http://www.vtr.org/maintain/carbs.html
http://www.teglerizer.com/sucarbs/garrettech.html
http://www.mame.mu.oz.au/salman/S.U.html
http://www.team.net:80/www/morgan/tech/tuning.html
From: Randall Young ryoung_at_NAVCOMTECH.COM
With today's unleaded
fuel, even a single bout of rich mixture (left the choke out a bit too long ?)
can coat the tailpipe with soot, which will then stay black essentially
forever. It simply doesn't get hot
enough way back there to burn the carbon off.
It was different with
leaded gas, when the exhaust was basically constantly being coated with white
paint ...
The correct grade oil
for the dampers in SU carbs is SAE20
From: Bill McLeod <wbmcleod_at_theriver.com>
Subject: Re: TR3 Electric Fuel Pump
Electric fuel pumps are all designed to push, not pull, the fuel. Therefore they have to be mounted as low as possible, so they have gravity feed. The second reason for a lower mounting point (like down on the frame under the floor pan) is that some fuel systems have very small pin-hole and smaller leaks, which are small enough that they will not leak a fluid, such as gasoline, but will leak air. In such a case, a higher mounted pump will suck air through the leak point in preference to or in addition to the gasoline. Such a leak, which does not show a fluid dripping, can drive you batty! In any case, for all reasons, you are far better off with your pump mounted at the lowest point you can find.
The SU fuel pump in
many of our LBCars is out of sight (in this case, my 1958 MGA), so there is
truth in the old saying, "Out of sight, out of mind." When turning on the ignition key, you
usually hear a clicking noise which of course is a good sign that fuel is being
pumped to the carburetors. But if you fail to hear clicks or hear only one or
two, that's a good sign that your pump may be getting tired, especially if
rapping it with a tool wakes it up some. This is a good time to remove the
pump, clean the filter, and most important clean the points.
This maintenance can
give you much added life before you need to rebuild or replace the pump. First disconnect the two fuel line unions,
then any ground wire, then the hot wire, and finally the two bolts that hold
the pump in place. Clamp the pump carefully in a vise and unscrew the large
brass cap nut, which gives you access to the pump filter screen. This can be blown clean with compressed air
(don't lose it). Check the filter chamber
for loose crud which can also be blown or picked out, then replace the filter
and nut. Unwrap any tape over the
plastic cap to pump body connection.
When you remove the cap, you will probably note that the four points are
black or rough, similar to used ignition points. I suggest removing only the top fixed points by removing a small
nut and the wire leads under it. Then
carefully clean the points with an ignition point file. Doing the same for the lower movable points
is trickier; I used a wire brush on my
Dremel tool. The movable points are not
easy to remove and replace without upsetting the factory adjustment.
Carefully reinstall
the upper points making sure they are aligned with the lower ones. Finally, reverse the steps you did to remove
the pump. You can also snug up the
series of diaphragm screws around the pump body. Do not tighten the union on the gas line going to the carbs. When
you turn on the ignition, you need to be sure that trapped air is purged from
that line until fuel begins to leak out, then tighten it. That should breathe new life into your SU
fuel pump.
From Francois fwildi_at_as.arizona.edu
I used a COUNTERBORE
and a REAMER from Joe Curt. At $65 and $110 respectively, you need a certain
number of carbs to make it worth it, but not too many. Anyhow, the counterbore
comes with a huge pilot and you can bore out the old bushings, with the
counterbore guided on both sides of the carb. Works at lot better on the
drillpress than on the lathe. The reamer is the same as the one in the Moss
catalogue, just STD rather than oversize.
1. Bore an old one out
2. press a new one in
3. repeat a) and b) 4 times
4. ream the new bushings
With the right tools
what a pleasure.
BUT: unlike what I was
told by other list members,
a) the diameter to
bore out is 3/8 and not 25/64 (I was doing HS6's)
b) the bushings have
to be reamed even when they are aligned correctly. The pressed-in bushing is
just too small to let the shaft through.
Randall says:
I've never had one stop
leaking on it's own, except when the float bowl is finally dry ! IMO you'll have to pull the jet assy again,
although like the float bowl bolts, this is possible with the carb still on the
car. Examine the jet carefully, the bottom half has to be very smooth. A nick
or scratch may cause it to leak. I have
also seen brand new jets that leaked where the clevis was attached. Remove the cork (or neoprene) seal from
inside the lower housing, and make sure the inner surface of the housing
(especially the tapered seat at the bottom) is clean and smooth. When
reassembling, be sure to put the lower cup washer with the cup towards the
seal, then the spring, then the upper cup washer the other way (with the cup
facing the upper seal). If you didn't replace the spring before, do it now, but
do not try to increase the tension by stretching it. Doing so will almost
certainly cause the jets to not return home when you release the choke.
BTW, I've been very
happy with the "O-ring" jet seals that Moss sells.
From: "Randall Young" <ryoung_at_navcomtech.com>
a) My rebuild kit features new jets, but the holes in their sides are
quite a bit smaller than the ones that are presently in the carbs. Does it make
any difference?
Shouldn't make any difference.
And, since it's almost impossible to judge wear inside the jet bore, I
would definitely use the new ones.
b) Where do the famous O-rings go? I see two possibilities: at the top
or the bottom of the spring that's just around the jet.
don't know that they're 'famous', but I assume you're talking about the
"high-tech" jet seals supplied by Moss. They actually go in both places, two per carb, one above that
spring and the other below it, in place of the original cork rings. However there are some small brass rings
that go between the O-rings and the spring.
New ones should have been supplied with your kit, but you can reuse the
old ones.
My 1959 TR3A H6
carbs are worn and leak air badly. Moss
Motors have a sale on a new pair of HS6 carbs (TR4A type) that I'd like to put
on my TR3A. I gather the only
modification is to the throttle & choke linkages. Is this correct and would you advise this change in carbs. Do I
also need to change the inlet manifold ? Moss do not have all the necessary
linkage items. Any idea where I can buy
the other bits I need to make this modification ?
For less than even the
sale price of a pair of HS6, you can have your H6 reconditioned to 'as new'.,
TRF.
The HS6 carbs will
bolt up to your TR3A manifold and work well with your motor. However, the linkage modifications are
substantial, since the throttle shafts turn the other way and actuate in the
centre, and you'll probably want to change to a later choke cable. I don't know of a source of all new linkage
parts, and used ones are somewhat scarce. Fuel and vacuum fittings may be
different as well.
Randall
I second this, and can
highly recommend Joe Curto, he just finished the SUs for my TR3 and did an
outstanding job, truly makes them "Like New" and for only $325.00
Bill Pugh
From: "Michael
Salter" <magicare_at_rogers.com>
You are on the right
track Don, The short drain pipes have black plastic hose fitted to them (TR6
fuel line is great for the job) and they pass through that grommet that you
noticed with the tubes being long enough to extend well down the side of the
engine.
Primer on Webers: http://www.inglese.com/tech.htm
Lots of TR relevant
info on Webers: www.cruzers.com/~twakeman/TR/index.html
From: LaJoMor_at_aol.com
Subject: Weber DCOM v. DCOE carburetor
For the general edification of the list I recently e-mailed Pierce
Manifolds (http://piercemanifolds.com/ ) and
ask what the difference was between Weber DCOM and DCOE carburetors. This is
their reply verbatim."Yes there is a DCOM carburetor. It is completely different then that
DCOE. They use a few of the same parts,
but not many. I would strongly recommend getting a DCOE instead of the DCOM.
"
http://www.faqs.org/faqs/autos/gasoline-faq/part1/index.html
for more than you ever
wanted to know about gasoline and octane.
·
TR3
24-26 mpg town
28-30 highway 60-70 mph
·
AH3000
regular 15-18 mpg, good 20-22 mpg
Mostly contributed by:
"Kai M. Radicke" kmr_at_pil.net with added inputs from Randall
Period superchargers
are cool... but that is about where their effectiveness ends. The 25% increase in power is probably a
decent estimate from the review, but a hot cam/carb combination is going to put
you pretty close to that figure anyway.
> -what is the
shorrock system, how does it compare to judson?
Favourably. Downside of the Judson is it is
high-maintenance and not very
efficient. Both are off-balance, vane
type superchargers. Shifting of the rotating vanes increase and decrease the
volume between the vanes, as they decrease in the volume the intake charge
trapped between the two vanes is compressed.
By off balance, I mean that rotating assembly inside is not centered in
the housing, this is what allows for the vanes to change displacement.
Randall:
Other than being
period correct, the Judson really is not very well designed by modern
standards, and has some problems. It
uses phenolic vanes that ride against an off-center cylinder as the pump
mechanism, which means the vanes have to be lubricated, and that they wear
out. The lubrication oil eventually
finds it's way into the intake, which lowers octane considerably (which is the
last thing you want to have happen with a blower). Apparently, the friction of
the vanes on the housing both consumes horsepower and produces a fair amount of
heat, both of which are also bad.
Last, the intake
manifold and 1 bbl downdraft carb that are used are quite restrictive, which
also doesn't seem like such a good idea.
I don't know how long the vanes last, but almost everyone I've heard
from with a Judson has either replaced the vanes, or is having trouble due to
damaged vanes. Replacing the vanes with Delrin is pretty popular, that's what I
plan to do with mine. Also, the drive
mechanism is a bit strange, it uses a
special
pulley on the water
pump, that takes the original wide belt, plus two narrow belts to drive the
Judson. The pulley on the Judson is
also a custom-cast part, which makes it difficult to adjust boost levels. BTW increasing engine displacement (like
87mm liners) will reduce boost, unless the pulley sizes are changed. Oh, and
many replacement water pumps do not have removable pulleys. The original types
are available, but you have to
check.
> -what is the
downside to doing this, except for price, and the normal engine wear from
increased HP questions?
Current views suggest
anything short of 9psi has no significant effect on the longevitity of your
motor, given an relatively fresh engine to begin with and the usual proper
maintenance. The other factor is your treatment of the car, if you abuse it
more now that it has more power of course it will wear more quickly. The Judson's can't run much more than 6psi
anyway -they are far to fragile.
Judsons will cost you
close to $2000USD for an entire rebuild kit. Shorrock's you'll have to get from
the UK, and will probably cost you just as much.
The Judsons typically
have their own intake manifold and crank pulley. You bolt both on, add the extra fan belt and then tune the carb
(SU, Holley or Rochestor) and timing to suit.
Well the Judson
requires about 500cc of Marvel Mystery Oil every 400 miles (especially the
larger displacement Judsons). The Shorrock too requires an external oiler and
periodic refilling.
Judson will eat vanes;
especially when they are out of oil. Both have known vibration issues resulting
in the rotor bearings wearing (remember the entire rotating assembly inside the
supercharger housing is off center and running at 2000-5000RPM). The vanes
scrape against the side of the housing, and this is what acts as the seal to
keep the intake charge between the two vanes - fairly high friction situation
(especially without the Marvel oil!).
Randall:
One of the carburettor
nuts on my original Judson is located in a really bad place. No room for a socket, no room for a wrench.
Current plan is to cut the side off of a socket that has wrench flats on it ...
> -what are the
sources for kits and spares?
http://www.bcsc.co.uk
is the Shorrock source and George Folchi (58 Merryall Road,
New Milford, CT 06776,
tel: 860 355 2807) in the US is your only Judson source for parts and rebuilt
kits. There is a Judson Supercharger list, hosted here on autox.team.net as
well. Often quiet though... Haddon Judson will tease people and say he is
thinking about re-releasing the Judson supercharger, but I doubt it will ever
happen.
> I think this will
be the last question for a while, simply because I have run out of horsepower
options to explore
Well I don't think
period superchargers are a wise horsepower option, they're just a "damn,
that's really cool" option. For
the $1500-$2000 you're going to spend on a PERIOD supercharger, you can more
than make up with it doing other performance things step by step on your motor.
The argument leans in favor of modern superchargers if there were a kit for
your TR4... but there isn't.
Randall:
IMO, unless you're
worried about period correctness, the thing to do is just get a bare Eaton (or
whatever) and make up the parts to use it on a TR4. One approach to the
manifold might be to cut an original intake manifold where the tubes meet the
'boxes' behind the carbs, and weld on a 4" square aluminum tube. Then machine the other side of the tube to
fit the blower, and weld plates over the ends.
A few years back, someone built a kit for the TR6 this way, and was
going to offer them for sale, but decided there wasn't enough interest. One lister (Kai Radicke ?) has (or at least
had) one of those prototypes on his TR6, he seemed very pleased with it.
http://www.magnusonproducts.com/
Of course, as others
have alluded to, you really need to drop the compression ratio to be able to
use any significant amount of boost on modern pump gas. To do it right, you'll also want to use some
ignition retard, basically to carry the vacuum advance curve out into positive
manifold pressure.
While I'm obviously
enthusiastic about such mods, I feel I should mention that you're literally
playing with fire. The road to
supercharger success seems littered with burnt pistons, broken rings and
whatnot.
There are some decent
period books that give a few pages to both the Judson and Shorrock units. One
is Alan Allard's Turbocharging and Supercharging (C1981,1983, 1986) and you
also have LJK Setright's Turbocharging and Supercharging for Maximum Power and
Torque (C1976). Allard was a
distributor for Shorrock superchargers in the UK (and also the man responsible
for Allard cars)... his book however is not biased towards Shorrocks. Pat Ganahl's recent book, Street
Supercharging (2nd Ed., C1999), devotes some pages to the Judson. All are
relatively cheap books, you can find the two older ones used for under $15 and
the new book for typically $15 online.
And if all this really fascinates you, then you should purchase Corky
Bell's new book Supercharged! (C Nov.
2001), it's $35 though.... $25 at Amazon.
http://mg-tabc.org/supercharger/Shorrock_ABC.pdf
There's a Team.Net list
for Judson blowers
http://www.magnusonproducts.com/
francois wildi
<fwildi_at_yahoo.com>
I am collecting ideas
and options for the rebuilt of the spare TR3B engine that I intend to do sometime
later this year. One option is to install electronic fuel injection. I have
found a company called Simple Digital Systems (www.sdsefi.com) and their kits
sell for a steep $1300 including programming module (plus fuel pump, injectors,
and all the plumbing mods).
Anyway, I just wanted
to know if anyone has experimented or heard of
EFI on TRactor
engines.
From: "J.H.
Roulleaux" <Jean.Roulleaux_at_skynet.be>
> EFI systems for
the TR6 other than the stock Lucas system?
- -----------
Revingtontr in U.K. is
offering complete Common Rail EFI kits for TRs ,4 or 6 cyl.
The kits are based on
Webcon Alpha or Lumenition hard/software and can be ordered with dizzy or crank
data pick up.The set comes with all parts included, as wiring loom/inlet
manifold/throttle bodies/injectors/ piping/ECU etc.... but at a price !!!
I converted my 6 a few
years ago to Lumenition EFI dizzy triggered system, just to keep things simple.
The advantage to Lucas is that as in modern cars the injection system works at
a much lower pressure is very accurate and takes account of air temp.,air
pressure, engine temp., throttle position and crank position and has a memory
to prevent ECU overreacting to sudden changes. I was able to fit it myself. the
biggest problem I encountered was the correct set-up. It has to be adapted to
the cars engine and there is no factory software available for TRs. The
Lumenition software has some basic set-ups and from that the engine is
calibrated on a rolling road to best performance. My car spent more than 4
hours on the rolling road and this again does not come cheap. I have seen some
other conversions where parts of the
Lucas system have been retained, but according to the owners they were about
the same price. Here too the programming of software was always the key factor
to high prices. If you wish to see how the system looks like,my car can bee
seen on www.carpictures.com . Look
for a 1970 jasmine TR6PI. I must say the cars runs great and no problems with
any fuel quality.