny Edelbrock foam
air cleaner, Crane hydraulic flat tappet H-216/285-2S-12 cam and Rhoads lifters
for an Edelbrock Performer Rover dual plane intake and Erson hydraulic flat
tappet cam with a 14" diameter Moroso air cleaner (2 1/2" tall K&N cotton-gauze
filter element). When I was runny the Offy intake and Crane cam, the 500 CFM
Edelbrock AFB carb was tuned with the following rods and jets:

0.083" primary jets, Carter #16-241 rods (0.066" cruise, 0.058" power steps)
0.080" secondary jets

After installing the new intake and cam, the engine specs are:

Moroso 14" diameter air cleaner case with 2 1/4" tall K&N cotton-gauze element
500 CFM Edelbrock AFB design carb
Erson RV10/RV15 (Wedge Shop custom grind) cam of the following specs:
280/288 degrees advertised duration (208/214 @ 0.050")
0.448"/0.460" lift
111 lobe separation angle
4 degrees advanced when installed straight up
2.0 ramp rate (compatible with the new but stock spec TR8 valve springs)
Rimmers tri-y headers and dual exhaust (H-pipe, no catalytic converters)
Mallory Unilite distributor with vacuum advance
MSD 6AL spark box
MSD Blaster 3 coil
NGK BPR5EY11 spark plugs gapped at 0.040"
stock 8:1 compression TR8 long block
stock Rover oil pump with TA Performance (Ruggles type) booster plate and
adjustable bypass spring

After installing the Edelbrock intake and Erson cam, I re-jetted the carb
using a wide band O2 sensor. I concentrated the tuning on getting the
cruise lean and ended up with:

0.086" primary jets, Edelbrock #1450 rods (0.070" cruise, 0.042" power steps)
0.080" secondary jets

The above combination is close to the leanest cruise and richest power mode
(#15) on the Edelbrock tuning chart for the 1404 carb (500 CFM AFB). I had
some mild surge in lower gears which smoothed out when I backed timing off
but I was probably too lean at cruise and WOT. This was confirmed when I put
the car on the chassis dyno. I went to the dyno hoping to optimize the timing
but left it where it was and only fooled with the carb. I was participating
in a local club's dyno day and only had 3 pulls available but ended only using
two pulls as the carb was too lean. The dyno's wide band (tail pipe probe)
recorded the air-fuel mixture as lean as 14:1 below 3500 RPM and 13.5:1 above.
I had a pair of rod that were richer

0.086" primary jets, Edelbrock #1449 rods (0.070" cruise, 0.037" power steps)
0.080" secondary jets

This made only a minor change in the mixture so I called it a day. Since I
was already as rich in power mode as the Edelbrock carb table shows for the
1404 carb, I wrote a little program to run through all the rod and jet
combinations. I iterated on 71 different Carter and Edelbrock rods and
16 different Edelbrock jets. I came up with a few new possible combinations
and installed:

0.089" primary jets, Edelbrock #1454 rod (0.073" cruise, 0.037" powers)
0.083" secondary jets

Those changes increase the effective cruise jet area by 3.9% and the power jet
area by 8.7%, along with a secondary jet area increase of 7.6%. That should
put me in the 12.5:1 range, perhaps even a litter richer. I need to buy a
set of Edelbrock 1455 rods (0.073" cruise step, 0.042" power step) which would
only increase the primary power mode jet area by 2.2%.

Main Jet Cruise Rod Power Rod Cruise Area Power Area Cruise Jet Power Jet P/N
Diameter Diameter Diameter Square Inch Square Inch Effective Effective
Diameter Diameter

0.0830 0.0660 0.0580 0.001989 0.002769 0.0503 0.0594 16-421 (Carter)

0.0860 0.0700 0.0420 0.001960 0.004423 0.0500 0.0750 1450 (Edelbrock)
0.0860 0.0700 0.0370 0.001960 0.004734 0.0500 0.0776 1449 (Edelbrock)

0.0890 0.0700 0.0420 0.002373 0.004836 0.0550 0.0785 1450 (Edelbrock)
0.0890 0.0730 0.0420 0.002036 0.004836 0.0509 0.0785 1455 (Edelbrock)
0.0890 0.0730 0.0370 0.002036 0.005146 0.0509 0.0809 1454 (Edelbrock)
0.0890 0.0720 0.0460 0.002150 0.004559 0.0523 0.0762 16P-7246 (Carter)
0.0890 0.0720 0.0400 0.002150 0.004965 0.0523 0.0795 16P-7240 (Carter)

I need to slap the wide band back to see where I'm at and whether I need to
order additional rods. I drove it to work today and didn't notice any low
speed surging so I should put a timing light on it and bump the timing back
up. I also need to order a spring and weight kit for the Mallory distributor.

Before I went to the dyno, I simulated the engine in Dynomation. It predicted
a peak HP of 155 at the rear tires. Strapped to the chassis dyno, the mighty
8:1 compression 1.5" intake valve 215 cube V8 made 157 RWHP :-). My simulation
program predicted 155 RWHP which equates nearly 1 HP per cubic inch at the crank.
With more timing, richer jetting and maybe a K&N stub stack, it should be 160+
RWHP. Using the flow data for my ported Buick 300 heads, my Rover 4.2L short
block should be in the 350 HP range at the crank. We'll see.

If I get really industrious, I'll try the Carter 400 CFM AFB carb on it.
The Edelbrock 500 CFM AFB has same body as 600 CFM carb but with big fat
primary boosters. The Carter 400 CFM AFB has smaller throttle bores and
more slender boosters. An Autolite 4100 (annular boosters) would be a good
choice too.

A few weeks later, I found I had a problem while I was on the dyno. One of
the rocker stand bolts had pulled the threads out of the head and eventually
bent the rockershaft.

FWIW, my the 393 cubic inch Cleveland Ford in my buddies Pantera made 411 RWHP
through a much too small paper element air filer and restrictive muffflers.
After his first pull, the dyno operator was impressed and said "I didn't expect
that!". I had Dynomation up on my laptop which read 417 RWHP and said "I did!"
By way of comparison, a supercharged 5.4L Shelby GT500 (stock except for a cold
air induction) made 392 RWHP so the normally aspirated street Cleveland acquitted
itself well. I though the TR8's little low compression engine was going to
register the lowest horspeower reading of the day but that honor went to a 4.0L
V6 Ford Mustang.

Dan Jones

Decisions, decisions. Maybe I should start with picking up a new electric choke and run a ground wire out to it in order to use the one with two prongs. Looks like it is under $20 bucks so it might be worth it if it would get her starting in a more reliable way, then I can start looking over the EFI articles and see where to go from there.

Curtis, I saw that one box is a self adjusting computer but has anyone priced that one lately? I went to the pick n pull a few times last year and all the ecu's were long gone.

Michelle, I'm told the Holley "Projection" has gotten better, over the years. Complete stand alone 2bbl conversion is $1,02. in Jeg's. Jus' sayin. roverman.

Call me crazy, but if the purpose of converting to EFI is ONLY to fix a choke problem, I'd spend $20 on the new choke coil before spending $1K-$2K on the EFI (and then the time to get it dialed in). Now, if you WANT EFI for driveability reasons, that's a whole different decision process, but the OP said it was due to choke problems. By the way, the coil on my E-brock 1403 is two wire. Simply run a ground wire to the second terminal.

Joe, I am going to try changing out the choke on the existing carb just to get her running faster but the long term plan is to go to EFI since I already have everything but the computer component sitting in the basement. Also the hubby's buddy is a machinist so shaving it down some should be a problem. I prefer the EFI to a carb but that is just me, but I also prefer a nice quiet exhaust to a grumbly one but I seem to have lost part of that battle unless I sneak and find a quiet one to change out. :)

Art, I hadn't seen may 2 bbl set ups on these cars, so I never thought of it as an option.

Michelle, Rated by Holley at 670 cfm., probably @ 3" hg. Still adequate for 400+ hp. ? Good Luck, roverman

Hey Art,

2 BBL Projection only good for 275 hp. Still OK for the Rover engine though.

Cheers
Fred

Michelle,

Peter Sherman just sent me this write up about Rover EFI systems. It looks really good for what I need to figure out so I thought I would pass it along...

[www.conehead.org]