[Saloon-lovers] Carb Rebuild Questions


(Andrew Waugh) #1

Hi all
I’m cross posing this on XK-Engine, E-type and Saloons in
the hope of getting the most answers. I’m just starting
rebuilding the carbs on a '62 3.8 Mk II. I have the rebuild
kit(s) from Burlen.
The reasons I’m rebuilding the carbs is that the car was
exceedingly difficult to start at times (unrelated to
engine/ambient temp, AED operating or not) and that the
vents for the AED were dribbling fuel over the whole carb.
The car was also less likely to start if parked on an
incline (A real problem in Switzerland)
The post mortem on disassembly revealed that the fwd carb
had at some point had enough water in the float bowl that
the orifice spring was rusted away to about 75% of its
original length, and that most of the seals were dry and
cracked.
Fair enough. I suspect that the carbs are original and
have not been rebuilt.

The instructions in the rebuild kit state (oohnooooo

copyright laws!)
''Note: Some HD8 Carbuertters are fitted with plastic
spindle bushes which are no longer available.
6. Dismatle the Carbuettor as described. Remove P.T.F.E.
bushes from Carburettor body where fitted
7. Line ream throttle spindle bores using a 9.5mm diameter
reamer. Finished bore size should be 9.5mm in diameter.

Question 1:
The play on the throttle spindle does not seem all that
excessive to me, but it is a LOT more than the bushing
supplied with the rebuild kit. As I read the instructions
from Burlen line boring will ensure that the bores are
coaxial, but since the bushings are pushed in to be flush
with the outer face on the casting I’ll end up with a large
annulus around the spindle in the throat. This strikes me as
being a bit counter productive to making the butterfly seat
all the way around the throat. Have I misunderstood
something? The only thing I can see restoring to the
original situation would be to push the busings too far in,
then ream/mill the throat out. My other option would be to
make a pair of oversize shafts with my watchmakers lathe,
but this kind of defeats the purpose of buying the rebuild kit.

Question 2:
It would appear to me that the pinned stop horn on the
(rear?) throttle is not an absolutely critical dimension.
Can anyone tell me otherwise?

Question 3:
On the piston lifting pins there is supposed to be a plain
and rubber washer under the circlip. On one carb I found
just a fibre washer, on the other a fibre washer and a gummy
hairy mass underneath it. The rebuild kit does not seem to
include washers suitable for this use. Is an o-ring
suitable for this location, or should I try silicone and
mold release?

Andrew–
1968 3.8S
Zurich, Switzerland
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(GNB) #2

In reply to a message from Andrew Waugh sent Sat 28 Feb 2004:

  HI Andrew: If there is a failure in the,Orfice spring, 

[Needle valve] positioning lever inside the float bowl it must be
replaced. flooding of the carb via the overflow is generally
related to these components. I do not know why Burlen has elected
not to supply the 0.015’’ Teflon bushes for the HD8 type carbs.Some
other stockist may have them,give Holdens a call and see.If you can
notfin them we can try here in theUS–Regards—GNB–
The original message included these comments:

the hope of getting the most answers. I’m just starting
rebuilding the carbs on a '62 3.8 Mk II. I have the rebuild
kit(s) from Burlen.
The post mortem on disassembly revealed that the fwd carb
had at some point had enough water in the float bowl that
the orifice spring was rusted away to about 75% of its
original length, and that most of the seals were dry and
cracked.


DAIMLER : V8 SALOONS SAFELY FAST IN AIR SMOOTH STYLE
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(Pete55Tbird) #4

Andrew, before you hone to install new bushing watch You Tube video of PTFE bushings being
replaced,. Very “low tech” and straight forward. Either University motors or company that bought
XK`S the parts supplier.
Something I found when I worked on my HD8 SU was the needle was loose in the piston and
when I separated the bell from the body of the carb it fell onto my workbench. Surprise.
Good luck. Pete

The company is Moss motors. After two cups of coffee.


(Pete55Tbird) #5

Andrew, here is the link to using PTFE to rebush HD8 SU carb. Pete


#6

Wow! To get an reply 15 years later, that must be a record! :slight_smile:
Let’s wait to hear if Andrew is still middle of the carb rebuild :slight_smile:


(Andrew Waugh) #7

Err, no.

But in the meantime the owner of that car is married to my former wife.


#8

Ooops, I’m sorry to open old wounds (Mom, Pete started it!). I read it too quickly and thought it was about your S-type.
Anyway, have a Great New Year (and the rest of Xmas)!
Köpi


(Robin O'Connor) #9

Was it a package deal?